Seasonal Climate Variability dependent effects of Conservation Agriculture practices across different Agroecologies in Ethiopia

Transcription

1 Seasonal Climate Variability dependent effects of Conservation Agriculture practices across different Agroecologies in Ethiopia WINNIPEG Tadesse Birhanu June 2014

2 Introduction A large body of country-level studies have confirmed that: Global climate change is predicted to adversely affect agriculture Negative impacts on agriculture due to raising temperatures and variability of RF (amount and distribution) Africa, Latin America, and India to be the most affected (Parry et al. 2004) Climate change - threat to food security, in particular among populations in low-income countries

3 Introduction Rain-fed agriculture the dominant production system in Africa But this system in sub-saharan Africa is a risky enterprise because it is dependent on low and erratic rainfall and subject to long dry spells (Barron et al., 2003, Tilya and Mhita, 2007) Agriculture is the source of livelihood to the overwhelming majority of Ethiopia s population. It employs over 80% of the labour force and contributes ~45% to the national GDP, on average.

4 Introduction The national food production depends only on the amount and distribution of annual RF subjected to fluctuations (Mulat et al., 2004). Land degradation due to soil erosion and declining soil fertility represent a major challenge to sustainable intensification (Rockstrom et al., 2003). plowing, removal of crop residues mono-cropping Climate change with higher rainfall variability is believed to worsen this trend leading to serious consequences on crop yield Based on long term RF analysis, in Ethiopia 10% decrease in annual rainfall can cause up to 4.4% decrease in the country s food production

5 Soil degradation and maize farming Maize performance under monocropping and poor management

6 Climate change & CA How to limit the negative effects of climate change in Africa s agricultural productivity? Adaptation to climate change: -Irrigation - Improved new crop varieties (better adapted to a specific environment)-drought tolerant varieties - Crop diversification (avoid monoculture) - Adoption of mixed crop and livestock systems - Change of planting dates (Planting windows)

7 Context of the study -ACIAR_CIMMYT_SIMLESA (since 2010) -Compare the long term effects of CA practices across the different agro-ecologies of Ethiopia (onstation/on-farm exploratory trials) -High potential subhumid (Bako) -Moisture stress CRV (Hawassa and Melkasa) -Best bet CA technologies in the different socio-economic context

8 Tillage practices Conservation tillage (CA) Conventional tillage (CP) Cropping systems Sole crop (maize/legume) Intercropping (maize/legume) Rotation (Legume/Maize) Evaluation of different tillage practices and cropping systems -Seasonal Climate variability across the zones -Evaluation of maize/legume yields across variable seasons -WUE and Soil Moisture evaluations between CA and CP - Economic analysis

9 On farm exploratory trials Maize / Bean rotation Maize under CA vs. CP Maize/bean intercropping Bean under CA vs. CP

10 Seasonal climate variability and effect on crop yield

11 Yearly rainfall (mm) Yearly rainfall (mm) Monthly rainfall (mm) Sub-humid agroecology (Bako) Semi-arid agroecology (Melkassa) Seasonal climate variability >Erratic rainfall distribution during the cropping season Biomodal rainfall (Hawassa) >High variability in yearly rainfall -Bako: 1290mm ( mm) -Hawassa: 1015mm ( mm) -Melkassa: 880mm ( mm) Apr May June July August Sep Oct Nov

12 Seasonal climate variability mm Central rift valley Rainfall distribution during cropping seasons Cumulated rainfall(mm) Shalla 273mm 292mm Meki 389mm mm Seasonal variability > 260mm Boset Days after sowing Adamitulu

13 Monthly Rain Fall (mm) 400 Annual Rain Fall (mm) Mean 100 Cropping Seasons Very low RF at Maize Rain fall variability is very high across seasons (between 882 and silking 1528 mm) and with PM stage more than 4/5 of annual rain fall occurring during the main rainy season between May to September Early termination In the lowest RF amount of all seasons (past 20 years) was received Jan Feb Mar April May Seasonal climate variability Below average RF amounts likely to occur 1/3 years June Sub-humid high potential - Bako July Aug Sep Oct Nov Dec Mean During the experimental seasons, 2012 was the season with, very low/lowest RF amount Characterized by late onset Erratic and lower at planting

14 Yield variability- CRV Better performance of CA vs. CP in Shalla & Adami Tulu Poor performance of CA in Bofa (water logging, Shaakitee soil)

15 Yield variability- CRV Yield (t ha -1 ) Maize Common b bean CA CP CA CP CA CP Sole maize Rotation Intercropping CA CP CA CP CA CP Sole bean Sole maize Rotation Intercropping -High variability of Maize grain yield under rainfed conditions (Hawassa) -Bean under CA provide a significant advantage under high season variability

16 Yield variability- SHHP-Bako Better performance of soybean_maize rotation under CA in low RF season maize yield Haricot bean yielded better than soybean in low RF season for all cropping systems

17 Yield variability- SHHP-Bako Maize Grain Yield (kg ha -1 ) CA CP Maize Grain Yield (kg ha-1) Rotation_CA Rotation_CP Intercropping_CA Intercropping_CP Sole Maize_CA Sole Maize_CP Cropping Season Cropping Systems -High variability of Maize grain yield under rain-fed conditions with lower yields in Maize under intercropping provided a significant advantage under high season variability

18 Why Yield variability across variable seasons and tillage systems? Soil MC? Soil moisture content at harvest Depending on CS, the MC is different under CA or CP Sole cropping vs. intercropping systems Possible better use of available water by intercropping in low moisture stress year,

19 50 Water use Efficiency? SOLE MZ_CA SOLE MZ_CP MZ+HB_CA MZ+HB_CP Daily Rain Fall (mm) WUE (kg ha -1.mm) Growth Degree Days Cropping seasons In 2012, early RF termination observed which had major effect on yield In this season, yield was related to WUE, intercropping under CA and CP had significant advantage

20 Water use Efficiency? Intercropping systems considerably increased water use efficiency In good season, soybean-maize intercropping efficiently utilized more rain water However, in low RF season, rotating maize after SB and haricot bean-maize intercropping- CA were more efficient Continuous production of maze in CA showed more water efficiency compared to farmers practices.

21 Cropping Systems Can CA/Intensification Maize-soybean downsize intercropping risks Cropping Seasons Total gross field returns (Birr kg-1) under CA Highest gross return Mean Sole maize_cp 31,520 22,867 13,992 22,793 Sole maize_ca 21,485 24,760 13,528 19,924 Sole haricot bean_cp 7,010 9,637 10,400 9,016 Sole haricot bean_ca 6,430 10,197 6,500 7,709 Maize/Haricot bean intercropping_cp 30,548 25,264 25,940 27,251 Maize production under CP recorded the highest total variable cost Maize/Haricot bean intercropping_ca 25,508 28,890 20,836 25,078 Net Returns (Birr kg-1) Sole maize_cp 28,337 17,865 7,392 17,865 Sole maize_ca 18,210 19,641 8,220 15,357 Sole haricot bean_cp 4,717 6,744 5,940 5,800 Sole haricot bean_ca 4,050 7,187 3,332 4,856 Maize/Haricot bean intercropping_cp 26,715 19,612 18,690 21,672 Maize/Haricot bean intercropping_ca 21,588 23,121 14,878 19,862 Variable costs The maximum net benefits, were obtained when soybean (15545 ETH birr/ha) and haricot bean (12693 ETH Birr/ha) were intercropped with maize Sole maize_cp Sole maize_ca Sole haricot bean_cp Sole haricot bean_ca Maize/Haricot bean intercropping_cp Maize/Haricot bean intercropping_ca

22 SUMMARY RF VARIABILITY AFFECTED MAIZE AND BEAN YIELDS DIFFERENTLY UNDER CA AND CP During Low RF seasons; Intercropping maize with beans under CA resulted in 25% yield advantage over sole production of the crop under both tillage systems in SHH agro-ecologies Maize rotated after HB under CA resulted in 21.4% (at Adami-Tullu) - 40% (Meki) higher yields than sole maize under CA in the CRV This yield were also higher than the farmers practices (Sole maize CP) 20.7% (Shalla) 31.4% (Meki) in the CRV Intercropping/ rotating maize with beans resulted in higher soil moisture and effective WUE

23 Diversifying crops through intercropping and rotation under CA (Maize/legume) resulted in higher net benefits in low RF seasons indicating that CA can be used in downsizing risks Highest gross return from maize-soybean intercropping under CA Highest total variable cost for Sole maize production under CP practices Maximum net benefit when soybean and haricot bean intercropped in maize For sole bean production, 34-36% reduction of total variable cost as compared to maize Highest B:C ratio(3:2) when soybean grown as sole in crop rotation or continuous under CA Minimum B:C ratio (1:7) from CP maize production Higher net return for maize production under CA than farmers practices since cost incurred for animal traction reduced by more than 25%

24 CA ADOPTION, VERY LOW IN AFRICA AND ETHIOPIA Residue management (communal grazing systems benefit those with cattle, net nutrient mining from the poor!) Yield increases may sometimes not be immediate but long term (farmers short term benefit oriented) Poor awareness (mindsets, lack of equipment, inputs (herbicides etc.) Poor policy incentives Agro-ecology-dependent strategy Adaptation of tested package Farm/Household size/composition Change of mindset of farmers ( pioneer spirit )

25 Conservation Agriculture Multiple Strategies Technological options High/Low Climate Variability Rainfall amount Identification of Agroecologies (Soil characteristics) Cropping Systems Maize Legumes/Forages Rotation Intercropping Adaptation to Climate change: - Irrigation - Improved new crop varieties or livestock species - Crop diversification - Adoption of mixed crop and livestock systems - Change of planting dates Socio-economic issues: -Farm size/typology -Household composition Relay/Double cropping Conventional Agriculture

26 Acknowledgements -Feyera Liben -Goshime Muluneh -Alemayehu Zemede -Shiferaw Tadesse -Zerihun Abebe -Solomon Admassu -Solomon Jemal -Hae Koo Kim -Frederic Baudron -Fred Kanampiu -Mulugetta Mekuria

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31 Thank You