Sustainable Intensification of Drylands Agriculture: Prospects for

Improved Varieties and Crop Management Technologies in SSA

Tom Walker with colleagues from ICRISAT and ICARDA

Agro-climatic challenges: Dry Spells

Early season drought 40 days to plant in the southern Sahel 80 days in the more rainfall-assured Guinean Zone Seedlings succumb to high soil temperatures

Differences in India and West Africa’s SAT Early season drought variable in West Africa Termination of the rainy season more variable in India Early onset means a longer growing season in West Africa

Chronic drought in West African in the 1970s and 1980s partially led to the demise of groundnut exports to Europe

Differences in cereal production and rainfall from their mean levels between 1960 and 2000

in Burkina Faso

Agro-climatic challenges: Poor Soils

Low native soil fertility Relics of 2 billion year old granites Volcanic soils richer, but fix P Severe micro variation within and across fields

Farmers strategy to intensify on fields near home Soil fertility gradient from near to far fields Far fields become infertile with shortening of fallows

N and P Macronutrients most lacking 80% of soils deficient in available P N supplied continuously; P managed as a stock 80% rock phosphate in Africa Nutrient mining okay sometimes Mineral fertilizers rarely damage the soil Both mineral fertilizers and manure are needed

Evidence for land degradation: Cassava in Malawi

Composition of rainfed crop area by Aridity Index Classes, length of growing season, and rainfall in SSA circa 2000

Type of rainfed area

Aridity Index

Classes

Average length of growing season (days)

Average rainfall (mm)

Share of rainfed cropped area (%)

Dryland 3 46 272 11

Dryland 4 99 546 18

Dryland 5 154 809 18

Dryland 6 196 1051 21

Rainfed wet 7 267 1520 33 Source: Constructed from the HarvestChoice database

Frequency distribution of maize yields weighted by area, by aridity index category

Constructed from HarvestChoice database, 2014

n – 10,204 n – 21,910 n – 22,745

n – 23,780 n – 40,635 n – 120,128

Frequency distribution of maize yields weighted by elevation

Constructed from HarvestChoice database, 2014

1 = 0-500 masl; n = 49,292 2 = 501-1000 masl; n = 31,378 3 – 1001-1500 masl; n = 29,472 4 = 1501-2000 masl; n = 6,835 5 = 2001-2500 masl; n = 1,910 6 = > 2500 masl; n = 941

Percent of dryland of total cropped area by commodity grouping

Constructed from HarvestChoice database, 2014

Prospects for Genetic Improvement

1. Maintaining and accelerating the pace of varietal change

2. Introducing new varieties well-adapted to the drylands of SSA

3. Improving the availability of cereal hybrids in West Africa

Coverage of the DIIVA Project (Diffusion of Improved Varieties in Africa)

20 crops in 30 countries 152 crop by country observations; 65 are the same as

in the Evenson and Gollin study 7 CGIAR centers Over 200 participating scientists, mainly from

national programs 17 nationally representative surveys 4 impact assessment case studies Project duration: December 2009 to August 2013

1,300 FTE scientists; 3,500 released cultivars; 1,150 improved varieties and hybrids adopted

35% area in MVs in 2010

44% MV adoption for continuing crops implies an annual gain of 1.45%

14 years: average varietal age

35% area in MVs declines to 31% if surveys were used instead of expert opinion

CGIAR share in adoption 65%; released varieties 40%

DIIVA: Key findings by the numbers

Varietal output in SSA by crop and decade

Food crop adoption in SSA in 2010

Change in estimated level of adoption of improved maize and cassava varieties between

1997/98 and 2009/10

Zimbabwe

Senegal Kenya

Ghana Burkina Faso

Nigeria

Tanzania

DR Congo

Maize

Cassava

Cameroon Uganda Togo

Angola

Mozambique

Tanzania

Zambia

Benin Malawi

Zimbabwe Uganda

Ethiopia

Malawi

Togo Kenya

Cote d’Ivoire

Guinea

Nigeria

Guinea Mali

Zambia

DR Congo

Benin

Ghana

Cameroon

Angola

Improving availability of cereal hybrids in West Africa

Almost no access to cereal hybrids in West Africa presently

Advantages of hybrids • higher yield potential • more yield stability • private sector incentives to fill the sub-regional profile

with hybrids and seed Indian farmers strongly prefer hybrids to improved

varieties in sorghum and pearl millet: the recent penetration of hybrids into Rajasthan

Drawing on the experience of maize hybrids in ESA Recent development of Guinean hybrids in sorghum in

Mali ICRISAT’s hybrid parents research consortium (HPRC)

Introducing new varieties well-adapted to the drylands (CRPs)

Dryland Grain Legumes 1. Drought and low phosphorus-tolerant bean, cowpea, and

soybean

2. Short-duration, drought-tolerant, and aflatoxin-free groundnut

3. Insect smart production systems in chickpea, cowpea, and pigeonpea

4. High nitrogen-fixing chickpea, common bean, faba bean, and soybean

5. Pigeonpea hybrids and management practices

Farmer showing Striga-damaged sorghum

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Collaborative lab work at ICRISAT

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Striga-resistance results

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Partners in Research: ICRISAT ASARECA BeaC BMZ KARI – Kenya IER-Mali University of Hohenheim National program: SUDAN (ARC), Eritrea, Kenya, and Mali

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Prospects for crop and land management technologies and for enhancing

livestock interactions

Conservation agriculture

Micro-dosing fertilizers

Improved intercropping systems

Soil conservation and land management

Animal traction

Conservation agriculture (no till, zero tillage)

Extent Over 100 million hectares in dryland conditions mainly in

the Americas and Australia Emerging interest in SSA since 1995; Very limited in India

Principles Minimal soil movement Permanent soil cover with crop residues Crop rotations

Characteristics Mulching with cereal straw Mechanical field operations limited to planting Limited traffic zones Weed management with herbicides

Plow Pan Damage

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Crop Residue Retention

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Minimum Tillage using a Hand Hoe

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Potential beneficial outcomes Increased water infiltration into the soil Increased soil organic matter resulting in

better soil structure, higher cation exchange capacity and nutrient availability, and greater water-holding capacity Increased and more stable crop yields Reduced production costs Increased biological activity in both the soil

and the aerial environment leading to more biological control of pests

CIMMYT’s experience in Malawi

Eight years in nine communities Low livestock densities Rainfall infiltration improved by 24-40% Yield advantage 22-24% over control plots Yield advantage greater in dry areas

Conclusion: CA can be practiced in diverse environments from sandy to clay soils, nutrient rich to infertile soils and from low to high rainfall areas as long as adequate inputs (fertilizer, herbicides and labor) are available with good extension support to farmers, especially in the initial years (Thierfelder et al. 2013, p. 147)

The Heretics’ View (Ken Giller and his colleagues) Site specific: Termites ate the mulch in Mozambique General: Benefits may be smaller and the costs greater than proponents expect in the drylands of SSA. Mulching materials have a high opportunity cost Yields may actually be lower in the near term CA practices may be more labor intensive The empirical evidence for improving soil organic matter,

soil fertility, and below-ground biological processes and for reducing soil erosion is scanty

CA as extended by NGOs and other agencies may not include fertilizer, and, when fertilizer is included, CA may require a higher dose to maintain yields on a par with those obtained through conventional tillage.

The feasibility of introducing legume rotations on a large scale is questioned

Adoption research and meta-analysis

Zambia - Conservation farming with planting basins Reportedly on about 100,000 hectares Positive benefits experimentally More labor but less labor seasonality Diligent and disciplined cotton farmers who cultivate about

1 ha by hand and desperately need fertilizer and herbicide No adoption in Mozambique (Too much labor and fertilizer

diverted to potatoes from maize) Meta-analysis Brighter prospects in dryer environments Need well-drained soils No yield response in wetter environments (waterlogging

with mulch) Need high input levels especially N

Micro-dosing Fertilizers

Small amount of fertilizer is added to the planting hole at time of sowing

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Began in the late 1990s A bottle cap of fertilizer per plant (6 grams) N or P; basal or top-dressed Solid evidence for response (Zimbabwe)

• 60,000 farmers participated • 17 kg per ha N or 25% recommendation • 15-45 kg of grain yield per kg of N

Often applied in subsidized conditions Generalizable research protocol that works

• Computer-based fertilizer response model • On-farm trials prior to pilot extension program

The perfect should not be the enemy of the good

Micro-dosing Fertilizers

Conclusions: Is the past prologue? What needs to be done to translate prospects into reality? 1. Investing in agricultural research National programs: Need more and younger scientists

in cowpea, groundnut, pearl millet, and sorghum improvement

CG centers: Need to recover from the doldrums of the late 1990s and early 2000s when staff strength was halved and regional crop networks discontinued (The B&M Gates Foundation)

2. Efforts need to be redoubled where adoption of improved varieties is lacking

Lagging countries (e.g., Angola and Mozambique in maize) Lagging crops (e.g., pulses and durum wheat in Ethiopia)

3. Improving seed availability in grain legumes in general and groundnut in particular

4. Improving access to cereal hybrids in West Africa Liberalized seed and varietal release policies Training programs in hybrid seed production to

demonstrate proof of concept Public provision of hybrid parental lines needed initially

5. Assessing the size of the opportunities afforded by marker-assisted selection, conservation agriculture and micro-dosing fertilizer

Marker-Assisted Selection

6. Adoption of new varieties in old backgrounds

7. Scope for use of established protocols in other important traits

Conservation agriculture: Unraveling its complexity to understand benefits and costs in varying edaphic, agro-climatic, and socioeconomic contexts

Micro-dosing fertilizer

8. Labor-saving innovations

9. Adoption studies on acceptance of fertilizer in general and micro-dosing in particular

10. Expanding the prospects for intensification Mitigating Trypanosomiasis Accelerating the spread of Bt cotton

11. Sub-regionally targeting crop management and land and water management technologies for intensification

Population density Market demand Soils

12. Targeting elevation in East & Southern Africa and length of the growing season in West Africa