Management of harvested C in smallholder mixed farming in Ethiopia
Full text
Managemen o ha es ed C in smallholde mixed a ming in E hiopia
Ka oliina Rimhanen
a,
⇑
, Helena Kahiluo o
b
a
MTT Ag i ood Resea ch Finland, La oka anonkaa i 9, 00790 Helsinki, Finland
b
MTT Ag i ood Resea ch Finland, Lönn o inka u 5, 50100 Mikkeli, Finland
a icle in o
A icle his o y:
Recei ed 8 Feb ua y 2013
Recei ed in e ised o m 3 June 2014
Accep ed 6 June 2014
A ailable online 3 July 2014
Keywo ds:
Ca bon flow
Ca bon loss
Ha es ed ca bon
Residue
Fa ming sys em
Ma e ial flow analysis
abs ac
Inc easing he sha e o he ha es ed C ending up in ood and e u ned o soil could con ibu e o clima e
change mi iga ion and ood secu i y. The aim o his s udy was o quan i y empi ically he p opo ion o
he ha es ed C ending up in ood and soil and he C losses occu ing when managing ha es ed C in
smallholde mixed a ming sys ems in E hiopia. Fou case a ms we e explo ed; one esou ce-limi ed
and one be e -o a m, in wo socio-ecologically con as ing egions impo an o ood p oduc ion.
Ma e ial flow analysis (MFA) was used o de e mine he flows o ha es ed C. The losses o ha es ed
C, om he li es ock, compos and household ene gy use we e quan ified based on C balances. The C
flows we e es ima ed as means o wo g owing seasons, 2008/2009 and 2009/2010, wi h low and
a e age p ecipi a ion, espec i ely. Analysis was ounded on semi-s uc u ed in e iews and sampling,
supplemen ed wi h in o ma ion om da abases and he li e a u e. F om he o al ha es ed C, 9–16%
was alloca ed o ood and 4–12% o ag icul u al soil. Since he esidues a e u ilized apa om human
exc e a wi h a negligible significance, inc easing he p opo ion o ha es ed C used o ood and e u ned
o soil is in hese a ming sys ems only possible by educing he gaseous C losses. The la ges losses o he
ha es ed C occu h ough biomass bu ning (15–60%), animal me abolism (16–44%) and compos ing
(5–23%). The la ge C loss h ough he eplaceable esidue bu ning seems o o e he mos accessible em-
edy o smallholde managemen o ha es ed C. Consequen ly, he p opo ion o ha es ed C used o uel
appea s as he main de e minan o he p opo ion o ha es ed C ending up in soil and ood. Ene gy
subs i u es o manu e and s aw, imp o ed manu e managemen and mo e s able ood and odde
supply o educe he equisi e numbe o animals a e all keys o close C cycles in he a ming sys ems.
Quan ifica ion o he o ganic C flows using MFA is use ul in e ealing he alloca ion o ha es ed C and
losses occu ing in i s managemen in a ming sys ems when measu emen o gaseous emissions and
leaching a e no easible.
Ó2014 The Au ho s. Published by Else ie L d. This is an open access a icle unde he CC BY-NC-ND
license (h p://c ea i ecommons.o g/licenses/by-nc-nd/3.0/).
1. In oduc ion
Clima e change poses a h ea o ood secu i y in sub-Saha an
A ica (SSA), whe e economies a e highly dependen on ag icul u e
(IPCC, 2007). Tho n on e al. (2011) es ima ed a 24–71% dec ease
in c op yields by 2090, and in places a shi om c op p oduc ion
o li es ock husband y, al hough hese figu es imply a high deg ee
o unce ain y. Simul aneously, high popula ion g ow h and soil
deg ada ion exe p essu es o inc ease ag icul u al p oduc i i y.
Ca bon (C) seques a ion in ag icul u al soils has he g ea es
po en ial o mi iga e clima e change in SSA ag icul u e (Smi h
e al., 2008), and o inc ease ag icul u al p oduc i i y (Lal, 2004).
In a ming sys ems, ood secu i y and C seques a ion can be
enhanced by alloca ing a high sha e o ha es ed C o ood and
ag icul u al soil. Such de elopmen can be con ibu ed o by educ-
ing C losses be o e ha es ed C ends up in ood o soil.
In ag icul u e, ca bon dioxide (CO
2
) is assimila ed du ing pho o-
syn hesis in c ops and angelands. Pa o his C is eleased back
in o he a mosphe e du ing plan and soil espi a ion o fi e, pa
o i being s o ed in soil o ganic ma e (SOM) and in ha es ed
biomass and animal p oduc s, and pa being liable o e osion
and leaching as dissol ed o ganic and ino ganic ca bon and me h-
ane. Biomass C is ha es ed as c ops and h ough g azing o li e-
s ock and collec ing uel wood. Ha es ed C can also be impo ed
in o he a m as odde , ood, uel, cons uc ion ma e ial and
o ganic soil amendmen s. The quan i y o ha es ed C lays he
g ound o a ailabili y o ood and soil amendmen , bu he e a e
also o he compe i i e uses o hese esou ces.
Ag icul u e in E hiopia is cha ac e ized by low-inpu and low-
ou pu p oduc ion (De e eux, 2000). The p essu e o sa is y he
need o he g owing popula ion o ood and uel has dec eased
holding size, in ensified ag icul u e, and educed o es co e
h p://dx.doi.o g/10.1016/j.agsy.2014.06.003
0308-521X/Ó2014 The Au ho s. Published by Else ie L d.
This is an open access a icle unde he CC BY-NC-ND license (h p://c ea i ecommons.o g/licenses/by-nc-nd/3.0/).
⇑
Co esponding au ho . Tel.: +358 295317676.
E-mail add esses: ka oliina. imhanen@m .fi (K. Rimhanen), helena.kahiluo o@
m .fi (H. Kahiluo o).
Ag icul u al Sys ems 130 (2014) 13–22
Con en s lis s a ailable a ScienceDi ec
Ag icul u al Sys ems
jou nal homepage: www.else ie .com/loca e/agsy
(Ba iono e al., 2007; Pohjonen and Pukkala, 1990) o a cu en 4%
o he land a ea (Be hanu, 2005). The dec ease in o es esou ces
has led o he use o d ied cow dung o uel, while c op esidues
a e mainly used as odde o li es ock (Co beels e al., 2000).
The e o e, e u n o esidue C o he soil is educed, which in u n
educes soil p oduc i i y.
Alloca ion o a highe sha e o ha es ed C in ood would
di ec ly imp o e ood secu i y. Fu he , e u ning a highe sha e
o ha es ed C no used as ood o soil would con ibu e o inc eas-
ing soil C s o age (Gi may e al., 2008) and imp o e soil nu ien
supply and wa e holding capaci y, and consequen ly soil p oduc-
i i y and s abili y o ood supply (Lal e al., 2011).
Abou 72% o g eenhouse gas (GHG) emissions in E hiopia o ig-
ina e om ag icul u e (WRI CAIT, 2013). Mos o he emissions
comp ise me hane (CH
4
), en e ic e men a ion being he la ges
sou ce, o alling 28,077,000 onnes o (CO
2
) equi alen (Tadeke,
2001). Mo e han wice as la ge emissions occu in biomass bu n-
ing in households o alling o e 66,000,000 onnes o CO
2
(Tadeke,
2001). Emissions om bioene gy a e no , howe e , added o in en-
o ies o na ional emissions epo ed o UNFCCC as hey a e consid-
e ed ‘‘ca bon–neu al’’, co esponding o he amoun o C bound
om he a mosphe e in pho osyn hesis (Me z, 2007). On a ms,
howe e , uel use and soil amendmen compe e o he sca ce
esou ce o esidue C.
Ma e ial flow analysis (MFA) (B unne and Rechbe ge , 2004)
allows di ec acing o C ma e ial flows and indi ec ly also he
gaseous losses om hese flows h ough C balance coun ing,
and hus quan ifica ion o he p opo ion o ha es ed C used
o ood and soil. Such analysis p o ides aluable in o ma ion ha
u he esea ch can exploi o assess he impac s o changes in C
managemen p ac ices on household wel a e and po en ial o
seques e C. Such a C budge app oach has s eng hs and weak-
nesses analogous o hose o nu ien budge app oaches
(Oenema e al., 2003; Öbo n e al., 2003), an impo an s eng h
being accessibili y o he p ima y da a o he esea che . To da e,
he e a e ew empi ical da a on he use o ha es ed C o ood
and soil amendmen , o abou he po en ial o imp o e he
esou ce-use e ficiency in a ming sys ems. To ou knowledge,
o ganic C flows and C losses in Eas A ican a ming sys ems ha e
no been s udied be o e. Empi ical quan i a i e case s udies o
he flows o ha es ed C and losses occu ing in i s managemen
in E hiopian a ming sys ems p o ide in-dep h unde s anding o
he use o his aluable, sca ce esou ce and o he significance
and causes o he a ious losses.
The aim o he s udy was o inc ease unde s anding abou he
po en ial o enhance he use o ha es ed C o ood and soil
amendmen on mixed smallholde a ms in Eas A ica. The exam-
ina ion ocused on he losses o ha es ed C educing he sha e
ending up in ood and soil. The ollowing esea ch ques ions we e
posed: Wha is he p opo ion o ha es ed C alloca ed o ood and
soil in smallholde mixed a ming sys ems in he E hiopian
highlands? Wha a e he majo losses o ha es ed C educing
he p opo ion alloca ed o ood and soil? Wha a e he de e mi-
nan s o he p opo ion o ha es ed C used o ood and soil
and o he C losses? The use ulness o MFA o indica e C he p o-
po ion o he C use and C losses in a ming sys ems was also dis-
cussed. Smallholde mixed case a ms wi h Good Ag icul u al
P ac ices (GAP) (FAO, 2003) in he E hiopian highlands, wi h lim-
i ed and g ea e esou ces we e s udied in wo egions con as ing
in ag oecological and socioeconomic condi ions.
2. Ma e ials and me hods
An ins umen al case s udy app oach was used, whe e he cases
we e explo ed o unde s and causal ela ions and mechanisms o
he phenomenon (C eswell, 2007; S ake, 1995). Documen s and
da a om he na ional and local a chi es and ag icul u al o fices
we e used in addi ion o in e iews, sampling and published li e -
a u e (Yin, 2003). Two ep esen a i e bu con as ing case egions
and wo a ms in each egion we e selec ed o his collec i e s udy
(S ake, 1995) o acili a e gene aliza ion (Yin, 2003).
2.1. Case cha ac e is ics
The opog aphy o E hiopia a ies since he Eas A ican G ea
Ri Valley di ides he high pla eau diagonally. The E hiopian econ-
omy elies on ag icul u e, which accoun s o 43% o o al GDP
(Coun ySTAT, 2012) and employs 85% o he popula ion (CIA,
2012). A ound 60% o E hiopian a ms cul i a e less han 0.9 ha
and 40% less han 0.5 ha (Ta esse e al., 2011). The p esen s udy
was ca ied ou in Kobo, on he bo de o he cool semi-a id and
wa m semi-a id ag oecological zones, and Si e, on he bo de o
cool semi-a id and cool sub-humid ag oecological zones (Ha es
Choice/IFPRI, 2009), on he slopes o he G ea Ri Valley (Fig. 1).
The si es ep esen ela i ely ood-insecu e and ood-secu e
egions o E hiopia, espec i ely (See Appendix A). Kobo is cha ac-
e ized by se e e soil deg ada ion and low soil e ili y, small land
holding size, high wa e s ess and low c op yields compa ed wi h
Si e (Wo ld Bank, 2004)(Appendix A). Low income, due o lack o
o - a m employmen oppo uni ies, has wo sened po e y and
hinde ed access o ood. A he u n o he 21s cen u y he numbe
o people ecei ing ood aid anged be ween 27% and 50% o he
o al popula ion (Ali, 2002). Si e ep esen s an a ea o g ea e
po en ial o ood p oduc ion as i has highe p ecipi a ion and
mo e land a ailable. Bo h dis ic s ep esen impo an ood p o-
duc ion a eas in E hiopia (Ta esse e al., 2011). Due o local a ia-
ion in p ecipi a ion and lack o wea he s a ion da a o ain all
in ensi y we elied on a me desc ip ions (Regassa e al., 2010)
o he annual wea he ela i e o he long- e m a e age (Appendix
A). Acco ding o a me s, 2008/2009 was low and 2009/2010 a e -
age in p ecipi a ion, on all o he case a ms.
Highland empe a e mixed a ming p e ails in bo h case
egions. I is he mos common a ming sys em ype in E hiopia
and is conduc ed on app oxima ely a hi d o he land a ea, a sha e
simila o ha alloca ed o pas o alism. In Eas A ica his a ming
sys em co e s 5% o he land a ea (Dixon e al., 2001; FAOSTAT,
2011). Li es ock ep esen s financial secu i y, d a powe , ans-
po a ion, uel and cul u al alues. Animals g aze eely on com-
munal angeland and on field plo s a e ha es ing. Poo
li es ock nu i ion due o lack o o age limi s p oduc i i y and
inc eases emissions pe p oduc uni . In Kobo, subsis ence p oduc-
ion domina es and is cons ained by e a ic ain all and lack o
inpu s. In con as o Si e, so ghum (So ghum bicolo L.) is widely
cul i a ed in Kobo o i s d ough ole ance. In Si e, c op o a ions
a e mo e di e se han in Kobo, and include cash c ops such as
pulses and ege ables. Ag o o es y is p ac ised a ound he home-
s eads on many a ms. The ag oecological and socioeconomic cha -
ac e is ics o he case egions we e desc ibed in de ail by Kahiluo o
e al. (2012).
As a ailable esou ces subs an ially influence he use o inpu s
in c opping (Mwaniki, 2005), in each o he wo egions we
selec ed one case a m wi h limi ed esou ces and ano he wi h
g ea e esou ces, compa ed wi h he a e age o he dis ic
(Table 1). Fa me s wi h limi ed esou ces pa icipa ed in he P o-
duc i e Sa e y Ne P og amme, a social p o ec ion scheme unde
he na ional Food Secu i y P og am, add essing ch onically ood-
insecu e people (Nega u, 2008). Be e -o a ms wi h g ea e
esou ces had mo e field a ea and li es ock and mo e ad anced
ag oecological managemen p ac ices han on a e age o he
egion. All ou case a ms applied GAPs (Table 1). Fa ms
ep esen a i e o size, numbe o li es ock, deg ee o ood aid,
and applied managemen we e selec ed om wi hin each o he
14 K. Rimhanen, H. Kahiluo o / Ag icul u al Sys ems 130 (2014) 13–22
wo socioeconomic g oups o each egion. The selec ion was done
wi h he help o local ag icul u al ad ise s wi h b oad local
expe ise.
2.2. Defini ion o he s udied sys em
The a ming sys em, defined on a unc ional basis, composed o
c opping, li es ock aising and g azing, compos ing and household
ood and ene gy consump ion (Fig. 2). The ha es ed C p oduced in
he c op fields we e g ain o ood, and s aw o odde and uel,
and in he angeland hay o li es ock odde and o compos -mak-
ing and uel wood o he household ene gy. In addi ion, ha es ed
C was supplemen ed om ma ke s, neighbo s and cha i y. The li e-
s ock included he animals o he a m ha p oduced animal p od-
uc s o household consump ion and o sale, and manu e and u ine
o uel and compos . The s udy ocused on he flows o he ha -
es ed C (i.e., he C managemen sys em), o quan i y he p opo -
ion o ha es ed C alloca ed o ood, soil and C losses (Fig. 2).
2.3. Ma e ial flow analysis
MFA was used o ace he C ma e ial flows and o quan i y he
p opo ion o ha es ed C used o ood and soil. C losses occu ing
be o e ha es ed C ended up in ood o soil we e calcula ed based
on ma e ial C balances o p ocesses o li es ock aising, compos -
ing and household biomass bu ning. The C flows we e quan ified
h ough semi-s uc u ed in e iews and sampling, and comple-
men ed and double-checked wi h in o ma ion om he published
li e a u e (see Sec ion 2.3.1). The C con en s o flows we e calcu-
la ed by mul iplying he mass o he flow pe single yea by i s C
concen a ion. To ge an a e age es ima ion, flows we e s udied
o e wo one-yea pe iods. The esul s we e epo ed as he mean
o he wo yea s. The e was no fi e o significan cons uc ion wo k
on he a ms du ing he s udy yea s.
2.3.1. Calcula ion o he C flows
2.3.1.1. C opping. The quan i y o impo ed seeds (Se) and compos
(Co), as well as he quan i y o expo ed c ops was based on a me
es ima ion. The c op (C ) and s aw (S ) yields es ima ed by he
esponden s o he 2009/2010 g owing seasons we e double-
checked by sampling. C op yields we e manually sampled a ha -
es ime o he main g owing season in Oc obe –No embe
2010. Two 1 m
2
plo s in each cul i a ed field we e ha es ed. The
esh weigh o g ain and s aw we e eco ded. Th ee eplica e
samples we e sepa a ed om each plo sample o u he analy-
ses. The DM% (w/w) was measu ed by d ying a 105 °C o 12 h
a Melkasa E hiopian Ins i u e o Ag icul u al Resea ch. Since he
expo o whea (T i icum L.) and e [E ag os is e (Zucc.) T o e ]
om E hiopia was o bidden, es ima ions o hei C concen a ions
we e based on p e iously epo ed figu es (Table 2). C concen a-
ions o seeds (Se) we e based on measu emen i a pa icula spe-
cies was analyzed o om he li e a u e. C concen a ion o g ain
and s aw o ha ico bean (Phaseolus ulga is L.), ba ley (Ho deum
ulga e L.) and so ghum we e de e mined using a Leco CN analyze
a he labo a o y o MTT Ag i ood Resea ch Finland (Table 3).
2.3.1.2. G azing. The quan i y o manu e (Ma) and u ine (U ) ha
emained in he angeland du ing g azing was es ima ed a 40%
o he o al manu e p oduc ion (Haileslassie e al., 2005; Manlay
e al., 2004). The DM con en o angeland hay (Ha) was es ima ed
a 93% (Kabaija and Li le, 1988). C concen a ion o hay was based
on epo ed figu es (Table 2).
2.3.1.3. Li es ock aising. The li es ock popula ion was con e ed
in o opical li es ock uni s (TLU). The con e sion ac o s we e
0.7 o ca le and mules, 0.15 o sheep and goa s, 0.5 o donkeys,
0.01 o chickens, 0.8 o ho ses, and 1 o camels (Jahnke, 1982).
The daily eed in ake was es ima ed by mul iplying he DM weigh
o manu e by eed diges ibili y (Ib ahim and Olaloku, 2000), as: DM
in ake (g/day) = 100/(100 diges ibili y)DM weigh o manu e,
whe e diges ibili y is gi en as a pe cen age. The diges ibili y o
eed was es ima ed a 50% (P es on and Leng, 1987; FAO, 1999)
and he p oduc ion o manu e (Ma) o one TLU a 3000 g DM pe
day o ca le (Haileslassie e al., 2009; FAO, 1999). The daily eed
in ake was es ima ed a 6000 g DM/day/TLU. To double-check his
esul we compa ed he figu e wi h he assump ion o daily eed
in ake o 2% o body weigh epo ed by FAO (1999). Ou esul di -
e ed om he p e iously epo ed alue by 4–17%.
Fig. 1. Loca ion o he case egions in E hiopia (Kahiluo o e al., 2012).
K. Rimhanen, H. Kahiluo o / Ag icul u al Sys ems 130 (2014) 13–22 15
The quan i y o impo ed s aw (S ) om c opping and ma ke s,
and li e animals (La) om ma ke s we e based on a me es ima-
ions. The amoun o g azed hay (Ha) was es ima ed by sub ac ing
he odde consumed a he a m om he o al es ima ed eed
in ake. The DM con en o s aw (S ) pu chased om he ma ke s
was assessed on he basis o measu emen s. The p oduc ion o ca -
le u ine (U ) was es ima ed a 530 g DM pe day (Tes aye e al.,
2006). The u ine p oduc ion pe TLU o o he animals was
es ima ed o co espond o ha o ca le. The quan i ies o expo ed
milk (Mi) and li e animals (La) we e based on a me es ima ions.
The quan i y o egg (Eg) p oduc ion was es ima ed a 60 eggs pe
10 ma u e bi ds pe yea (Dessie and Ogle, 2001). C concen a ions
o manu e (Ma), u ine (U ), milk (Mi), eggs (Eg), and li e animals
(La) (Table 2) we e based on figu es epo ed in he li e a u e.
2.3.1.4. Compos ing. The quan i ies o impo ed manu e (Ma) and
hay (Ha) we e based on a me es ima ions. C concen a ion was
based on epo ed alues (Table 2). The quan i y o p oduced
compos (Co) was based on a me es ima ion.
2.3.1.5. Household ood and ene gy consump ion. The quan i y o
impo ed c ops (C ), seeds (Se), li e animals (La), mea (Me), milk
(Mi), eggs (Eg), s aw (S ), ene gy sou ces, including manu e
(Ma), s aw (S ) and wood (Wo), and he quan i y o ma ke ed
c ops (C ), li e animals (La) and Milk (Mi) we e based on a me
es ima ions. The li e and ca cass weigh s o animals we e based
on figu es epo ed in he li e a u e (Table 4). The annual p oduc-
ion o human aeces was es ima ed a 50 kg (20% DM) and u ine a
500 kg (4% DM) pe pe son (Heinonen-Tanski and Van Wijk-
Sijbesma, 2005; Jönsson e al., 2004; Malkki, 1999). In he analysis,
human aeces and u ine we e epo ed join ly as exc e a (Ex). The
quan i y o aeces and u ine o child en below 15 yea s o age was
es ima ed o be hal ha o adul s. C concen a ions o c ops (C )
we e based on measu emen s o epo ed figu es, and hose o
li e animals (La), mea (Me), milk (Mi), eggs (Eg), wood (Wo),
human aeces and u ine we e based on p e iously epo ed in o -
ma ion (Table 2).
2.3.2. Calcula ion o he p opo ion o ha es ed C used o ood and
soil and C losses
The p opo ion o ha es ed C used o ood and soil was calcu-
la ed as: The quan i y o ha es ed C ending up in ood and soil
(kg)/The quan i y o o al ha es ed C p oduced on a m and
impo ed o he a m (kg)100.
C losses we e calcula ed as he di e ence be ween C impo s
and expo s o each p ocess ollowing ha es ing and impo s.
Fo he li es ock he C loss was calcula ed as: (hay + s aw + li e
animals) – (manu e + u ine + li e animals + milk + eggs). The posi-
i e balance indica ed C loss h ough animal me abolism. Fo he
compos C loss was calcula ed as: (hay + manu e) (compos ).
And o he household ene gy use he C loss was calcula ed as:
s aw + manu e + wood. We also es ima ed C losses om un apped
human exc e a and o al. Howe e , hese losses occu ed a e he
ha es ed C had ended up in ood. C loss ega ding he un apped
human exc e a was calcula ed as: aeces + u ine and C loss ega d-
ing o als expo ed o wildli e as: 0.5o al. The es was exploi ed
a he household sys em.
2.4. In e iews
Adul household membe s who pa icipa ed in a m wo k we e
included in he in e iews, comp ising one o h ee pa icipan s.
The in e iews we e conduc ed a he p oduce s’ associa ions in
Oc obe 2010 by wo local socioeconomic esea che s om he
na ional ag icul u al esea ch sys em, ained by he au ho s. The
in e iews, conduc ed in Amha ic in Kobo and O omia in Si e, we e
ape- eco ded, ansc ibed and ansla ed in o English. The leng h
o he in e iews anged be ween h ee and six hou s. The in e -
iew guide included de ailed ques ions abou he a m cha ac e is-
ics and esou ces, land use his o y, ag icul u al managemen
p ac ices a field plo le el, including specific ques ions abou c op
o a ion, use o manu e, c op esidues and o he inpu s, compos -
ing, ha es ing losses, li es ock managemen and g azing, house-
hold die and acquisi ion o ood, cash c ops and expo s o
animals, use o uel wood and managemen o o ganic household
was e wi hin he a ming sys em in 2008/2009 and 2009/2010.
2.5. Unce ain y analysis
The model o Hedb an and Sö me (2001), de eloped o unce -
ain y analyses o MFA, was used o es ima e he unce ain ies o
he MFA da a and he esul s. The unce ain y ac o s, which define
he a e o unce ain y o he da a, we e de e mined based on
Hedb an and Sö me (2001), applied by An ikainen e al. (2005)
and Danius (2002). The da a sou ces we e classified in o fi e
unce ain y in e als (Table 5) on he basis o unce ain y by com-
pa ing he ypes o da a in his s udy o An ikainen e al. (2005)
and Danius (2002). Fo example, he numbe o ca le on he a m
was gi en an unce ain y ac o o 1.1 and he quan i y o manu e
used as uel an unce ain y ac o o 2, meaning ha quan ifica ion
o manu e included subs an ially mo e unce ain y han quan ifi-
ca ion o he numbe o ca le.
Table 1
Cha ac e is ics o he esou ce-limi ed and be e -o case a ms in Kobo and Si e egions.
Kobo Si e
Resou ce-limi ed Be e -o Resou ce-limi ed Be e -o
Holding size
a
, ha 0.75 1.5 2.5 6.25
Numbe o household
membe s
467 7
Numbe o TLU’s
b
0.85 5.3 5.0 13.2
Numbe o oxen 1 2 2 7
C op o a ion Te –so ghum Te –so ghum–onion Whea /ba ley– e –ha ico
bean/whea
Onion–whea –ha ico bean– e
GAP’s
c
Fa mland e acing, a ea
enclosu es
d
Fa mland e acing, a ea
enclosu es
d
Compos ing Ag o o es y since 2001, ploughing agains
slope, compos ing
Sou ces o li elihood apa
om a ming
Ca pen e G ain b oking Sale o g ain and animals House en ing
a
Includes owned and en ed land.
b
TLU = T opical li es ock uni .
c
Good ag icul u al p ac ices.
d
A eas p ese ed om human and animal in e up ion.
16 K. Rimhanen, H. Kahiluo o / Ag icul u al Sys ems 130 (2014) 13–22
When calcula ion o a flow equi es mul iplica ion o da a, he
unce ain y inc eases (Hedb an and Sö me, 2001). An example
o he mul iplica ion is calcula ion o he quan i y o C in manu e
p oduced pe day. In he case o he be e -o a m in Kobo, he
numbe o TLU’s is 5.26, he amoun o p oduced manu e 3 kg
DM and he C concen a ion o manu e 35%. The likely alue (m)
o C con en in manu e p oduced pe day is calcula ed as:
m
a
b
c
¼m
a
m
b
m
c
i:e:
m¼5:26 3kg0:35 ¼5:5kgC:
The unce ain y ac o s a e de e mined o each ype o da a
(Table 5). In his case, he numbe o TLUs was gi en an unce ain y
ac o o 1.1, he amoun o p oduced manu e ac o 2 and he C
concen a ion o manu e ac o 1.33.
The unce ain y ac o ( ) is calcula ed acco ding o Hedb an
and Sö me (2001) as:
a
b
c
¼1þðð
a
1Þexp2þð
b
1Þexp2þð
c
1Þexp2Þexp0:5
i.e. in ou example he unce ain y ac o ( ) is calcula ed as:
¼1þðð1:11Þexp2þð21Þexp2þð1:331Þexp2Þexp0:5¼2:06
The C con en in he daily manu e p oduc ion is e y likely o be
5.5 kg
/2.06. Thus, he C con en p obably lies be ween 2.7 and
11.3 kg. The analyses we e pe o med using Mic oso O fice Excel
2007.
In addi ion, we conduc ed a sensi i i y analysis o es whe he
he unce ain y ange influenced ou conclusions abou he o de
o he g ea es C losses.
3. Resul s
3.1. The p opo ion o ha es ed C used o ood and soil
The flows o ha es ed C we e gene ally no ably la ge in Si e
han in Kobo and on he be e -o a ms han on he esou ce-lim-
i ed ones (Fig. 3a–d). The majo flows o C we e hay om he
angeland o odde , and s aw om he c opland o odde and
uel. In o al, 16–28% o he ha es ed C was used o ood and soil.
The sha e used o ood was 9–16% and o soil amendmen 4–12%.
The sha e o ood used a household le el was highe on he
esou ce-limi ed a ms (Fig. 4a). All o he a ms p epa ed compos .
The use o manu e o compos was highe on he be e -o a ms
(Fig. 4b). The applica ion a e o compos on he esou ce-limi ed
a ms was 53 and 176 kg ha
1
and on he be e -o a ms 264
and 1320 kg ha
1
on a e age, in Kobo and Si e, espec i ely.
A la ge sha e o ha es ed s aw was used o ca le odde in Si e.
3.2. C losses
The sha e o he o al C loss was sligh ly highe in Kobo, 83–84%
han in Si e, 72–76% (Fig. 3a–d). The la ges C loss was animal
me abolism, excep o he esou ce-limi ed a m in Kobo whe e
he la ges loss was caused by biomass bu ning o household
ene gy. The loss om he animal me abolism was la ge on he
be e -o a ms han on he esou ce-limi ed a ms. On he
esou ce-limi ed a ms, a g ea e po ion o manu e was used o
uel han on he be e -o a ms (Fig. 4b). Compos ing caused la -
ge C losses on he be e -o a ms han on he esou ce-limi ed
a ms. Du ing compos ing he quan i y o C was educed by
96–97% on he esou ce-limi ed a ms and by 66–97% on he
be e -o a ms. Bu ning o biomass caused mo e C losses on he
be e -o a m han on he esou ce-limi ed a m in Si e and
ice e sa in Kobo (Fig. 3a–d). The main sou ces o uel we e d ied
manu e, s aw and wood (Fig. 4c). On all a ms human exc e a was
no ecycled as e ilize o he field bu was dug in o he soil on
was eland soil. In addi ion, he inedible sha e o o al was h own
o hyenas. These losses occu ed howe e a e ha es ed C was
managed o ood and ep esen ed a negligible losses (exc e a
36–63 kg C and o al 0.2–6 kg C) om he sys em.
4. Discussion
4.1. De e minan s o he p opo ion o ha es ed C ending up in ood
and soil
The sha e o he ha es ed C ending up in ood and soil in o al
was sligh ly highe in Si e han Kobo. The egions di e ed in use o
Fig. 2. The concep ual model o he a ming sys em p ocesses wi h hei flows and s ocks o C. The ed bounda y ames he managemen sys em o ha es ed C explo ed in
his s udy. Ma e ial C flows, ep esen ed as black solid line we e quan ified di ec ly. C losses occu ing in he managemen sys em o ha es ed C, ep esen ed as ed sca e ed
line we e calcula ed indi ec ly based on balance coun ing o uel use, li es ock and compos ing.
K. Rimhanen, H. Kahiluo o / Ag icul u al Sys ems 130 (2014) 13–22 17
ha es ed C o uel. The use o s aw o uel was highe in Kobo
han in Si e due o educed a ailabili y o uel wood, he esul o
hea y de o es a ion in he No h and una ailabili y o al e na i e
ene gy sou ces. The use o s aw as uel educed he use o odde
and hus he sha e o ha es ed C ending up in ood. In Si e whe e
he use o s aw o odde was highe , he use o manu e as uel
was g ea e so ha in bo h cases he lack o al e na i e ene gy
sou ces educed he alloca ion o o ganic ma e ials o ag icul u al
soil. In Si e, he sho e cul i a ion his o y, la ge holding size,
legumes in he o a ion and la ge amoun o manu e h ough
g ea e numbe o animals may ha e con ibu ed o highe soil e -
ili y and hus highe yields. In p e ious s udies (e.g. Elias e al.,
1998; Be y, 2003) he sha e o c op esidues used o soil amend-
men anged om 10% o 30% in E hiopia. Ou s udy indica es e en
lowe u iliza ion a es, possibly due o nega i e de elopmen in
esou ce a ailabili y du ing he las decade. The quan i y o com-
pos used on fields es ima ed by he p esen s udy, anging om
53 o 1320 kg ha
1
a
1
, and use o 10–48% o manu e o uel,
was in line wi h epo s o Mekonnen and Köhlin (2008), and
Co beels e al. (2000), bu lowe han ha o Edwa ds e al.
(2007), who epo ed use o 5000–15,000 kg ha
1
on fields in
E hiopia.
The highe c op p oduc ion and mo e di e se c op species
enabled c op sales on he be e -o a ms whe eas on he
esou ce-limi ed a ms he majo sha e o edible plan biomass
p oduced was consumed on a m. G azing on he communal ange-
land, and on fields a e ha es ing, ep esen ed a c i ical odde
supply in he case egions. The la ges ha es ed C flow o he
a ming sys ems was hay o he li es ock sys em; howe e a no a-
bly small sha e o odde was con e ed in o animal p oduc s in all
a ms.
4.2. C losses
The g ea es C losses occu ed om he li es ock sys em, p ob-
ably due o he need o ha e a high numbe o ca le in ela ion o
he quan i y o a ailable odde , o se e as d a powe and insu -
ance agains c op ailu e. Su ficien high-quali y odde could
educe C losses om li es ock me abolism by imp o ing animal
p oduc i i y and indi ec ly h ough educing he equisi e numbe
o animals (Abegaz e al., 2007). Managemen o g azing in ensi y
could enhance g assland p oduc i i y (Schönbach e al., 2011)
and in eg a ion o ees p oducing odde in he c opping sys em
could di e si y and s abilize odde supply. Fu he , mo e s able
and di e se income sou ces could c i ically educe he need o
la ge he d size as insu ance.
In he p esen s udy, he calcula ed C loss om compos ing was
20–30% highe han epo ed in p e ious s udies (Ti onell e al.,
2010; Tiquia e al., 2002; Somme , 2001). High C losses may be
Table 2
C concen a ions o he o ganic ma e ial flows ( o ull e e ences see Appendix B).
Ma e ial C% Sou ce
Te , g ain 43.0
ae,ao,ap,aq
Te , s aw 45.0
ae,ap,a ,as,a ,au,ax
Whea , g ain 43.0
ae,ao,ap,aq
Whea , s aw 45.0
ae,ap,a ,as,a ,au,a
Co n cob 49.0
a ,au
Co n s o e 45.0
a ,au,a ,ax
Onion 45.0
ay,az
Pas u e hay 50.0
a ,bb,bc,bd
Manu e 35.0
a ,be,b
Cow u ine 1.0
ba,bg
Compos 25.0
be,b ,bh
Milk 45.0
a ,bi,bj,bk
Mea 56.0
a ,bi,bl,bm,bn
Egg 56.0
bi,bn,bo,bp
O al 56.0
a ,bi,bm,bn
Li e animals 56.0
a
Wood 50.8
a ,au,bq
Human aeces 50.0
b ,bs,b
Human u ine 20.0
bs,b ,bu
ae
P ima y da a (2010).
ao
Mengesha (1966).
ap
Me ah e al. (1999).
aq
Woldeab e al. (1991).
a
Kahiluo o e al. (2011).
as
Leh omäki e al. (2008).
a
P asinski e al. (2007).
au
Demi bas (1997).
a
P es on and Leng (1987).
ax
Tole a and Sunds ol (2000).
ay
Raines e al. (2009).
az
Fu lan and Be nie -Ca dou (1989).
ba
Edwa ds and A aya (2010).
bb
Kabaija e al. (1989).
bc
Kabaija and Li le (1988).
bd
Ib ahim and Olaloku (2000).
be
Lekasi e al. (2001).
b
Paul e al. (2009).
bg
Tegegne e al. (2007).
bh
Bie wi h (2001).
bi
Fineli (2011).
bj
Zublena e al. (1997).
bk
WHFoods (2011).
bl
Malek e al. (2009).
bm
USDA (2011a).
bn
USDA (2011b).
bo
Ma e al. (2009).
bp
FAO (2003).
bq
Toky and Singh (1995).
b
F y (1973).
bs
Jönsson e al. (2004).
b
Heinonen-Tanski and Van Wijk-Sijbesma (2005).
bu
Malkki (1999).
Table 3
D y ma e (DM) and ca bon (C) concen a ions o he cul i a ed plan s on he case
a ms.
Ma e ial DM% C% in DM
Mean Range
So ghum, g ain (n= 12) 93 41.14 40.61–41.86
So ghum, s aw (n= 12) 71 40.40 38.77–42.27
Ba ley, g ain (n= 12) 88 41.14 40.83–41.56
Ba ley, s aw (n= 12) 96 41.15 39.78–42.28
Ha ico bean, g ain (n= 6) 78 40.93 40.66–41.24
Ha ico bean, s aw (n= 6) 53 40.39 39.92–40.59
Table 4
Li e and ca cass weigh s used o he domes ic animals. Hal o he o al was assumed
o be consumed by he households ( o ull e e ences see Appendix B).
Animal species Li e weigh (kg) Ca cass weigh (kg)
Camel 400
a
Ca le 250
ag,ah
108
ai
Cal a weaning s age 50
aj
Donkey, mule, ho se 105
ak
Goa , sheep 14
al
8
al
Chicken 1
am
0.6
an
Chicken egg 0.04
am
a
Ku u (2004).
ag
Abdelhadi and Babike (2009).
ah
Osuji and Cappe (1992).
ai
FAOSTAT (2011c).
aj
Sidibé-Anago e al. (2008).
ak
Geb eab e al. (2000).
al
Legesse and Abebe (2008).
am
Dana (2011).
an
Mogesse (2007).
18 K. Rimhanen, H. Kahiluo o / Ag icul u al Sys ems 130 (2014) 13–22
due o CH
4
p oduc ion esul ing om anae obic condi ions in
dense compos piles (Pel e al., 1997), om apid deg ada ion o
o ganic ma e ial a high empe a u e (Sánchez-Monede o e al.,
2010) o due o leaching as dissol ed o ganic ca bon. Pa o he
C may also be seques a ed in soil below he compos pile. Ou p e-
ious findings ega ding heal h p oblems due o gaseous emissions
while u ning and anspo ing compos (Kahiluo o e al., 2012)
suppo he p esen conclusions o high C losses. Howe e he
esul s include unce ain y as he biomass ou pu om he com-
pos ing was based on a me es ima ion.
Con a y o li es ock me abolism and compos ing losses, C
losses om esidue bu ning a e o ally a oidable when p oducing
ood and soil amendmen . A ailabili y o al e na i e ene gy
sou ces o subs i u e o manu e and s aw as uel would likely
inc ease hei use as soil amendmen . In oduc ion o new echnol-
ogies using less uel would conse e ha es ed C so ha i could be
used o imp o e soil C s ocks and p oduc i i y. Anae obic diges ion
in manu e handling could educe nu ien and C losses and also
imp o e ood sa e y and u iliza ion. In eg a ion o ees in he
a ming sys em could o ally a oid esidue use as uel. C loss om
Table 5
Unce ain y ac o s wi h sou ces o da a and examples. The inpu da a (X) may ange om X di ided by unce ain y ac o (Y) (X/Y) o X mul iplied by Y (X Y) (Hedb an and
Sö me, 2001; An ikainen, 2005; Danius, 2002) ( o ull e e ences see Appendix B).
Le el Fac o Da a sou ce Type o da a Sou ce
1 1.1 In e iewees Numbe o people and animals, a ea o ag icul u al land
Measu ed C concen a ions o ha ico bean, ba ley, so ghum
Li e a u e C concen a ions o whea , co n, onion, pas u e hay, milk, eggs
ao,ap,aq,a ,as,a ,au,a ,ax,ay,az,bb,bc,bd,bi,bj,bk,bn,bo,bp
2 1.33 Li e a u e C concen a ions o li e animals, mea , manu e, u ine, o al, compos , wood,
human aeces, human u ine
a ,a ,au,ba,be,b ,bg,bh,bi,bl,bm,bn,bq,b ,bs,b ,bu
3 1.5 Measu ed G ain and s aw yields
4 2 Li e a u e S aw and hay in ake, quan i y o p oduced manu e, u ine and human
exc e a, animal weigh s
a ,ag,ah,ai,aj,ak,al,am,an,ap,a ,as,a ,au,ax,bb,bc,bd,bs,b ,bu
Li e a u e on c op
cha ac e is ics
ex apola ed o o he
c ops
C concen a ions o e
ao,ap,aq,a ,as,a ,au,ax
In e iewees Quan i y o g ain and s aw yields, impo ed ood aid, c ops, mea , seeds,
manu e, s aw and li e animals, use o g ain and s aw, hay, compos ,
manu e, woods, milk, eggs and li e animals, quan i y o ha es ing losses,
expo ed c ops, li e animals, milk, exc e a, o al and skin
5 4 In e iewees The amoun o uel wood woman and donkey can ca y
a
Ku u (2004).
ag
Abdelhadi and Babike (2009).
ah
Osuji and Cappe (1992).
ai
FAOSTAT (2011c).
aj
Sidibé-Anago e al. (2008).
ak
Geb eab e al. (2000).
al
Legesse and Abebe (2008).
am
Dana (2011).
an
Mogesse (2007).
ao
Mengesha (1966).
ap
Me ah e al. (1999).
aq
Woldeab e al. (1991).
a
Kahiluo o e al. (2011).
as
Leh omäki e al. (2008).
a
P asinski e al. (2007).
au
Demi bas (1997).
a
P es on and Leng (1987).
ax
Tole a and Sunds ol (2000).
ay
Raines e al. (2009).
az
Fu lan and Be nie -Ca dou (1989).
ba
Edwa ds and A aya (2010).
bb
Kabaija e al. (1989).
bc
Kabaija and Li le (1988).
bd
Ib ahim and Olaloku (2000).
be
Lekasi e al. (2001).
b
Paul e al. (2009).
bg
Tegegne e al. (2007).
bh
Bie wi h (2001).
bi
Fineli (2011).
bj
Zublena e al. (1997).
bk
WHFoods (2011).
bl
Malek e al. (2009).
bm
USDA (2011a).
bn
USDA (2011b).
bo
Ma e al. (2009).
bp
FAO (2003).
bq
Toky and Singh (1995).
b
F y (1973).
bs
Jönsson e al. (2004).
b
Heinonen-Tanski and Van Wijk-Sijbesma (2005).
bu
Malkki (1999).
K. Rimhanen, H. Kahiluo o / Ag icul u al Sys ems 130 (2014) 13–22 19
he uel use was o he same size in all he a m households,
indica ing ha p e en ing ha loss could o e a cons an educ ion
in C losses on smallholde a ms. Human exc e a and o al we e he
only un apped ecyclable C sou ce in he a ming sys em, ep e-
sen ing a negligible p opo ion o ha es ed C in mixed a ming.
4.3. Gene ali y and eliabili y
The con as ing case egions in he highlands o he Cen al Ri
Valley, highly impo an o ood p oduc ion in E hiopia, and he
smallholde mixed a ming sys ems, exempli ying a b oad ange
o esou ce a ailabili y and he mos common a ming sys em ype
in he coun y, make he esul s ep esen a i e o E hiopian ood
p oduc ion. The ac ha he esul s we e ela i ely simila among
he con as ing a ms suppo s his gene ali y. Empi ical da a om
wo di e en yea s oge he co e ing a ep esen a i e ange o
wea he a ia ion p o ide a s ong basis o unique es ima es o
flows and losses o ha es ed C in Eas A ican mixed a ming
sys ems.
In e iews and pa ial eliance on he li e a u e, as me hods o
collec da a, imply unce ain y. Howe e , he esul s we e
double-checked by using se e al da a sou ces o dec ease e o s.
Es ima ions o C flows ha a e based on mul iplicand da a, such
as consump ion o angeland hay, he use o manu e, compos
applica ion, and use o animal p oduc s, esul in he g ea es
unce ain y. In con as , o esul s ha o igina e om ou mea-
su emen s, e.g. yields, he unce ain y is smalle . The e a e
undoub edly unce ain ies o he o de o g ea es C losses (Appen-
dix D).
4.4. MFA in calcula ing he use o ha es ed C and iden i ying C losses
MFA includes a sys ema ic assessmen o he flows and s ocks
o ma e ials wi hin a sys em defined in space and ime (B unne
and Rechbe ge , 2004) and as such o e ed a use ul ool o quan i y
flows and alloca ion o he ha es ed C and indica e he e ficiency
in i s use o ood and soil. MFA allowed quan i ying he C losses
including he gaseous ones, h ough calcula ion o he C balance
o he p ocesses (Pi es e al., 2011) wi hin he ha es ed C manage-
men sys em. The analysis is no a p ac ical me hod o illus a e
he en i e ca bon cycle o ca bon budge o he a ming sys em
due o es ic ions in accoun ing o gaseous exchange among he
Fig. 3. (a–d) Alloca ion o ha es ed C (kg pe yea ) o ood, soil and losses on he case a ms. The ha es ed C flows a e ep esen ed as black solid lines and C losses as ed
sca e ed lines. Values a e means o 2008/2009 and 2009/2010. The unce ain y anges o he alloca ion o ha es ed C flows o ood and soil a e p esen ed in Appendix C and
o he C losses in Appendix D.
20 K. Rimhanen, H. Kahiluo o / Ag icul u al Sys ems 130 (2014) 13–22
a mosphe e, plan s and soil. The analysis o he C losses indica es
low u iliza ion o a m esou ces and o ms he basis o u he
esea ch o assess di e en means o p e en losses o C om
a ming sys ems. MFA seems a sui able ool o guide managemen
o o ganic ma e ials on a ms. These uses could be acili a ed
h ough de elopmen o s anda d p ocedu es and guidelines in C
budge ing and unce ain y analyses in an analogy o nu ien bud-
ge ing app oaches (Oenema e al., 2003).
5. Conclusions
This s udy sugges s ha he esidue biomass is ca e ully u ilized
in hese a ming sys ems and consequen ly he main C losses a e
gaseous. The majo C losses in smallholde mixed a ms occu in
animal me abolism and bu ning o biomass. The la ge and cons an
C losses h ough he en i ely eplaceable esidue bu ning o e he
mos accessible emedy o smallholde managemen o ha es ed
C. Consequen ly, he p opo ion o ha es ed C used o uel
appea s as he main de e minan o he p opo ion o ha es ed
C ending up in soil and ood. C ea ion o ene gy subs i u es o
manu e and s aw, imp o ed manu e managemen h ough, e.g.
anae obic diges ion o esidues and mo e s able ood and odde
supply o educe he equisi e numbe o animals a e all keys o
close C cycles in he a ming sys ems. Quan ifica ion o he flows
o ha es ed C is a use ul app oach ha e eals he use and losses
o ha es ed C when measu emen o gaseous emissions is no ea-
sible. Such assessmen s a e o a g ea alue in guiding sus ainable
managemen o ha es ed C in smallholde a ms.
Acknowledgemen s
This s udy was conduc ed wi hin he SOILMAN (Decision No.
270106) and Al e CLIMA (Decision No. 127405) p ojec s o he
Academy o Finland. Ou special hanks go o he a me s in Kobo
and Si e who pa icipa ed in he s udy, E hiopian assis an s Gi ma
Shumi and Kb om Be he, who helped us collec he da a, Reimund
Rö e who coo dina ed he Al e CLIMA p ojec , and o p o esso s
Ma kku Yli-Halla and Juha Helenius (Uni e si y o Helsinki) o
help ul commen s.
Appendix A. Supplemen a y ma e ial
Supplemen a y da a associa ed wi h his a icle can be ound, in
he online e sion, a h p://dx.doi.o g/10.1016/j.agsy.2014.06.003.
Fig. 4. (a–c) Use o (a) ha es ed C om c opping and (b) use o C in manu e, and (c) sou ces o C in uel (kg pe yea ) on he case a ms. The size o each pie ep esen s he
o al amoun o C managed in each a m.
K. Rimhanen, H. Kahiluo o / Ag icul u al Sys ems 130 (2014) 13–22 21