Conservation Agriculture for Environmental Sustainability in A Semiarid Agroecological Zone

19 Pages·2017·3.2 MB·English

sustainability
Article
Conservation Agriculture for Environmental
Sustainability in A Semiarid Agroecological Zone
under Climate Change Scenarios
ZhangHong1,MsafiriY.Mkonda1,2,* ID andXinhuaHe1,3,* ID
1 CentreofExcellenceforSoilBiology,CollegeofResourcesandEnvironment,SouthwestUniversity,
Chongqing400715,China;[email protected]
2 DepartmentofGeographyandEnvironmentalStudies,SolomonMahlanguCollegeofScienceand
Education,SokoineUniversityofAgriculture,Morogoro3038,Tanzania
3 SchoolofBiologicalSciences,UniversityofWesternAustralia,Crawley6009,Australia
* Correspondence:[email protected](M.Y.M.);[email protected](X.H.)
(cid:1)(cid:2)(cid:3)(cid:1)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:1)
(cid:1)(cid:2)(cid:3)(cid:4)(cid:5)(cid:6)(cid:7)
Received:11February2018;Accepted:26April2018;Published:4May2018
Abstract: Using the Mann–Kendall Test to analyze data from a survey of 400 farmers, this study
compared the rate of adoption of conservation agriculture (CA) in two contrasting villages of
Mnyakongo and Ugogoni locating in the Kongwa District, a semi-arid zone in central Tanzania.
ResultsexhibitedthatthelevelofCAadoptionwas<10%ofthetotalhouseholds. ThetrendofCA
adoptionwasdeterminedatthecoefficientofR2=0.95,0.90,0.68and0.57formulching,croprotation,
agroforestryandlittletillage,respectively. Despitelittletillageandcroprotationhavinghighacreage
underCA,therateofmulchingadoptionwassignificantlyhigherthanthatofothers. Furthermore,
there were significant correlations between the CA adoption and crop yields or environmental
sustainability (p < 0.05). Maize, sorghum and millet yields were significantly greater under CA
(1.7tha−1)thanno-CA(0.7tha−1). Particularly,maizeyieldswereincreasedfrom1.3to2.3tha−1
from2000to2015underCAwhenitwasintercroppedwithlegumes. Themajorityfarmers(>70%)
assertedthatCAhadoptimizedtheiryieldsforbothfoodandeconomicincentives. Thus,thisstudy
recommendstheadoptionofCAinthesemi-aridagro-ecologicalzones.
Keywords: climate change; crop yields; environmental services; intercropping; legumes;
Mann–Kendalltest;vulnerability;Tanzania
1. Introduction
Thesignificanceofsoilorenvironmentalconservationtolimitsoildegradationhasbeenadvocated
since1903[1]. The currentsituationofa rapidpopulationincrease andglobalclimatechangehas
necessitatedthepracticabilityofsuchsoilconservation[2]. Forexample,theUSAgovernmenthas
invested millions of dollars yearly to support conservation related projects [3,4]. To increase fruit
production and environmental conservation in organic Australian vineyards, both mulching and
compositeareusedasconservationagriculturalpractices[5]. Thispracticeincreasescropyieldsand
environmentalconservationinvariousareasofthecountry.
The increasing extreme of weather changes especially for temperature and precipitation has
significantly impacted the nutrient cycling and soil moisture in most of Sub-Saharan Africa [6,7].
Theseweatherchangescouldintensifyinthefutureasvariousclimatemodelshavebeenpredicting
furtherclimatealterations. Asaresult,acropproductionsystemanditsproductivityaretoworsen
withpossiblyhighoutbreakofdiseases,pestsandpathogens.
To intervene with these authentic and potential consequences, we need to develop resilient
agriculturalsystemsthroughrationalandaffordablestrategiesthatmaintaintheecosystemfunctions
Sustainability2018,10,1430;doi:10.3390/su10051430 www.mdpi.com/journal/sustainability
Sustainability2018,10,1430 2of19
andprotectlivelihoods[8–10]. Studieshaverecommendeddifferentconservationagriculture(CA)
practices to mitigate, and adapt to, climate impacts [11]. CA features in various forms such as
organicsoilmanagement,agroforestry,croprotation,etc. Bennettetal.[12]andMalviyaetal.[13]
in their models found that N -fixing legumes hve potential for both crop yields optimization and
2
environmentalservices. Moreover,Zhuetal.[14]realizedthatorganicmatterfromdeaddebrisand
litterdecomposition are importantfor improvingsoil fertilityin variousecosystems. Organicsoil
managementisanimportantaspectofCA.
Sincesmallholderfarmersarevulnerabletoextremechangeofrainfallpattern,CAcanbetheir
bestprepositiontoelevatetheirresilience[15,16]. Thisisparticularlyimportantbecauseitisexpected
that, by2030, Africawillhave120–150millionsmallholderfarmersandmostofthemwillrelyon
rain-fed agriculture for their subsistence [17]. While the dependence on rainfed-fed agriculture is
expected to increase, the projections from an assessment of 12 CMIP3 (CMIP3 - Coupled Model
IntercomparisonProjectThree)(AR4-4th AssessmentReport)GCMs(GlobalClimateModels)over
Africasuggestanextremevariationinrainfallbytheendofthe21stCentury[18]. Inthatrespect,the
susceptibilityofthefarmerswillfurtherincreaseduetosuchincreasedchallengingcondition[19,20].
Specifically, the farmers’ vulnerability with less rainfall is expected to be worst in arid and
semi-aridareasduetoincreaseddroughteffectsinthesealreadystressedareas[18–21]. Sucheffectsin
theseareascannotbeunderestimatedbecausetheglobaldrylandareascoverabout41%ofEarth’s
surface and sustain the livelihoods of about two billion people [21,22]. In these areas, drought is
greatlyexacerbatedbytheglobalincreaseintemperatureanddecreaseinrainfall[23]. Forinstance,
studieshaverevealedtheaverageincreaseofglobalsurfacetemperatureas0.8◦Cduringthepast
centuryorthelastthreedecades[24],leadingtothedeteriorationofagriculturalsystems.Subsequently,
thisdeteriorationhasexertedmorepressureonalreadystressedenvironmentalresourcesthrough
overutilization,thusaddingmorecomplexitytosustainableagriculturemanagement[22–25].
Thefrequentlyexcessivedroughtsinmostdrylandareashaveledtosignificantdegradationof
soilfertility[26]. Suchsoilfertilitydegradationisfurtheraccruedbypooragronomicpracticesand
excessivechemicalfertilization[27–29],andstudieshaveshownthatdifferentformsandprinciplesof
CA,suchasterracesorridges,minimumtillagecropping,covercropping,largepitsandintercropping
especiallylegumeintercroppingofsweetbeansandlablab,havethepotentialtoimprovesoilfertility
andmitigateclimatechangeimpacts.
Similarly,soilfertility,cropproductionandcarbonsequestrationhaveincreasedinmostareas
where CA has been effectively applied [20]. Under CA, soil microbial communities become more
functionalthanwithoutCAandcaninfluenceawiderangeofsoilfunctionsandecologicalservices
such as organic matter turnover and nutrient cycling (nitrogen, phosphorus and carbon), among
others [30,31]. Thus, CA has been recently proposed as Climate-Smart Agriculture (CSA) in most
Africancountriesbecauseitiseconomicallyviableandenvironmentallyfriendly[20,30–32]. According
toFAO[33],theCApracticecouldelevatefoodsecurity,resilienceand/oradaptivecapacitytoclimate
variabilityimpactsbysequestratingcarboninbothplantbiomassandsoils.
Similarly,Lal[34]promotedthatreducedtillageisapowerfultoolforretainingsoilcarbonand
improvingsoilfertilityforhealthycropgrowthandbiochemicaltransformationofbiomasscarbon
intosoilorganicmatterorhumus. Itwasevidencedthatconventionaltillagelosessoilnutrientsand
waterthroughinfiltration[35]. Evenminorsoildisturbancehassignificantecologicaleffectsonsoil
fertilityineasternandnorthernTanzania[36,37].
However,despitethissignificance,therehasbeenhighinconsistenceofCAadoptioninmostof
Sub-SaharanAfricawhereabout70%ofagricultureindustryisundersmallholderfarmerswhoare
mostvulnerabletoglobalclimatechanges. Theirvulnerabilityisaccruedbythehighdependenceon
rainfedagriculture[38]. Thus,Sub-SaharanAfricancountrieshaverecentlyadoptedtheCApractice,
althoughtheadoptionratehasnotbeensufficientinmostofSub-SaharaAfrica(Figure1).
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Figure 1. Development of conservation agriculture over the last 20 years by world region in total area
Figure1. Developmentofconservationagricultureoverthelast20yearsbyworldregionintotal
(ha) and as an average percentage across the adopting countries of the respective region. African
area(ha)andasanaveragepercentageacrosstheadoptingcountriesoftherespectiveregion.African
countries seem to adopt conservation agriculture slowly. It needs more emphasis for a good take off.
countriesseemtoadoptconservationagricultureslowly. Itneedsmoreemphasisforagoodtake
Afterwards, the continent will increase crop yields in terms of quantity and quality as well as
off. Afterwards,thecontinentwillincreasecropyieldsintermsofquantityandqualityaswellas
conserving the ecosystems (Source: Adopted from FAO [17]).
conservingtheecosystems(Source:AdoptedfromFAO[17]).
Most Sub-Saharan countries recently started the adoption of CA. For example, Malawi, Zambia
MostSub-SaharancountriesrecentlystartedtheadoptionofCA.Forexample,Malawi,Zambia
and Zimbabwe intensified their CA adoption in the 1990s [6,7,37]. Having been informed on the
and Zimbabwe intensified their CA adoption in the 1990s [6,7,37]. Having been informed on the
significance of CA, there is an immediate need to emphasize the optimal adoption and utilization of
significanceofCA,thereisanimmediateneedtoemphasizetheoptimaladoptionandutilizationof
CA in the region (Sub-Sahara Africa) where most farmers are destitute and marginalized.
CAintheregion(Sub-SaharaAfrica)wheremostfarmersaredestituteandmarginalized.
An Overview of Conservation Agriculture in Tanzania
AnOverviewofConservationAgricultureinTanzania
Most Tanzanian communities adopted indigenous agricultural conservation practices, e.g., the
Most Tanzanian communities adopted indigenous agricultural conservation practices, e.g.,
Matengo pits (terraces) in Ruvuma, Chagga garden (agroforestry) in Kilimanjaro and Ngitiri
the Matengo pits (terraces) in Ruvuma, Chagga garden (agroforestry) in Kilimanjaro and Ngitiri
(enclosed pasture) in Shinyanga regions to intervene the challenges associated with environmental
(enclosedpasture)inShinyangaregionstointervenethechallengesassociatedwithenvironmental
stress. These practices have shown promise for optimizing crop yields, increasing fodder, controlling
stress. Thesepracticeshaveshownpromiseforoptimizingcropyields,increasingfodder,controlling
soil erosion and conserving moisture and fertility [27,39]. However, CA has only been operated in
soilerosionandconservingmoistureandfertility[27,39]. However,CAhasonlybeenoperatedinfew
few regions including Dodoma, Manyara, Arusha and Southern highlands of Tanzania [40]. Few CAs
regionsincludingDodoma,Manyara,ArushaandSouthernhighlandsofTanzania[40]. FewCAshave
have been practiced in the aforementioned regions that involve agroforestry, crop cover and crop
breoetnatpiornac atincded airne tmheosatfloyr einmfleunetniocende dbyre gpiroivnasteth oart ignovvoelrvnemaegnrot foorrgeasntriyz,actrioonpsc [o4v1e-r53a]n. dThcruosp, rreoltiaatbiloen
apnodliacrye cmoousltdl ygirneflatulyen acfefdecbt ythper iCvAat eaodropgotivoenr ninm tehnet coorguanntriyza. tAiotn psr[e4s1e–n5t3, ]C.ATh ruesc,erievleias blliettlpeo alitctyenctoiounld
gfrreoamtly thaeff eTcatntzhaenCiaA Aagdroicputilotunrainl Pthoeliccoyu [n54tr]y a.sA tthpe reexsiesntitn,gC Aporleiccye iavdesvolicttalteesa tttheen tgiorenefnr ormevothluetTioann zthanatia
Aegmripchualtsuizraels Pmoolircey o[n54 c]oansvtehnetieoxnisatli ntigllapgoel iacnyda dchveomcaitceasl tfheretiglirzeaetniorne.v o lutionthatemphasizesmoreon
conveAntti othnea lhtoiullsaegheoaldn dlecvheel,m thicea aldfeorptitliiozna toiof nC.A or any other agricultural technology is reached after
the Aadtothpetehr oius sseahtoislfdielde vweli,thth ethaed dopectiiosinono.f ICnA moorsat ncyasoetsh,e trhaeg rhiocuulsteuhroalldt eacdhonpotlso gnyewis raegarcihcuedltuarfatel r
thteechandoolpotgeyr (iis.es.,a CtiAsfi) ewdhwosieth netht beedneecfiitssi oanre. sIingnmifiocsatntclays gesre,attheer thhoauns tehhoosled oaf dano petxsisntienwg taegchrincoullotugyra. l
teInch tnhoilso gaypp(ir.oea.,cCh,A p)rwohspoescetinveet bneenwe fittescharneosloiggnyi fiacdaonptltyergs reoabtseerrtvhea nthteh ousteiliotfy agnaeinxiesdti nbgy tethche neoalrolgyy .
Inadthoipstaeprsp broefaocrhe, apdroosppteincgti vtheante twechtencohlnooglyo.g Tyhaisd ocapnte brse odbessecrrvibeetdh einu vtialirtiyougsa imneoddeblys tahse foelalrolwysa.d opters
beforeFaodr oepxatimngplteh,a tthtee Hchencoklmogayn. mThoidsecla [n43b]e spdeecsicfriiebde dthien dveacrisioiouns amnodd eexltseanst foofl tloecwhsn.ology adoption
as foFlolorwexs:a mple,theHeckmanmodel[43]specifiedthedecisionandextentoftechnologyadoption
asfollows:
Ci = Ziφ + εi (CA adoption) (1)
Ci=Ziφ+εi(CAadoption) (1)
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Yi=Xiβ+µi(extentofCAadoption) (2)
whereCiisadummyvariableforCAadoption;ZiisavectorofdeterminantsofCAadoption;Yiisthe
extentofCAadoption(proportionoflandareaunderCA);XiisavectorofdeterminantsofCAextent
ofadoption;θandβarevectorsofparameterstobeestimated: andεiandµiareerrorterms.
BasedontheHeckmanmodel[43],fortheestimatedparametersofEquation(b)tobeefficient,
thereshouldbenocorrelationsbetweenthetwoerrorterms(εiandµi). Nevertheless, thesample
selection bias has resulted in a non-zero correlation between the two errors. To correct for this
selectionbias,theHeckmanmodelfirstlyestimatesEquation(a)toobtainasampleselectionindicator,
i.e.,theInverseMillsRatio(IMR).Thisissuitableformeasuringthecovariancebetweenthetwoerrors.
The study by Rogers [9] had agreement with Heckman model, as it informed that “the
innovation-decisionprocesscanleadtoeitheradoption,adecisiontomakefulluseofaninnovation
asthebestcourseofactionavailable,orrejection,adecisionnottoadoptaninnovation”. AfewCA
studieshavebeenconductedtoevaluatetheextentofCAinTanzaniaincludingonmaizeyieldsinthe
UluguruMountains(EasternArcMountains)[26].
The present study focused on the semi-arid agroecological zone in Tanzania, where maize,
sorghumandmilletarethemajorcrops,becausethissemi-aridareaisthemostvulnerabletoclimate
changeimpactsandenvironmentaldegradation. Intheseareas,CAisthemostreliablewayoflimiting
thesetwomajorchallenges. Thedominantfarmingsystemsinthemostsemi-aridregionsinclude:
cropping,pastoralismandagro-pastoralism(integrationofcropswithlivestock). Suchintegrations
increase the biomass inputs of perennial plants and the optimization of nutrient amendments in
the soil [30,39]. These systems can also increase the mutual interactions between plants roots and
mycorrhizaefungi,andeventuallynutrientsuptakeandresistanttopathogensbyplants.
AlthoughthescienceofCAanditssignificanceatthegloballevelisprogressingrapidly,various
knowledgegapsstillexist,particularlyindevelopingcountries. Thispresentstudywasgearedto
assesstherateofCAadoptionanditsecologicalsignificanceinthesemi-aridareasofcentralTanzania.
AlthoughseveralFAO-CAprojectshavebeenconductedinseveralTanzanianregions,theirimpacts
haveremainedtrivial[41,42]. Thisstudywashypothesizedasfollows:
H . TherateofCAadoptionisinfluencedbythedesireoffarmerstohaveoptimalyields,preservationofsoil
1
moistureandfertility,controlofsoilerosion,andreductionoflaborwork.
H . TherateofCAadoptionisnotinfluencedbythedesireoffarmerstohaveoptimalyields,preservationofsoil
2
moistureandfertility,controlofsoilserosion,andreductionoflaborwork.
Theabove-mentioneditemsinthehypotheseswerewidelyknowntotherespondents,thusitwas
possibletodifferentiateand/orsynthesizeoneanotherduringdatacollectionandinterpretation.
Here,weinvestigatedthelevelofCAadoptioninthesemi-aridagroecologicalzoneofcentral
Tanzania. Itwasquiteimportanttoconductsuchastudybecausemostsemi-aridareasexperience
frequent food-shortage associated with environmental degradation and extreme climate change
impacts.Thus,thepresentstudyexploredtherateofCAadoptionandissocio-ecologicalsignificanceto
thecommunityandenvironment. Toachievethisobjective,therateofCAadoptionwashypothesized
against the factors for its adoption. The findings of such a study are expected to have significant
contribution to the establishment of CA promotion policies in Tanzania with an earmark to the
vulnerablecommunitiesandecosystems. ThepolicyadvocacyonCAisasignificantmovetoward
sustainableadoptionofCAinallcountries’agroecologicalzones.
Atpresent,theadoptionofCAisdeterminedbypersonalcharacteristics(i.e.,knowledgeand
experience),physicalfactor(landavailability),andsocialandfinancialfactors.Despitetheinsignificant
willingnessintheCAadoption,thepracticehasnumerousfruitfulresults,asitimprovesbiological
functionsofthesoilthroughmycorrhizaefungi,antsandwormsthatcanenhancenutrientsuptake
byplants. Thebasisofthestudy’sfindingswasfieldworkwithaconstructedconceptualframework
(Figure2)enlistingthesignificantaspectsoftheCA.
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uptake by plants. The basis of the study’s findings was fieldwork with a constructed conceptual
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framework (Figure 2) enlisting the significant aspects of the CA.

FFiigguurree 22.. CCoonncceeppttuuaall ffrraammeewwoorrkk ffoorr ccoonnsseerrvvaattiioonn aaggrriiccuullttuurree ((SSoouurrccee:: AAddoopptteedd ffrroomm MMkkoonnddaa aanndd
HHee [[4444]]))..
The framework portrays the major roles of CA as a tool firstly for increasing crop yields and
The framework portrays the major roles of CA as a tool firstly for increasing crop yields and
secondly for environmental conservation to improve soil fertility through no- or reduced-tillage,
secondly for environmental conservation to improve soil fertility through no- or reduced-tillage,
mulching, agroforestry and crop rotation [50–61]. It also increases crop yields in terms of quality and
mulching,agroforestryandcroprotation[50–61]. Italsoincreasescropyieldsintermsofqualityand
quantity. By so doing, it curbs food insecurity and abject poverty. It further preserves biodiversity
quantity. Bysodoing,itcurbsfoodinsecurityandabjectpoverty. Itfurtherpreservesbiodiversityand
amnidti mgaitteigsatthees ethmei sesmioinssoiofng roefe gnrheoeunsheoguassee gsa(sGeHs (GGsH),Ge.sg)., Ce.Og. C,COH2, CaHn4d aNndO N.2O.
2 4 2
22.. MMaatteerriiaallss aanndd MMeetthhooddss
22..11.. PPrrooffiillee ooff tthhee SSttuuddyy SSiittee
TThhiiss ssttuuddyy wwaass ccaarrrriieedd oouutt iinn tthhee KKoonnggwwaa DDiissttrriicctt,, aa sseemmiiaarriidd zzoonnee ooff CCeennttrraall TTaannzzaanniiaa bbeettwweeeenn
JJuunnee aanndd SSeepptteemmbbeerr 22001166 ((FFiigguurree 33)).. TThhiiss ddiissttrriicctt iiss llooccaatteedd oonn tthhee leleeewwaarrdd ssiiddee ooff UUkkaagguurruu MMoouunnttaaiinnss
wwiitthh aann aarreeaa ooff ~~44004411 kkmm22 aanndd aa vvaarryyiinngg eelleevvaattiioonn bbeettwweeeenn 990000 aanndd 11000000 mm aa..ss..ll.. ((66°◦1199′(cid:48)666600”” LLaattiittuuddee
(S) and 36◦15(cid:48)36”Longitude (E)). The typical vegetation in the Central Tanzania is bush or thicket.
Sustainability 2017, 9, x FOR PEER REVIEW 6 of 19
Sustainability2018,10,1430 6of19
(S) and 36°15′36”Longitude (E)). The typical vegetation in the Central Tanzania is bush or thicket.
The mean annual precipitation is 400–600 mm (most between December and April) and the mean
Tahnenumael atnemapnneruaatulrper eicsi p2i6t a°tCio. nTihse4 s0o0i–l 6i0s0 cmlasmsif(imedo satsb CethwroemenicD Leucevmisoblesr (athned FAApOri l)Soainl dTathxeonmoemainc
aSnynsuteamlt)e mwpitehr aatu rseanisd2y6 ◦loCa.mTh teesxotiulries.c lTahssei fiseidlt acsoCnhteronmts icoLf utvhies oslosi(ltsh eaFt AdOiffSeorielnTta xfoarnmoms iwcSeyres tenmot)
wsiigthniafiscaanndtlyy ldoaifmferteexnttu (rpe .>T 0h.0e5s)i latncodn rteanntgseodf 1th7e0–so2i5l5s agt kdgif–f1e rseonilt wfairtmh saw beurlekn doetnsisgitnyi fiocfa 1n.t2ly5–d1i.f6fe5r eMngt
(mp–>3 [03.075,4)4a–n4d8]r. anged170–255gkg−1soilwithabulkdensityof1.25–1.65Mgm−3[37,44–48].

FFiigguurree 33.. LLooccaattiioonn aanndd ssaammpplliinngg ppoossiittiioonnss ooff tthhee sseelleecctteedd vviillllaaggeess iinn tthhee KKoonnggwwaa DDiissttrriicctt.. TThhee ssttuuddyy
ssiitteess aarree aallssoo ddeennootteedd wwiitthh llaattiittuuddee aanndd lloonnggiittuuddeess ddeeggrreeeess( (SSoouurrccee:: IIRRAA GGIISS LLaabb,,U UDDSSMM::2 2001166))..
2.2. Agricultural Systems in the Area
2.2. AgriculturalSystemsintheArea
WWiitthh 33663377 kkmm22 ooff aarraabbllee llaanndd,, tthhee ssttuuddyy aarreeaa iiss ddoommiinnaatteedd bbyy ccrrooppppiinngg ssyysstteemmss,, ppaassttoorraall ssyysstteemmss
and mixed farming. About 80% of the cropping systems are under smallholder farmers (~2.5 hectares
andmixedfarming. About80%ofthecroppingsystemsareundersmallholderfarmers(~2.5hectares
per household) who use a hand hoe as the main farming tool. Medium scale farmer (about 17%) use
per household) who use a hand hoe as the main farming tool. Medium scale farmer (about 17%)
power tillers while large scale farmers (about 3%) use tractors. The dominant food and cash crops
use power tillers while large scale farmers (about 3%) use tractors. The dominant food and cash
include maize, sorghum, millet, common beans, cassava, sweet potatoes, chick peas, sesame,
cropsincludemaize,sorghum,millet,commonbeans,cassava,sweetpotatoes,chickpeas,sesame,
cashews, sunflower and groundnuts. The dominant animals are cattle, sheep, pigs, donkey and goats.
cashews,sunflowerandgroundnuts. Thedominantanimalsarecattle,sheep,pigs,donkeyandgoats.
IInn aaddddiittiioonn,, oonnee rraanncchh ((~~225500 kkmm22)) aanndd oonnee ppaassttuurree ((~~115500 kkmm22)) aarree oowwnneedd bbyy tthhee NNaattiioonnaall RRaanncchhiinngg
Company and Livestock Research Center, respectively.
CompanyandLivestockResearchCenter,respectively.
22..33.. MMeetthhooddoollooggyy
22..33..11.. DDaattaa CCoolllleeccttiioonn aanndd SSaammpplliinngg DDeessiiggnn
AA ssimimppleler arnadnodmomsa msapmlipnlginwg awseams pelmoypeldoyiends eilne cstienlgectthinegs tuthdey satrueda.yW aerepai.c kWede opnieckthede Koonneg wthae
dKiostnrgicwtaa mdoisntrgicnt uammeoronug snduimstreircotsuso fdtihsetriscetms io-af rtihdez osenmeio-farTiadn zzoanniea othf aTtaanrzeasneivae rthelayt iamrep ascetveedreblyy
cimlimpaactetecdh abnyg celiamnadtef rcehqaunegnet faonodd fsrheoqruteangte .foPoudr pshosoirvtaegsea. mPpulripnogswivae sseammpplloinyge dwians seemlecptlionygedtw ion
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representativevillages,i.e.,MnyakongoandUgogoni. Prioritywasgiventovillagesthathavebeen
practicingCA.AreconnaissancesurveywasdoneinApril2016,twomonthsbeforetheactualdata
collection. Duringthisphase,datacollectiontoolsweretestedtodeterminetheireffectiveness. Wealso
usedthisphasetoprocesstherequiredresearchpermitsanddeterminedsomekeyinformants. All
discrepanciesraisedduringthisphasewerefixedbeforetheactualprocessofdatacollection.
Data collection including household surveys, group discussions, informative interviews and
physical observation was conducted from June to September 2016. These activities were simple
and suitable because they optimally involved relevant stockholders. A simple random sampling
wasappliedwhenselectinghouseholdswhileasystematicsamplingwasusedtoformgroupsfor
discussions. Inaddition,purposivesamplingwasemployedinselectingtheinterviewees.
We also conducted intensive interviews with agricultural experts, extension officers and few
elders. DataonCA(i.e.,acreageunderCA)andcropsyieldsweregatheredfromtheKongwaDistrict
AgriculturalandLivestockDevelopmentOfficer(DALDO)andtheMinistryofAgriculture,Livestock
andFishery,Tanzania.
The acreage data about areas under irrigation were gathered from the Dodoma Region
Zonal Irrigation Office (in which Kongwa is affiliated). A total of 400 questionnaires were
collectedfromhouseholdheadsofsmallholders(farmer/livestockhouseholds),asshowninTable1.
Thequestionnairesinvolvedbothclosedandopenquestions. Theselectionofhouseholdswasdone
bydividingthetotalnumberofhouseholdsineachvillagebytherequiredsamplesize(about10%).
Thehouseholdlistswereobtainedfromthevillage’sgovernmentleadersinthestudyarea.
Table1.SummaryofquestionnairesadministrationandPRAstoolsinthesampledvillages.
Mnyakongo Ugogoni
Questionnaires(n=400) TotalHH(2050) TotalHH(2080)
Numberofhouseholdsinterviewed 200 200
Cropfarmers(%) 70 80
Livestockfarmers(%) 10 10
Bothcropandlivestockfarmers(%) 20 10
Focusgroupdiscussion(n=30)
Cropfarmers 12 10
Livestockfarmers 0 2
Bothcropandlivestockfarmers 3 3
Interview(n=20)
Cropfarmers 8 9
Livestockfarmers 0 0
Bothcropandlivestockfarmers 2 1
*PRAs=ParticipatoryRuralAppraisal;*HH=Householdheads;*n=Numberofobservations.Source:Field
SurveyData,2016.
Interviews and household surveys were used to collect socio-ecological data at a society
level. We collected both quantitative and qualitative data at the field and farm household level.
About 258,219 ha (71%) of the total arable land (363,690 ha) in the district was cultivated by
45,271 households. The two representative villages had 4500 farming households with about
16,000ha. SinceweaimedtoexploretherateofCAadoption,weselected400households(farmers)
from the two villages on a random basis. In total, these 400 households had 1600 ha (an average
of2.0–4.0haperhousehold)undercropproduction. Wedeterminedtheoverallfarmers’perception
onCA,anditstypesandbenefits. Intheprocess,wealsodeterminedtheavailabilityofextension
services. Finally,informationonsoilcharacteristicswasmainlyobtainedfromtheKongwaDistrict
LandUseandPlanningofficeandliteraturereview.
Sustainability 2017, 9, x FOR PEER REVIEW 8 of 19
Both crop and livestock farmers 2 1
* PRAs = Participatory Rural Appraisal; * HH = Household heads; * n = Number of observations.
Source: Field Survey Data, 2016.
2.3.2. Data and Statistical Analyses
We analyzed the quantitative data using the Mann–Kendall Test (at 95% level of confidence),
Saunsdta iMnabiiclirtoys2o01ft8 ,e1x0c,1e4l 3(0window 13) software. In this regard, the p-values less than 0.05 were supp8oosfe1d9
to be statistically significant (p < 0.05). The qualitative data from the household surveys were analyzed
using theme content methods, whereas qualitative information was summarized and inserted in the
TheParticipatoryRuralAppraisalmethod(PRA)wasalsoemployedtocollectsocio-economic
text during discussions.
data at the field level. These PRAs include informative interviews, group discussions, physical
observation,etc. TheapplicationofthePRAmethodhasbeenusedtoexploreperceptionsofrural
3. Results
communities on environmental issues that affect their lives [49–51]. One group discussion with
15peoplewasconvenedineachvillage,andinterviewswereconductedwith20agriculturalexperts,
3.1. Recent Adoption of Conservation Agriculture
farmers,livestockkeepersandvillagegovernmentleaders.
Results showed that, despite the recently increased rate of CA adoption (Figures 4–6), <10% of
2h.o3u.2s.eDhoaltdasa hnaddS atdatoispttiecdal iAt. nFoalry isnesstance, in the two representative villages, 400 households cultivated
an area of about 1600 ha for crop production, while 200 ha of CA were practiced by 10% of these
We analyzed the quantitative data using the Mann–Kendall Test (at 95% level of confidence),
households. At the district level, there were 45,271 farming households who had cultivated 258,219
andMicrosoftexcel(window13)software. Inthisregard,thep-valueslessthan0.05weresupposedto
ha (Table 2), but only 4300 households had adopted the CA for an area of 20,000 ha.
bestatisticallysignificant(p<0.05). Thequalitativedatafromthehouseholdsurveyswereanalyzed
CA practices had been more adopted in Ugogoni than in Mnyakongo. The former had a higher
usingthemecontentmethods,whereasqualitativeinformationwassummarizedandinsertedinthe
averaged land size and total cultivated lands (Table 2). This brought significant differences in terms
textduringdiscussions.
of socio-ecological benefits to both the community livelihoods and the environment.
3. Results
Table 2. Current and estimated land under conservation agriculture in the sampled villages.
3.1. RecentAdoptionofConservationAgriculture
Total Cultivated Average-Landholding Average Land Adoption Estimated Land
Village
ResultsshowedLtahnadt (,hda)e spitethereSceiznet (lhya)i ncreasedurnadteer oCfAC (hAa)a dopRtaitoe n(%()F iguruensde4r– C6A), (<h1a)0 %of
Mnyakongo 8600 3.5 0.34 8.7 90
householdshadadoptedit. Forinstance,inthetworepresentativevillages,400householdscultivated
Ugogoni 9200 4.1 0.38 11.4 105
an area of about 1600 ha for crop production, while 200 ha of CA were practiced by 10% of these
* The adoption rate was from the agricultural officers and others from local farmers in a 2016 field
households. Atthedistrictlevel,therewere45,271farminghouseholdswhohadcultivated258,219ha
survey. Source: Field Survey Data, 2016.
(Table2),butonly4300householdshadadoptedtheCAforanareaof20,000ha.
CApracticeshadbeenmoreadoptedinUgogonithaninMnyakongo. Theformerhadahigher
In addition, the major types of the CA in the study area were agroforestry, mulching, crop
averagedlandsizeandtotalcultivatedlands(Table2). Thisbroughtsignificantdifferencesintermsof
rotation and minimum tillage. The lands allocated to CA were corrected by the total lands under
socio-ecologicalbenefitstoboththecommunitylivelihoodsandtheenvironment.
farming (p < 0.05). Hence, predictions and extrapolations could be done based on such dimension.
Conservation agriculture in the study area
5000
a,w a,w a,w a,w a,wa,x
)a 4000 a,x
h
(
s 3000 b,x
a b,x b,x
e
r
a
e 2000
z a,y
iS a,y a,y a,yb,y a,y
1000 b,z
b,y c,z
d,z
0
1995 2000 2005 2010 2015
Year
Little tillage Crop rotation Agroforestry Mulching

Figure 4. Variation in land use or farming systems from 1995 to 2015 (five-year averaged data) in
Figure4. Variationinlanduseorfarmingsystemsfrom1995to2015(five-yearaverageddata)in
Mnyakongo and Ugogoni villages of the Kongwa District, a semi-arid zone in central Tanzania. Data
MnyakongoandUgogonivillagesoftheKongwaDistrict,asemi-aridzoneincentralTanzania.Data
(means±SD,n=5)withdifferentlettersdenotesignificantdifferencesbetweenaveragedyearsfor
thesameCApractice(a,b,c,d,e)andbetweendifferentCApracticesforthesameaveragedyear(w,
x,y,z)atp<0.05.Note:Littletillageinvolvesshallowcultivation(minimumtillage)ofthefarm(i.e.,
non-conventional).Source:FieldSurveyData,2016.
Sustainability 2017, 9, x FOR PEER REVIEW 9 of 19
(means ± SD, n = 5) with different letters denote significant differences between averaged years for
the same CA practice (a, b, c, d, e) and between different CA practices for the same averaged year (w,
x, y, z) at p < 0.05. Note: Little tillage involves shallow cultivation (minimum tillage) of the farm (i.e.,
Sustainability2018,10,1430 9of19
non-conventional). Source: Field Survey Data, 2016.
FInigaudrdei t4io inn,dtihceatmesa jtohret ytepmespoofrtahl etrCeAndin otfh CeAst uaddyoparteioanw werietha gsrpoefcoiraels ftoryc,ums uolnc hliinttgle, ctriollpagreo,t actrioopn
arontdatmioinn, imaguromfotriellsatgrye .aTnhde mlaunldchsinalglo. cTahteerde twoaCsA a wsleigrehtc oinrcrerecatesde ibny atlhmeotsott aallll aCnAd spurancdteicrefsa, rwmhinilge
(rped<u0c.e0d5 )t.ilHlaegnec ae,npdr cerdoipct iroontastaionnd wexetrrea pmoolareti oandsopcoteudld cobmedpoarneedb taos eodthoenrss. uchdimension.
FFiigguurree 54 sinhdowicas ttehset hadeotpemtiopno rdailsptraernitdieso fbCetAweaedno cprtoiopn rowtaitthiosnp aencida lrefodcuucsedo ntillliattglee. tMilloagree ,lacnrodps
rwoittaht ioCnA, apgrroacfotirceesst rywearned umnudlecrh irnegd.uTcehde retilwlaagsea (s5l0ig00h thinac) rethaasen inunadlmero sctroapll CroAtaptiroanc ti(c4e5s0,0w hhail)e.
rMedeauncwedhtiillel,a cgreoapn rdotcartoiponr owtaatsi osnigwniefriceamntolyre madoroep ateddopcotemdp (aRr2e =d 0to.9o0)t htherasn. reduced tillage (R2 = 0.57).
UndeFri gsuurceh 5psrhemowissesth, eit awdaosp teivoindednist ptahraitt ireesdbuectewde teinllacgroep hraodt alteisosn naenwd areddoupcteerds ttihllaang ec.rMopo rreotlaatniodns
wdiidth, pCrAobparbalcyt ibceecsawuseere itu hnadde ralrreedaudcye dbeteilnla agdeo(p5t0e0d0 bhya )ththea lnagugnadredrs c(rlaotpe raodtoatpiotenrs(4).5 T0h0ehsae) r.eMsuelatns waghrielee,
cwriotph rroedtautcioend wtilalasgsei gbneiifincga nthtley lemaodrienga dCoAp tiend T(aRn2z=an0ia.9, 0a)ltthhoaungrhe ditu icse dintteilglaragteed(R w2i=th0 m.57u)l.chU, ncrdoepr
scuovcher parnedm liesgeus,mitesw [2a6s]e. vident that reduced tillage had less new adopters than crop rotation did,
probaInbl yadbdeictaiounse, mituhlacdhianlrge aadnyd baegernofaodroepsttreyd (bFyigtuhreel a6g) ghaardd ssm(laatleleard loapntdesr s()1.0T0h0e hsea)r ewsuitlhts aa ghrigeeh wraitthe
roefd CuAce dadtiollpatgieonb.e iOngf tthheeslee atdwinog, mCAulcinhiTnagn zaapnpiae,aareltdh otuog hhaivteis hinigtehgerra ateddopwtiitohnm ruatlech (,Rc2r o=p 0c.o9v5e) rtahnadn
laeggruomfoeress[t2r6y] .did (R2 = 0.68) while the former received more new adopters. This was because most of
the adInopadtidonit iwona,s mdounlceh winigthainn dthaeg proafsot r2e0s tyreya(rFs i(g1u9r9e56–)20h1a5d).s mallerlands(1000ha)withahighrate
of CAIn afdacotp, ttihoenr.e Oisf atnh eimsemtwedoi,atme unlecehdin tgo aesptpaebalirsehd ctoomhpaevlleinhgig ehffeorratsd toop mtioanker aCteA (uRn2d=er0s.t9a5n)dtahbalne
aangrdo fsourestsatrinyadbilde (tRo2 =far0m.68er)sw (hTialebtleh e3f)o. rmAner irnetceenivsievde maodroepntieown aodfo pCtAer sw. Tohuilsdw tahserbeefcoarues eopmtiomstizoef
tshuestaadinoapbtlieo nlivwealishdooondes,w esitpheicniathlley pfoars tv2u0lnyeeraarbsle(1 a9n9d5– d2e0p15ri)v.ed smallholder farmers.
1
2

Figure5.Adoptionrateofcroprotation(A)andlittletillage(B)asCApracticesintheMnyakongoand
UgogonivillagesoftheKongwaDistrict,asemi-aridzoneincentralTanzania.Source:FieldSurvey
Data,2016.
Sustainability 2017, 9, x FOR PEER REVIEW 10 of 19
Figure 5. Adoption rate of crop rotation (A) and little tillage (B) as CA practices in the Mnyakongo
Sustainaabnildity U20g1o8g,o1n0,i 1v43il0lages of the Kongwa District, a semi-arid zone in central Tanzania. Source: Field1 0of19
Survey Data, 2016.
1
2
Figure 6. Adoption rate of mulching (A) and agroforestry (B) as CA practices in the study area. Source:
Figure6.Adoptionrateofmulching(A)andagroforestry(B)asCApracticesinthestudyarea.Source:
Field Survey Data, 2016.
FieldSurveyData,2016.
Table 3. Responses (%) of effectiveness to the conservation agriculture practices by local farmers in
Table2.Currentandestimatedlandunderconservationagricultureinthesampledvillages.
the sampled villages (n = 200 in each village) during a 2016 field survey.
TotalCultivated VerAyv Eerfafgeec-tLiavned hoMldiondgerAavteer EagfefeLcatnidve ANdoopt tSiounreR ateNotE EstfimfeactteidvLea nd
Village
Conservation LManedth(hoad)s Size(ha) underCA(ha) (%) underCA(ha)
Mn Ug Mn Ug Mn Ug Mn Ug
Mnyakongo 8600 3.5 0.34 8.7 90
Agroforestry 18 19 76 77 0 0 6 4
Ugogoni 9200 4.1 0.38 11.4 105
Crop rotation 71 73 22 25 7 2 0 0
*Theadoptionratewasfromtheagriculturalofficersandothersfromlocalfarmersina2016fieldsurvey.Source:
FieldSurLvietytlDe attial,la20g1e6 . 15 16 67 71 13 10 5 3
Mulching 27 29 62 64 9 5 3 2
Infact,thAebrebriesvaiantiiomnsm: Medni,a Mtennyeaekdontogoe, satnadb lUisgh, Ucogmogpoenlil;i nSgouerfcfeo: rFtsietldo SmuarvkeeyC DAatua,n 2d0e1r6s. tandableand
sustainabletofarmers(Table3). AnintensiveadoptionofCAwouldthereforeoptimizesustainable
Results in Table 3 indicate that most farmers (50%–70%) asserted that the effectiveness of CA
livelihoods,especiallyforvulnerableanddeprivedsmallholderfarmers.
had been either very high or moderate. Most farmers (71%) asserted that crop rotation (e.g., maize,
ResultsinTable3indicatethatmostfarmers(50%–70%)assertedthattheeffectivenessofCA
sorghum, millet, groundnuts, etc.) has been very effective, while 7% of them were not sure if the
hadbeeneitherveryhighormoderate. Mostfarmers(71%)assertedthatcroprotation(e.g.,maize,
sorghum, millet, groundnuts, etc.) has been very effective, while 7% of them were not sure if the
practicewaseffective. Likewise,mostfarmers(76%)assertedthattheeffectivenessofagroforestryhas
beenmoderate,while6%didnotthinkitwaseffective.