Effect of organic amendments on the afforestation performance of plant species on degraded semiarid conditions
Abstract
Vegetation plays a fundamental role in soil conservation, so it is common to consider an increase in vegetation cover as one of the techniques to mitigate the effects of desertification in Mediterranean forest environments. There are two factors limiting the establishment and growth of seedlings in dry environments: (i) an excessive radiation and, (ii) the limited availability of water during the summer drought. During an afforestation plan, soil preparation is always necessary to reduce sapling mortality. The goal of this study was to analyze the effect of various organic amendments on soil according to chemical and hydrological properties, and to assess the effects of these parameters on an afforestal proposal under Mediterranean climate conditions. Five amendments were applied in an experimental set of plots: straw mulching (SM); mulch with chipped branches of Aleppo Pine (PM); TerraCotten hydroabsobent polymers (HP); sewage sludge (RU); sheep manure (SH) and control (C). Plots were afforested following the same spatial pattern, and amendments were mixed with the soil at the rate 10 Mg ha -1 . Under bare soil conditions (C), most of mortalities occurred during the summer period of the first year. A substantial positive effect of SM, PM and HP on the survival rates have been clearly observed. Conversely, when the soil was amended with SH, the survival rate quickly decreased or remained more or less constant regarding to C. In this study, the lack of differences on chemical properties indicates that there may exist other reasons to justify the differences that were found in the pattern of vegetation. However, regarding to the hydrological properties some differences have been found. In C, soils were registered below the wilting point during 4 months a year, and therefore, in the area of water unusable by plants. These months were coinciding with the summer Mediterranean drought and can justify the high mortality found on plants. Conversely, in SM, PM and HP, soil moisture remained below the wilting point less period than C and, the plant available water was also higher. In these treatments, the survival sapling rates measured were the highest. SH showed water holding capacity slightly more limited than C. For this treatment, the survival sapling rates measured were the lowest. In conclusion, from a land management standpoint, the PM, SM and HP have been proved as a significant method to reduce sapling mortality rates during the Mediterranean summer drought.
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BOOKS OF ABSTRACTS
2 BOOKS OF ABSTRACTS FOURTH INTERNATIONAL CONFERENCE ON BIOHYDROLOGY Walking on drylands Edited&by:& Yolanda'Cantón'Castilla' Roberto'Lázaro'Suau' Alberto'Solé'Benet' Isabel'Miralles'Mellado' Emilio'Rodríguez'Caballero' Sonia'Chamizo'de'la'Piedra' &
3 Editorial Universidad de Almeria ISBN: 978-84-16642-38-0 DEPOSITO LEGAL: AL 1377-2016
4 ORGANIZING INSTITUTIONS •'Arid'Zones'Experimental'Station'(EEZA),'Spanish'National'Research'Council'(CSIC),' Almería,'Spain.' •'University'of'Almeria,'Almería,'Spain.' •'Institute'of'Hydrology,'Slovak'Academy'of'Sciences'(SAS),'Bratislava,'Slovakia.' ' ' STEERING COMMITTEE Lubomir&Lichner&(Chairman)&& Roberto'Lázaro'' Yolanda'Cantón'' Albert'SoléQBenet'' Jorge'MataixQSolera' Gabriele'E.'Schaumann' Paul'D.'Hallett' ' ' ORGANIZING COMMITTEE Roberto&Lázaro&(Chairman)& Yolanda'Cantón'' Elisa'Alvarez' Isabel'Miralles' Sonia'Chamizo' Emilio'RodriguezQCaballero'' Ancillary'members'of'the'local'team:'Lourdes'Luna,'Rosario'Moya,'Albert'SoléQBenet,' Francisco'Domingo,'Gabriel'del'Barrio,'Juan'Puigdefábregas,'Beatriz'RonceroQRamos,' Raúl'Román' ' ' SCIENTIFIC COMMITTEE Q'Yolanda&Cantón&(Chairman)&–&University&of&Almeria,&Almeria,&Spain' Q'Lubomir'Lichner'–'Institute'of'Hydrology'SAS,'Bratislava,'Slovakia' Q'Roberto'Lázaro'–'Arid'Zones'Experimental'Station,'CSIC,'Almeria,'Spain' Q'Albert'SoléQBenet'–'Arid'Zones'Experimental'Station,'CSIC,'Almeria,'Spain' Q'Jorge'MataixQSolera'–'Miguel'Hernández'University,'Elche,'Alicante,'Spain' Q'Gabriele'E.'Schaumann'–'University'of'KoblenzQLandau,'Landau,'Germany' Q'Esteban'Jobbagy'–'CICQ'CONICET.'IMASL'Universidad'Nacional'de'San'Luis,'Argentina' Q'Bradford'Wilcox'Q'Texas'A&M'University,'Texas'77843Q2138,'USA' Q'Giora'Kidron'Q'Hebrew'University'of'Jerusalem,'Jerusalem,'Israel' Q'Patrick'Lane'Q'The'university'of'Melbourne,'Melbourne,'Australia' Q'Francisco'Domingo'–'Arid'Zones'Experimental'Station,'CSIC,'Almeria,'Spain'
5 ' ' Q'Mariano'Moreno'de'las'Heras'–'Institute'of'Environmental'Assessment'&'Water' Research,'CSIC,'Pedralbes,'Barcelona,'Spain' Q'Erik'Cammeraat'Q'University'of'Amsterdam,'Amsterdam,'The'Netherlands' Q'Andrea'Carminati'Q'GeorgQAugustQUniversity'of'Göttingen,'Göttingen,'Germany' Q'Artemi'Cerdá'–'University'of'Valencia,'Valencia,'Spain' Q'Matthias'Boer'–'Western'Sydney'University,'Hawkesbury'Campus,'Richmond,' Australia.' Q'Saskia'Keesstra'Q'Wageningen'University,'Wageningen,'The'Netherlands' Q'Paulo'Pereira'Q'Mykolas'Romeris'University,'Vilnius,'Lithuania' Q'Jörg'Bachmann'Q'Leibniz'University'of'Hannover,'Hannover,'Germany' Q'Keith'R.J.'Smettem'–'University'of'Western'Australia,'Crawley,'Australia' Q'Tammo'S.'Steenhuis'Q'Cornell'University,'Ithaca,'USA' Q'Fernando'T.'Maestre'–'King'Juan'Carlos'University,'Mostoles,'Madrid,'Spain' Q'Juan'Puigdefábregas'–'Arid'Zones'Experimental'Station,'CSIC,'Almeria,'Spain' Q'Xiao'Yan'Li'Q'Beijing'Normal'University,'Beijing,'China' Q'Cristina'Armas'Q'Arid'Zones'Experimental'Station,'CSIV,'Almeria,'Spain' Q'Rony'Wallach'Q'Hebrew'University'of'Jerusalem,'Rehovot,'Israel' Q'Susana'Bautista'–'University'of'Alicante,'Alicante,'Spain' Q'Jan'Frouz'Q'Charles'University,'Prague,'Czech'Republic' Q'Mathieu'Javaux'Q'Forschungszentrum'Jülich'IBGQ3,'Jülich,'Germany' Q'Radka'Kodešová'Q'Czech'University'of'Life'Sciences,'Prague,'Czech'Republic' Q'Pete'Robichaud'Q'USDA,'Rocky'Mountains'Research'Station,'Moscow,'ID,'USA' Q'Horst'H.'Gerke'Q'LeibnizQCentre'for'Agricultural'Landscape'Research,'Müncheberg,' Germany' Q'Marcus'A.'Horn'–'University'of'Bayreuth,'Bayreuth,'Germany' Q'Nicholas'Jarvis'Q'Swedish'University'of'Agricultural'Sciences,'Uppsala,'Sweden' Q'Kálmán'Rajkai'Q'Research'Institute'for'Soil'Science'and'Agricultural'Chemistry'HAS,' Budapest,'Hungary' Q'Peter'Matthews'Q'Environmental'and'Fluid'Modelling'Group.'PoreXpert'Ltd.,' Plymouth,'UK'' Q'Stanley'J.'Kostka,'Aquatrols,'Paulsboro,'NJ,'USA' Q'Rainer'Horn'Q'Cristian'Al'University'of'Kiel,'Germany' & & Web&of&the&congress& http://www.biohydrology2016.es/'
ORGANIZERS SPONSORS We would like to thank the support received from:
7 CONTENTS From Editors 21' Plenary Lectures 22' Q'Soil'Science'Societies'and'their'role'for'improving'soil'governance'at'a'global' level' Rainer Horn 23' Q'Hyperplains:'The'unique'ecohydrological'imprint'of'extreme'flatness' Esteban(G.(Jobbágy( 25' Q'Biotic'controls'of'ecosystem'functioning'in'global'drylands'under'global'change' Fernando(T.(Maestre( 27' Q'Forest'survival'and'hydrologic'feedbacks'in'a'seasonally'dry'deep'regolithic' environment:'options'for'management' K.R.J.(Smettem,(R.J.(Harper,(J.K.(Ruprecht,(B.(Dell( 28' Q'Community'gully'conservation'with'biological'and'structural'controls'in'the' humid'ethiopian'highlands' Tammo(Steenhuis,(Seifu(Tilahun,(Eddy(Langendoen( 29' Session 1: Water-limited conditions and biohydrology 30' Session 1: Keynote Lectures 31' Q'Water'release'through'plant'roots'in'drylands:'consequences'at'the'plant'and' community'level'' Cristina(Armas( 32' Q'Disentangling'the'multiQscale'ecoQhydrological'feedbacks'that'underlie'dryland' functioning'and'dynamics'' Susana(Bautista( 33' Q'Dryland'shrub'as'ecosystem'engineer'to'modulate'hydropedological'processes' and'water'use'source'in'waterQlimited'environment'' XiaoHYan(Li( 34' Q'Emergent'changes'in'social'behaviour'and'ecohydrological'dynamics'driven'by' landscape'change'in'the'Southern'Great'Plains,'USA' Bradford(P.(Wilcox( ' 35'
8 ' Session 1: Contributions presented in oral form 36' Q'The'key'role'of'biocrusts'in'drylands'water'cycle' Sonia(Chamizo,(Emilio(RodríguezHCaballero,(Francisco(Domingo,(José(Raúl( Román,(Beatriz(RonceroHRamos,(Yolanda(Cantón( 37' Q'Remote'sensing'and'geophysics'to'infer'ecosystem'dependence'on' groundwater:'Ziziphus'lotus'matorrals'in'SE'Spain'' J(E.(Guirado,(D.(AlcarazHSegura,(J.P.(RigolHSanchez,(J.(Gisbert,(F.J.(MartínezH Moreno,(J.(GalindoHZaldívar,(L.(GonzálezHCastillo,(J.(Cabello( ( 39' Q'Soil'water'dynamics'and'water'utilization'of'six'typical'ecosystems'in'Heihe' Watershed,'China' Yongmei(Huang( ( 40' Q'The'dual'and'contradictory'effect'of'biocrusts'on'perennial'plants'' Giora(J(Kidron,(Irith(Aloni( ' 41' Q'Modelling'the'irrigation'management'options'during'water'shortage'period'to' improve'the'crop'yield'and'water'productivity'using'AquaCrop'model'' V.S.(Manivasagam,(R.(Nagarajan( ' 42' Q'Mechanisms'of'stabilization'of'organic'carbon'in'sediments'flowing'along' dryland'rivers'' María(MartínezHMena,(María(Almagro,(Elvira(DíazHPereira,(Noelia(GarcíaH Franco,(Carolina(BoixHFayos( ' 43' Q'RainfallQexclusion'experiments:'to'roof'or'not'to'roof'controls?'' Angeles(G.(Mayor,(Luna(Morcillo,(Peter(de(Ruiter,(Jacob(Keizer,(Alejandro( Valdecantos,(Giovanni(Quaranta,(Ioannis(Daliakopoulos,(Michalakis( Christoforou,(Susana(Bautista( ( 45' Q'Aridity'induces'nonlinear'effects'of'human'disturbance'on'precipitationQuse' efficiency'of'Iberian'Quercus(ilex'woodlands' Mariano(Moreno(de(las(Heras,(Esther(Bochet,(Tíscar(Espigares,(José(Manuel( Nicolau,(María(José(Molina,(Patricio(GarcíaHFayos( ( 46' Q'Water'redistribution,'a'key'driver'for'vegetation'functioning'in'drylands'' Emilio(RodríguezHCaballero,(Sonia(Chamizo,(Beatriz(RonceroHRamos,(Raúl( Román,(Yolanda(Cantón( ( 47' Q'Modelling'ecogeomorphology'feedbacks'in'Australian'banded'vegetation' hillslopes'' Patricia(M.(Saco,(Mohammadjafar(Solatanjalili,(Samira(Azadi( ' 49'
9 ' ' Q'The'forgotten'dimensions'of'carbon'flux'in'drylands:'potential'effects'of'land' degradation'' Laura(Turnbull,(John(Wainwright( ( 51' Session 1: Contributions presented as posters' 52' Q'Patterns'of'surface'runoff'at'hillslope'scale:'insights'into'sourceQsink' biohydrologic'relationships'' Eva(ArnauHRosalén,(Isabel(MolinaHSanchís,(Mónica(Ladrón(de(Guevara,(Roberto( LázaroHSuau,(Adolfo(CalvoHCases,(Carolina(BoixHFayos( ( 53' Q'Soil'infiltration'rates'under'different'soil'tillage'managements'in'vineyards'in' Eastern'Spain'' Maria(Burguet,(Simone(Di(Prima,(Massimo(Prosdocimi,(Artemi(Cerdà( ( 54' Q'Soil'water'repellency'in'urban'parks'' Maria(Burguet,(Paulo(Pereira,(Artemi(Cerdà( ( 55' Q'Soil'infiltration'rates'and'water'repellency'on'organic'and'chemically'managed' citrus'plantation'in'in'Eastern'Spain'' Rafael(GonzálezHCamarena,(Saskia(Keesstra,(Artemi(Cerdà( ( 56' Q'The'influence'of'weeds'on'net'ecosystem'CO2'assimilation'and'water'use' efficiency'in'an'irrigated'olive'orchard'of'SE'Spain'' Sonia(Chamizo,(Penélope(SerranoHOrtiz,(Enrique(P.(SánchezHCañete,(Ana(LópezH Ballestero,(José(Luis(VicenteHVicente,(Sara(Marañón,(Andrew(S.(Kowalski( ' ' 57' Q'Phreatophytic'vegetation'and'grasslands'showed'contrasting'responses'to'soil' water'availability'in'drylands&& E.(Guirado,(E.(RodríguezHCaballero,(P.(Escribano,(A.(Reyes,(J.(M.(Requena,(M.J.( Salinas,(J.(Cabello( ( ' 58' Q'Estimating'runoff'length'from'runoff'plots'under'natural'conditions:'a'proposal'' Roberto(Lázaro(Suau( ' 59' Q'The'effect'of'rain'pulses'in'the'net'CO2'exchange'of'a'semiarid'grassland'in' southern'Spain' Ana(LópezHBallesteros,(Penélope(SerranoHOrtiz,(Enrique(P.(SánchezHCañete,( Cecilio(Oyonarte,(Andrew(S.(Kowalski,(Óscar(PérezHPriego,(Francisco(Domingo( ( 61' Q'Soil'moisture'and'environmental'factors'interactions'control'the'CO2'exchange' in'biocrusts'from'drylands' Isabel(Miralles,(Emilio(RodriguezHCaballero,(Mónica(Ladrón,(Sonia(Chamizo,( Roberto(Lázaro,(Bas(van(Weseamel,(Raúl(Ortega,(Yolanda(Cantón( 62'
16 ' ' Q'Evaluation'of'drought'response'of'four'coniferous'species'based'on'the' analysis'of'their'radial'stem'growth' Adriana(Leštianska,(Katarína(Merganičová,(Katarína(Střelcová,(Radoslav(Kandrík( ( 132' Q'Transpiration'and'stem'circumference'changes'affected'by'drought'in'mature' beech'stand'(Fagus(sylvatica(L.)'Q'irrigation'experiment' Paulína(Nalevanková,(Katarína(Střelcová,(Zuzana(Sitková,(Marek(Ježík( ( 133' Q'The'amount'of'dew'condensed'on'small'trees'of'European'beech'(Fagus( sylvatica(L.)'and'Norway'spruce'(Picea(abies((L.)(Karst.)'in'depend'on'microQ meteorological'conditions' Jaroslav(Skvarenina,(Jozef(Mindas,(Jana(Skvareninova,(Martin(Bartik,(Jaroslav( Vido,(Miriam(Valková,(Miriam(Hanzelova( ( 134' Q'Drought'impact'on'autumn'phenological'phases'of'selected'tree'species'in'the' central'part'of'Slovakia' Jana(Škvareninová,(Jaroslav(Škvarenina,(Miriam(Váľková,(Martin(Bartík,(Jaroslav( Vido( ( 135' Q'Metaproteomics'of'wettable'and'repellent'grassland'soils' Geertje(van(Keulen,(Gerry(Quinn,(Martin(Swain,(Ed(Dudley,(Stefan(Doerr,(Ingrid( Hallin,(Tom(Delmont,(Lewis(Francis,(S.(Andrea(Gazze,(Richard(Whalley,(Peter( Matthews( ( 136' Q'How'to'monitor'drought'in'forest'ecosystem'using'simple'drought'index' Jaroslav(Vido,(Katarína(Střelcová,(Paulína(Nalevanková,(Adriana(Leštianska,( Radoslav(Kandrík,(Alena(Pástorová,(Jaroslav(Škvarenina,(Tsegaye(Tadesse( ( 137' Session 4: The impact of forest fires on hydrology ' 138' Session 4: Keynote Lectures' 139' Q'Hydrologic'response'to'fire'of'eucalypt'forests'in'southQeastern'Australia:' effect'of'soils,'climate'and'vegetation' Patrick(Lane,(Gary(Sheridan,(Petter(Nyman,(Phillip(Noske,(Christoph(Langhans,( Richard(Benyon,(Rene(Van(Der(Sant( ( 140' Q'Erosion'as'affected'by'natural'and'managed'vegetation'recovery'after'wildfires' in'the'western'United'States' Peter(R.(Robichaud( ' 141'
17 ' ' Session 4: Contributions presented in oral form' 142' Q'Prescribed'fires'effects'on'physicalQchemical'properties'and'quantity'of'runoff' and'soil'erosion'in'a'Mediterranean'forest' Manuel(Esteban(LucasHBorja,(Pedro(Antonio(AlvarezHPlaza,(Javier(Sagra,(Raquel( Alfaro(Sánchez,(Daniel(Moya,(Pablo(Ferrandis,(Jorge(de(las(Heras(Ibáñez( ' 143' Q'Effect'of'prescribed'fires'on'different'soil'properties'in'a'Mediterranean'pine' forest' P.A.(PlazaHÁlvarez,(Daniel(Moya,(Javier(Sagra,(Raquel(Alfaro(Sánchez,(Manuel( Esteban(Lucas(Borja,(Pablo(Ferrandis,(Jorge(de(las(Heras(Ibáñez( ' 144' Session 4: Contributions presented as posters' 145' Q'The'impact'of'ant'mounts'as'a'source'of'sediments'and'sink'of'runoff'in' recently'fire'affected'scrublands'in'Eastern'Spain' Artemi'Cerdà,'Marcos'Francos,'Xavier'Úbeda,'María'Burguet'Marimon,'Agata' Novara,(Paulo(Pereira( ( 146' Q'LongQterm'runoff'and'soil'yield'after'forest'fires'in'the'Massis'del'Caroig' Artemi'Cerdà,(Marcos(Francos,(Xavier(Úbeda,(Meritxell(Alcañiz,(Antonio(Jordán,( Paulo(Pereira( ( 147' Q'Hydrological'connectivity'in'a'Mediterranean'forest'before'and'after'a'wildfire' in'South'of'Spain:'modelling'scenarios' Juan(F.(MartínezHMurillo,(Manuel(LópezHVicente( ( 148' Q'Soil'water'retention'curves'and'related'properties'two'years'after'salvage' logging'treatments'in'a'Mediterranean'burnt'forest' Jorge(MataixHSolera,(Pavel(Dlapa,(Katarina(Chrenková,(Victoria(Arcenegui,( Fuensanta(GarcíaHOrenes( ( 149' Q'Rainfall'and'wet'and'dry'cycles'effect'on'ash'hydrophobicity:'A'laboratory' experiment' Paulo(Pereira,(Saskia(Keesstra,(Piet(Peeters,(Artemi(Cerda( ( 150' Q'The'analysis'of'long'term'forest'fire'weather'indices'in'National'Park'Slovak' Paradise'in'relation'to'the'risk'of'climate'change' Jaroslav(Skvarenina,(Jan(Holecy,(Jaroslav(Vido,(Jana(Skvareninova,(Martin( Bartik,(Miriam(Valková( ' 151'
18 ' ' Session 5: The role of biogeochemical interfaces in biohydrology ' 152' Session 5: Keynote Lectures' 153' Q'Characterization'of'intact'biopore'walls'and'aggregate'coatings'for'describing' interQdomain'mass'transfer'during'preferential'flow'in'structured'soils' Horst(H.(Gerke,(Ruth(H.(Ellerbrock,(Martin(Leue( ( 154' Q'Microbial''hot'spots''of'pollutant'degradation:'Common'themes'of'burrow' walls'and'hyporrheic'zones' Marcus(A.(Horn,(Anja(Dallinger,(Cyrus(R.(Njeru,(Harold(L.(Drake,(YaHJun(Liu,( ShuangHJiang(Liu( ( 155' Q'LongQterm'effects'of'crop'management'on'the'structure'of'a'silt'loam'soil'in'a' cold'temperate'climate' Nicholas(Jarvis,(Mats(Larsbo,(John(Koestel,(Astrid(Taylor,(Thomas(Kätterer,( Johannes(Forkman( ( 156' Session 5: Contributions presented in oral form' 157' Q'A'new'method'to'enhance'rhizosheath'formation' Katayoun(Ahmadi,(Mohsen(Zarebanadkouki,(Stanley(J.(Kostka,(Yakov(Kuzyakov,( Andrea(Carminati( ' 158' Q'The'effect'of'pH'modification'on'wetting'kinetics'of'a'naturally'water'repellent' coniferous'soil' Ahmad(Amer,(Dörte(Diehl,(Gabriele(Schaumann( ( 159' Q'PoreQscale'mechanisms'of'water'repellency'in'the'rhizosphere' Pascal(Benard,(Andrea(Carminati( ( 160' Q'The'“gel'effect”:''effect'of'mucilage'on'water'properties'in'the'rhizosphere' Mathilde(Brax,(Christian(Buchmann,(Gabriele(Ellen(Schaumann( ( 161' Q'Hydrogel'swelling'in'soil'and'its'contribution'to'soil'microstructural'stability' Christian(Buchmann,(Gabriele(Ellen(Schaumann( ( 162' Q'Effect'of'flow'interruption'on'transport'and'retention'of'iron'oxide'colloids' Jannis(Florian(Carstens,(Jörg(Bachmann,(Insa(Neuweiler( ( 163'
19 ( ' Q'Integration'of'nanoscale'imaging'and'quantitation'of'(bio)'nanomechanical' properties'of'wettable'and'repellent'soils'using'Atomic'Force'Microscopy' Geertje'van'Keulen,'S.'Andrea'Gazze,'Stefan'Doerr,'Peter'Matthews,'Ed'Dudley,' Ingrid'Hallin,'Gerry'Quinn,'Lewis'Francis' ' 164' Q'How'to'link'soil'wetting'properties'and'surface'elemental'composition?' An'XPS'pilot'study' Susanne(K.(Woche,(MarcHOliver(Goebel,(Robert(Mikutta,(Georg(Guggenberger,( Joerg(Bachmann( ( 165' Q'Rhizosphere'water'repellency:'Implications'for'irrigation'efficiency' Mohsen(Zarebanadkouki,(Katayoun(Ahmadi,(Mutez(A.(Ahmed,(Stanley(J.(Kostka,( Andrea(Carminati( ( 166' Session 5: Contributions presented as posters' 167' Q'Prediction'of'unsaturated'hydraulic'conductivity'and'capillaryQsorption' potential'of'water'in'cultivated'and'uncultivated'soils' AbdelHMonem(Mohamed(Amer( ( 168' Q'Impact'of'interfacial'properties'on'aggregate'stability'of'volcanic'ash'soils' Jörg(Bachmann,(MarcHOliver(Goebel,(Jiem(Krüger( ( 169' Q'Impact'of'bacterial'biomass'on'soil'particle'wettability' MarcHOliver(Goebel,(Anja(Miltner,(Dörte(Diehl,(Gabriele(E.(Schaumann,(Matthias( Kästner,(Jörg(Bachmann( ( 170' Q'Links'between'nanoscale'and'macroscale'surface'properties'of'natural'root' mucilage'studied'by'atomic'force'microscopy'(AFM)'and'contact'angle' Robin(Kaltenbach,(Gabriele(E.(Schaumann,(Dörte(Diehl( ' 171' Q'Flow'cell'sampling'technique:'A'new'approach'to'analyze'physical'soil'and' smallQscale'surface'properties'of'undisturbed'soil'samples' Jiem(Krueger1,(Julian(Heitkötter2,(Martin(Leue3,(Jörg(Bachmann( ( 172' Q'The'integrated'effect'of'organic'matter'and'moisture'content'on' phytoremediation'characteristics'of'a'CuQspiked'soil'by'Brassica(juncea'L.' Shahin(Oustan1,(Fatemeh(Mokarram,(Seyed(Jalal(Tabatabaei,(Nosratollah(Najafi( ( 173' Q'Increased'ambient'air'temperature'alters'the'severity'of'soil'water'repellency' Geertje(van(Keulen,(Kat(Sinclair,(Emilia(Urbanek,(Gerry(Quinn,(Stefan(Doerr,( Peter(Matthews,(Ed(Dudley,(Ingrid(Hallin,(Lewis(Francis,(S.(Andrea(Gazze,( Richard(Whalley( 174'
20 ' ' Q'Temperature'dependent'surface'tension'of'biosolids'derived'dissolved'organic' matter' Zhang(Wei,(Pavel(Trifonov,(Gilboa(Arye( ( 175'
21 From Editors BioHydrology 2016 is the fourth international conference on biohydrology, after those of Prague (2006), Bratislava (2009) and Landau (2013). As the previous conferences, the aim is providing a forum to discuss any question related to the interactions between biotic systems and hydrology. Such interactions can be simple, bidirectional or including feedback, and occurring at any spatial or time scale. The conference is addressed to experts from ecology, hydrology, geography, soil science, environmental sciences, biology, geomorphology, forestry and similar; but any expert focusing in this issue is welcome and interdisciplinary contributions are encouraged. The conference includes five topics covering a wide thematic range. This time the congress moves from central Europe to Almeria, at the extreme south-east Spain, probably the most arid region in Europe, and the peculiarities of the interactions between living organisms, biocenosis or organic matter and hydrological processes in drylands is the first topic. The areas were water is a limiting factor during at least a part of the year account for more than the 40% of the emerged land at planetary scale. The increasing human population as well as its socio-economic development increases the water demand and the availability of water is already a concern in most countries. On the other hand, this concern tends to increase due to climatic change. The deep understanding of these natural biohydrological processes, even those studied at very detailed scales, can have important consequences, e.g., in food production, water harvesting, nature conservation, flood prevention, ecosystem function understanding, land management or guidelines for sustainable land uses. The conference includes some plenary lectures from top international scientists, and a session for every topic, with keynote lectures from relevant scientists in every session as well as oral and poster communications from the participants. CONTENTS
22 PLENARY LECTURES CONTENTS
23 Soil Science Societies and their role for improving soil governance at a global level Rainer Horn Institute for Plant Nutrition and Soil Science, CAU Kiel, Germany, Email: [email protected]kiel.de Abstract The International Union of Soil Sciences with ist more than 60,000 soil scientists around the world plays an important role in not only improve our understanding of the non-renewable skin of the earth – our soils- . We must also define the boundaries for a sustainable landuse as well as for adequate soil and management systems depending on the geological, parent material and climatic conditions worldwide. It is wellknown that soils as 4-dimensional bodies at the land surface with liquid, gaseous and solid components containing inorganic and organic materials, including living organisms in a great number and variety must be used carefully according to their resilience and elasticity for the long-term maintenance of key properties and processes. Thus, non-site adjusted land-use and soil management will result in a mostly irreversible degradation, and because soil amelioration is seldom or only on the very long run perhaps partly effective, we may lose the basis for our future life. The declaration of the International Year of Soils 2015 by the United Nations in Dec. 2013 has provided IUSS the best opportunity to discuss from now on more recognized the critical topics of “soils and their very specific properties” and “their sensitivity concerning the irreversible vulnerability due to mismanagement”. Thus, we have the great chance to show the beauty of the soil types and the variability in the landscape, but to also increase the awareness of their limited (or defined) resilience for a sustainable land use worldwide. The limited resource “soil” with its various functions – from plant production to soil heritage - needs to be protected and only used according to the site specific properties and functions. It is obvious that we need more food in the near future for a growing population on a declining area (because of an irreversible soil degradation worldwide with a loss of more than 300km² /d), but this can be only achieved if the functionality of soils is at least maintained. These topics have to be discussed at various levels ranging from the Kindergarten to the public, to politicians, and scientists all over the world and should result in an improved handling of soils in the future. The public awareness must be increased with the slogan “healthy soil for healthy food” or “better soil functionality results in higher resilience”. Thus, if we define urgently needed soil properties and ways how to gain the certainty for the future to stop hunger, to optimize soil use efficiency and to guarantee long-term soil conservation, these properties and functions need to be linked to an increased level of: 1) internal soil strength which is improved by a higher microbiological activity, more even distributed root growth and corresponding strengthening of the total rhizosphere due to swell shrink properties, exudation and coinciding glueing of single particles, 2) actual accessibility of surfaces of grains, aggregates, organic compounds, or pores in order to improve the nutrient storage and availability and more effective filtering and buffering 3) the quick and effective exchange of gas, or water by an enhanced and more effective biological activity in our soils which optimizes these uncounted functions of the hidden half under our feet as the basis for our long-term wellbeing. CONTENTS
24 Within the lecture several of these topics will be discussed in more detail. Key Words Sustainability, soil threats, soil degradation, microand macroscale, rigidity.
25 Hyperplains: The unique ecohydrological imprint of extreme flatness Esteban G. Jobbágy Grupo de Estudios Ambientales / IMASL – CONICET & Universidad Nacional de San Luis - Argentina Abstract The limitation of horizontal water fluxes imposed by the extremely low regional hydraulic gradients of hyperplains (large sedimentary regions with regional slope <0.1%) drives distinctive ecohydrological features that are starting to become acknowledged over the last decade as many of these areas host rapid land use changes. Globally, extreme flatness, much more than climate, determines the widespread presence of shallow water tables (<3 m deep), favouring an intense coupling between groundwater and ecosystems that goes beyond riparian or lowland environments, engaging the majority of the landscape. Four key distinctive features that emerge from this condition are illustrated for the plains of Southern South America: (i) Long-term flooding cycles, (ii) salt accumulation/redistribution processes, (iii) groundwatervegetation feedbacks, (iv) need for hydro-informed adaptation strategies for farmers and land managers. Floods originated by saturation excess runoff and water table level raises shift from seasonal regimes in humid plains (e.g. Northern Campos) to sporadic multiyear episodes in subhumid plains (e.g. Pampas) to novel episodes with no precedents over the last century in semiarid plains (e.g. Chaco). Remote sensing and field observations show that although periods of high rainfall trigger these flooding episodes, the massive expansion of annual crops displacing perennial pastures and native vegetation have increased their frequency, extension and intensity. The almost complete predominance of evapotranspirative water outputs over liquid outputs in semiarid and subhumid hyperplains limits solute flashing creating large salt accumulations in the deep vadose zone across the whole landscape (Chaco forests) or closer to the surface in lowlands or areas of high groundwater discharge (Pampas, Chaco croplands). Models suggest that groundwater-vegetation feedbacks are a central organizer of these systems shaping both flood regimes and plant production. Canopy water use capacity (leaf area + roughness), rooting depth, and salinity/watertlogging tolerance are the main vegetation attributes influencing groundwater levels and transport. Observations show that the replacement of the deep rooted vegetation (native woodlands in the Chaco, alfalfa pastures in the Pampas) by shallow rooted annual crops is favouring recharge pulses during wet years and limiting steady groundwater discharge during dry years, what ends favouring flooding and triggering salt redistribution processes. Waterlogging and salt tolerance, found across many native species of the Pampas and Chaco let native ecosystems increase groundwater use under raising water table conditions. This regulatory feedback gets inpaired under annual croplands where waterlogging/salinity drastically reduces plant transpiration an even inhibits farmers from planting. In hyperplains groundwater introduces reciprocal connectivity across contiguous vegetation patches or crop paddocks creating both challenges and opportunities to regulate water table levels through land use management and landscape design. This possibilities are just starting to get understood and implemented by farmers. Applying the simpler, one-way perspective of vegetationgroundwater interactions coined in sloped regions of the world into hyperplains is a perfect road for failure and frustration. As agriculture expands and intensifies across the South American hyperplains, adaptative farming and nature conservation schemes CONTENTS
32 Water release through plant roots in drylands: consequences at the plant and community level Cristina Armas Estación Experimental de Zonas Áridas-CSIC. Almería, Spain Abstract Water relations are key to understand the ecology of terrestrial plant communities, and one of the components that determines water balance is the process of hydraulic redistribution. Hydraulic redistribution (HR) is the passive movement of water between different soil parts via the root system driven by water potential gradients in the soil– plant–atmosphere continuum that takes place under some environmental conditions. HR enhances plant transpiration and other water-related processes. Recent experimental evidence suggests that HR has an effect on organic matter decomposition, nutrient uptake, and root foraging behaviour. At the community level there is evidence that HR affects net primary productivity and has an impact in plant-plant interactions, ultimately altering water, biogeochemical and vegetation dynamics. Plant-plant interactions mediated by HR range from negative to positive and the outcome is dependent on species functional groups, plant life stage, whether water is released to the soil or directly transferred to other plant through shared mycorrhizal networks and, ultimately, the composition of the water redistributed through the root-soil system. Evidence obtained in a semi-arid sand dune system suggests that some salt-tolerant species can release salty water in upper soil layers through HR. Deep-rooted, salt-tolerant Pistacia lentiscus shrubs exert a negative effect on the performance of salt-intolerant Juniperus phoenicia shrubs caused by the release of salty groundwater into shallow soil layers by Pistacia. Plant physiology, mortality patterns as well as community spatial structure reflect this interference of Pistacia on Juniperus, negating the potential positive effects of an additional water source via hydraulic redistribution. Overall, should water-soluble compounds like ions and some nutrients be redistributed with water, HR could have important consequences for the biogeochemical cycles of some elements in these waterlimited systems. Key Words Hydraulic lift, hydraulic redistribution, nutrient cycling, plant-plant and plant-soil interactions, salinity, semi-arid. CONTENTS
33 Disentangling the multi-scale eco-hydrological feedbacks that underlie dryland functioning and dynamics Susana Bautista Department of Ecology, University of Alicante, Alicante, Spain Abstract The biotic and spatial structures of dryland vegetation are tightly coupled to dryland functioning, dynamics, and stability. These structure-function relationships are critically influenced by eco-hydrological interactions and feedbacks that operate over as well as across different spatial and temporal scales. Both positive and negative feedbacks between plant spatial pattern, resource redistribution, and productivity, combined with the effect on and response of plant functional traits and diversity, create a complex network of interactions that underlies dryland function and resilience, nonlinear dynamics, and sudden shifts. A growing family of community-scale manipulative experiments is contributing to efforts to disentangle the multiple feedbacks and interactions involved and incorporate them into a new generation of dryland models. Using dryland mesocosms, with plant communities of particular species composition and spatial patterns created ad hoc, these experiments show that both plant cover and plant pattern exert a critical role in controlling water and soil conservation in drylands, with the connectivity of bare-soil emerging as the most critical pattern attribute for explaining both global resource losses from dryland slopes, and local resource gains at the patch scale. The response of dryland vegetation to these losses and gains depends on the functional types in the plant community, which modulate the strength and sign of the eco-hydrological feedbacks involved. Overall, the resilience and restoration potential of dryland ecosystems appear to be largely controlled by the combined effect of their spatial and biotic structures, which in turn result from the interplay between pattern-dependent resource redistribution and trait-dependent plant responses. Key Words Drylands, ecohydrological feedbacks, plant spatial pattern, mesocosm experiments, nonlinear dynamics, sudden shifts. CONTENTS
34 Dryland shrub as ecosystem engineer to modulate hydropedological processes and water use source in water-limited environment Xiao-Yan Li College of Resources Science and Technology, Beijing Normal University, Beijing 100875, China Abstract Dryland shrubs locally modify soil structure and infiltrability, and therefore affect hydropedological processes. The spatial and temporal dynamics of water flow aboveand belowground are altered by woody plants. Aboveground, woody plant canopies interact with characteristics of rainfall (e.g., rainfall intensity) and/or human disturbance (e.g., grazing), to influence patterns of soil water content through rainfall interception and shading the soil surface. Belowground, roots of woody plants and soil texture influence flow path and temporal soil water utilization. Shrubs tend to have deep roots, high ratio of leaf to sapwood areas, low vertical shading, and strong morphological plasticity to adapt to variations in climate and soils. Shrub traits and soil architectures coordinate each other to evolve a self-organized strategy and holistic soil-vegetation adaptation system to accumulate water, storage, and efficient use at different scales. At the stomata scale, shrub stomata usually can tolerate much more severe soil water stress as compared to the grass stomata. Kocacinar and Sage found the mean hydraulic conductivities are 3.24*10-4 and 0.46*10-4 kg m-1s-1 MPa-1 for C3 and C4 species, respectively. At the individual plant scale, shrub captures water through stem–root preferential flow systems to divert water to deeper soil layers to reduce evaporation. Our study showed that stemflow could lead to 1.5–3.2 times increase in infiltration depth, and as much as 10–140% increase in soil water content for shrubs of Sminthopsis psammophila and Helianthemum scoparium as compared to that without stemflow in north China. Meanwhile shrub can transport water from deep, moist soil layers to shallow, dry soil layers by a process known as "hydraulic lift" (HL). In desert zones, hydraulic lift can supply between 15% and 20% of daily water requirements of shrubs during the dry season. At the patch or plant community scale, shrub patches and bare/grass ground couple in a landscape mosaic of sources and sinks of water, sediments, and nutrients, which is an efficient rainwater harvesting system with the bare ground serving as a runoff producing zone and vegetation as a waterand nutrient-concentrating zone; shrub also tends to use water from shallow soil in wet season but from deep soil layers in dry condition. At the regional scale, shrub divergently responses to rainfall pulses along a precipitation gradient, and the shapes and sizes of the shrub patches also varied with annual rainfall to optimize water use. We found that shrub in the Gobi desert and typical steppe responded much faster with 3.6 ± 2.0 day and 6.4 ± 4.6 day, respectively, contrast with a durable response in Desert steppe (10.2 ± 6.5 day). At the temporal scale, we take examples of shrub encroachment, conversion of cropland into grassland and co-evolution of vegetation and soil development during sand-dune stabilization to highlight that vertical soil water switches between shallow and deep soil layers are closely associated with shrub-grass transitions. Key Words Shrub, soil architecture, soil moisture, arid and semiarid region CONTENTS
35 Emergent changes in social behaviour and ecohydrological dynamics driven by landscape change in the Southern Great Plains, USA Bradford P. Wilcox Ecosystem Science and Management, Texas A&M University, College Station, Texas, USA Abstract Land cover in the Southern Great Plains of the United States has changed dramatically over the last 150 years, in the wake of historic overgrazing and the consequent shifting patterns of cultivation. The former grasslands and open savannas have been largely replaced by more dense savannas or woodlands, and in some regions even forests. For much of the State of Texas, this transformation has already occurred: what were once open rangelands are now largely woodlands or closed-canopy savannas. Interestingly, in the northern portions of the Southern Great Plains (states of Oklahoma and Kansas), trees are continuing to expand. The most likely reason for this transformation is the overall reduction in the frequency and intensity of fires. In addition, as some have suggested, rising levels of CO2 may also be a factor. In any case, the net result is that this region is more wooded and perhaps more vegetated that at any time in the last 150 years or more, leading to cascading and nonlinear feedbacks with respect to both society and the water cycle. But the particular responses are region specific. In Oklahoma and Kansas, there is good evidence that as woodlands have expanded, streamflows and groundwater recharge have declined. In contrast, towards the south—and largely within Texas—the greater number of trees has actually increased infiltration, which has led to a reduction in overland flow (a primary mechanism for streamflow) as well as an increase in groundwater recharge. For much of the State of Texas, higher storage of groundwater has actually contributed to increasing springflows, particularly in those regions where the underlying geology is karst. People have adapted to the changing landscape with a combination of resourcefulness and resilience. In some areas, more woodland cover has resulted in greater biodiversity and higher numbers of large game species, both of which are viewed as assets, for economic as well as recreational reasons. Key words Savanna, semiarid, woody plant encroachment. CONTENTS
36 Session 1: Contributions presented in oral form CONTENTS
37 The key role of biocrusts in drylands water cycle Sonia Chamizo1,2, Emilio Rodríguez-Caballero3,2, Francisco Domingo4, José Raúl Román2, Beatriz Roncero-Ramos2, Yolanda Cantón2 1 Applied Physics Department, University of Granada, Granada, Spain 2 Agronomy Department, University of Almería, Almería, Spain 3 Max Planck Institute for Chemistry, Multiphase Chemistry Department, Mainz, Germany 4 Experimental Station of Arid Zones, CSIC, Almería, Spain Abstract Dryland landscapes are structured as a mosaic composed of two phases: discrete vegetation patches and neighboring patches between the plants. The soil heterogeneity created by both patch types results in a spatial mosaic where patches are not isolated but dynamically connected and functionally linked by source-sink processes. During the episodic rainfall events, runoff is generated in the non-vegetated areas and redistributed to adjacent vegetation, which acts as surface obstruction for water, sediments and nutrients. Hence, functioning of vegetation is strongly conditioned by the hydrological response of interplant areas. In most drylands, these interspace patches are covered by a community of organisms comprised of cyanobacteria, lichens, algae and bryophytes, known as biocrusts. Despite being only a few millimeters thick, they play a major role in hydrological processes. Biocrusts influence numerous properties that affect water movement and retention through soils such as roughness, porosity, hydrophobicity, cracking, and albedo, and thus play a key role in different elements of the water cycle. However, their role in water processes is not completely clear, and published studies show very controversial results. The influence of biocrusts may greatly depend on their developmental stage. In addition, most existing studies have examined the influence of biocrusts on isolated components of the soil water balance, but few of them have tackled this topic from an integrated point of view, addressing the key components of the water balance together. In this study, we examine the influence of different developmental stages of biocrusts and their removal on infiltration, evaporation and soil moisture, in two semiarid ecosystems of SE Spain with contrasting soil texture, topography and distribution of biocrusts. The ultimate objective is to elucidate the role that these communities play in the soil water balance in semiarid ecosystems. Our results show that site characteristics including topography and soil texture and biocrust characteristics such as cover and composition greatly condition the influence of biocrusts on hydrological processes. In addition, biocrust hydrological response is strongly conditioned by rainfall characteristics, mainly rainfall intensity, and the spatial scale at which infiltration-runoff processes are surveyed. Overall, we found that biocrusts have a positive effect on the water balance by increasing infiltration and soil moisture and reducing soil evaporation compared to biocrust-devoid soils. As a result, the available water to plants in the upper most layer of the soil is increased by the presence of biocrusts. Therefore, through their effect on water availability and redistribution in drylands, biocrusts may exert a strong effect on the structure and function of vegetation as well as soil biota communities, thus eventually controlling general ecosystem functioning in drylands. Key words Biological soil crust, hydrological processes, water availability, developmental stage. Acknowledgements: This work was funded by the Spanish National Plan for Research, Development and Innovation and including European Union of Regional Development Funds, CONTENTS
38 under BACARCOS (CGL2011-29429) and RESUCI (CGL2014-59946-R) research projects. We also thank the Viciana brothers, the landowners and Alfredo Durán for his assistance with the field work.
39 Remote sensing and geophysics to infer ecosystem dependence on groundwater: Ziziphus lotus matorrals in SE Spain J E. Guirado1,2*, D. Alcaraz-Segura1,3,4, J.P. Rigol-Sanchez1, J. Gisbert1, F.J. MartínezMoreno5, J. Galindo-Zaldívar5,6, L. González-Castillo5 , J. Cabello1,2* 1 Departament of Biology and Geology, University of Almería, Almería, Spain 2 Andalusian Center for Assessment and Monitoring of Global Change, University of Almería, Almería, Spain 3 Department of Botany, School of Sciences, University of Granada, Granada, Spain 4 Interuniversity Earth System Research Institute, University of Granada, Granada, Spain 5 Department of Geodynamics, University of Granada, 18071-Granada, Spain 6 Andalusian Institute of Earth Sciences, CSIC-University of Granada, Granada, Spain Abstract Phreatophytic vegetation is characterized by deep roots that are used to obtain groundwater directly from the aquifer. Identification of its spatial distribution and pattern across the landscape and their relationship with the access to fresh water is a key aspect to understand their functioning and this has been extensively analyzed in the riparian ecosystems from humid regions. However, in arid regions, non-riparian phreatophytes are very frequent and they play a key role from ecosystem to regional and local scales. For example, the phreatophytic shrub Ziziphus lotus, which has leaves and high photosynthetic rates during the Mediterranean summer drought, and it has deep roots up to 60 m in depth. The object of this work is to identify whether the spatial distribution of Ziziphus lotus is linked to fracture zones that provide access to groundwater in a semi-arid ecosystem from the southeast of the Iberian Peninsula drylands. Firstly, Object-based Image Analysis has been used to map the population of Ziziphus lotus and a map of fracture zones was derived from geomorphologic LiDAR DEM analysis. Secondly, Electrical Resistivity Tomography, a geophysic method, was used to validate the existence of fractures. And finally, the observed distance between fractures and Ziziphus lotus shrubs have been showed congruence between both from Average Minimum Distance analysis. The importance of the study lies in the combination of different technologies to disentangle spatial vegetation patterns in the context of drylands without a non-apparent water supply. Ziziphus lotus cartography showed high accuracy (0.90) and we have identified about 1832 individual shrubs of Ziziphus lotus, with a different shape, texture, and roughness. Shrubs showed a clear positive trend with dependence on groundwater, differencing two cohorts in Ziziphus population in relationship to the size of shrubs and the minimum distance of more than 20 km of fractures in directions N140ºE to N160ºE and N40ºE to N45ºE. This provides information about the size of shrubs and its relationship on groundwater dependence in fracture zones as corridors of groundwater. Therefore, smaller shrubs could be vulnerable to decreases the water table level. In addition, although these shrubs are considered a priority for conservation under the Habitats Directive (habitat 5220), establishing its links to groundwater allow support also their conservation in the context of Water Framework Directive (WFD, 2000/60/EC). This is particularly important since the inventory of Groundwater Dependent Ecosystems (GDEs) and its conservation represents a new mandate for environmental management in Europe. In fact, the overexploitation of groundwater resources can be the main threats to Ziziphus lotus, even when their populations include inside protected areas. Key words Average minimum distance, electrical resistivity tomography, fracture zones, groundwater dependent ecosystems, LiDAR, object-based image analysis, semi-arid, Ziziphus lotus. CONTENTS
40 Soil water dynamics and water utilization of six typical ecosystems in Heihe Watershed, China Yongmei Huang1 1College of Resources Science and Technology, Beijing Normal University, Beijing 100875, China Abstract Heihe River Watershed (HRW) is located in the middle part of the Hexi corridor in arid region of Northwestern China. Soil water content in 0cm-160cm depth of six ecosystems, i.e. alpine meadow, montane coniferous forest, montane steppe, desert shrub, cropland, and riparian forest, were automatically monitored every 30 min. from Jan., 2013 to Dec., 2014 in HRW. Alpine meadow, montane coniferous forest, and montane steppe are the typical ecosystems located in the upper-part of HRW with humid /semi-humid weather. There are croplands and riparian forests in midand lowerstream oasis, and extensive desert shrubs distribute in midand lower-stream with arid weather. To better understand the characteristics of vegetation-soil-atmosphere water exchange, soil water storage in growing season, temporal variability of soil water, and rainfall redistribution were analyzed based on the high temporal resolution soil water content data. The soil water storage in cropland was the largest, followed by riparian forest, alpine meadow, montane coniferous forest, montane steppe, and desert shrub in HRW. The annual supply to soil water which was calculated with hourly soil water contents was greater obviously than annual rainfall in montane coniferous forest, and it also happened in desert shrub. The annual soil water recharge from irrigation was about 540mm in cropland and riparian forest. Soil water storage remained stable in cropland, but it declined continuously in riparian forest because it was usually irrigated only once in March each year. Seasonal soil frozen was observed in the six ecosystems, but soil water dynamic was only greatly impacted by freezing and thawing processes in alpine meadow. Alpine ecosystems constitute the main water source in HRW. Not only cropland and riparian forest but also montane coniferous forest and some desert shrubs need soil water recharge to maintain the ecosystem stability. The water exchange among different ecosystems is more intense in arid regions watersheds. Key words Soil water dynamics, soil water storage, water recharge, alpine, montane, oasis, desert. CONTENTS
41 The dual and contradictory effect of biocrusts on perennial plants Giora J Kidron1, Irith Aloni2 1 Institute of Earth Sciences. The Hebrew University, Israel. [email protected].ac.il 2 Department of Life Sciences. Ben Gurion University, Israel Abstract The effect of biocrusts on plants is not always clear. In the Nizzana research site in the western Negev Desert (Israel), frequent droughts in the last two decades resulted in high shrub mortality. This was especially the case for shrubs inhabiting the biocrusted interdune (such as as Cornulaca monocantha, Noea mucronata, Artemisia monosperma), explained by the negative effect of the dark low-albedo crusts on soil water evaporation. Alternatively, although inhabiting the biocrusted surfaces of the interdune, previous findings indicated that some shallow-rooted perennial plants such as Panicum turgidum and Cyperus spp. exhibit relatively little mortality. These hemicryptophytes can withstand long months of desiccation without losing their ability to regenerate new tissues once moisture is available again. Hypothesizing that these low-rooted perennials grow at or adjacent to small 2-4 m2 and sparsely distributed depressions (ID-PONs), which serve as sink for short-distance runoff that takes place at the undulating microtopography of the crusted interdune, twenty five 5 x 5 m plots were demarcated in the uncrusted dune crest and the interdune, and the number and cover of live perennials in the dune crest and the interdune (in relation to ID-PONs) was monitored. In addition, moisture measurements at 0-40 cm were undertaken during 2011-2014 at a pair of ID-PONs and adjacent loci at the interdune, and at the uncrusted dune crest. The data show a substantially high survival rate at the uncrusted dune crest, and a clear link between P. turgidum and Cyperus spp and ID-PONs. Substantially higher moisture content was recorded at the dune crest (explained by reduced evaporation) and ID-PON (explained by addition of runoff) in comparison to the remaining interdune. The findings highlight the dual and contradictory role played by the biocrust: while being responsible for the mortality of shallowand medium-rooted plants in most of the interdune following increased evaporation by the crust, biocrusts assist the growth and survival of some relatively shallow-rooted perennial at ID-PON following their role in runoff generation. Key words Soil water dynamics, soil water storage, water recharge, alpine, montane, oasis, desert. CONTENTS
48 Key words Runoff, arid and semiarid ecosystem, biocrusts. Acknowlodgements: This work was supported by the Spanish National Plan for Research, Development and Innovation and including European Union of Regional Development Funds, under BACARCOS (CGL2011-29429) and RESUCI (CGL2014-59946-R) research projects. The first author is currently supported by the Max Planck Society and the Paul Crutzen Nobel Laureate Fellowship. We also thank the Viciana brothers, the landowners, and Alfredo Durán for his assistance with the field work.
49 Modelling ecogeomorphology feedbacks in Australian banded vegetation hillslopes Patricia M. Saco, Mohammadjafar Solatanjalili, Samira Azadi Civil, Surveying and Environmental Engineering, Thr University of Newcastle, Australia. Abstract Dryland areas function as tightly coupled eco-geo-hydrological systems with strong feedbacks and interactions occurring over a range of fine to coarse scales. It is not uncommon for the vegetation of these regions to display a mosaic of patches with high biomass cover interspersed within bare soil. In many areas, a key process behind the development of these patterns is the emergence of a spatially variable infiltration field with low infiltration rates in the bare soil areas and high infiltration rates in the vegetated areas. Enhanced infiltration rates under vegetated patches are due to improved soil aggregation and macroporosity (and are therefore both the cause and consequence of the pattern). This spatially variable infiltration is responsible for the development of a runoff–runon system which, together with the effect of vegetation on soil erodibility, modulates the resulting sediment erosion and depositional areas, and can therefore affect soil depth. Here we present results from a modelling framework that couples evolving vegetation, erosion, and soil depth to explore hillslope-scale ecohydrologic interactions between vegetation patterns and sediment movement in arid and semi-arid regions. The model reproduces the observed dynamics of banded vegetation patterns in mild slopes, as well as stippled or spotted patterns for steeper areas (details about the model can be found in Saco et al., 2007; Saco and Moreno de las Heras, 2013). The effects of climate variability on the hydrology and erosion are analysed and compared to the observations available from banded vegetation sites in Australia. Model results highlight the importance of incorporating feedbacks between vegetation, soils and topography in order to correctly capture the redistribution of resources in these regions and assess possible responses to disturbances induced by changes in land use and/or climate. While the timescales of response of the vegetation are of the order of a few years, the coupled soil organization responds more slowly (decades or longer). This suggests the possibility of an out of phase response between hillslope runoff generation and vegetation response, which is qualitatively different in natural undisturbed and disturbed systems. Recent simulations on the effects of different plant functional types on the ecohydrologic responses of these systems will be also presented. The relevance and implications of these results for the successful reclamation of water-limited environments, in which vegetation stability largely depends on the redistribution of the scarce water resources, will be discussed. These implications will be illustrated using data and observations from agricultural sites across a (semi-arid) gradient in Australia. Finally, the need for additional work considering other alternative relevant mechanisms will also be examined which will hopefully trigger debate and future directions. Key words Ecogeomorphology, banded vegetation patterns, runon, erosion, feedbacks. References: Saco, P. M., G. R. Willgoose, and G. R. Hancock (2007), Eco-geomorphology of banded vegetation patterns in arid and semi-arid regions, Hydrology and Earth System Sciences, 11, 1717-1730. CONTENTS
50 Saco P. M., and M. Moreno-de las Heras, 2013. Ecogeomorphic coevolution of semiarid hillslopes: Emergence of banded and striped vegetation patterns through interaction of biotic and abiotic processes, Water Resources Research, 49, doi:10.1029/2012WR012001.
51 The forgotten dimensions of carbon flux in drylands: potential effects of land degradation Laura Turnbull, John Wainwright Department of Geography, Durham University, Durham, DH1 3LE, United Kingdom Abstract There has been a significant emphasis recently on the role of vegetation change and land degradation in drylands on carbon sequestration and the provision of related ecosystem services. Studies have typically focussed on the storage of carbon in biomass over short timescales. Over longer timescales, an important component of carbonrelated ecohydrological processes is the way in which carbon is transferred from biomass to soil organic matter, and also the sequestration and storage of carbon in soil carbonates. These transfers are significantly affected by land degradation via erosion processes which may result in redistribution and net loss of carbon from the local system. Many drylands are underlain by significant stores of inorganic carbon, some of which is deposited from aeolian material, but vertical transfer from the surface stores is also an important process. Numerous studies suggest that these stores are in place from thousands to millions of years and contain carbon that has long been taken out of the global cycle, and thus is considered to be ‘inert’. As progressive land degradation occurs, these stores are increasingly being exposed at the surface, and thus reactivated as part of the global cycle. In the context of climate change where increasingly stormy conditions are likely to accelerate the mobilization of sediment and associated carbon, and where increasingly acidic rainfall exacerbates dissolution of inorganic carbon, there is the potential for a significant addition to atmospheric carbon at regional and global scales. We will evaluate the relative importance of this mechanism compared to sequestration in vegetation and discuss the implications for maximizing ecosystemservice provision in drylands. Key words Carbon, land degradation, hydrology, erosion, ecohydrology. CONTENTS
52 Session 1: Contributions presented as posters CONTENTS
53 Patterns of surface runoff at hillslope scale: insights into source-sink biohydrologic relationships Eva Arnau-Rosalén1, Isabel Molina-Sanchís2, Mónica Ladrón de Guevara3, Roberto Lázaro-Suau2, Adolfo Calvo-Cases1, Carolina Boix-Fayos4 1 Department of Geography. University of Valencia, Spain 2Experimental of Arid Zones . EEZA-CSIC. Almería, Spain 3Departament of Biology and Geology, University Rey Juan Carlos, Móstoles, Spain 4Centro de Edafología y Biología Aplicada del Segura (CEBAS-CSIC). Murcia, Spain Abstract In semiarid ecosystems, eco/bio-hydrological relationships are crucial and complex because of the variable and limited amount of water and the existence of thresholds in several key processes. Soil water redistribution during rainfall events constitutes the first modulating effect on the water availability for plant use, where overland flow plays a fundamental role. Therefore, increasing knowledge on runoff response thresholds and hydrological connectivity become essential to deal with ecosystems functioning. This requires a methodology that considers the high spatial (pattern) and temporal (process) heterogeneity that characterizes these environments with a bottom-up approach across scales. Our hypothesis is that soil surface components (i.e. vegetation, biocrusts, rock fragments and others) have a variable runoff response and are the main source of spatial heterogeneity at the patch scale, arriving to determine the hydrological response up to hillslope scale. With the aim of investigating the hydrologic functioning of the ecosystem, our objective is to ascertain the spatial dynamics of surface runoff at hillslope scale during a high intensity rainfall. In the experimental site of Balsa Blanca (Almería, SE-Spain) characterized by a Mediterranean-semiarid-climate, the following specific goals have included: (i) to obtain the cartography of soil surface components (SSC) of a hillslope transect from a photo-mosaic with a centimetre resolution; (ii) to characterize the runoff response of each SSC type by means of rainfall simulation experiments under dry soil conditions and fitted to a hortonian model to obtain the corresponding hydrograph type for each SSC; (iii) to approximate a effective saturation threshold for each SSC type from the analysis the soil moisture dataset. The applied methodology consisted in the integration of the spatial and temporal dimension of the process by means of the development of an empirical-based model powered by the hydrograph type of each SSC (patch scale) and distributed according the SSC cartography (hillslope scale). Furthermore, it incorporates a threshold criterion of effective saturation of the soil, allowing the scaling-up from path to hillslope. The results show the evolution of the spatial patterns of runoff and infiltration during a simulated rainstorm of high intensity (55 mm h-1). In this way we have been able to explore de potential source-sink relationships between vegetation and bare soil that determines the general connectivity of the whole hillslope transect. Key words Spatio-temporal patterns, surface runoff, infiltration, hillslope scale, soil surface components, threshold, connectivity, source-sink relationships. CONTENTS
54 Soil infiltration rates under different soil tillage managements in vineyards in Eastern Spain Maria Burguet1*, Simone Di Prima1, Massimo Prosdocimi2, Artemi Cerdà1 1 Soil erosion and Degradation Research Group, Department of Geography. Universitat de Valencia, Valencia, Spain. 2 Department of Land, Environment, Agriculture and Forestry, University of Padova, Agripolis, Legnaro (PD), Italy. Abstract Vineyard is one of the main crops in the Mediterranean region and it forms, along with wheat and olive, what it is known as the ’Mediterranean triad’. The degraded soil conditions, especially due to bad soil management practices, favour surface runoff at the expense of infiltration. Infiltration, apart from being a key hydrological process when determining surface runoff, can be used as an indicator of the soil quality as it is highly dependent on the soil organic matter and soil structure. The infiltration rates of the soils are highly determined by the land management and the soil properties. In fact, two practices are likely to affect infiltration: tillage, with superficial tillage of the interrow and chemical weeding of the row, and no tillage, with chemical weeding of the whole field. The objective of this research was to determine the impact of conventional tillage (CT) and no-tillage (NT) soil management systems in the infiltration rates in a vineyard farm, using the ring infiltrometer and the mini disk infiltrometer (MDI). Regarding the ring infiltrometer method, no statistical differences were found for the different soil tillage systems applied On average, NT presented infiltration rates of 325.88 mm h-1 whilst CT had average infiltration rates equal to 263.71 mm h-1. As for the saturated hydraulic conductivity (𝐾!), no statistically significant differences were found between both managements. The maximum 𝐾! values were measured under NT soil tillage (151.43 mm h-1), and the minimum values were reported for the CT soil management (37.00 mm h-1). For the MDI, statistical differences were neither found for the different managements nor between lanes. In terms of average values, NT presented infiltration rates of 248.61 mm h-1 whilst CT had 246.16 mm h-1 average infiltration rates. As far as unsaturated hydraulic conductivity (𝐾!)!is concerned, no statistically significant differences were found between soil managements. The maximum and minimum 𝐾! values were measured for the NT soil management (159.22 and 14.51 mm h-1 respectively). Statistical differences were found between the methodology used (ring PI and MDI), however, no statistical differences were observed between soil managements (CT and NT) and Ksf values. Average Ksf values were higher under ponding conditions than under tension conditions. The differences found between ring and mini disk might be influenced by other soil hydraulic properties related to ρb and θ0. Key words Vineyards, soil tillage, infiltration, ring infiltrometer, mini-disk. CONTENTS
55 Soil water repellency in urban parks Maria Burguet1*, Paulo Pereira2, Artemi Cerdà1 1 Soil erosion and Degradation Research Group, Department of Geography. Universitat de Valencia, Valencia, Spain. 2 Environmental Management Centre, Mykolas Romeris University, Vilnius, Lithuania. Abstract Urban areas and thus, the process of urbanization is a worldwide issue. The expansion of those areas is usually done towards the surrounding areas. The involved areas are forest lands, range lands and agricultural lands as reported by the Natural Resources Conservation Service, NRCS (2014). According to the Demographia of World Urban Areas (2015), 10.2% of Europe population live in urban areas. One of the main characteristics of these areas is the sealing processes in the soil by urban grey infrastructures. In fact, Prokop et al., (2011) reported that 2.3% of the European territory is sealed. As the world population prospects in 2015 is of continuing increasing up to about 10 billion in 2050 (United Nations, 2015), a better understanding of the environmental processes involved in urban soils is of need. We present the characterization of the soil water repellency conditions in the Turia River Park (Valencia, Spain). A spatial analysis from the tree trunk (0 cm) up to 100 cm distance of the Water Drop Penetration Time test (WDPT) and the molarity of ethanol droplet (MED) test were conducted for a total of 8 tree species (Schinus molle, Platanus orientalis, Nerium oleander, Casuarina, Pinus halepensis, Laurus nobilis, Grevillea robusta, Araucaria heterophylia). For the MED test, a total of 10 drops at ethanol/% 1, 3, 5, 8.50, 13, 18, 24 and 36 were measured for each specie at a 10 cm interval. Our results show that soil water repellency values were higher (>100 s) for the Pinus halepensis, Laurus nobilis and Grevillea robusta species. In fact, soil water repellency values followed a decreasing trend: values were higher near the tree trunk (first 30 cm), decreased to 0 s and then rise at the 60 cm. This trend might be associated to a higher concentration in organic matter due to the leave decomposition, as observed in other tree species such as olive. Key words Urban parks, water repellency, infiltration, ring infiltrometer, mini-disk. References: Prokop, G., H. Jobstmann, and A. Schönbauer. 2011. Report on best practices for limiting soil sealing and mitigating its effects. Study contracted by the European Commission, DG Environment, Technical Report-2011-50, Brussels, Belgium, 231 pp. CONTENTS
56 Soil infiltration rates and water repellency on organic and chemically managed citrus plantation in in Eastern Spain Rafael González-Camarena1*, Saskia Keesstra2, Artemi Cerdà1,2 1 Soil erosion and Degradation Research Group, Department of Geography. Universitat de Valencia, Valencia, Spain. 2 Soil Physics and Land Management Group, Wageningen University, Wageningen, The Netherlands. [email protected]. Abstract Organic farming is widespread in many regions of Europe, and in Spain is being applied in different crops and regions. Citrus were chemically managed during decades, but the growth of the organic agriculture is making that the soil management will move to the organic farming strategy: apply manure, avoid any pesticide or herbicide, use catch crops and chop the pruned branches. To determine the impact of organic farming management on soil hydrology three paired plots on citrus plantations were selected in Easter Spain. Measurements with ring infiltrometer (10 in each plot x 3 sites x 2 paired = 60 measurements), and Water Drop Penetration Time (WDPT) measurements 1000 drops x 3 sites x 2 paired = 6000 measurements) allow us to determine that organic farming increases the infiltration rates of soils but also increased the water repellency. This means that organic farming promote the water repellency due to the increase in organic matter, but also favours an increase in the infiltration rates due to the macropore flow. Key words Citrus, organic farming, infiltration, ring infiltrometer, WDPT. CONTENTS
57 The influence of weeds on net ecosystem CO2 assimilation and water use efficiency in an irrigated olive orchard of SE Spain Sonia Chamizo1,2, Penélope Serrano-Ortiz3,4, Enrique P. Sánchez-Cañete5,4, Ana LópezBallestero6,4, José Luis Vicente-Vicente7, Sara Marañón1, Andrew S. Kowalski1,4 1 Applied Physics Department, University of Granada, Granada, Spain 2 Department of Agronomy, University of Almeria, Almeria, Spain. 3 Ecology Department. University of Granada, Granada, Spain 4 Inter-University Institute of Research of Earth System in Anadalucia, (IISTA -CEAMA), Granada, Spain 5 Biosphere 2. University of Arizona, Tucson, USA 6 Experimental Station of Arid Zones. CSIC. Almería, Spain 7 Department of Animal Biology, Vegetal Biology and Ecology. University of Jaen, Jaen, Spain Abstract Climate in the Mediterranean area is typically characterized by high potential evaporation and low rainfall during the growing season. These dry conditions during the period of higher vegetation activity limit growth and yield in croplands. Olive tree is considered one of the best adapted species to the semiarid environment, however under water stress, its photosynthetic activity is often reduced. As water supplied by rainfall is not enough to satisfy water needs by olive trees, water deficit is usually compensated by irrigation and thus, many traditional olive orchards have been converted to irrigation. On the other hand, conservation practices consisting on the maintenance of spontaneous resident vegetation cover (hereinafter, "weeds") from autumn to spring are increasingly adopted in these crops in order to combat soil erosion and degradation problems caused by conventional practices. The influence of weeds on the increase of soil organic carbon content in olive crops is well recognized, however little is known about their effect on CO2 sequestration at ecosystem scale. Moreover, knowledge about the effect of weeds on evapotranspiration fluxes at ecosystem scale is scarce and this information is crucial to optimize irrigation conditions and ultimately, to improve crop management. In this study, we measure Net Ecosystem CO2 Exchange (NEE) and Evapotranspiration (E) in an irrigated olive orchard of SE Spain under two management treatments, conservation of weeds and weed removal with a glyphosatebased herbicide, using two eddy towers. Water Use Efficiency (WUE), defined as the ratio NEE/E, and the Bowen ratio (the ratio of sensible (H) to latent heat (LE) fluxes) were examined for both treatments. Our results show that during the main growth period (March-April), net C uptake was higher in the treatment with weeds compared to the weed-free treatment. Similarly, E was also higher in the treatment with weeds. Despite greater E in the former, ecosystem WUE was higher in this treatment due to the increase in the ratio of fixed C to water loss. Thus, under similar water loss, the treatment with weeds was able to increase C uptake by up to 4 times compared to the treatment without weeds. The presence of weeds also decreased the Bowen ratio. During weed growth, the Bowen ratio was lower in the weed-cover treatment than in the weed-free treatment. In spring, after weeds were cut and the hay left on the soil, the Bowen ratio markedly increased in this treatment and exhibited similar values to those of the weed-free treatment. Therefore, conservation of weeds represents a sustainable strategy to optimize C fixation relative to water loss in olive orchards as well as other Mediterranean crops where water scarcity restricts crop productivity. Key words Carbon uptake, evapotranspiration, Bowen ratio, conservation agriculture. CONTENTS
64 Virtual experiments on root sampling methods to infer the specific root traits by inverse modelling Shehan Morandage1, Andrea Schnepf1, Jan Vanderborght1, Mathieu Javaux1, 2, Daniel Leitner3, Harry Vereecken1 1 Agrosphere, Forschungszentrum Juelich, Germany 2 Earth and Life Institute, Universite catholique de Louvain, Belgium 3 Department of Forest and Soil Sciences, University of Natural Resources and Applied Life Sciences, Vienna, Austria Abstract Plant phenotyping methods based on architectural root traits to develop new genotypes are becoming increasingly important. These traits play a key role for crop performances under non-optimal environmental and climatic conditions. However, the main challenge in root phenotyping programs is the limited accessibility to the root system because it is hidden in the soil. Although lab based methods are widely used to retrieve root system architecture characteristics, these experiments are not capable of replicating the plant growth in the field, and often the studies are not carried out for the entire lifespan of a plant. On the other hand, classical field root sampling methods provide only the root distribution with depth or arrival times at each depth in the soil profile, which do not provide direct information about the root system architecture of the plant. In order to overcome these challenges, we instigate the possibility of obtaining information about the root system architecture (RSA) using field based root sampling schemes. The root growth model “RootBox” was used to generate virtual 3-D root systems of 200 individual wheat plants. Ground truth of the virtual experiment was established for coring, trench profile and rhizotron methods. From these data, root length density (RLD), root intersection density (RID) profiles and arrival curves for rhizotubes were computed and considered as observation data. Morris OAT sensitivity analyses method was performed to quantify the sensitivity of each parameter of the root growth model to the observation data. The sensitive parameters will be optimized using “DREAM” inversion algorithm based on the observation data. The optimized parameters and the input parameters will then be evaluated with the sampling methods to determine the suitability of the sampling schemes to identify specific traits or parameters of the root growth model. Finally, the virtual experimental method will be applied in real field samples to obtain information about the specific traits of different genotypes for plant breeding programs. By combining sensitivity analyses with inverse modelling, parameters of a root system architecture model that can be inferred indirectly from traditional field observation methods were identified. This is an important step in the characterization of root traits from field observations. In a next step, these root architectures can be used in models that simulate water and nutrient uptake so as to evaluate the performance of root systems with certain traits. Key words Optimization, RootBox, root system architecture, sensitivity analysis. CONTENTS
65 Influence of precipitation on subterranean CO2 molar fraction from a deep soil profile in a semiarid ecosystem experiments M. Rosario Moya1, Enrique P. Sánchez-Cañete2, Ana López-Ballesteros1,3, Sonia Chamizo5,7, P. Serrano-Ortiz3,4, Cecilio Oyonarte5,6, Andrew S. Kowalski3,7, Francisco Domingo1 1 Experimental Station of Arid Zones. CSIC. Almería, Spain ([email protected]) 2 Biosphere 2. University of Arizona, Tucson, USA 3 Inter-University Institute of Research of Earth System in Anadalucia, Centro Andaluz de Medio Ambiente (IISTA - CEAMA), Granada, Spain 4 Ecology Department. University of Granada, Granada, Spain 5 Department of Agronomy, University of Almeria, Almeria, Spain. 6 Andalusian Center for Assessment and Monitoring of Global Change, University of Almería, Almería, Spain 7 Applied Physics Department, University of Granada, Granada, Spain Abstract Despite being the largest biome on the planet, semiarid ecosystems have been poorly investigated regarding their role in the global carbon balance. Most researchers have studied ecosystem-level CO2 exchanges using eddy covariance towers and soil CO2 fluxes at the top soil layer through respiration chambers, neglecting CO2 exchanges at depth. However, recent studies focused on deeper soil layers have found large variations in the CO2 molar fraction (Xc) associated with variations in atmospheric pressure or wind. Numerous studies have explored the role of rainfall variability and extreme events in the soil Xc, but always focused on the first soil centimeters. The effect of rain pulses on the carbon balance in semiarid ecosystems depends on the intensity of rainfall and the level of drought stress. Here, we studied the precipitation effect together with other determinants of the subterranean Xc. In order to characterize the main factors influencing subterranean CO2 variability, we analysed edaphic and atmospheric data over two years (2014-2015) in a semiarid grassland situated in Cabo de Gata-Níjar Natural Park (Amoladeras; 36°50’0.96’’N, 2°15’8.279’’W). A vertical soil profile was installed to measure Xc, temperature, and humidity at four depths (0.05, 0.15, 0.5 and 1.5 m) in June 2013. Results show that rain events influenced Xc variations exclusively at 0.05m, whereas in deeper layers, atmospheric pressure change was the principal driving factor. In the top layer, soil water content increases and the decomposition of soil labile organic matter accumulated by microorganisms provoked Xc rising in soil pores. Significant differences (P<0.05) were found in diel patterns of soil CO2 molar fraction induced by small and large rainfall events. Small rainfall events increased shallow Xc (0.05m), whereas larger rainfall events were required to produce increases in deep Xc (0.15, 0.5 and 1.5 m). However, the most common rainfall magnitudes were insufficient to affect deeper soil layers, and neither rewetted nor activated microbial activity in the deeper soil layers. We conclude that, in our experimental site, Xc variations produced by rain events solely occur in shallow layers while their effect is negligible in deeper layers (≥0.15m), where atmospheric pressure acts as the most important factor. Key words Carbon balance, rain pulses, drylands, subterranean CO2 processes, pressure pumping, soil respiration. CONTENTS
66 Soil water repellency as a vegetation-driven strategy in arid ecosystems: a case study in Banksia woodlands (Western Australia) Miriam Muñoz-Rojas1,2,3*, Nicasio T. Jiménez-Morillo3,4, José A. González-Pérez4, Lorena M. Zavala3, Jason Stevens2, Ana Alonso Lobo2, Antonio Jordán3 1 School of Plant Biology, The University of Western Australia, Crawley, Western Australia, Australia 2 Kings Park and Botanic Garden, Botanic Gardens and Parks Authority, Kings Park, Western Australia, Australia 3 MED_Soil Research Group, Departamento de Cristalografía, Mineralogía y Química Agrícola, Universidad de Sevilla, Sevilla, Spain 4 Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS-CSIC), Sevilla, Spain Abstract Soil water repellency (SWR) is caused by hydrophobic organic substances released by plant residues, roots or soil microorganisms that inhibit or delay rainwater infiltration. Banksia woodlands (BW) are iconic ecosystems of semi-arid environments of Western Australia (WA) comprised by an overstorey dominated by Proteaceae, e.g. Banksia menziesii and Banksia attenuata, in combination with other species, such as Eucalyptus spp. Although located in poor dune soils, BW provide numerous ecosystem services and sustain a high biodiversity. A characteristic feature of BW is their dimorphic root architecture, formed by a proteoid (cluster) system that radiate from the parent root and spreads to form thick mats below the soil surface. These clusters secrete large amounts of organic acids and phenolics to increase the uptake of P and other minerals that can be related to SWR. In contrast, the parent root penetrates soil deeply, reaching the water table. This study, conducted in natural BW of WA, aimed to assess SWR and its impact on water economy in relation with soil functioning and plant strategies for water uptake in pristine BW. Soil samples were collected at different depths (0-1, 1-10, 20-30 and 4050 cm) based on the different SWR severities found in each layer under field conditions. SWR was assessed under laboratory conditions in oven-dry samples (48 h, 105 ºC) and the chemical organic assemblage of bulked soil subsamples from each layer was analysed by direct analytical pyrolysis (Py-GC/MS). SWR distributed discontinuously through the soil profile. The first thin layer (0-1 cm) composed of coarse sand and litter, located immediately above Banksia root clusters, showed wettable conditions. In contrast, the well aggregated soil layer where the cluster root system is located (1-10 cm) was severely water-repellent. The 20-30 and 40-50 cm deep layers rendered wettable or subcritically water-repellent. After Py-GC/MS analysis, major compounds were identified and grouped according to their probable biogenic origin. Among other soil organic compounds, well resolved bimodal alkane/akene (C8-C31, maxima at C13 and C26) and fatty acids series (short-chained, C5-C9, and long-chained even-numbered C12-C18) were associated to the root cluster soil layer (1-10 cm). Also, a relatively high contribution of fire-derived polycyclic aromatic hydrocarbons (PAHs) was observed (7%). These results point to possible indirect links between organic substances released by roots and soil wettability involving soil microorganisms. Further discussion should shed light on possible ecological plant strategies and specific adaptations for water uptake in such arid ecosystems of WA. Key words Soil moisture, soil hydrophobicity, analytical pyrolisis, ecological strategies, soil organic matter. CONTENTS
67 Spatio-temporal diversity of surface waters in semiarid rivers depends on groundwater. Case study of the Andarax catchment (Almería) Francisco Navarro-Martínez, Francisco Sánchez-Martos, Juan Gisbert-Gallego; Luis Molina-Sánchez, Juan Pedro Rigol Sánchez Water Resources and Environmental Geology Research Group (RNM-189), Campus de Excelencia Internacional en Agroalimentación (CEIA3) University of Almería, Spain Abstract The interactions between surfaceand groundwaters in semiarid regions are complex and varied and favour a diversity of surface water. We present examples from along the three largest watercourses of the Andarax catchment (Andarax river, Nacimiento river and Tabernas rambla) of the influence of groundwater onsurface waters. The Andarax river is continuous in its headwaters, temporary in its middle reach and ephemeral in the lower reach. Its spatio-temporal variability has been studied based on a series of differential gauges and monitoring of surface water salinity. In the middle reach of the catchment, two zones are identified with permanent flow and salinity. One of them has more homogeneous and, less saline water (550 - 600 µS/cm), which reflects the influence of the carbonate aquifer Sierra de Gádor on the surface water flow. The other zone was characterized by a saltier water (1000 - 1800 µS/cm). The surface water flow shows a marked spatio-temporal variability and showed the highest salts content, as a consequence of the influence of the groundwater feed from the detritic aquifer. The Nacimiento river is an intermittent and ephemeral watercourse, although its middle reach contains a small permanent flow of saltier water (1440 – 2010 µS/cm), which is linked to a diffuse flow from the detritic aquifer. In the Tabernas Rambla, there is a series of small permanent saline surface water, discontinuous in space, which are continuous over time but have a very high and variable salinity (7730 – 13000 µS/cm). These permanent streams are associated with diffuse discharges of groundwater whose saline content is slightly lower (6800 - 9100 µS/cm). In the Andarax catchment, riparian vegetation is affected by surface water with contrasted characteristics. The availability of surface water and its relationship to groundwater determines the spatial distribution of permanent and intermittent reaches and its highly variable salinity. It is necessary to emphasize the importance of knowing all the processes linked to the groundwater-surface water interactions in semiarid areas, since the presence of different water types and their spatial-temporal variability markedly favours biodiversity. Key words Groundwater-surface water interaction, hydrochemistry, Andarax. Acknowledgements: This research has been supported by the project P11-RNM-8115 financed by the Consejería de Economía, Innovación y Ciencia of the Regional Government of Andalucia (Junta de Andalucía). CONTENTS
68 Tracking differences in the physiological response of vegetation and biocrusts to rain events based on multitemporal NDVI sequences from Landsat images Emilio Rodríguez-Caballero1,2, Tanja Knerr3, Burkhard Büdel3, Joachim Hill4, Bettina Webber1 1 Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany. e.rodriguez- [email protected] 2 Department of Agronomy, University of Almeria, Almeria, Spain. 3 Plant Ecology and Systematics, University of Kaiserslautern, Kaiserslautern, Germany 4 Environmental Remote Sensing and Geoinformatics Department, University of Trier, Trier, Germany Abstract Dryland vegetation developed morphological and physiological strategies to cope with drought. However, as aridity increases, vascular plant vegetation and coverage gets sparse. Under these conditions biocrusts become a key player in ecosystem productivity. They are complex communities of poikilohydric life forms (cyanobacteria, algae, microfungi, lichens and bryophytes), that cover the uppermost millimeters of the soil surface and dry out and remain dormant when water availability decreases. Biocrusts modify soil properties and control water availability and erodibility. Moreover, they show a faster phenological response to water pulses than vascular vegetation, turning green (in a similar way as vegetation does) almost immediately after small rains, fixing atmospheric carbon and nitrogen. However, biocrusts have been traditionally not considered, probably also due to their largely inconspicuous growth. Thus, spatially and temporally continuous information about their response to water pulses is still necessary, and will help to advance the knowledge about their role in ecosystem productivity. Remote sensing data provide spatially continuous information that can be used to analyze biocrust dynamics by means of long-term series of vegetation indices, like the normalized difference vegetation index (NDVI). In the present study, we used thirty six different LANDSAT images acquired during the year 2008 at to different study areas within the South African Succulent Karoo (15 from Soebatsfontain and 21 from the Knersvladkte quartz fields) to analyse biocrust response to water pulses, and we compared these with the vegetation response. The results showed that biocrust and vegetation greenness are controlled by water availability, showing minimum values during dry periods that increased after the rainy season and decreased again at the onset of drought. However, biocrusts and vascular plant vegetation responded physiologically differently to water pulses, which resulted in some differences in their NDVI dynamics. Biocrusts turned green almost immediately after small rains, producing a small NDVI peak only few days after rainfall, whereas longer time was necessary for vegetation to grow new green tissue. However, once the photosynthetic tissue of vegetation was restored, it caused the highest increase of NDVI values after the rain. Thus, multitemporal NDVI data are extremely helpful to not only analyze the vegetation density and response upon water pulses. It can also be used to distinguish between vascular vegetation and biocrusts and to analyze the relevance of biocrusts and its development during processes of global change. Key words Biological soil crust, remote sensing, vegetation indices, arid and semiarid ecosystems. CONTENTS
69 Biocrust recovery after disturbance improves soil fertility and reduce runoff and sediment yield Raúl Román1, Sonia Chamizo1,2, Emilio Rodriguez-Caballero1,3, Beatriz RonceroRamos1, Yolanda Cantón 1 1 Agronomy Department. University of Almeria, Almería, Spain. 2 Applied Physics Department. University of Granada, Granada, Spain. 3 Multiphase Chemistry Department. Max Planck Institute for Chemistry. Mainz. Germany Abstract Biological soil crusts or biocrusts are widespread components in drylands where they are known to play key roles in numerous ecosystem processes. By forming microbiotic assemblages on the soil surface, biocrusts strongly protect soils from raindrop impact and the erosive action of overland flow, constituting one of the main protective agents from soil water erosion in drylands. In addition, biocrusts modify numerous soil properties including surface roughness, porosity, water retention capacity and hydrophobicity, thus having a key influence on hydrological processes. However, biocrusts are easily disturbed by human activities and climate changes, facts that may have strong implications on water redistribution and the loss of vital resources in drylands. Knowing how biocruts evolve after disturbance and contribute to restore soil functions is crucial to develop dryland rehabilitation techniques. In this work, we explored the influence of biocrust recovery after disturbance by removal on the evolution of soil properties as well as their influence on runoff and sediment yield in a semiarid badlands catchment. Runoff and sediment yield rates were measured during an intense rainfall in 2012 on small plots covered by intact biocrusts (mainly cyanobacteria-dominated) and soils where the biocrust was removed in 2007 and 2012 and have remained unaltered since then. Hydraulic conductivity was also measured in these plots with a mini disk tension infiltrometer. Crust samples were collected annually in adjacent plots where the crust was removed in 2007 and have been unaltered since then in order to analyze the evolution of soil properties with biocrust recovery. We found that runoff and, especially, sediment yield, were higher in the plots where the biocrust was recently removed but similar in the undisturbed and 5-year recovery biocrust plots. Hydraulic conductivity and soil organic carbon and nitrogen contents increased with greater biocrust development, as soil was newly colonized by cyanobacteria after biocrust removal. Our results highlight the need to protect interplant soils in drylands, where biocrust disturbance has great impacts on the loss of soil fertility and runoff and erosion processes. In addition, the relatively fast growth of a cyanobacterial-dominated crust after disturbing arise the possibility of exploring their use in restoration projects in semiarid lands. Key words Biocrusts, disturbance, runoff, erosion, soil fertility, semiarid. Acknowledgements: This work was funded by the Spanish National Plan for Research, Development and Innovation and including European Union of Regional Development Funds, under the RESUCI (CGL2014-59946-R) research project and the FPU predoctoral fellowship from the Educational, Culture and Sports Ministry of Spain and the foundation Tatiana Pérez de Guzmán el Bueno, under its predoctoral fellowship programme. We also thank the Viciana brothers, the landowners, and Alfredo Durán for his assistance with the field work. CONTENTS
70 Effect of different levels of pumice on sorption and retention of water in soil and Russian olive seedling growth Davoud Zarehaghi1, Mohammad Ebrahim Sadeghzadeh Reyhan2, Reza Hassanpour1 1 Soil Science Department, University of Tabriz, Tabriz, Iran 2 Agricultural and Natural Resources Research Center of East Azerbaijan, Iran Abstract Using superabsorbent materials for holding moisture in soil, prevention from its evaporation and to increase irrigation efficiency is one of the practical methods in soil and water science. Pumice is one of these superabsorbent materials that it is a noncrystalline mineral made from aluminium silicate. This mineral has high ability for moisture absorption and retention. This research was performed in the Khajeh research station from 2012 to 2014 on the basis of randomized complete block design with four treatments and three replications to evaluate the effects of different amounts of pumice on water holding capacity in the soil and growth characteristics of Russian olive (Elaeagnus angustifolia L.) seedling in rainfed conditions. Experimental treatments were four rates of pumice (0, 10, 20 and 30% pumice). To apply treatments, a hole with depth and diameter of 70 cm was drilled and an olive seedling was planted at each hole. Also, a pair of TDR sensors with length of 70 cm was placed at each hole to measure soil moisture content. The dug-out soil from each hole was mixed with pumice at levels of 0, 10, 20, and 30% by volume and again returned to the holes. During the experiment, the average soil moisture content was measured by TDR every 10 days. Also, some vegetative characteristics of olive seedling such as height, stem diameter and leaf area were measured. Results showed that for control treatment (0% pumice), mean volumetric water content through growth period was the lowest. Volumetric soil water content considerably increased with the addition of pumice to soil. For control treatment, seedling height, stem diameter and leaf area were 56 cm, 6.2 mm and 62 cm2, respectively. While at 30% pumice, these values increased considerably reaching values of 116 cm, 16.4 mm and 304 cm2, respectively. Adding pumice to soil improves soil physical conditions (total porosity, water holding capacity of soil and prevent the formation of crust on the soil surface) leading to higher plants growth and yield. Therefore, pumice, due to its low bulk density, high porosity and high capacity for water absorption, leads to an increase in soil porosity, decreases bulk density and reduces soil surface crusting and it providing suitable physical conditions for roots growth. Also, pumice capacity to absorb and retain rain water, prevents water deficit stress of plants during growth season. Furthermore, pumice is cheaper than similar materials such as perlite and vermiculite, making economically possible its application on wide areas under rainfed conditions to increase production. Key words Russian olive, soil moisture, soil porosity, superabsorbent. CONTENTS
71 Pumice mulch effect on corn growth and yield Mehdi Nasiry, Davoud Zarehaghi, Mohammad Reza Neyshabouri Department of Soil Science, University of Tabriz, Iran Abstract Mulching is one of the important agronomic practices in conserving the soil moisture and modifying the soil physical environment. The most serious problem facing humanity in the twenty-first century is the water crisis. The increase in world population and humans’ exceeding demand for water in order to provide food supply on one hand and the phenomena of climate change as well as reduced precipitation and prevalence of droughts on the other hand has aggravated the situation. The application of mineral mulches such as pumice to soils has led to the increase of water retention, decline in water evaporation and consumption, and thus would have a significant impact on plant performance and growth. The present research was conducted in a complete randomized block design with three replications in a farm plots planted with corn (hybrid modified Maxima). The treatments consisted of four levels 0, 30, 60 and 90 tons per hectare of pumice. Irrigation was performed on a weekly basis. The pumice mulch produced a significant effect on corn morphological traits and yield. The highest and lowest levels of plant height, number of leaves, stem diameter, leaf area index, fresh and dry weight of leaves, fresh and dry weight of stems were obtained from 90 tons per hectare of pumice treatment and control treatment, respectively. Between 90 and 60 tons per hectare of pumice treatments, there was no significant difference in terms of the measured parameters. Key words Corn, morphological traits, mulch, pumice, yield. CONTENTS
72 SESSION 2 BIOHYDROLOGY IN LAND DEGRADATION AND RESTORATION Conveners:& Albert'SoléQBenet,'EEZAQCSIC,'Almería,'Spain' Mariano'Moreno'de'las'Heras,'IDAEAQCSIC,'Barcelona,'Spain' CONTENTS
73 Keynote lectures CONTENTS
80 Effect of organic amendments on the afforestation performance of plant species on degraded semiarid conditions Paloma Hueso González1, Juan Francisco Martínez Murillo1, José Damián Ruiz Sinoga1 1 Physical Geography and Land Management Research Group RNM279, Department of Geography, University of Málaga, Andalucía Tech, Málaga, Spain. [email protected]. Abstract Vegetation plays a fundamental role in soil conservation, so it is common to consider an increase in vegetation cover as one of the techniques to mitigate the effects of desertification in Mediterranean forest environments. There are two factors limiting the establishment and growth of seedlings in dry environments: (i) an excessive radiation and, (ii) the limited availability of water during the summer drought. During an afforestation plan, soil preparation is always necessary to reduce sapling mortality. The goal of this study was to analyze the effect of various organic amendments on soil according to chemical and hydrological properties, and to assess the effects of these parameters on an afforestal proposal under Mediterranean climate conditions. Five amendments were applied in an experimental set of plots: straw mulching (SM); mulch with chipped branches of Aleppo Pine (PM); TerraCotten hydroabsobent polymers (HP); sewage sludge (RU); sheep manure (SH) and control (C). Plots were afforested following the same spatial pattern, and amendments were mixed with the soil at the rate 10 Mg ha-1. Under bare soil conditions (C), most of mortalities occurred during the summer period of the first year. A substantial positive effect of SM, PM and HP on the survival rates have been clearly observed. Conversely, when the soil was amended with SH, the survival rate quickly decreased or remained more or less constant regarding to C. In this study, the lack of differences on chemical properties indicates that there may exist other reasons to justify the differences that were found in the pattern of vegetation. However, regarding to the hydrological properties some differences have been found. In C, soils were registered below the wilting point during 4 months a year, and therefore, in the area of water unusable by plants. These months were coinciding with the summer Mediterranean drought and can justify the high mortality found on plants. Conversely, in SM, PM and HP, soil moisture remained below the wilting point less period than C and, the plant available water was also higher. In these treatments, the survival sapling rates measured were the highest. SH showed water holding capacity slightly more limited than C. For this treatment, the survival sapling rates measured were the lowest. In conclusion, from a land management standpoint, the PM, SM and HP have been proved as a significant method to reduce sapling mortality rates during the Mediterranean summer drought. Key words Afforestation, organic amendments, soil properties, restoration, degraded areas. CONTENTS
81 The effect of restoration strategies on soil physical properties, hydrological behaviour and the plant growth in calcareous quarries under arid-semiarid climate Lourdes Luna1, Isabel Miralles2, Roberto Lázaro1, Nadia Vignozzi3, Sergio Pellegrini3, Albert Solé-Benet1 1 Estación Experimental de Zonas Áridas, CSIC, 04120-Almería, Spain 2 Georges Lemaître Earth Sciences Center, Université Catholique de Louvain, Louvain-La-Neuve, Belgium 3 CREA-ABP, Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria, Centro di Ricerca per l'Agrobiologia e la Pedologia, Firenze, Italy Abstract The addition of organic amendments and mulches are common soil restoration strategies in calcareous quarries, with proven benefits under sub-humid and semiarid environments. In this presentation both techniques were used in a quarry from SE Spain, in the climatic boundary arid-semiarid, and the results, four to six years after the experiment implementation, discussed. Sewage sludge from urban water treatment plant and compost from domestic organic wastes were the organic amendments. Siliceous fine gravel (GM) and woodchips (WM) were used as mulches. Nine experimental plots, 5 m x 15 m, were set in a two-way crossed design to test the two organic amendments, the two mulches, and the corresponding controls. Undisturbed natural soils around the quarry were used as soil quality reference. Soil aggregate stability was determined by two methods, wet sieving and drop test, and the soil hydrological behaviour (infiltration rate, wetting front, sediment production) by means of rainfall simulations (50 mm h-1 during 1h) over the experimental plots. Survival and growth of three autochthonous planted species (Anthyllis cytisoides, A. terniflora and Macrochloa tenacissima) were monitored at months 6, 18, 36 and 48 after plantation. The combination of organic amendments and mulches enhanced the soil aggregate stability compared to the non-amended substrates, but still far from the values of the natural, reference soil. Both types of organic amendments increased infiltration and decreased water erosion, but mulches contributed to either enhance runoff (GM) or increase infiltration (WM) though water did not reach the soil below the mulch. Plant growth was favoured by both organic amendments and especially by compost, which improved the physical soil properties. Conversely, mulches did not show effective, conclusive results. Therefore, the use of organic amendments should be encouraged in quarry soil restoration for its proven environmental benefits. Key words Aggregate stability, organic amendments, mulch, rainfall simulation. CONTENTS
82 Evaluation of surfactant seed coating to improve cover of turfgrass under deficit irrigation in amended wettable sands Mica McMillan1, Matthew Madsen2, Samira Daroub3, John Erickson3, Kimberly Moore3, Jerry Sartain3, John Cisar3, Stanley Kostka1 1 Aquatrols Corporation of America, NJ, USA. 2 Brigham Young University, Utah, USA 3 University of Florida, FL, USA. Abstract Lack of moisture retention on predominantly sand soils in golf course greens may reduce seed establishment. Water conservation in drought prone areas has also induced turfgrass managers to amend soils to enhance water retention to improve seed germination and cover. Our objective was to evaluate sand amendments and a new surfactant application technique to determine the best method for enhancing seed germination and growth under reduced water input. Two greenhouse studies were conducted at the Fort Lauderdale Research and Education Center in Florida, USA. A 100% sand (SAND), 90:10 sand:peat v/v (SP) and a 90:10 sand:calcined clay v/v (CC) were seeded with either uncoated perennial ryegrass (Lolium perenne var. unknown) or coated with a 10% alkyl-terminated block copolymer surfactant (SC) and placed under an irrigation regime of 2.5 mm of water every other day. To account for differences in seed weight, 2x the number of seed were sown in the uncoated treatment. Days to emergence (DTE) and percent cover (PC) were measured. Once established, dry downs were initiated and volumetric water (VWC) collected. SC did not significantly enhance DTE. PC was similar or significantly greater in SAND and SP treated with SC despite being sown with fewer seeds. VWC was greater in SAND and SP when sown with SC. Both PC and VWC results in CC were variable. Overall, SC enhanced percent cover and increased VWC and SP or CC yielded higher PC than SAND. Coating seeds with SC and sowing in peat or calcined clay amended sand may provide better establishment results in drought stricken areas. Key words Surfactant seed coating, peat, calcined clay, deficit irrigation. CONTENTS
83 An integrated approach to overcome soil limitations in restoration of arid ecosystems Miriam Muñoz Rojas1,2, Amber Bateman1,2, Todd E. Erickson1,2 , David. J. Merritt1,2 1 School of Plant Biology, The University of Western Australia, Crawley 6009, Western Australia, Australia 2 Kings Park and Botanic Garden, Botanic Gardens and Parks Authority, Fraser Avenue, Kings Park 6005, Western Australia, Australia Abstract Intensive land use and management, large scale disturbances such as extractive operations (e.g. mining), and global climate change have extensively contributed to degradation of arid ecosystems worldwide. Restoring these lands is particularly challenging due to limited rainfall, high temperatures, and soils with low nutrients level and decreased water holding capacity. Land degradation and altered environmental conditions such as changes in soil water availability, may significantly shift seedling recruitment or the composition and distribution of plant species from the pre-disturbed conditions. These limitations can be compounded by unfavourable edaphic conditions. Accordingly, understanding and improving soil physical, chemical and microbiological properties can be decisive for successful revegetation. Here we report on an integrated approach combining ecophysiological and hydrological measurements with analytical techniques and experimental and modelling methods to understand plant-soil-water relations and optimise vegetation establishment in restored arid environments. Specifically, we have assessed morphological and physiological plant responses and changes in soil physical, chemical and microbiological properties in reconstructed soils. These restored soils include blends of original topsoil and alternative materials in combination with different doses of organic and inorganic amendments. Here, we present our latest results obtained from laboratory and glasshouse experimental studies and field trials in the arid zone of Western Australia, and propose a set of soil quality indicators to assess functionality of restored soils. The methods used in our research can be effectively applied in a broad range of restoration projects in arid and semiarid environments. Key words Restoration seedbank initiative, mine rehabilitation, Pilbara, growth media, soil quality indicators, soil water retention. CONTENTS
84 Defining slope length and steepness factor for estimating soil loss in urbanizing mountainous landscapes Dara Park, Dhanuska Wijesinghe, David White, William Bridges Clemson University, Clemson, South Carolina, USA Abstract As mountainous regions become more urbanized, estimating soil loss is important for urban planning and natural conservation efforts, especially since more intense rainfall events have been occurring in recent years. The Revised Universal Soil Loss Equation is the most common way to predict soil erosion. However the model was developed for relatively flat agricultural fields. Limitations of the slope length and steepness factor (LS factor) does not allow for reliable estimates in more complex topography where water erosion is the main type of soil loss, and where with various landscape uses. While various model modifications to address this issue have been made, many fall short in either validation through ground-truthing slope length and steepness, have lower variability in length slopes and steepness, and or are too resource intensive (time and computer power to run models) to be utilized. To address this, PYTHON script was used to identify water flow pathways and R code was used to estimate the LS factors for two GIS parcel data sets (sub-catchment (large scale) and land cover (small scale)) in three watersheds of the Piedmont region of South Carolina, USA. Slope lengths and angles were ground-truthed to identify if model modifications were correct. The majority of slope length estimates based on land cover were within RUSLE restrictions (≤122m), whereas they were not when determined on the sub-catchment scale. Regardless of parcel data set used, the estimated slope angles were < 25%, which is the restriction for calculating RUSLE. Since land cover estimated lower LS factors, lower soil erosion rates were predicted when using this scale. This project identified that using land cover data is in most cases an appropriate size for determining the LS factor and estimating soil loss in urbanizing mountainous regions. Finally integrating PYTHON script to determine flow direction and R code to determine LS factors from polygons can reduce computing time and power in estimating soil loss. Key words RUSLE, soil loss, slope length, steepness factor. CONTENTS
85 Plant restoration after prescribed fires: testing the effect of seed provenance and seed predation in Mediterranean forest Javier Sagra, Pedro Antonio Alvarez-Plaza, Raquel Alfaro Sánchez, Manuel Esteban Lucas-Borja, Daniel Moya, Pablo Ferrandis, Jorge de las Heras Ibáñez Escuela Técnica Superior de Ingenieros Agrónomos y de Montes de Albacete, Universidad de Castilla La Mancha. Abstract Wildfires have an important influence in many different elements of the forest ecosystems. In order to reduce fire risk and occurrence, prescribed fires with low fire intensity have been widely used as a fuel reduction tool and silvicultural treatment in Mediterranean forest ecosystems. However, other than the fact that fire may alter microsite conditions, little is known about the impact of prescribed burning on natural regeneration or plant species renewal at the same time. Also, and after prescribed fires, some plant provenances may be more appropriated that other when ecosystem restoration is aimed. In this study, we compared the effects of prescribed burning on initial seedling recruitment of different seed provenances (P. pinaster and P. halepensis from Spanish dry and wet locations) after a low intensity prescribed fire was applied using a sowing experiment in 60 plots (30 burned and 30 control) set up in the Lezuza forest (Albacete, central-eastern Spain). Also, seed predation was evaluated since this is one of the most important factors limiting seedling recruitment. Different forest stand characteristics (slope, tree density, basal area and shrub/herbal cover) affecting each plot were measured. Our results showed that prescribed fires do alter initial seedling recruitment dynamics. Seed coming from dryer and warmer sites perform better in burned plots whereas seed from wetter and colder sites regenerates better in control areas. Seed predation was a really important factor in both burned and control plots. Understanding and balancing seed emergence and seedling survival in Mediterranean Pinus forests should help to improve prescribed burning plans with no debilitation of pine tree vitality or plant community persistence and aiming properly plant restoration. Key words Seed emergence, seeding survival, Mediterranean forest, prescribed fires, ecological restoration. CONTENTS
86 Long-term effect of afforestation and land abandonment on soil hydrological characteristics in semi-arid Spain Jeroen Zethof1, Erik Cammeraat2, Estela Nadal-Romero3 1 University of Amsterdam, Institute for Biodiversity and Ecosystem Dynamics (IBED), Amsterdam, Netherlands ([email protected]) 2 University of Amsterdam, Institute for Biodiversity and Ecosystem Dynamics (IBED), Earth Surface Science, Amsterdam, Netherlands ([email protected]) 3 University of Zaragoza, Department of Geography and Regional Planning, Environmental Sciences institute (IUCA), Zaragoza, Aragón, Spain ([email protected]) Abstract Land abandonment is common in Mediterranean landscapes and vegetation succession is hampered, as climatological conditions are not favourable. This makes their soils vulnerable for degradation and forestation projects have been conducted over the past 70 years with the aim to protect the landscape from degradation, although the effectiveness of these measures is not well known, especially on longer time scales. So far the focus has been on the effect of land abandonment, natural succession, or land use change on soil hydrology, but not by afforestation. More soil hydrological data is needed to model catchment response, as until now most assumptions that are made rely only on changes in agricultural land use (e.g. Bormann et al., 2007). The aim of this study was to link changes of soil chemical and physical parameters to observed changes in soil hydrological characteristics. Fieldwork has been carried out in Murcia, south-eastern Spain, to study the effects of land abandonment and afforestation on a wide range of soil quality indicators along a chronosequence, including two afforested areas (from the early ‘70s and 1993). The Pinus halepensis trees were planted in rows, for which the underlying calcrete was broken. Soil hydrological properties between the afforestation projects, abandoned agricultural plots of similar age, semi-natural vegetation and cereal crop fields were determined using a portable rainfall simulator. Furthermore, undisturbed soil samples were taken for further testing in the laboratory. As the natural vegetation is characterized by a spotted pattern of bare areas and trees, forming so-called “islands of fertility”, both bare and vegetation covered sub-sites were sampled. First results indicated important changes in soil physical and chemical properties. The afforested areas showed a strong enhancing effect on soil quality compared with secondary succession on abandoned fields. Despite similar levels of SOM in the older afforested sites, aggregate stability lacked behind in undisturbed plots. These changes in soil physical and chemical parameters closely linked to observed changes in soil hydraulic and hydrological properties. Key words Afforestation, land abandonment, soil hydrology, soil quality. References: Bormann, H., Breuer, L., Gräff, T., & Huisman, J. A. (2007). Analysing the effects of soil properties changes associated with land use changes on the simulated water balance: A comparison of three hydrological catchment models for scenario analysis. Ecological Modelling, 209(1), 29-40. CONTENTS
87 Session 2: Contributions presented as posters CONTENTS
88 Assessment of Libyan soil resources and degradation Gandura Abagandura, David White, William Bridges, Dara Park Clemson University, Clemson, South Carolina, USA Abstract Soil degradation is considered one of the most important factors limiting agricultural development in Libya, however no serious efforts have been taken to identify the distribution of soil degradation occurrence and type for the country. Limited existing soil texture, landscape features and degradation data from Libya’s five primary agricultural regions were assembled into one map allowing for summarization and model development of soil occurrence and type. Thirty-three percent of the total soil area of the primary agriculture regions is degraded. A logistic regression model that included slope and soil texture was determined to best predict soil degradation occurrence (P =0.0003, χ2 = 8.432, and Akaike Information Criterion = 34.02). Using the Leave-One-Field-Out validation approach, 62-82% of the model’s degradation occurrence predictions were correct. Using the model, 53.5 % of all of Libya was predicted to have degraded soils. Using existing data for the primary agricultural regions, the proportions of degradation type (salinization, water, and wind erosion) were determined to change across soil textures found in the primary agricultural regions (p < 0.001). Salinization was found in all textures except sand, which only was degraded by wind erosion. Knowing this relationship, a multinomial logistic regression model using the same variables from the logistic model was developed to determine soil degradation type for the remainder of the country. This model predicted that salinization was the primary type of soil degradation (46.4 %) in Libya, with water erosion and wind erosion only causing 6.4 % and 0.66 % of soil degradation, respectively. The empirical models can assist stakeholders in identifying where agriculture is most likely to be sustainable, and determine measures to counter further degradation of existing agricultural regions. The models can also be used for neighboring countries with similar climate and soils in North Africa. Key words Libya, soil resources, soil degradation, multinomial logistic regression analysis. CONTENTS
89 Hydrological soil behavior in Beni Chougrane Mountains (Algeria) Yahia Boukhari1, Marta Ginovart2, Antoni M.C. Verdú3, M. Teresa Mas3, Khalladi Mederbal4, Ramon Josa3 1 Research Laboratory for Biological Systems and Geomatics, University of Mascara, Mascara, Algeria 2Department of Mathematics, Universitat Politècnica de Catalunya, Barcelona, Spain 3Department of Agri-Food Engineering and Biotechnology, Universitat Politècnica de Catalunya, Barcelona, Spain 4Research Laboratory for Biological Systems and Geomatics, University of Tiaret, Tiaret, Algeria Abstract In northern Algeria, the physical degradation of land by water erosion is one of the most important forms of degradation. As is well known, vegetation plays an important role against water erosion. In the mentioned area the potential natural vegetation called maquis is currently characterized by a certain level of degradation often ranging between sparse cover and bare soil. In the Oued Fergoug watershed belonging to the Beni Chougrane Mountains (NW of Algeria), a trial was carried out with a mini rainfall simulator designed by ORSTOM to evaluate the runoff rate and the sediment load at experimental plot scale and in a situation of bare soil. A total of 18 rainfall simulations were carried out on regular square plots each measuring 1 m2. An experimental area located on the same parent material was selected on two different surface slope: 12.5% (7.12°) and 25% (14.04°) slopes. Nine plots were established in each area, distributed in a 3 by 3 matrix of plots, with 3 different rainfall intensities (30, 50 and 80 mm h-1), and 3 levels of initial soil moisture (dry, moist and very moist). In dry conditions the soils had not received rainfall for more than 25 days (soil moisture < 3% w/w). In moist and very moist states, rains of 10 mm h-1 intensity were applied to plots before the simulation. In moist conditions (near field capacity) the experiment was carried out 24 hours after rain application (soil water ranges around 29% w/w). In the very moist state (near saturation) the water content in the soil ranged from 32% to 35% w/w. In this case rainfall simulation was carried out 15 minutes after previous rain. The highest runoff values observed exceeded 0.50 mm min-1 and the maximum sediment load yield was 94.2 g L-1 per square meter. Summarizing, the intensity of rain is the main factor for runoff generation, independently of slope value and initial soil moisture. The only practice that is effective for protecting the soil against erosion is to provide protective plant ground cover. Vegetation ground cover is a crucial component in maintaining stable slopes and thus limiting soil losses. The different factors involved in this land degradation and the present success of some bioengineering techniques to obtain ground cover vegetation should be taken into account in this context. Moreover, rainfall simulations would be an adequate technique to evaluate the abovementioned restoration work. Key words ORSTOM rainfall simulator, Algeria, slope, rainfall intensity, initial soil moisture, contour strip-cropping. CONTENTS
96 Therefore, using a consortium of cyanobacteria to inoculate degraded soils seems to be a more promising strategy to restore soils than inoculating with individual species. Our results underline the benefits of cyanobacteria inoculation on biocrust development and the increase in SOC sequestration which could facilitate further plant cover establishment. Key words Restoration, cyanobacteria, biological soil crust, carbon fixation, semiarid. Acknowledgements: This work was supported by the Spanish National Plan for Research, Development and Innovation and including European Union of Regional Development Funds, under the RESUCI (CGL2014-59946-R) and CGL2013-44870-R research projects, the FPU predoctoral fellowship from the Educational, Culture and Sports Ministry of Spain and the foundation Tatiana Pérez de Guzmán el Bueno, under its predoctoral fellowship programme.
97 Understanding gully erosion to reduce reservoir sedimentation in North-West Ethiopia. The case of Koga catchment Amara Selamawit Damtew1,2, Saskia Keesstra1, Martine van der Ploeg1, Tammo Steenhuis2,3, Seifu Tilahun2 1Soil Physics and Land Management Group, Wageningen University, Wageningen, The Netherlands 2Faculty of Civil and Water Resources Engineering, Bahir Dar Institute of Technology, Bahir Dar University, Bahir Dar, Ethiopia 3Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, USA Abstract Gully erosion control is an important challenge the world is facing. Despite the immense on-site and off-site damages caused by gullies, studies on the process of gully and its management strategies in Ethiopian highlands are limited. This is especially true for low land gullies which form under different conditions and are caused by different processes than hillslope gullies. Therefore, this study will look into these processes at Koga watershed (mainly at the valley floor where gully expansion rate is found to be quite severe) located in the Blue Nile basin. The watershed drains to the Koga dam, Lake Tana, where the new Ethiopian great renaissance dam is now under construction. To make sure the water resource development activities are sustainable, insights are needed in the onsite effects of gullies and the influx of sediment these erosion features cause. The objective is to gain a better understanding on the process of gully formation and thereafter to find the best reclamation measures. Thus, in more detail the objectives of this research are: (1) A Review on the causes, controlling factors and existing management practices of gullies, (2) Quantifying long term gully changes using satellite imagery, aerial photograph and google earth, (3) Investigating the dominant mechanism of gully formation, (4) Measuring the impact of soil types and soil characteristics on the development and formation of gullies, and (5) Testing the effectiveness of integrated physical and biological gully reclamation measures. For this purpose a group of data on hydrological and metrological, soil hydrology and hydraulics, soil properties and types, aerial photograph and satellite imagery, drainage area characteristics of the gullies will be collected. Data analysis will be done by GIS and different statistical software. In this way a better understanding of the processes involved in the formation of low land gullies in the Koga catchment will gained. Finally, the aim is to set up a series of different gully reclamation measures to test the most effective gully prevention strategies, which will be used to give recommendations to catchment managers. Key words Gully, process, factor, reclamation, Koga. CONTENTS
98 SESSION 3 HYDROLOGICAL EFFECTS OF PLANT-SOIL COMPLEX FROM PATCH TO LANDSCAPE Conveners:& Lubomir'Lichner,'Institute'of'Hydrology'SAS,'Bratislava,'Slovakia' Erik'L.H.'Cammeraat,'Univ.'of'Amsterdam,'The'Netherlands' Andrea'Carminati,'GeorgQAugustQUniversity'of'Göttingen,'Germany'' Artemi'Cerdà,'University'of'Valencia,'Spain' CONTENTS
99 Keynote lectures CONTENTS
100 Combining mechanistic model with water stable isotopes for identifying root water fluxes Mathieu Javaux1,2, Félicien Meunier1, Jan Vanderborght2, Valentin Couvreur1, Harry Vereecken2, Youri Rothfuss2 1 Earth and Life Institute, Université catholique de Louvain, Belgium 2 IBG3 Agrosphere, Forschungszentrum Juelich GmbH, Germany Abstract Plant root water uptake and release are very important component of the terrestrial water cycle but hardly measurable. Water stable isotopic analyses have been used for decades to quantify water uptake sources. By confronting the hydrogen and oxygen isotopic compositions (δ2H and δ18O) of plant xylem water with the isotopic compositions of other potential water pools, authors could determine the relative contributions of these water pools to plant water uptake. The objectives of this presentation are twofold: first, review and compare the different methods to quantify water uptake distribution from stable isotope analyses and second, to demonstrate with the analysis of a controlled experiment how mechanistic models can help improve our knowledge on the root water uptake and release processes. In the model comparison study, we use classical methods to analyse virtual experiments and compare their results with an inverse modelling method using a mechanistic root water uptake model. This benchmarking illustrates how one can benefit from using process-based models to retrieve entire RWU profiles but also to gain crucial information on the dynamics of root and plant resistances to water flow. This comparison also allowed us to quantify the uncertainty associated with the different statistical methods. However, this method requires other variables to be measured (profiles of root length density, soil water content or soil water potential, and time series of transpiration flux) in addition to water isotopic composition, which might be difficult to obtain under field natural conditions. In a second stage we used this inverse modelling method to retrieve the water uptake and release profile of Ryegrass (Lolium multiflorum Lam.) grown under controlled experimental conditions in a rhizotron and subject to a non-uniform profile of soil water stable isotopes. We could demonstrate the release of water in shallow layer (hydraulic lift). The combined use of mechanistic models and stable water isotopes as tracers, and specific controlled experimental conditions not only bring information on the water uptake and release profile but also allow one to obtain information on the hydraulic parameters of the soil-plant systems. Key words Water stable isotopes, root water uptake, soil-plant atmosphere continuum. CONTENTS
101 The effects of land management on soil characteristics and hydrological connectivity: combining insights from the COST Action ES1306 Saskia Keesstra1,2, Artemi Cerdà1,3, Paulo Pereira4, Agata Novara5, João Pedro Nunes1,6, Rens Masselink1 1Soil Physics and Land Management Group, Wageningen University, Wageningen, The Netherlands 2 Civil, Surveying and Environmental Engineering, The University of Newcastle, Callaghan, Australia. 3 Soil Erosion and Degradation Research Group, Department of Geography, University of Valencia, Valencia, Spain. 4 Environment Management Laboratory, Mykolas Romeris University, Vilnius, Lithuania 5 Dipartimento dei Sistemi Agro-ambientali, University of Palermo, Italy 6 CESAM: Centre for Environmental and Marine Sciences, University of Aveiro, Portugal Abstract Agricultural management has distinct impacts on the properties and functions of the soil. Management strategies such as pesticides, ploughing, cover crops or mulching have distinct impacts on soil properties, ecosystem services and the related hydrological functioning of these areas. In addition, large areas in the Mediterranean are not managed at all anymore, since they were abandoned by farmers and encroached by natural vegetation. Agricultural management, or the lack of it, changes not only the hydrological functioning of the fields that are revegetated, but also the hydrology of the catchment these fields are part of. This is related to the connectivity of water transfer paths within catchments. Connectivity is a relatively new concept can be useful to understand the catchment system dynamics in terms of water and sediment budgets. However, quantifying connectivity is a challenge which is still largely ahead of us. Relating water and sediment transport processes from plot scale, to hillslope and catchment scale and Parameterizing models with these data is part of the work of the COST Action CONNECTEUR (ES1306). Within this scientific network we work on understanding how connectivity is useful as a concept, how we can measure and model it, and how this information can be used to develop management strategies to come to a more sustainable use of the landscape. Key words COST Action ES1306, connectivity, soil properties, water and sediment transfer. CONTENTS
102 Impact of plants on soil composition and transport processes in soils Radka Kodešová Czech University of Life Sciences Prague, Czech Republic Abstract It has been demonstrated by many studies that land use considerably modifies soil properties including soil structure and associated transport processes. Decomposition of organic material, i.e. different vegetation litter (grass, leaves or needles from trees etc.), leads to different soil-pore composition and consequently to different soil hydraulic properties (i.e. soil water retention and hydraulic conductivity curves). Micromorphological images of thin soil sections for instance showed that decomposition of grass parts resulted in larger and more compact round clusters, which had larger retention ability in comparison to those under the spruce forest. Micro-morphological images and laboratory and field measurements of hydraulic properties also documented that plant parts decay and roots under the permanent grass cover considerably improved soil aggregation and hydraulic properties of the Haplic Luvisol and Haplic Cambisol in comparison to those at the arable land. However, plant roots strongly influence also soil structure and associated properties of arable soils causing their temporal variability, which was for shown instance for the Greyic Phaeozem, Haplic Luvisol and Haplic Cambisol. Roots may cause uneven water and solutes infiltration at the surface and even non-equilibrium water flow and tracer transport within the soil profile, which was documented for these three soil types at the macroand micro-scale. Important plant function influencing soil hydrology is root water and solute uptake. Soil structure modification and root-uptake depends on root structure (i.e. depth, density, hierarchy etc.). For instance definition of vertical and horizontal root distribution for wheat and barley obtained using different techniques resulted in different simulated root water uptakes. Solute uptake is in addition affected by its characteristics and behavior in soilwater system (i.e. size of the molecule, sorption affinity on soil constitutes etc.) and ability of different plant to extract particular solute from soils (described in study employing three pharmaceuticals, three soils and five plants). Key words Soil structure, micromorphological images, soil hydraulic properties, non-equilibrium water flow, roots, solute transport. CONTENTS
103 Relating the effects of soil hydrophobicity at atomic, molecular, core and national scales Peter Matthews2, Geertje van Keulen1, Stefan Doerr3, Lewis Francis1,4, Martin Swain5, Ed Dudley1, Richard Whalley6, Ingrid Hallin2, S. Andrea Gazze1,4, Gerry Quinn1, Kat Sinclair1, Tom Delmont7, Rhys Ashton6 1 Institute of Life Science, Medical School, Swansea University, Swansea, Wales, UK 2 School of Geography, Earth and Environmental Sciences, Plymouth University, Plymouth, UK 3 Department of Geography, College of Science, Swansea University, Swansea, Wales, UK 4 Centre for NanoHealth, Medical School, Swansea University, Swansea, Wales, UK 5 Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, Wales, UK 6 Sustainable Soil & Grassland Systems, Rothamsted Research, Harpenden, UK 7 University of Chicago Medical Centre, Chicago, USA Abstract The detrimental impacts of soil hydrophobicity include increased runoff, erosion and flooding, reduced biomass production, inefficient use of irrigation water and preferential leaching of pollutants. Its impacts may exacerbate flood risk associated with more extreme drought and precipitation events predicted with UK climate change scenarios. The UK’s Natural Environment Research Council (NERC) has therefore funded a major research programme to investigate soil hydrophobicity over length scales ranging from atomic through molecular, core and landscape scale. This presentation gives an overview of the findings to date. The programme is predicated on the hypothesis that changes in soil protein abundance and localization, induced by variations in soil moisture and temperature, are crucial driving forces for transitions between hydrophobic and hydrophilic conditions at soil particle surfaces. Three soils were chosen based on the severity of hydrophobicity that can be achieved in the field: severe to extreme (Cefn Bryn, Gower, Wales), intermediate to severe (National Botanical Garden, Wales), and subcritical (Park Grass, Rothamsted Research near London). The latter is already highly characterised so was also used as a control. Hydrophobic/ hydrophilic transitions were measured from water droplet penetration times. Scientific advances in the following five areas will be described: (i) the identification of these soil proteins by proteomic methods, using novel separation methods which reduces interference by humic acids, and allows identification by ESI and MALDI TOF mass spectrometry and database searches, (ii) the examination of such proteins, which form ordered hydrophobic ridges, and measurement of their elasticity, stickiness and hydrophobicity at nanoto microscale using atomic force microscopy adapted for the rough surfaces of soil particles, (iii) the novel use of a picoliter goniometer to show hydrophobic effects at a 1 micron diameter droplet level, which avoids the averaging over soil cores and particles evident in microliter goniometry, with which the results are compared, (iv) measurements at core scale using water retention and wicking experiments, and (v) the interpretation, integration and upscaling of the results using a development of the PoreXpert void network model, a significant advance on the Van Genuchten approach. An explanation will also be given as to how the results will be incorporated into the JULES hydrological model of the UK Meteorological Office, used to predict flooding for different soil types and usage. CONTENTS
104 Key words Soil water repellency, switching, across scales: molecular-nano-core-landscape.
105 Contributions presented in oral form Sub-session 3-1. Biophysical interactions between soil and roots. Soil water repellence Converners:& Andrea'Carminati,'GeorgQAugustQUniversity'of'Göttingen,'Germany' Erik'L.H.'Cammeraat,'Univ.'of'Amsterdam,'The'Netherlands CONTENTS
112 Non-invasive analysis of root-soil interaction using complementary imaging approaches Christian Tötzke1, Sabina Haber-Pohlmeier2, Andreas Pohlmeier3, Nicole RudolphMohr1, Nikolay Kardjilov4, Eberhart Lehmann5, Sascha E. Oswald1 1 Institute of Earth and Environmental Science. University of Potsdam, Potsdam, Germany 2 Institute for Macromolecular Chemistry. RTWH Aachen, Aachen, Germany 3 Institute of Bioand Geoscience. Research Center Jülich, Jülich, Germany 4 Institute of Applied Materials. Helmholtz Center for Materials and Energy, Berlin, Germany, 5 Neutron Imaging and Activation Group. Paul Scherrer Institute, Villigen, Switzerland Contact: [email protected] Abstract Plant roots are known to modify physical, chemical and biological properties of the rhizosphere, thereby, altering conditions for water and nutrient uptake. We aim to capture the dynamic processes occurring at the soil-root interface in situ. A combination of neutron (NI), magnetic resonance (MRI) and micro-focus X-ray tomography (CT) is applied to monitor the rhizosphere of young plants grown in sandy soil in cylindrical containers (Ø 3 cm). A novel transportable low field MRI system is operated directly at the neutron facility allowing for combined measurements of the very same sample capturing the same hydro-physiological state. The combination of NI, MRI and CT provides three-dimensional access to the root system in respect to structure and hydraulics of the rhizosphere. The high spatial resolution of neutron imaging and its sensitivity for water is exploited to analyze the 3D architecture of the root system and the three-dimensional water content in the immediate root vicinity and bulk soil. MRI can yield complementary information about the mobility of water, which can be bound in small pores or in the polymeric network of root exudates (mucilage layer). Additional CT measurements provide information on the pore structure of soil, which is affected by the mechanical interaction of roots and soil, e.g. soil compaction or formation of cracks and macropores. We co-register the NT, MRI and CT data to integrate the complementary information into an aligned 3D data set. This allows, e.g., for co-localization of compacted soil regions or cracks with the specific local soil hydraulics, which is needed to distinguish the contribution of root exudation from mechanical impacts when interpreting altered hydraulic properties of the rhizosphere. Differences between rhizosphere and bulk soil can be detected and interpreted in terms of root growth, root exudation, and root water uptake. Thus, we demonstrate that such a multi-imaging approach can be used as powerful tool contributing to a more comprehensive picture of the rhizosphere. Key words Dynamics of soil-root interface, neutron, magnetic resonance, micro-focus X-ray tomography, soil water content and mobility, soil pore structure CONTENTS
113 Soil CO2 fluxes affected by seasonal changes in soil water repellency Emilia Urbanek Department of Geography, College of Science, Swansea University, Swansea, UK Abstract Soil water repellency (SWR) is a seasonally variable phenomenon controlled by moisture and simultaneously regulating the infiltration, distribution and conductivity of water in the soil. Water availability is vital for biological processes in soil including the decomposition of soil organic matter by microorganisms. The microbial respiration is the main contributor to the CO2 fluxes from soil therefore it has been hypothesised that under water repellent conditions the microbial activity decreases due to water stress resulting in lower CO2 fluxes from soil. The hypothesis has been tested under field conditions by monitoring CO2 fluxes, soil water repellency, moisture and temperature for 3 consecutive years at 2 sites (grassland and pine forest) in East Anglia, UK. High seasonal variability in soil water repellency have been observed at both investigated sites with extreme (WDPT >3600s) to moderate (WDPT 60-3600s) SWR persisting for most of summer and early autumn periods. On most sampling occasions the severity of water repellency was variable; only on few instances soil had uniform WDPT values for all subsamples. The high spatial variability in WDPT values linked closely with higher deviations in soil water contents. The response of CO2 fluxes to seasonal changes in soil temperature, moisture content and SWR was evident with temperature affecting the CO2 emissions to great extent. Unexpected results have been observed for the CO2 fluxes under SWR conditions. SWR indeed reduced CO2 fluxes but only under uniform extremely water repellent state, while under variable severity of SWR the overall CO2 fluxes have significantly increased. The main conclusion of the study is that the spatial variability of SWR could enhance the microbial activity in the ‘hot-spots’ leading to overall higher CO2 fluxes from soils. Key words Soil water repellency, CO2 flux, hydrophobicity, preferential flow, gas exchange. CONTENTS
114 Sub-session 3-2. Hydrology of vegetation-soil complex Conveners: Lubomir'Lichner,'Institute'of'Hydrology'SAS,'Bratislava,'Slovakia' Saskia'Keesstra,'Wageningen'University,'The'Netherlands' ' ' CONTENTS
115 Application of minidisk infiltrometer to estimate soil water repellency Vicenzo J. Alagna1, Massimo Iovino1, Vicenzo J. Bagarello1, Jorge Mataix-Solera2, Ľubomír Lichner3 1 Dipartimento di Scienze Agrarie e Forestali, Università degli Studi di Palermo, Palermo, Italy 2 Departamento de Agroquímica y Medio Ambiente, Universidad Miguel Hernández, Elche, Spain 3 Institute of Hydrology, Slovak Academy of Sciences, Bratislava, Slovak Republic Abstract Soil water repellency (SWR) reduces affinity of soils to water resulting in detrimental implication for plants growth as well as for hydrological processes. During the last decades, it has become clear that SWR is much more widespread than formerly thought, having been reported for a wide variety of soils, land uses and climatic conditions. The repellency index (RI), based on soil-water to soil-ethanol sorptivity ratio, was proposed to characterize subcritical SWR that is the situation where a low degree of repellency impedes infiltration but does not prevent it. The minidisk infiltrometer allows adequate field assessment of RI inherently scaled to account for soil physical properties other than hydrophobicity (e.g., the volume, connectivity and the geometry of pores) that directly influence the hydrological processes. There are however some issues that still need consideration. For example, use of a fixed time for both water and ethanol sorptivity estimation may lead to inaccurate RI values given that water infiltration could be negligible whereas ethanol sorptivity could be overestimated due to influence of gravity and lateral diffusion that rapidly come into play when the infiltration process is very fast. Moreover, water and ethanol sorptivity values need to be determined at different infiltration sites thus implying that a large number of replicated runs should be carried out to obtain a reliable estimate of RI for a given area. Minidisk infiltrometer tests, conducted under different initial soil moisture and management conditions in the experimental sites of Ciavolo, Trapani (Italy) and Javea, Alicante (East Spain), were used to investigate the best applicative procedure to estimate RI. In particular, different techniques to estimate the water, Sw, and ethanol, Se, sorptivities were compared including i) a fixed 1-min time interval, ii) the slope of early-time 1D infiltration equation and iii) the two-term transient 3D infiltration equation that explicitly accounts for the effects of gravity and lateral expansion. According to Pekárová et al. (2015), the combination of all the ethanol and water sorptivities was used to calculate an aggregated repellency index, RIa, that accounts for the influence of spatial variability. Alternatively, the plot of the water cumulative infiltration vs. square root of time, exhibiting a clear “hockey-stick-like” shape, was used to estimate a single-test repellency index, RI*, that overcomes the limitations of the traditional approach given that information on both the hydrophobic and the wettable states of soil are gathered from a unique infiltration test. The mean RI values were affected by the technique used to estimate Sw and Se. In particular, the choice of a fixed time interval lead to overestimation of RI up to a factor of 3.2 as compared with the other techniques. The RIa yielded unbiased estimations of the mean RI values and also allowed to quantify the variability of SWR within a given area. A statistically significant relationship was found between RI* and RI but also between RI* and the water retention cessation time, that is the time hydrophobic turns into wettable soil, thus indicating that RI* is potentially able detect both the degree and the persistence of SWR. CONTENTS
116 Key words Infiltration, soil water repellency, minidisk infiltrometer, repellency index. References: Pekárová P., Pekár J., Lichner Ľ. 2015. A new method for estimating soil water repellency index. Biologia, 70 (11):1450-1455.
117 New insights of sediment connectivity and vegetation in contrasting Mediterranean catchments: an essential ecogeomorphological framework Joan Estrany1, Aleix Calsamiglia1, Julián García-Comendador1, Josep Fortesa1, Bartomeu Alorda2, Maurici Ruiz-Pérez3, Jorge Gago4 1 Department of Geography. University of the Balearic Islands, Palma, Mallorca, Spain 2 Department of Physics. University of the Balearic Islands , Palma, Mallorca, Spain 3 Service of GIS and Remote-Sensing. University of the Balearic Islands , Palma, Mallorca, Spain 4 Department of Biology. University of the Balearic Islands , Palma, Mallorca, Spain Abstract Soil-plant interactions are one of the most interesting challenges to let us understand the complex relationship between the biotic and abiotic components of the ecosystems. Connectivity, defined as the transfer of matter between two different landscape compartments, can be used as a synthetic approach linking ecology, hydrology and geomorphology. Little research explicitly recognizes the different scales over which hydrological connections take place and its relationship with plant communities’ behaviour. New technologies and methodologies with improved spatial and temporal resolution represent a good opportunity to monitor the vegetation evolution as well as the erosion and transport processes across different spatial and temporal scales. The remote sensing approaches on geosciences research has seen during the last two decades a revolution in topographic data measurement, with both a considerable increase in the rate at which it is possible to acquire precise, three-dimensional terrain data and the simplicity with which related methods can be applied. In conjunction with remote sensing technologies, there is a possibility to develop hybrid approaches using developments in a range of technologies together to achieve a better approximation of processes. Therefore, geomorphological models that explicitly include biotic effects are necessary to explore how intrinsically small-scale biotic processes can influence the form of entire landscapes, and to determine whether these processes create a distinctive topography. A previous survey developed by the research team showed a local significant relationship between the sediment connectivity index and the plant vigour through the Blue Normalized Vegetation Index (BNDVI) using high-resolution imagery obtained from an Unmanned Aerial Vehicle (UAV) in a micro-catchment. We pretend to up-scale this relationship using satellite imagery from a range of contrasting Mediterranean catchments as typical examples of drylands ecosystems. The utility of this methodology to study the local relationship between sediment connectivity and vegetation patterns will be further discussed for the assessment of ecosystem dynamics and management. Key words Ecogeomorphology, soil-plant interactions, plant community, dryland ecosystems. CONTENTS
118 Concepts, applications, and opportunities of biohydrology in turfgrass ecosystems Michael Fidanza1, John Cisar2 1 Division of Science, Berks Campus, Pennsylvania State University, Reading, PA, USA. 2 Retired from University of Florida, Ft. Lauderdale, FL, USA; currently Cisar Turfgrass Services, Plantation, FL, USA. Abstract Biohydrology encompasses cross-disciplinary scientific inquiry in the areas of ecology and the environment, hydrology, biology, plant and soil sciences, and more. Turfgrass science is an excellent example of the complex role of plants and soils in biohydrological interactions. Turfgrass is a principal component in lawns and landscapes, parks and recreation, conservation land and roadsides, athletic pitches and golf courses, sod farms, and more. In turfgrass ecosystems, the complex interactions of soil biological, chemical, and physical properties occur at the spatial and temporal scale. Biohydrology research in turfgrass science includes investigations of water management and water conservation, water quality, irrigation and the use of soil surfactants to improve water use efficiency, soil water repellency and the use of soil surfactants to ameliorate soil hydrophobicity, soil moisture and environmental monitoring, pest management, plant ecology, plant pathology, plant physiology, the role of plant nutrition and biostimulants on phytobiomes, and sustainability. Managed turfgrass ecosystems are not evaluated in terms of yield like agricultural crops, rather qualitative and quantitative measurements are used to determine aesthetic value, function, and performance. Results of biohydrology research of turfgrass ecosystems have contributed greatly to fundamental scientific knowledge of turfgrass science, which therefore has translated to sustainable turfgrass management solutions for the practitioner. Key words Sustainable, turf, turfgrass. CONTENTS
119 Drought enhances net CO2 release via vadose zone ventilation in a semiarid grassland of southern Spain Ana López-Ballesteros1,2, Penélope Serrano-Ortiz2,3, Andrew S. Kowalski2,4, Enrique P. Sánchez-Cañete2,5, Russel L. Scott6, Francisco Domingo1 1 Departamento de Desertificación y Geo-ecología, Estación Experimental de Zonas Áridas (CSIC), Almería, Spain 2 Instituto Interuniversitario de Investigación del Sistema Tierra en Andalucía (IISTA-CEAMA), Granada, Spain 3 Departamento de Ecología, Universidad de Granada, Granada, Spain 4 Departamento de Física Aplicada, Universidad de Granada, Granada, Spain 5 Biosphere 2, University of Arizona, Tucson, Arizona, USA 6 Southwest Watershed Research Center (ARS, USDA), Tucson, Arizona, USA Abstract Recent research has highlighted the important role of arid and semiarid ecosystems in the global carbon (C) cycle. However, investigation of the biophysical processes involved is still necessary in order to fully understand how drylands behave and to determine the main factors affecting their C balance. In the present study, we explore the potential biological and abiotic processes that may compose the net CO2 exchange in a semiarid grassland in SE Spain by means of eddy covariance measurements registered over six hydrological years (2009-2015). Results point out the great importance of subterranean ventilation, an advective transport process responsible for net CO2 release from the vadose zone to the atmosphere, especially during drought periods and under high-turbulence conditions. Accordingly, extreme annual CO2 release was measured over the whole study period, on average 230 g C m-2 year-1, which was very unlikely to correspond to variations of in situ organic C pools given the low concurrent biological activity. Additionally, contrary as expected, CO2 molar fraction within the vadose zone reached its maximum during the dry season at 1.5 m depth below the surface, and showed sustained high values at 0.15 m depth. Therefore, we hypothesize, based on published literature, that potential origins of the released CO2 can be (i) geological CO2 degassing or (ii) subterranean translocation of CO2 in both gaseous and aqueous phases. However, future research is needed in order to understand how CO2 transport and production processes interact and modulate the C balance of semiarid and arid regions through the interaction between atmosphere, biosphere, pedosphere, vadose and saturation zones. Overall, the present study exposes how subterranean ventilation and hydrogeochemistry can improve the interpretation of the terrestrial C cycle and how it will be perturbed by climate change. Key words Net CO2 flux, drylands, advective transport, eddy covariance, non-local CO2 source, vadose zone, pressure pumping. CONTENTS
120 Application of soil wetting agents with urea fertilizer increases plant uptake of nitrogen and reduces nitrogen leaching Dara Park, Gandura Abagandura, William Bridges, Kristen Brown Clemson University, Clemson, South Carolina, USA Abstract Increasing nitrogen (N) plant uptake efficiency may result in less nitrogen susceptible to leaching and potential contamination in to surrounding environments as well as reduced N inputs needed. Soil wetting agents have been previously documented to increase water infiltration and enhance water uniformity throughout the soil profile. Applying a wetting agent along with a fertilizer may assist in more fertilizer available to the plant rootzone. To investigate this theory, common bermudagrass pelts were trimmed and placed on leaching columns filled with one of three soils (sand, sandy loam and a sandy clay loam). Once pelts were established, 15N labeled urea was applied with one of three wetting agent treatments (NONE = no wetting agent, just water, SWA1 = DGlucopyranose, oligomeric, decyl octyl glycoside, and SWA2 = 10% an oleic acid esters of coblock polymers). An unfertilized control irrigated with water for determining background 15N was also replicated in each soil. Each treatment combination was replicated five times and the greenhouse experiment was repeated. Grass quality and density, leachate volume, and volumetric water content were determined over a 28d period following application. At experiment termination 15N in soil (%RFN), plant (% UFN) and leachate were determined and used to develop a 15N mass balance. The split plot repeated measure design was tested using a two-way ANOVA with main effects and interactions tested at P = 0.05. Experiment was not found as a significant main effect and thus data was pooled over the two experiments. Soil was found to be a significant main effect and thus results are discussed for each soil separately. On six of the 12 measurement events the sandy loam soil treated with the SWA2 had greater volumetric water content than SWA1, which was greater than NONE. This trend was also found in the sandy clay loam for five of the 12 measurement events. Treatment differences were less apparent in the sand soil. Bermudagrass grown on the sandy loam and sandy clay loam soils had greater %UFN when either SWA was applied compared to bermudagrass receiving the labeled urea alone. SWA did not influence %UFN in the sand soil. Regardless of soil texture, similar %RFN in the soil was determined for all SWA treatments. Applying a surfactant with urea can increase bermudagrass N uptake efficiency and reduce potential N leaching. Key words Soil wetting agent, nitrogen isotope, nitrogen uptake efficiency, 15N, bermudagrass. CONTENTS
121 Electrical capacitance measurement for monitoring root growth and activity in soil Kálmán Rajkai, Tünde Takács, Krisztina R. Végh, Anna Füzy, Imre Cseresnyés Institute for Soil Sciences and Agricultural Chemistry, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary Abstract Measurement of electrical capacitance (EC) is a potential method to assess root system size in situ. The EC detected in plant–soil systems is proportional to the actual uptake activity of the root system, indicating plant responses to the environment. The influence of various environmental factors on root growth was investigated in pot experiments. We showed in situ the growth-impeding effect of total herbicide treatment, drought stress and weed competition in maize. We found the method suitable for detecting the enhanced rhizosphere activity of maize colonized by arbuscular mycorrhizal fungi. In this case, the increased host’s root EC was due to the higher water and nutrient uptake activity of root associated with external hyphae. The technique was successfully applied for monitoring the cultivar-specific differences and the phenological changes in root water uptake using several crops. In our research we examine possibilities for developing the method, focusing mainly on selection of the efficient measuring current frequency and significance of the detectable capacitive loss to improve the authenticity of measurement data. A comprehensive investigation is in progress currently to quantify the relationship between the water content of growth medium and EC detected. This awareness offers us an opportunity to apply the method for continuous monitoring of root activity under real field conditions (in soil with changing moisture content). The method may be of interest for future applications; it can partially substitute the intrusive and time-consuming techniques, or may be combined with other physiological investigation methods. It can play a role in applied agricultural research including breeding programs aiming to produce crop cultivars with improved performance under stressed conditions (e.g. drought or nutrient limitation), or in detection of plant responses to changing environment. Indicating the plant status, EC detects soil hydrology or soil environment in a wider scale. Mitigation of the influence of some external factors affecting capacitance measurements is an important objective of our future research. Key words Environmental stress, in situ root investigation, plant response, rhizosphere activity, root electrical capacitance. CONTENTS
128 The use of straw mulches to reduce the soil losses in citrus plantations Artemi Cerdà1,2, Saskia Keesstra2, María Burguet Marimon1, Jesús Rodrigo Comino3,4, Andrés García Díaz5, Agata Novara6, Paulo Pereira7 1 Soil Erosion and Degradation Research Group, Department of Geography, University of Valencia, Valencia, Spain. [email protected] 2 Soil Physics and Land Management Group, Wageningen University, Wageningen, The Netherlands 3 Department of Physical Geography, Trier University, Trier, Germany. 4 Instituto de Geomorfología y Suelos, Málaga University, Málaga, Spain 5 Applied Research Department, IMIDRA, Finca El Encín, Alcalá de Henares, Spain. 6 Department of Scienze Agrarie e Forestali – University of Palermo, Palermo, Italy. 7 Environmental Management Centre, Mykolas Romeris University, Vilnius, Lithuania Abstract Chemically managed sloping citrus plantations result in high erosion rates. The use of catch crops or weeds is efficient but is usually rejected as a management option by farmers due to the tradition to avoid other plants than the crop in the orchards. The use of straw mulch is more welcomed by farmers, but little is known about the impact of straw and the cover (doses) that should be applied. A laboratory research was conducted under different straw mulch covers to reduce soil and water losses in 0.5 m2 plots under 43 mm h-1 rainfall intensities during one hour. Seven straw covers were selected: 0, 5, 15, 25, 50, 75 and 100 % and five experiments were carried out at each cover. The results show that the erosion rates were 9.43 Mg ha-1 y-1 on bare soils, and that a cover of 5 % reduced the soil losses to 5.34 Mg ha-1 y-1, and the cover of 15 % to 3.23 Mg ha-1 y-1. The 25 % cover contributed to 1.54 Mg ha-1 y-1 and 50 % cover to 1.05 Mg ha-1 y-1. The cover of 75 and 100 % cover reduced the soil losses to 0.89 Mg ha-1 y-1 and 0.76 Mg ha-1 y-1, respectively. The results show that a cover of 25 % reduces the soil losses by one order of magnitude at the scale of 1 m length. Increasing the straw cover increase the expenses but does not result in a relevant reduction in soil losses. Key words Citrus, erosion, straw, mulches, management. Acknowledgements: The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 603498 (RECARE project). CONTENTS
129 Microorganisms and physical-chemical properties of summer snow patches in Slovak mountains Miriam Hanzelová1, Zuzana Perháčová2, Jaroslav Škvarenina1 1 Department of Natural Environment, Faculty of Forestry, Technical University in Zvolen, Slovak Republic 2 Department of Biology and General Ecology, Faculty of Ecology and Environmental Sciences, Technical University in Zvolen, Slovak Republic Abstract Snow cover plays an important role in the climate, hydrological and ecological systems not only in the polar area but also in other regions. Despite the fact that it is one of extremely cold environment it provides space for development microbial community. The High Tatras Mts., the highest mountains of the Carpathians, were the most studied mountain area in the Europe in terms of cryoflora. Currently in Slovakia absent actual knowledge about microorganisms linked to the snow and their living conditions. The aim of the study is investigation of the occurrence and environment of snow microbiota in high mountains of Slovakia (High Tatras, Low Tatras, Veľká Fatra Mts., Malá Fatra Mts.). In samples of taken snow dominated cf. Chloromonas nivalis which is considered as cosmopolitan species. We recorded only occasionally the colourful surface of snow patches caused by the snow algae. Similarly, in snow samples we also identified individuals of cyanobacteria, microscopic fungi, ciliates, rotifer and tardigrade. Recorded daily running of air temperature above the snow patches with the appearance of sub-zero temperatures in late summer and high intensity of PAR can cause stress on the development of microbiota in the snow. The pH values were slightly acidified, in some cases neutral. The conductivity of water from melted snow had high coefficient of variation. We recorded values characteristic for distilled water until values 160 µS.cm-1. Chemical analysis determined a significant content of N-NO3, N-NH4 a P-PO4. We explained it by the possible leach out of organic matter stored on the snow surface mixed with water from melted snow. This paper yield information about occurrence of cryoseston in the mountains of Slovakia, but also there is another researcher challenges related to examine the microbial community living in one of the most extreme conditions on the Earth. Key words Cryoseston, snow algae, snow patches. CONTENTS
130 Quantification of soil macropores under alpine vegetation using computed tomography in the Qinghai Lake watershed, NE Qinghai-Tibet Plateau Xia Hu1, 2, Zong-Chao Li1, 2 1 Key Laboratory of Environmental Change and Natural Disaster of Ministry of Education, Beijing Normal University, Beijing, China. Email: [email protected]du.cn. 2 Academy of Disaster Reduction and Emergency Management, Beijing Normal University, Beijing, China. Abstract The importance of soil macropores as preferential pathways for water, air, and chemical movement in soils has long been recognized. However, studies concerning macropores of soils under alpine vegetation remain scarce. The objective of this study was to quantify the architecture of soils beneath Alpine Kobresia meadow, Achnatherum splendens steppe, and Potentilla fruticosa shrubs using computed tomography in the Qinghai Lake Watershed of northeastern Qinghai-Tibet Plateau. Nine soil cores (0–50 cm deep) were taken at three sites with three replicates. At each site, the three cores taken were scanned with a GE HISPEED FX/I Medical Scanner. The number of macropores, macroporosity, and macropore equivalent diameter within the 50-cm soil profile were interpreted from X-ray computed tomography, to analyze soil architecture. The results indicated that soils under Achnatherum splendens steppe and P. fruticosa shrubs had greater macroporosity, and developed deeper and longer macropores than those in the other vegetation types. For the Alpine Kobresia meadow, macropores were distributed mainly in the 0–100-mm soil layer, while they were distributed in the 0–200mm soil layer for A. splendens steppe and in the 0–200-mm soil layer for P. fruticosa shrub. The large number of macropores found in the soil surface layer under Alpine Kobresia meadows can be attributed to “mattic epipedon”. The large number of macropores found in soil under A. splendens steppe and P. fruticosa shrubs can be attributed to greater root development. Soil hydraulic conductivity was significantly greater for A. splendens steppe and P. fruticosa shrub (great macroporosity) than for Alpine Kobresia meadow (small macroporosity). Key words Alpine Kobresia meadow, achnatherum splendens steppe, potentilla fruticosa shrub, vegetation, soil architecture, macropore, root, mattic epipedon. CONTENTS
131 Water dynamics in the rhizosphere - a new model of coupled water uptake and mucilage exudation Eva Kroener1, Maire Holz2, Mutez Ahmed2, Mohsen Zarebanadkouki2, Marco Bittelli3, Andrea Carminati2 1 Department of Environmental and Soil Chemistry, Universitaet Koblenz-Landau, Landau, Germany 2 Division of Soil Hydrology, Georg-August-University Göttingen, Göttingen, Germany 3 Department of Agricultural Sciences, University of Bologna, Bologna, Italy. Abstract The flow of water from soil to plant roots is affected by the narrow region of soil close to the roots, the so-called rhizosphere. The rhizosphere is influenced by mucilage, a polymeric gel exuded by roots that alters the hydraulic properties of the rhizosphere. Here we present a model that accounts for: (a) an increase in equilibrium water retention curve caused by the water holding capacity of mucilage, (b) a reduction of hydraulic conductivity at a given water content due to the higher viscosity of mucilage and (c) the swelling and shrinking dynamics by decoupling water content and water potential and introducing a non-equilibrium water retention curve. The model has been tested for mixtures of soil and mucilage and we applied it to simulate observations of previous experiments with real plants growing in soil that show evidences of altered hydraulic dynamics in the rhizosphere. Furthermore we present results about how the parameters of the model depend on soil texture and root age. Finally we couple our hydraulic model to a diffusion model of mucilage into the soil. Opposed to classical solute transport models here the water flow in the rhizosphere is affected by the concentration distribution of mucilage. Key words Mucilage, root water uptake, hydraulic properties. CONTENTS
132 Evaluation of drought response of four coniferous species based on the analysis of their radial stem growth Adriana Leštianska, Katarína Merganičová, Katarína Střelcová, Radoslav Kandrík Faculty of Forestry, Technical University in Zvolen, Department of Natural Environment, Slovakia ([email protected]) Abstract! The contribution deals with the dynamics of stem circumference changes and stem water deficit of four coniferous species: Scotch pine (Pinus sylvestris L.), Norway spruce (Picea abies Karst), European larch (Larix decidua Mill.) and Silver fir (Abies alba Mill.) during the growing season of the year 2015 and the drought period that occurred during the growing season. The individual tree species are located at four different parts of the Borová hora Arboretum (Zvolen valley, Slovakia) which has a character of uplands with altitudes from 290 m a.s.l. to 377 m a.s.l. The species originate from different regions of Slovakia (larch, fir), Ukraine (pine) and Russia (spruce, pine) characterised by different environmental conditions (climate, soil, bedrock). Stem circumference was continuously measured and recorded at 20 minute intervals with digital dendrometers DRL26 which were installed on five trees per species at the beginning of the growing season 2015. The air temperature average in the growing season of the year 2015 was extremely above-average compared to the longterm average (1961–1990). Although the precipitation total of the growing season was normal, we recorded significant intra-seasonal fluctuations of precipitation. We determined one drought period (39 days; from 10 June to 19 July 2015) when soil water potential fell below -1.0 MPa and which was bounded by days with heavier precipitation events. The analysis of variance of the annual radial increments showed a significant effect of tree species on the annual stem circumference change. The regression analysis of the daily mean radial fluctuations in the drought period revealed that P. sylvestris and L. decidua reacted to the drought period by continuous stem contraction, whereas the stem circumferences of N. spruce and A. alba were slightly increasing during the drought. Daily stem water deficit (∆W) was extracted from the daily mean stem circumference changes. Pearson correlation statistics (r) was calculated between daily time series of environmental variables (global radiation, precipitation, relative air humidity, vapour pressure deficit, air and soil temperature, soil water potential) and ∆W for the period April–October and the drought period. During the drought period, ∆W of all species reached higher values and was more closely related to the environmental variables (P<0.05) than for the whole studied period. For all species, the highest correlation was found between soil water potential and stem water deficit. The results suggested that the origin of the individuals has a significant effect on their response to environmental conditions. Key words Conifers, stem water deficit, dendrometer, environmental variables. Acknowledgement: This work was supported by the Slovak Research and Development Agency under the contact No. APVV-0480-12 and by the Grant Agency of the Slovak Republic under the project VEGA No. 1/0367/16. CONTENTS
133 Transpiration and stem circumference changes affected by drought in mature beech stand (Fagus sylvatica L.) - irrigation experiment Paulína Nalevanková1, Katarína Střelcová1, Zuzana Sitková2, Marek Ježík3 1 Technical University in Zvolen, Faculty of Forestry. Zvolen, Slovakia. Corresponding author: [email protected] 2 National Forest Centre, Forest Research Institute, Zvolen, Slovakia 3 Institute of Forest Ecology, Slovak Academy of Sciences, Zvolen, Slovakia Abstract Recurrent droughts, the severity and frequency of which is likely to be amplified by climate change, may adversely affect large tracts of temperate forests. The presented study addresses the ecophysiology of mature beech forest in Central Europe (Slovakia, 450 m a.s.l.) exposed to drought during the growing seasons of 2012–2014. Sap flow, stem circumference changes and increment of European beech (Fagus sylvatica L.) were measured in two contrasting treatments (drought vs. irrigation). We assessed the impact of atmospheric and soil drought on the growth and physiological performance of adult beech trees. Reduced water availability induced stem contraction and significantly limited the transpiration extrapolated using sap flow measurements. Trees stressed by drought conditions in years 2012 and 2013 showed remarkably lower values of morning tree water status (ΔW, morning net stem shrinkage) in comparison with irrigated group. This suggests: i) lower water potential of the stems’ conducting hydraulic tissues, and ii) increased use of internally stored water to maintain daily transpiration. Morning ΔW showed close relationship with soil water potential in the non-irrigated trees (in 2012 and 2013). Statistical analysis showed that potential evapotranspiration, vapor pressure deficit and global radiation were the main drivers of sap flow variability in the irrigated group of trees. In the non-irrigated group, these explained less of the variability in sap flow than in the irrigated group of trees. Key words Drought, irrigation, European beech, stem circumference changes, sap flow. CONTENTS
134 The amount of dew condensed on small trees of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) Karst.) in depend on micro-meteorological conditions Jaroslav Skvarenina1, Jozef Mindas2, Jana Skvareninova1, Martin Bartik1, Jaroslav Vido1, Miriam Valková1, Miriam Hanzelova1 1 Technical University,Zvolen, Slovakia, 2 University of Central Europe, Skalica, Slovakia Abstract In conditions of the temperate climate of Central Europe is dew only a minor component of the water balance. Dew has a positive impact on the reduction of evapotranspiration of plants, especially in dry periods. However the dew has also negative influence for pathogens and pollutants because of creating a moist environment for them. The observation was recorded in mountain area Kremnické vrchy (840 m a.s.l.), we analyzed the measurements of dew quantities formed on five beech tree seedlings (FS) and spruce seedlings (PA) collaterally with control measurements on rosografe M35. Similarly, we measured the micro-meteorological parameters: air temperature, soil temperature, air humidity, evaporation, wind speed vertical profile 2 - 120 cm. Beech tree seedling leaf area was 0.0814 - 0.1998 m2 and leaf area of spruce seedlings was 0.3058 - 0.6023 m2. The amount of water from dew, attributable to the area of assimilation organs, represented 3-196 (FS) and 13-87 g.m2 (PA) during night. The amount of dew 13-130 g.m2 per night was measured by dew recorder. The amount of dew and its curve course significantly depended on real Miko-meteorological conditions (e.g temperature and humidity gradient, wind speed and cloud). Key words Dew, beech, spruce, microclimate, mountain forest, hydro-meteorological elements. CONTENTS
135 Drought impact on autumn phenological phases of selected tree species in the central part of Slovakia Jana Škvareninová, Jaroslav Škvarenina, Miriam Váľková, Martin Bartík, Jaroslav Vido Technical University in Zvolen, Zvolen, Slovak Republic Abstract The contribution presents the knowledge of the drought impact on the onset of leaf yellowing and leaf fall of selected tree species (Quercus robur L., Fagus sylvatica L., Crataegus laevigata (Poir.) DC.) at elevations between 290 and 320 m a.s.l. In the years from 2009 to 2015, we recorded 10% occurrence of the phenological phase on 10 trees of each tree species. From meteorological parameters we examined precipitation, number of tropical days, and their periods from June to August. We revealed distinct differences in temperature and precipitation between the years, which affected the onset of autumn phenophases. Based on the values of Thornthwaite moisture index and climatic water balance, the year 2014 was the wettest with the shortest periods of tropical days, which shifted leaf yellowing of all tree species to a later period. The year 2015 was the driest and warmest, and the yellowing of leaves of beech and hawthorn started by 6 to 12 days earlier than their 25-year-long average of this phenophase. Oak was the least sensitive to weather extremes, and had the lowest variation of this phenophase in the monitored period as well as of the long-term average. The largest variation of leaf fall was recorded for beech, and the lowest for hawthorn. This phenological phase reflects temperature and precipitation conditions in summer months, as well as the weather pattern in autumn after leaf yellowing. Wind and heavy rain can accelerate its onset. The onset of the phenophases of all tree species was observed later than their long-term averages, which can be a signal of climate changes at the studied site. Key words Drought, phenology, forest-tree species, Slovakia. CONTENTS
136 Metaproteomics of wettable and repellent grassland soils Geertje van Keulen1, Gerry Quinn1, Martin Swain2, Ed Dudley1, Stefan Doerr3, Ingrid Hallin4, Tom Delmont5, Lewis Francis1,6, S. Andrea Gazze1,6, Richard Whalley7, Peter Matthews4 1 Institute of Life Science, Medical School, Swansea University, Swansea, Wales, UK 2 Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, Wales, UK 3 Department of Geography, College of Science, Swansea University, Swansea, Wales, UK 4 School of Geography, Earth and Environmental Sciences, Plymouth University, Plymouth, UK 5 University of Chicago Medical Centre, Chicago, USA 6 Centre for NanoHealth, Medical School, Swansea University, Swansea, Wales, UK 7 Sustainable Soil & Grassland Systems, Rothamsted Research, Harpenden, UK Abstract Soil water repellency is a common phenomenon affecting the hydrological responses of many soil and land use types in different climates. This now recognised ‘extreme’ environment leads to decreased water infiltration, reduced vegetation cover, fertiliser run off and soil erosion. The fundamental (biological) causes of (bulk) soil repellency and its dynamic behaviour remain poorly understood. We have applied soil metaproteomics, the systemic extraction and identification of proteins from a soil, to understand the biological (adaptive) processes and potential for bio-modification of mineral surfaces, which occur at the molecular level in soils switching between wettable and repellent states. Extreme, moderate and sub-critical water-repellent UK silt-loam soils under permanent grass vegetation, including Park Grass at Rothamsted Research, were sampled below the root zone depth under wettable and repellent conditions. Soils were subjected to our new extraction methods for determining the specific ultrahydrophobic and total metaproteomes. Comparative profiling of the total metaproteomes of wettable and repellent soils revealed similarities and dissimilarities in proteomes and microbial diversity, which have created a deeper understanding of soil biomolecular processes common and adaptive to soil moisture and to the severity of repellence. Using our ultrahydrophobic extraction protocol, we have identified novel ultrahydrophobic microbial proteins, which could be extracted from hydrophobic grassland soils with medium to low soil moisture levels, but were absent in the comparable wettable soils. These proteins have the potential to act as soil biomarkers for precision land management, especially in irrigation. Key words Soil water repellency, proteins, metaproteomics, bulk soil, microbial adaptation. CONTENTS
137 How to monitor drought in forest ecosystem using simple drought index Jaroslav Vido1, Katarína Střelcová1, Paulína Nalevanková1, Adriana Leštianska1, Radoslav Kandrík1, Alena Pástorová1, Jaroslav Škvarenina1, Tsegaye Tadesse2 1 Department of Natural Environment, Faculty of Forestry, Technical University in Zvolen, Zvolen, Slovakia. 2 The National Drought Mitigation Centre, University of Nebraska-Lincoln, Lincoln, Nebraska. Abstract The contribution presents relationship between the Standardised Precipitation Index (SPI) and physiological responses of individual trees in a beech stand using an example of an experimental plot in Bienska valley (Zvolen, Slovakia). SPI is a widely used tool for monitoring both short-term and long-term droughts, and for the assessments of drought impacts on agriculture. Due to the complex ecosystem bonds, monitoring of drought in forests often requires a sophisticated technological approach. The aim of the contribution was to correlate the SPI on the physiological responses of trees that were recorded during the performed physiological research (sap flow, and stem circumference increment) at the site in the growing seasons (May to September) of the years 2012–2014. The results revealed a relationship between the index and the physiological responses, although the problem with the impact of other environmental factors has also come up. The secondary correlation, in which soil water potential that significantly affects physiological responses of forest tree species was used as a dependent variable, showed a tighter relationship with the SPI. We found the highest correlation between the soil water potential and the values of SPI aggregated for five weeks. This indicates that the beech forest has a five week resistance to drought stress. The results also enable simple monitoring of the initiation of the drought stress by applying SPI for five weeks. Key words Drought, physiological responses, beech, standardised precipitation index, soil water potential. CONTENTS
144 Effect of prescribed fires on different soil properties in a Mediterranean pine forest P.A. Plaza-Álvarez, Daniel Moya, Javier Sagra, Raquel Alfaro Sánchez, Manuel Esteban Lucas Borja, Pablo Ferrandis, Jorge de las Heras Ibáñez Escuela Técnica Superior de Ingenieros Agrónomos y de Montes de Albacete, Universidad de Castilla La Mancha. Abstract The use of prescribed fire as a tool for reducing fuel accumulation in forest areas has become more important in the recent years. This is mainly due to their effectiveness, and low cost in comparison to other techniques, such as thinning or scrubbing. In this context, the objective of this work is to evaluate the effect of three prescribed fire in several soil properties (water repellency, infiltration, respiration, changes in texture, structure or nutrient content). For this purpose, we conducted prescribed fires in three areas: a mixed mass of Pinus halepensis and P. Pinaster located in Lezuza, province of Albacete, Spain, a mixed mass of P. pinaster with P. nigra located in El Pozuelo, and a pure mass of P. nigra in Beteta, the two last zones in province of Cuenca, Spain. In spite of low intensity of fire, we found differences in changes of texture, infiltration, water repellency and efflux, which were higher in the pure P. nigra forest. In general, tendencies pointed to an increase in water repellency and reduction of infiltration values mainly due to loss of organic matter and soil texture. Moreover, soil respiration decreased, indicating a loss of biological activity. Key words Low-intensity fires, infiltration, water repellency, soil respiration. CONTENTS
145 Session 4: Contributions presented as posters CONTENTS
146 The impact of ant mounts as a source of sediments and sink of runoff in recently fire affected scrublands in Eastern Spain Artemi Cerdà1,2, Marcos Francos3, Xavier Úbeda3, María Burguet Marimon1, Agata Novara4, Paulo Pereira5 1 Soil Erosion and Degradation Research Group, Department of Geography, University of Valencia, Valencia, Spain. [email protected] 2 Soil Physics and Land Management Group, Wageningen University, Wageningen, The Netherlands 3 GRAM (Grup de Recerca Ambiental Mediterrània) Department of Geography, Universitat de Barcelona 4 Department of Scienze Agrarie e Forestali – University of Palermo, Italy. 5 Environmental Management Centre, Mykolas Romeris University, Vilnius, Lithuania. Abstract After forest fires soil erosion and runoff generation mechanism are accelerated. This is a consequence of the lack of vegetation cover, the combustion of the litter, and changes in the soil properties. After the fires there is still life. Flora and fauna recover. Ants easily survive to the forest fires in the nests, and after few hours they built new mounts and collect seeds. The effect of the ant mounts on soil erosion and runoff production is researched here in the Massís del Caroig (Eastern Spain) by means of rainfall simulation experiments in the field on 0.25 m2 plots under 55.4 mm h-1 rainfall intensities during one hour to determine the changes in the detachment as a consequence of the fire and the ant burrowing and nest construction. We selected plots with ant mounts (10) and control plots without (10), in fire affected (10) and in the nearby non-fire affected land (10). The results show an average erosion rate of 1.23 Mg ha-1 y-1 on the fire-affected area, and 0.12 Mg ha-1 y-1 in the non-fire affected. The plots with ant mounts yield 3.55 Mg ha-1 y-1 on fire-affected soils and 1.87 Mg ha-1 y-1 in the vegetated ones. The runoff coefficient was 23.2 % in the fire-affected area, and 7.8 % in the non-fire affected sites. The plots with ant mounts yield 33.23 % and 55.34 % of the rainfall as runoff on fireaffected soils and in the vegetated ones, respectively. The results shows that the ant mounts activate the sediment delivery and increase the soil erodibility and they act also as a source of runoff due to the morphology of the nest. Key words Fire, ants, erosion, runoff, scrubland. Acknowledgements: The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 603498 (RECARE project) and the CGL201347862-C2-1-R national research project. CONTENTS
147 Long-term runoff and soil yield after forest fires in the Massis del Caroig Artemi Cerdà1,2, Marcos Francos3, Xavier Úbeda3, Meritxell Alcañiz3, Antonio Jordán4, Paulo Pereira5 1 Soil Erosion and Degradation Research Group, Department of Geography, University of Valencia, Valencia, Spain. [email protected] 2 Soil Physics and Land Management Group, Wageningen University, Wageningen, The Netherlands 3 GRAM (Grup de Recerca Ambiental Mediterrània) Department of Geography, Universitat de Barcelona 4 MED_Soil Research Group. Dep. of Crystallography, Mineralogy and Agricultural Chemistry, University of Seville, Spain. 5 Environmental Management Centre, Mykolas Romeris University, Vilnius, Lithuania Abstract Forest fires are recurrent in Mediterranean-Type Ecosystems and they accelerate the runoff and the soil erosion rates. Most of the research focussed on the changes after two years, or they are based in the comparison of the burn and non-burn sites. However, little is known about how this will evolve at long-term. In order to determine the longterm changes in soil and water losses in Mediterranean type ecosystems ten study sites were selected in the Canyoles River watershed on limestones with 0, 1, 2, 5, 10, 14, 25, 37, 51, >100 years after fire. Ten plots per study site (10 plots x 10 sites, 100 experiments) under simulated rainfall in the field on 0.6 m2 plots under 46.6 mm h-1 rainfall intensities in summer 2014 show that the soil erosion is active in the first 2 years, and specially high during the year after the fire. The soil erosion rates measured were 0.54, 5.87, 3.23 Mg ha-1 h-1 for the 0, 1 and 2 years after the fire. The low erosion rates measured during the first year is due to the ash cover as mulch. The lack of vegetation cover (3 and 13 % in the first and second year after the fire) is the reason of the high erosion rates found. After five years the vegetation reached 40 % and the erosion rates dropped to 1.23 Mg ha-1 h-1. The soil erosion rates were 0.88, 0.65, 0.43, 0.21, 0.12, 0.03 after 10, 14, 25, 37, 51 and 100 years after the forest fire in average values for 10 plots, respectively. The runoff rates follow the sequence of 12.2 %, 54.3 %, 32.0 %, 21.4 %, 15.3 %, 12.6 %, 8.3 %, 5.2 %, 4.3 %, 2.9 % respectively for 0, 1, 2, 5, 10, 14, 25, 37, 51, >100 years after fire. The vegetation cover was the main factor of the soil erosion control as it moved from 35 % in the area burnt 5 years before to 51 %, 60 %, 68%, 72 %, 83 % and 91 % respectively for the 10, 14, 25, 37, 51, >100 years after fire study sites. There is a clear reduction in the soil and water losses with the time since the fire, which is very efficient in the period between 5 and 10 years after the fire. Key words Erosion, runoff, plants, forest fires, mediterranean. Acknowledgements: The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 603498 (RECARE project) and the CGL201347862-C2-1-R national research project. CONTENTS
148 Hydrological connectivity in a Mediterranean forest before and after a wildfire in South of Spain: modelling scenarios Juan F. Martínez-Murillo1, Manuel López-Vicente2 1 Instituto de Geomorfología y Suelos (IGSUMA), Universidad de Málaga. Málaga, Spain. 2 Department of Soil and Water, Estación Experimental de Aula Dei, EEAD-CSIC, Zaragoza, Spain. Abstract Overland flow connectivity depends on the spatiotemporal interactions of hydrological and geomorphic processes as well as on the human footprint on the landscape. This study deals with the modelling of hydrological connectivity in a burned area with different levels of fire severity. Namely, the objectives are to i) characterize and ii) modelling the pre and post-fire scenarios, as well as iii) evaluate the effect of the vegetation changes due to the fire and the initial post-fire management practices (construction of new skid trails) on the magnitude and spatial pattern of connectivity. The study area corresponds to eight disconnected headwater sub-catchments that were totally or partially burned in 2014, 27 June. This area is located in the province of Malaga, South of Spain, and covers a total surface of 275 ha. The landscape is mainly mountainous, with very steep slopes and marble rocks, Mediterranean climate, and a land use of shrubs and pine forests (pre-fire scenario). Settlements appear at the bottom of the slopes. After the wildfire, land management was carried out in order to remove completely the burned trees and thus new skid trails were built. The different scenarios of linear landscape elements, vegetation cover, and modifications on the topography related to the construction of new trails were included in the simulations. The Connectivity Index was chosen to perform this metric at a spatial resolution of 5 x 5 meters. The analysis of the different spatial patterns and temporal changes was done considering the different levels of fire severity and changes in hydrological connectivity were also analysed at the outlet of each sub-catchment. Key words Hydrological connectivity, wildfire, connectivity index, modelling, scenarios. CONTENTS
149 Soil water retention curves and related properties two years after salvage logging treatments in a Mediterranean burnt forest Jorge Mataix-Solera1, Pavel Dlapa2, Katarina Chrenková1,2, Victoria Arcenegui1, Fuensanta García-Orenes1 1 GEA, Department of Agrochemistry and Environment, University Miguel Hernández, Elche, Alicante, Spain ([email protected]) 2 Department of Soil Science, Faculty of Natural Science, Comenius University, Bratislava, Slovak Republic Abstract In Mediterranean areas, water availability for plants is the main limiting factor for ecosystem restoration after fire. Post-fire management can have a negative impact on the soils that in some cases is even more severe than the fire itself. Salvage logging (SL) is a common management technique in fire-affected areas, but carrying it out, by using heavy machinery, leads to a consequent increase in the vulnerability to erosion and soil degradation. We monitored some soil properties in an area affected by a big forest fire (>500 has) in July 2012. The study area is located in the “Sierra de Mariola Natural Park”, Alicante (E Spain). The forest was composed mainly of Pinus halepensis trees with an understory of typical Mediterranean shrub species. The soil was classified as a Typic Xerorthent developed from Miocene marls. In February 2013, the SL treatment, comprising a complete extraction of the burnt wood using heavy machinery, was applied in a part of the affected forest. Plots for monitoring were installed and in a similar nearby area there was no treatment (control, C) for comparison. Soil samplings were done immediately after treatment and every 6 months. We found that all soil properties were negatively affected by SL treatment compared with C plots: a progressive decrease with time of soil organic matter content, microbial biomass, soil respiration, aggregate stability, water holding capacity and an increase in bulk density were observed. In May 2014, undisturbed soil cores (100 cm3) from both treatments (C and SL) were taken in order to study water retention curves. Results showed differences between treatments, most likely due to differences in the pore size distribution of soils and the strong influence of parent material. The underlying marl rocks contain only very fine pores and thus they are “impermeable” once saturated with water. The water does not infiltrate into these rocks but flows down the surface and increases the erosion. The soil samples from SL treatments have higher content of coarse pores and thus they retain more water under wet conditions compared C samples where the humus horizon is preserved. But they have a lowered ability to retain water at high water tension in dry conditions. The soil samples from C plots showed the best properties. The soils have relatively stable structure and higher content of finer pores and thus the soil retains more water in dry conditions compared to the eroded soil at SL plots. Key words Forest fire, salvage logging, water retention curves, aggregate stability, soil quality. Acknowledgements: We thank to the “Ministerio de Economía and Competitividad” of Spanish Government for finance the POSTFIRE project (CGL201347862-C2-1-R) and Alcoi council. CONTENTS
150 Rainfall and wet and dry cycles effect on ash hydrophobicity: A laboratory experiment Paulo Pereira1, Saskia Keesstra2, Piet Peeters2, Artemi Cerda3 1 Environmental Management Center, Mykolas Romeris University, Vilnius, Lithuania 2 Soil Physics and Land Management Group, Wageningen University, The Netherlands, 3 Soil Erosion and Degradation Research Group, Department of Geography, University of Valencia Valencia Abstract Ash is the main soil protection in the immediate period after the fire. Fire severity has implications on the ash properties and consequently in their resistance to erosion, type and amount of nutrients release and water repellency since ash hydrological properties are strongly dependent on the type of vegetation and degree of combustion. It is assumed that ash produced at low fire severity are hydrophobic, occurring the opposite when the ash is produced at high severity. The objective of this work is to study the effects of rainfall and wet-dry cycles in ash hydrophobicity. Litter from Oak (Quercus robur) and Spruce (Picea abis) were collected, cleaned with deionized water to remove the impurities and exposed during 2 hours to produce ash at 200 and 400 ⁰C. An ash layer of 15 mm was spread on a water repellent soil (placed carefully in 24x32 cm diameter boxes). Boxes were placed at a 17% of inclination. After this task, a rainfall intensity of 55 mm/h for 40 minutes was applied. After the rainfall simulation, the plots were stored in an Oven at the temperature of 25 ⁰C during four days, in order to identify the effects of wet and dry cycles. Ash hydrophobicity was measured previous to the first rainfall (PFR), after the first rainfall (AFR), before the second rainfall (BSR) and after the second rainfall (ASR). The results showed that PFR, the ash produced by Oak at 200 ⁰C was significantly more hydrophobic that the ash produced by Spruce at the same temperature. The opposite was observed at 400 ⁰C. At 200 ⁰C, the hydrophobicity of Oak ash AFR, BSR, and ASR was significantly higher than the ash produced by Spruce. This pattern was also identified at 400 ⁰C. At 200 ⁰C in Oak and Spruce ash, hydrophobicity decreased significantly AFR, increasing also significantly BSR. ASR ash hydrophobicity decreases significantly in relation to BSR in both species. At 400 ⁰C, no significant differences were identified among the treatments in Oak ash. In relation to Spruce ash, the water repellency was significantly higher PFR in comparison to the other treatments. Finally, the hydrophobicity of ash produced at 200 ⁰C was significantly higher than at 400 ⁰C for Oak in all the experiments. In relation to Spruce ash, we identified the same pattern with the exception of ASR, were no significant differences were observed between temperatures. Key words Wet and dry cycles, ash, hydrophobicity, Quercus robur, Picea abis. Acknowledgments: The authors are thankful to the Soil Physics and Land Management Group from Wageningen University, The Netherlands for providing the infrastructure to develop this work, to the RECARE project (grant agreement n° 603498), and to the COST action ES1306: Connecting European Connectivity Research for funding an STSM at the Wageningen University. CONTENTS
151 The analysis of long term forest fire weather indices in National Park Slovak Paradise in relation to the risk of climate change Jaroslav Skvarenina, Jan Holecy, Jaroslav Vido, Jana Skvareninova, Martin Bartik, Miriam Valková Technical University, Zvolen, Slovakia, Abstract The territory of the National Park of Slovak Paradise is highly vulnerable to occurrence of forest fires. From our point of view, there are several reasons why this territory is susceptible to burn and so strongly vulnerable from the forest fire occurrence: e.g., limestone and karst relief, shallow soils, mostly coniferous forest stands, rain shadow of the High Tatras, etc. This contribution is focused on the detection of a climate change within the territory of Slovak Paradise National Park during the period of years 1970 – 2014. The objective of a study is to investigate the significance of a climate change progression trend measured by the values of particular fire weather indices (FWI) recorded in this experimental territory for the whole observed period. For the purposes of the analysis the following 3 FWIs describing the development of a fire occurrence danger here have been selected: the Angström index, the Nesterov ignition index and the Baumgartner index. The significance of assumed linear trends of a climate change progression described by each particular FWI was tested by means of the Student`s (t) test by using the significance levels of (α) = 0.05 and 0.01. To master the more thorough statistical analysis, the original scaling concerning all 3 FWI was changed. The values of 0, 1, 2, 3 and 4 instead of former values 1, 2, 3, 4 and 5 have been used. The null hypotheses concerning the observed differences between particular couples of Fn(t) were investigated by using the Kolmogorov-Smirnov two-sample test. The results of the above described analysis have revealed a very significant (Rxy = 0.470744 and α = 0.01) trend of a climate change progression in the experimental territory, measured by the annual totals of days when the Angström FWI values approached degrees 4 and 5. As the best measure of the change concerning fire occurrence risk in the experimental area, here, again the Fn(t) of the Angström FWI can be regarded. The significant increase of fire danger was detected, what obviously points out the significant change of a climate as well. Key words Forest fire, hydro-meteorological elements, forest fire weather indices. CONTENTS
152 SESSION 5 ROLE OF BIOGEOCHEMICAL INTERFACES IN BIOHYDROLOGY Conveners:& Gabriele'Schaumann,'University'of'KoblenzQLandau,'Landau,'Germany' Jörg'Bachmann,'University'of'Hannover,'Hannover,'Germany CONTENTS
153 Keynote lectures CONTENTS