The overall debate question is: “…. What are the policy frameworks that really will increase soil fertility [in Africa] in ways that will boost production in a sustainable fashion, where the benefits of the interventions are widely distributed, meeting broader aims of equitable, board-based development?”

We suggest the following design principles as a basis for effective policy.

1. Distinguish between increasing national food production and achieving full household level food security.

1. Raising national food output does not necessarily lead to improved household and individual food security and nutrition: it may, however, contribute to lower food prices and hence increase the amount and possibly quality of food that poor families can afford to buy
2. If very small-scale farmers, who themselves are food insecure, increase their output, this is likely to improve their food security and nutrition
3. If increased food production comes mainly from small-scale farmers rather than large-scale farmers, this is likely to contribute indirectly to greater food security in rural communities, because production systems are more labour-intensive and hence more people receive earnings (or, in some cases, payments in food) from food production related activities.
4. In most situations, higher levels of productivity are attained on small-scale rather than large-scale farms, and hence, where land is scarce, strategies for expanding food output mainly by small-scale farmers are not only more equitable but also likely to be more successful in raising output.

2. There are very few situations in which full household food security can be attained simply by raising national food production: income redistribution measures, especially targeted cash transfers (or other social security programmes) must be part of the solution, even in rural areas.

3. In many areas of Africa, there is unused land with reasonable agricultural potential. As long as labour is amply available and there is easy access to land, growth in production by small farmers in these areas can continue to come from expanding the agricultural frontier, with limited use of external inputs.

4. In other regions, where rural population density is high, intensification offers the only route for expanding food output.

5. In most agricultural land use situations in Africa, avoiding reductions in soil organic matter (OM) content is essential if soils are to be cropped intensively on a sustainable basis. If OM levels are allowed to fall, there will be a progressive decline in soil fertility.

6. Where soils are not already seriously depleted in organic matter, using inorganic fertilizers and soil amendments (including lime) can help to increase vegetative material production and build up soil OM content, provided that crop residues are retained on the land and soils are not disturbed by tillage.

7. Inversion soil tillage, whether by hoe or plough, accelerates the decline in soil OM content and the biotic activity it supports, and destroys soil porosity, and is best avoided or restricted to crop “planting stations”.

8. Use of Conservation Agriculture (CA) principles and practices (minimal or no-till, soil cover with mulch and residues, and crop rotations, especially with legumes) results in an increase in soil OM and nitrogen levels and hence can do much to maintain soil health and fertility.

9. CA is the foundation for a greener revolution that can make intensive farming sustainable, cut energy use (whether human or fuel-derived energy) in food production, decrease agro-chemical contamination in the environment, reduce greenhouse gas emissions, minimize run-off and soil erosion, make a higher proportion of rainfall available for crop growth, and improve the quality and dependability of fresh water supplies.

10. But the CA requirement for retention of crop residues and use of cover crops is difficult to reconcile, especially in low-rainfall areas, with other demands for crop residues – livestock feed, fuel, brick-making. In these situations, CA systems need to incorporate components that provide for animal feed and fuel while at the same time enabling adequate soil surface residue cover.

11. Moreover, where no-till systems have to use herbicides for weed control, this will usually decrease their attractiveness to small-scale farmers who do not have access to herbicides or the equipment to apply them, or want to engage in organic farming.  Manual or non-chemical weed control can be difficult and time-consuming in the first years of practicing a CA system but, after a few years of good weed control and use of cover crops weed populations decline and become more manageable.

12. Best approaches to sustainable soil fertility improvement are likely to be location specific due to diverse agro-ecological and socioeconomic situations: “wholesaling” of standard solutions is unlikely to be feasible. However, mainstreaming of CA principles adapted to these diverse situations over time should form a policy goal for increasing soil fertility and enabling sustainable crop intensification.

13. In most situations, a shift to sustainable practices based on Conservation Agriculture principles requires fundamental changes in the ways in which farming is currently practiced and cannot be induced by top-down “message delivery” type extension services, though these may succeed in promoting greater use of fertilizers.

14. Instead, it is necessary to enable farmers to raise their level of understanding of the underlying causes of declining soil fertility and to engage them in testing CA-based options for improvement. The experiential learning methods practiced in Farmer Field Schools are very relevant to creating local capacities for moving towards more sustainable intensive farming systems with CA, adapted to local situations.

15. To the extent that farmer-facilitated and self-financing field school models are taken up, they have the advantage of imposing only limited demands on highly skilled staff and on recurrent budgets and hence can be scaled up rapidly without running into serious institutional, manpower and funding constraints.

16. Policies (e.g. subsidies) that promote fertilizer uptake or ploughing without linking these to the more complex changes in farming systems that may be needed to mainstream CA practices in Africa will undermine a shift towards sustainable soil fertility management and should therefore be avoided. In contrast, policies that compensate farmers for the enhanced provision of environmental services associated with the application of CA principles could accelerate a move towards more sustainable land use systems.

There is growing evidence of successful management of soil fertility for crop intensification on both large and small-scale farms using Conservation Agriculture practices in Africa from countries as diverse as Ghana, Kenya, Madagascar, Morocco, Swaziland, South Africa, Tanzania, Tunisia, Zambia and Zimbabwe, covering a range of agro-ecological and socioeconomic conditions. The fact that Conservation Agriculture is now practised on almost 100 million hectares worldwide implies that the principles on which it is based are recognised by farmers as one major potential alternative for enhancing soil fertility and for sustainable agricultural intensification in Africa and internationally.

Andrew MacMillan, former Director
FAO Field Operations Division
andrew.macmillan@alice.it

Amir Kassam, Senior Agricultural Research Officer
CGIAR Interim Science Council Secretariat
kassamamir@aol.com