Dr. Shamie Zingore Africa Program Director, IPNI Prof. Ken Giller Chair, Plant Production Systems Group, Wageningen University

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1 Challenges and opportunities for reversing soil fertility depletion in heterogeneous smallholder farming systems Dr. Shamie Zingore Africa Program Director, IPNI Prof. Ken Giller Chair, Plant Production Systems Group, Wageningen University

2 International Plant Nutrition Institute (IPNI)

3 International Plant Nutrition Institute (IPNI) Not-for-profit, science-based organization with a focus on agronomic education and research support.

4 IPNI Current Programs Eastern Europe and Central Asia North America Middle East China Northern Latin America Brazil Africa South Asia SE Asia Latin America Southern Cone Australia/ New Zealand

5 IPNI focus 4R concept

6 Status of productivity

7 Sub- Saharan Africa low per-capita food production Cereal crop yields t/ha Per capita food production FAO, 2002

8 Underlying causes World Bank, 2008

9 Land use dynamics Changes in cropping patterns in eastern Uganda and western Kenya over the past 40 years Fermont et al., 2008

10 Attention to nutrient management a priority Fertilizer an important factor but use limited by Unavailability High costs Viability and risk Organic resources essential but use limited by Limited availability Low quality High labour demand Farming systems highly heterogeneous What works, where, how, when

11 Attention to nutrient management a priority The goal to sustainably improve crop productivity in SSA will remain illusory until the fundamental issues of providing the plant with adequate nutrients are properly addressed.

12 Heterogeneity in smallholder farming systems

13 Poor soil fertility a major challange

14 But highly variable

15 Potential solutions - Nitrogen fixing legumes Legume green manures Grain legumes Legume tree fallows Forages

16 Reality on the ground.

17 Farm(er)s are not all the same! Resource-rich farm Resourcepoor farm

18 Farmer typologies Farm type No of farms Household size Farm size (ha) Cattle Oxen Goats Chickens Scotch carts Manure (t season -1 ) RG RG RG RG

19 Farmer typologies Resourcepoor farm N P N P N P N P

20 Farm and plot level crop productivity Yields differ strikingly within and across farms

21 NPK NPK NPK Options

22 Comparison within Hierarchies: Farm the focal point Rainfall 400 mm 2000 mm Cereals Cereals + Bananas Forest/crop Locations (8) Rich Comparison between Poor

23 Targeting technologies System and farm type specific oaccess to external inputs and organic resources oaccess to implements olabour ogender Time to yield/economic benefits Risk

24 Defining soil fertility zones

25 Characterizing fertility zones Simple typologies can be derived in terms of field responses. Broad heterogeneity of fields can be reduced and summarized across farms fertile fields unresponsive to nutrients intermediate fields, highly-responsive to nutrients infertile fields unresponsive to nutrients Recommendations for technologies can be derived specific to each typology

26 Variable response to fertilizer on different plots at landscape level

27 Integrated soil fertility management Agronomic efficiency A Increase in knowledge B C Rehabilitation of less-responsive soils Responsive soils Poor, less-responsive soils Appropriate nutrients and adapted germplasm Organic resources as a Adapt to local conditions Current practice Germplasm & fertilizer Move towards ISFM Germplasm & fertilizer + Organic resource mgt Germplasm & fertilizer + Organic resource mgt + Local adaptation Full ISFM

28 Fertilizer and germplasm Typical yield responses under different soil fertility conditions Maize grain yield (t ha -1 ) High Medium Low 4 5 kg/ kg N kg/ kg N 1 1 ~ kg/ kg N 25 kg/ kg N N applied (kg ha -1 ) N applied (kg ha -1 ) N applied (kg ha -1 ) 4 Attainable yields with and yield response decrease with decreasing soil fertility

29 Fertilizer and germplasm Balanced fertilization 7 6 Control N N+P N+P+K+Ca+Zn+B Grain yield (t/ha) Low Medium High Soil Fertility Status

30 Impact of fertilizer in SOC management Fertilizer + residues Fertilizer No fertilizer No systems are sustainable on mineral fertilizers alone

31 Impact of fertilizer in SOC management Commercial system Fertilizer use >6 t residues retained every year

32 Cereal crop residues Potentially high availability with best nutrient management Stimulating productivity in degraded soils Many competing uses N immobilization Pest and diseases problems Most effective when combined with reduced tillage

33 Crop residue and conservation agriculture Likelihood of adoption by farmers? Flat land Clayey soils Poor productivity Many livestock Little capacity to invest Farmers with little experience of using inputs Insecure land tenure Large land holdings Poor markets Poor institutional environment Steep slopes Sandy/loam soils Abundant biomass Few livestock Wealthier farmers who can afford inputs Farmers with experience of cash-cropping Secure land tenure Small land holdings Good markets Enabling institutional environment

34 Rainy season North East Zimbabwe Conservation agriculture Dry season

36 Recycling nutrients in integrated croplivestock systems

37 Livestock manure Sandy soil Clay soil t manure ha t manure ha -1 Organic C (Mg ha -1 ) Baseline Baseline Time (years) Time (years) Effective at SOC sequestration Limited quantities High labour demand High grazeland:cropland ratio required

38 Crop rotation grain legume Attractive for nutrition, soil N and (income?) High N harvest indices Fast decomposing Fail to perform in poor soils

39 Grain legume yields and allocated area FAO stats, 2008 N fixation far below potential low productivity and small land area.

40 Grain legumes The right legume for the right purpose

41 Grain legumes Legumes require P to fix N

42 Grain legumes Soyabean grain yield (t/ ha) Control P Manure+P Adapted germplasm with ISFM

43 Agroforestry / cover crops Multiple benefits Long-term investment Competition for land and labour Fail to perform in poor soils/low rainfall areas

44 Agroforestry / cover crops Manure/compost Indi-fallows

45 Dealing with the complexity

46 Dealing with the complexity Understanding of farmer reality, socioeconomic and biophysical heterogeneity necessary Promote flexible, farmer-friendly, market oriented technologies Promote local adaptability

47 Awareness of N management among farmers Nitrogen management Farmer condition Attribute Confined by poverty Aware of options Effectively empowered Awareness of nitrogen cycling Unaware of N and its management Acquire limited N inputs and reduce N losses Effectively combine mineral and organic N, practice regular N replacement to offset losses Awareness of nitrogen deficiency Unable to interpret nitrogen deficiency symptoms Able to identify N deficiency symptoms on major crops Install diagnostic N fertilizer test strips and adjust N management to early deficiency symptoms Use of N fertilizer Apply little or no mineral fertilizer inputs Applies some N fertilizer based upon availability and season Applies pre-plant and top-dressed N fertilizers, calculates return to investment Management of symbiotic BNF Poor management of BNF Cultivate legumes that nodulate well under field conditions. Inoculate legume seed with rhizobia as required, combine inoculants with other legume seed technologies Management of livestock manure Few or no livestock and limited use of manure Manure collected and applied to crops in a manner that improved mineral nutrition Manure collected and usd separately, combined with other inputs in ways that prevent nitrogen loss Knowledge of organic N Utilize organic resources without considering their N content Recognize that some materials contain greater amounts of nutrients and use them accordingly Understand that different organic resources may be combined in strategic manner Household protein management Consume carbohydrate-rich diets, risk protein, mineral and vitamin deficiency Routinely complement grain legumes and greens with carbohydrates Effectively combine plant and animal proteins within nutritionally complete diets Woomer, 2008

48 Institutional organization Private sector Input Mkt Farmer X, Y, Z Input production and supply Appropriate technologies Input market research Soil management Technology Policy support Output market research Germplasm improvement Marketing Product quality and storage Output market

49 Field tools for site-specific nutrient management

50 Field tools for site-specific nutrient management

51 Concluding remarks Smallholder highly complex complex Holistic systems approaches necessary to develop effective interventions that recognize: Biophysical and socioeconomic heterogeneity The role of input/output markets Information systems Conditions for fitting technologies cropping systems: Farm size Crop diversification (integrate food and cash crops) Balancing crop-livestock integration Tillage system Market integration

52 Thank you

SOC sequestration in farming systems in Africa: Potential, opportunities and challenges

SOC sequestration in farming systems in Africa: Potential, opportunities and challenges S. Zingore Africa Programme Coordinator Condition for farmers in SSA Depend strongly on recycling of organic matter,