* Any views expressed in this article are those of the author and not of Thomson Reuters Foundation.Improving soil fertility is a good start
Mali’s remarkable fertility (population will triple to reach 45 million by 2050) is said to be a great threat to the country’s food security and sovereignty. Three out of four Malians live on a farm and the remaining live in mushrooming Bamako and other cities. The climate is unpredictable and tough, bringing droughts, flash floods, not enough or too much rain, and often at the wrong time. Farming families complain of not having enough good land to cultivate. Yet the large stretches of Savannah along the road from Bamako to Segou hint at the room for expansion.
Look more closely and you realise that declining soil fertility has become another major farming constraint in the Sahel. Only baobab trees loom over the naked sandy or lateritic fields and patches of thorny bushes, where huge yellow gourds bake in the sun, waiting to be carved into useful household vessels. Small tornadoes of red dust further erode Mali’s impoverished soils.
Poor soils means poor farmers
Echoing the Montpellier Panel conclusions in their “No ordinary matter” report, sustainable soil management is urgently needed because land degradation is a huge burden, particularly in developing countries. Nearly 3.3 percent of agricultural GDP in sub-Saharan Africa is lost annually because of soil and nutrient losses, estimated at over 30 kg/ha/year.
Malian agricultural policies do not precisely state preservation of soil fertility as a priority. The high population growth rate (2.9 percent per year) means the land under cultivation is continually expanding, but this cannot continue. Fallow periods are getting shorter, and farmers cultivate even marginal land. On average, farmers in Mali use less than 9.5 kg per hectare of fertilizer compared to 200 kg per ha in western Europe, and they have limited access to organic manure.
Not surprisingly, yields of major staple crops are low, painstakingly reaching one ton per hectare for sorghum or groundnut in most sub-Saharan African countries. The majority of farms do not produce enough for their own consumption and financial needs. So hunger intensifies during the lean period when the climate is least favourable. Even in good years, yields are too low to plan better for the worst years.
Often farmers like Sitan Sidibe, mother of ten in Ngolobougou village, complain that over the last two decades rains have been stopping 15 to 30 days earlier before the sorghum crops, their main staple food, have had enough time to fill their grain. But the rain is not the sole issue. Plummeting levels of soil phosphorous in over-used plots leave Sahelian soils lacking in soluble phosphorus needed for seedlings to grow. Retarded seedling growth means crops are late to flower and not mature enough when rains stop, leading to terrible harvests.
Can the right solutions be scaled up?
Research shows that some traditional farming practices, using local resources, can improve soil fertility. Stone bunds and zaï planting holes, combined with the application of organic or inorganic fertilizer are climate smart practices that preserve food production in adverse conditions, while limiting water run-off and soil erosion. Womens’ groups in Niger used such techniques to transform degraded lands into productive vegetable and fruit trees plots.
Farmers can boost plant growth during the critical seedling stage by making “seed balls”, nestling the seeds in local loam, charcoal, wood ash, manure and residual fertilizers. This offers a solution for Sub Saharan African smallholder farmers with little access to fertilizers. An ongoing large-scale on farm study is fine tuning this seed coating technique under the Sorghum and Millet Innovation Lab (SMIL) programme.
Another local adaptation is the leguminous ‘miracle tree’ Faidherbia. A source of fodder and firewood, these trees help soil water retention and nitrogen fixation. Research shows that nutrient levels are 42 percent (nitrogen), 25 percent (potassium) and 31 percent (organic carbon) higher under a Faidherbia canopy. Like other organic farming practices, there is the problem of scale and sustainability. How do you finance Faidherbia nurseries to promote and expand this agroforestry farming system? Good quality compost also adds essential soil nutrients and improves soil structure but labour – time to collect and apply manure - and water availability hinder widespread practice. In Mali, a farm would produce enough compost for up to 2 hectares. Not enough for larger fields of staple crops to ensure all year long family food security.
Sustainable inorganic fertilizer use is part of the solution. It can quickly improve African farming productivity but most farmers have little access to inputs and often lack financial resources to invest. The African fertilizer value chain needs modernizing with a more effective agrodealer network. As well as enabling access, farmers need to use the most sustainable methods to boost yields.
Microdosing, applying bottle caps of fertilizer at the plant roots during sowing, can increase millet and sorghum yields by 44 – 120 percent using less than ten kgs of fertilizer per hectare. But a system needs to be in place to scale this up. A financial arrangement between rural banks and farmer organisations called ‘warrantage’ means farmers can benefit from a collective grain stockmarket where profits generated provide credit for farmers. This can then be invested in inputs for the next growing season. As its labour intensive, microdosing would also become more popular if mechanized. Rural innovator Djemourou Kouyaté, a farmer from Kaya village in South Mali, has customized a seed and fertilizer drill tool (named dogon seeder) to make microdosing less onerous. Further research into effective training schemes and optimal timing of fertilizer application will increase the impact on soil health.
To ensure these improved practices are adopted on a large scale, we need to invest in sharing the proof they work. Training and hands-on learning through farmer field schools and videos is crucial. For example, a module on integrated soil fertility management in Niger and Ghana helped reach 200,000 farmers. A partnership with a Kenyan bank may catapult the potential audience to millions.
The bigger picture
Long term trials in Niger show that mineral fertilizers alone cannot sustain yields in the long run. The answer is to combine mineral fertilizers with crop residue or manure as well as cereal-legume intercropping or rotation.
Legumes not only enrich soils by fixing nitrogen at root level but also help recover phosphorus from insoluble form to make it available for other crops through intercropping or rotation. Promoting legume cultivation has also proven to improve family nutrition. Yet only a mere 5 to 10% of land is dedicated to legumes as there are no market or policy incentives. Support for legume seed systems and markets could revolutionise crop farming systems like the example of chickpea in Ethiopia.
Plant genetics can help farmers cope better with poor soils. Research shows a large variation in varietal tolerance of low phosphorous soils. By combining tolerance to low phosphorous with high yielding traits, sorghum varieties particularly adapted to Sahelian soils will be developed, which would help boost harvests. Such research will certainly grab more attention in the coming years with the risk of phosphorous peak and rising fertilizer prices.
Inclusive innovation platforms
Whatever the strategies to adapt and restore soils, it is important to work through farmers’ organisations. Innovation can stem from NGOs, academics, the private sector and farmers themselves. For example, Simon Masila a farmer from Machakos District in Kenya has developed a system for planting finger millet through seedlings grown in a nursery to overcome water and nutrient scarcity. The farmer innovators network Prolinnova is scaling up this local innovation.
Experts from different research and development organisations will gather on 24th March in Berlin to plan for a world without hunger. There are many challenges and successes to be discussed and partnerships to be built. Because soil matters.
This is the point stressed by The Montpellier Panel, an expert group chaired by Sir Gordon Conway of Imperial College London. The Panel aims to get better European government support of national and regional agricultural development and food security priorities in Sub-Saharan Africa.
“Given that soil is the cornerstone to food security, better rural livelihoods and agricultural development; its conservation, restoration and enhancement must be a global priority,” says Ramadjita Tabo, Director of ICRISAT’s West and Central Africa Regional Hub and member of the Montpellier Panel.