D3.4_AGROECOseqC_WP3_10.5281zenodo.14161917

Towards climate-smart sustainable management of agricultural soils AGROECOlogical strategies for an efficient functioning of plant - soil biota interactions to increase SOC sequestration AGROECOseqC Deliverable 3.4 Final report on soil fauna and C sequestration Due date of deliverable: MX Actual submission date: XX.XX.202X Deliverable 3.4 Final report on soil fauna and C sequestration This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 862695, and from the ...... 2 GENERAL DATA Grant Agreement: 862695 Project acronym: EJP SOIL Programme title: Towards climate-smart sustainable management of agricultural soils Programme website: www.ejpsoil.eu Project title: AGROECOlogical strategies for an efficient functioning of plant - soil biota interactions to increase SOC sequestration - AGROECOseqC Project website: https://ejpsoil.eu/soil-research/agroecoseqc Start date of the project: February 1st, 2020 Project duration: 60 months Name of lead contractor: INRAE Funding source: H2020-SFS-2018-2020 / H2020-SFS-2019-1 Type of action: European Joint Project COFUND DELIVERABLE NUMBER: 3.4 DELIVERABLE TITLE: Final report on soil fauna and C sequestration DELIVERABLE TYPE: Report WORK PACKAGE N: WP3 WORK PACKAGE TITLE: Title DELIVERABLE LEADER: Sara Sánchez Moreno AUTHOR: DOI: Sara Sánchez Moreno, Joaquín Cobos, Jordi Moya-Laraño. 10.5281/zenodo.14161917 LICENSE DISSEMINATION LEVEL: CC BY 4.0 CO Deliverable 3.4 Final report on soil fauna and C sequestration This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 862695, and from the ...... 3 ABSTRACT The main objective of this activity was to determine relationships between soil animal diversity and carbon cycling. Different samplings were carried out and organisms were identified to main taxonomical or functional groups. Soil organic carbon data obtained in other work packages were used to look for associations or relations between soil diversity and SOC, but, contrary to our expectations, soil organic carbon was negative related to the abundance of some groups of soil fauna. In general, an increase in SOC did not lead to an increase in the diversity or abundance of soil organisms, although we did detect some changes in soil food web structure that might indicate positive effects of SOC in soil food web structure. Deliverable 3.4 Final report on soil fauna and C sequestration This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 862695, and from the ...... 4 Table of Contents List of Figures ........................................................................................................................................... 4 List of acronyms and abbreviations ......................................................................................................... 4 1. Introduction ..................................................................................................................................... 5 2. Executive summary (if required) ..................................................................................................... 5 3. Main text ......................................................................................................................................... 5 3.1. Subpart 1 ................................................................................................................................. 6 3.2. Subpart 2 ......................................................................... Errore. Il segnalibro non è definito. List of references ..................................................................................................................................... 8 List of Figures Figure 1. Relationships between total organic carbon (TOC) and different groups of soil fauna (Fu tot= total fungivore nematodes; PO proportion= Proportion of predator and omnivore nematodes; ba tot= total bacterivore nematodes; endeo tot= total endeostigamata mites; acari tot= total mite abundance). Figure 2. Relationships between soil moisture and bulk density with total organic carbon (TOC) across all core sites. List of acronyms and abbreviations WP Work Package EU European Union TOC Total Organic Carbon SOC Total Organic Carbon Deliverable 3.4 Final report on soil fauna and C sequestration This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 862695, and from the ...... 5 1. Introduction The main objective of this activity was to determine key attributes of the soil food web which drive C cycling. Along the project, different samplings have been performed to extract and identify the main groups of soil micro, meso and macrofauna. Due to different plot sizes and crop characteristics bot all organisms were sampled in all core sites. Once organisms were identified to main taxonomical or functional groups, soil organic c data obtained in other work packages were sued to look for associations or relations between soil diversity and SOC. 2. Executive summary (if required) Contrary to our expectations, soil organic carbon was negative related to the abundance of some groups of soil fauna. Across our core sites, an increase in SOC did not lead to an increase of soil organisms. However, we did detect some changes in soil food web structure that might indicate positive effects of SOC in soil food web structure, as the positive effect of SOC on the predator + omnivore nematodes, indicators of soil food web structure and of ecosystem services such as the soil suppressive capacity (Sánchez-Moreno et al., 2007). The absence of the expected patterns on the relationship between soil animal abundances and SOC might be due to the large heterogeneity of the pedoclimatic and agronomical conditions across core sites. Increases in SOC are usually associated to increases in soil moisture due to the increased water retention ability, and also to decreases in bulk density. Bulk density is a key soil attribute determining soil fauna abundance, since soil organisms need soil pores to move through the soil matrix. Our results, however, show a negative relation between TOC and bulk density, which might have, probably together with other undetected factors, negatively affect the total abundance of some soil organisms. 3. Main text Soil organisms were sampled in different core sites depending on the experimental conditions. For macrofauna groups, only core sites with large enough plots that permitted effective sampling were sampled. Similarly, only microand mesofaunal organisms, that provided sufficient replication, were considered to assess the relationship between soil organic carbon and soil animal diversity. Nematodes were extracted from by Baermann funnels (Barker, 1985) from soil samples collected in 8 core sites. Once extracted, all nematodes in each sample were counted under a binocular and 100 individuals were classified into functional groups. All nematode abundances were expressed as no. of Deliverable 3.4 Final report on soil fauna and C sequestration This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 862695, and from the ...... 6 nematodes /100 g of dry soil. Nematodes were classified into six functional groups (Yeates, 1993; Ferris et al., 2001): • Opportunistic bacterivores: Bacterial-feeding nematodes that respond rapidly to increases in bacterial biomass. When the soil is fertilized or amended with organic products, bacterial biomass rapidly increases, and such increase is followed by a rapid enhancement of opportunistic bacterivore populations • Generalist bacterivores: Bacterial-feeding nematodes that do not respond so fast to enrichment, with more stable populations and extremely resistant to environmental perturbation. • Fungal feeding nematodes: Nematodes that feed on soil fungi by piercing fungal hyphas with a stylet. • Root associates: plant-feeding nematodes that feed on root hair, with a limited damage potential to plant health. • Plant-parasitic nematodes: Endoand ecto-parasites that feed on plant root with medium to high damage potential to plant health. • Omnivores: nematodes able to feed in plants and other soil animals by piercing the food source with a stylet. • Predators: nematodes that feed on other soil animals (including other nematodes) either by piercing with a stylet or by ingesting them. Acari and collembola were sampled and identified in 5 core sites, and further identified into main orders/suborders (Oribatida, Endeostigmata, Prostigmata, Heterostigmata, Mesostigmata and Astigmata). Significant relationships between TOC and soil organisms’ abundances were assessed through correlation on the R software (R core team, 2022). Only significant relations at p<0.05 are shown. 3.1. Results and discussion Several elements of the soil fauna presented significant relationships with TOC, which will be explored in further analyses. In relation to the nematode community, TOC was related to the relative abundance of predator and omnivore nematodes (r=0.49, p>0.05) (Fig. 19), while the total abundances of bacterivores and fungivores presented negative relations (r= -0.31 and r= -0.26 respectively, p<0.05 (Fig. 19). Deliverable 3.4 Final report on soil fauna and C sequestration This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 862695, and from the ...... 7 Similarly, and opposite to our expectations, the abundance of several groups of mesofauna presented negative relation with TOC levels. The abundance of endeostigmata (r = -0.36) and total acari (r= -0.28) presented significant (p>0.05) and negative relations to TOC (Fig. 1). Fig.1. Relationships between total organic carbon (TOC) and different groups of soil fauna (Fu tot= total fungivore nematodes; PO proportion= Proportion of predator and omnivore nematodes; ba tot= total bacterivore nematodes; endeo tot= total endeostigamata mites; acari tot= total mite abundance). Deliverable 3.4 Final report on soil fauna and C sequestration This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 862695, and from the ...... 8 Across core sites, TOC did positively relate to soil moisture (r= 0.34, p>0.05), and negatively to bulk density (r= 0.25, p<0.05) (Fig. 2). Fig. 2. Relationships between soil moisture and bulk density with total organic carbon (TOC) across all core sites. List of references Barker, K.R., 1985. Nematode extraction and bioassays. p. 19-35. In K.R. Barker, C.C. Carter, and J.N. Sasser (ed.). An Advanced Treatise on Meloidogyne, Vol 2 Methodology. North Carolina State University Graphics. Raleigh, N.C. In K.R. Barker, C.C. Carter, and J.N. Sasser (Ed.). An Advanced Treatise on Meloidogyne, Vol 2 Methodology. North Carolina State University Graphics. Raleigh, N.C., 19–35. Yeates, G.W., Bongers, T., de Goede, R.G.M., Freckman, D.W., Georgieva, S.S., 1993. Feeding habits in soil nematode families and generaAn outline for soil ecologists. J. Nemat. 25(3), 315–331. Ferris, H., Bongers, T., de Goede, R.G.., 2001. A framework for soil food web diagnostics: extension of the nematode faunal analysis concept. App. Soil Ecol. 18, 13–29. Sánchez-Moreno, S., Ferris, H., 2007. Suppressive service of the soil food web: Effects of environmental management. Agric. Ecosyst. Env. https://doi.org/10.1016/j.agee.2006.06.012