Soil management in Africa: ways forward

Some years ago, as part of the e-debate hosted by the Future Agricultures Consortium we had a discussion on ways forward on soil fertility management policy. The conclusions are just as relevant today. In reviewing the excellent contributions to the debate (well worth a read), I highlighted 6 themes.

Context matters. Contexts – social, economic and ecological – must be taken into account in policy. Simple, blanket solutions do not work. They have been tried before and failed; and we should avoid making the same mistakes, no matter how urgent the situation is or who much money there is to be disbursed.

The argument against continent-wide (or even national) blueprint programmes has of course been long made. That is not new. Which contexts matter and what implications does this have for what should be done on the ground? This relates to the question about the merits of using inorganic fertilizers as the entry point to an integrated soil fertility management approach. There are contrasting, often ideologically-charged views on this. But there may be more consensus if we get specific about context.

Figure 1 offers a very simple, rather crude matrix of contexts. One axis focuses on agro-ecological contexts (from low to high responsive soils and available soil moisture). The other axis focuses on socio-economic contexts (from conditions where returns to inputs are high to those where they are low), emphasising context-specific input profitability and affordability.

Figure 1: Contexts for soil fertility management


Low responsive soils (loworganic matter, low rainfall) High responsive soils
Poor returns to inputs(profitability and affordability low)



Low external input options make more sense – external support required 


Efficient application (e.g. micro- dosing) critical – market assisted 
High returns Mixed strategy appropriate Application of inorganics make sense – market based

In situations where soils are highly responsive (to external inputs, such as inorganic fertilizers, and so have above-threshold levels of organic matter), and where returns to inputs are significant (and are perhaps the major factor constraining production – i.e. land tenure, market and other production constraints are not so important), then programmes focused on inorganic fertiliser use appear to make a lot of sense.

This does not mean that these should be high-level, blanket recommendations – all sorts of efficiency measures (such as micro-dosing) make sense. It equally doesn‟t mean that investing in the building up of organic material (through cover crops, green manuring, low/no-till etc.) is irrelevant. Far from it: the responsiveness of soils, and therefore the returns to inorganic fertiliser, is highly dependent on this being sustained.

But what about in situations where soils are less responsive (due to low organic matter, poor rainfall, or a combination of both), or where returns to inputs are low (due to high prices of the inputs, low prices of farm products and poor market and transport linkages)? Here the conclusion is less obvious. Here an integrated, and long-term effort is essential, with combination of technologies, services and policies.

Contexts outside the bottom-right hand box of Figure 1 are by far the most numerous in Africa, and are where most poor people live. Unfortunately most programmes, at least implicitly, seem to focus on the bottom right corner, as contexts are not considered as explicitly as they need to be.

Scale matters too. A consideration of context must occur at different scales. Figure 1 could be applied at regional, national, district, village, farm or field levels. The two axes can vary over very short distances, as both agroecologies and market conditions change.

The responsiveness of soils (and so the appropriateness of different fertility inputs) can vary dramatically within a farm and field, and farmers’ own soil fertility management strategies are often geared to this micro- scale. Micro-dosing with inorganic fertilisers, complemented by organic fertiliser applications, can allow very fine-tuned approaches at these micro scales.

Thus larger-scale programmes must be able to respond to scale variations and be flexible in their design and approach. They equally need to be supported by both participatory, bottom-up design principles, but also by effective soil diagnostic, testing and mapping approaches.

Socio-economic differentiation is important. Different soil fertility management strategies make sense to different farmers, depending on their own socio-economic context. In other words, in relation to Figure 1, the vertical axis varies across households (and even within households, say between men and women) depending on patterns of socio-economic differentiation.

This is clearly important for targeting and the design of programmes, such as differentiation between households with different levels of market access. Designing input support schemes requires a detailed understanding of such socio-economic variation. In some areas and for some households simple market mechanisms, perhaps supporting the growth of agro-dealer networks, may work well. In other areas, focused ‘smart subsidies’ may allow a positive spiral to develop, where more farm output leads to more investment in soil fertility inputs. In other areas for other households a more broad-based support will be needed, focused on providing a social safety net.

Past experience, and much current practice, avoids such differentiation, opting instead for a bureaucratically easier and more politically-saleable blanket approach, open to political manipulation. This has been the case in Zimbabwe, as elsewhere, with fertiliser subsidy and handouts being part of political patronage networks, involving both the state and non-state actors. This is dangerous, generating distortions, disincentives and inefficiencies.

Don’t forget longer-term dynamic trends. As discussed, contexts matter, but they are not fixed. They vary across space and across socio-economic group. They also change over time. A number of longer-term dynamic trends are mentioned across the contributions, each of which can dramatically affect the configuration of the axes in Figure 1.

Climate change, and with this changing rainfall and temperature patterns, is especially significant. A drying climate, with more variable rainfall and hotter temperatures (as predicted for significant areas of Africa) may make the application of inorganic fertilisers less like a good bet, as the contexts shift (to the left in Figure 1). In some areas, of course, the opposite may happen. This deep uncertainty about the long- term dynamics of climate must affect planning for soil fertility programmes. Adaptation measures which improve resilience will have to be part of these – and this means thinking about water, sanitation systems and soils at the same time. Basic soil and water conservation measures can go a long way, as can low/no till approaches, mulching and cover crops, as long as labour costs are not too excessive. Integrating cropping with livestock production has many spin-off benefits for soil fertility management.

Another trend – and in the last period a dramatic shift – is the price of inorganic fertiliser. This is a key factor in shifting the profitability and affordability – and the relative balance of different options. With inorganic fertiliser prices (of N and P) having increased by many fold, this clearly has shifted contexts too (to the top of Figure 1). Many questions arise: Is this going to be a long-term trend or a blip, potentially reversed by declines in oil prices? What will drive long-term change? How will fertiliser manufacturing and packaging investment in Africa make a difference?

There were no easy answers to these questions. But they need addressing in any future designs of policy and programmes, with measures to protect against future shocks and long term trends. Past interventions have often been disastrous, undermining the capacity of the African agricultural sector to respond. The abolition of fertiliser subsidies and the virtual ban on parastatals in the 1980s/1990s was a big mistake according to many. As with the technical responses on the ground, diversity and flexibility in design are the key words, if long-term resilience and sustainable development pathways are the aim.

In thinking about policy we need to have long-term trends in mind. if people are moving out of farming, or engaging as part-time farmers, straddling different livelihoods, the economics of soil fertility management may be seen in a very different way. Designing programmes on the assumption of full-time farming is increasingly problematic, and serious attention needs to be paid to the soil fertility management needs of ‘future farmers’ not just assumed ‘ideal type farmers;; potentially with quite different scenarios playing out in different places for different people.

Cultural dimensions of soil fertility management need to be central. There are many dangers of a ‘technical fix’ mode to solving soil fertility problems. It’s important to ask how farmers frame the problem themselves. Farmers often don’t see things the way some soil scientists do. Their understandings of soils are more holistic, centred on a perspective that looks at the wider ‘health’ of the soil-plant system.

Local peoples‟ knowledge, which consists not merely in picturesque representations of the properties and potentials of local soils, inherited from the past (“indigenous‟ knowledge) but also in experiential and adaptive knowledge from project successes or failures as found relevant to their livelihood circumstances.

The solution is not necessarily to apply some ‘medicine’ (or fertiliser), but to deal with the problem systemically. Indeed, in some contexts, inorganic fertilisers are viewed with suspicion, being seen as foreign contaminants of soils. This holistic perspective is more akin to agro- ecological approaches, where a more integrative view of soil systems is required.

A shift in perspective on the part of science and policy may be needed if the slogans of ‘soil health; for Africa are to have purchase. The indigenous, cultural understandings of soils and their management need to be taken on board, and seen as central to the design of programmes and policies.

Understandings that really get to grips with the complexities and dynamics of complex systems are essential. A variety of professional, institutional and other biases often prevents scientific analysis and policy-making from engaging with this. This remains a massive challenge, especially for the implementation of large programmes focused on soil fertility, and suggests a substantial capacity development focus for the future.

So how to go beyond the diagnostic-prescriptive framework for designing intervention and promoting change, driven by aggregate figures and simplistic framings? How to get nuance and specificity into the “special initiatives” or “Africa-wide programmes” that no doubt will follow from the International Year of Soils. As Ken Giller from Wageningen has argued, we must go from an obsession with ideal designs, or even ‘best bet‟ technologies or ‘best practice‟ management, to a ‘best fit‟ approach, that takes context – and so agro-ecological and socioeconomic contexts – as the starting point.

Perhaps some version of Figure 1 might therefore offer a just the sort of heuristic to help such a design as part of a conversation between planners, scientists and farmers that helps get us beyond the ruts that soil management policy has got into. This is vital for the post-settlement support necessary in the land reform areas in Zimbabwe, just as it is across smallholder Africa. If the 2015 International Year of Soils, that this blog series marks, is to have any meaning, the lessons and cautions noted above, and in previous blogs must be heeded.

This post was written by Ian Scoones and appeared first on Zimbabweland



1 Comment

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One response to “Soil management in Africa: ways forward

  1. am

    The nuancing makes it all very complicated and the management of the same almost impossible. I thought at one time of a national database of soil type and rainfall with an initial soil test defining starting point and improvements needed. But it is a big job and expensive to set up and populate with data.

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