Africa SOIL: Soil Organic matter Improves Livelihoods

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Context:Southern Africa is being severely impacted by climate change, resulting in widespread poverty and under-nutrition. These effects are exacerbated by increasing population pressure, limiting resources (e.g. nutrients, water and soils), resulting in low, unstable yields, progressive soil degradation and depletion of inherent soil resources, such as soil organic matter. Smallholder systems, dependent on degraded soil of low fertility, are particularly vulnerable and lead to abject poverty. Maize is the single most important crop for more than 160 million people in eastern and southern Africa, occupying between 50-90% of the cultivated land area (over 17 million hectares, excluding South Africa), with a total production of 31 million tonnes. However, without new practices in the face of climate change and low soil nutrient availability, yields which are already low are predicted to further decline and farmers cannot escape this poverty trap. Technologies are urgently required for these systems that couple sustainable crop production and protection of the soil resource under changing conditions. Breeding for new maize varieties with greater tolerance to drought and enhanced ability to take up nitrogen from soil organic matter holds much promise to transform these cropping systems. Aims and objectives:Our aim is to provide a solution to this problem by empowering smallholder farmers with the knowledge and tools to replenish and utilise nutrients in soil more efficiently. Specifically, this will involve coupling conservation agriculture practices with selection of maize varieties best able to source nitrogen from soil organic matter. This will reduce the requirement and dependency for inorganic fertiliser application to improve yields. This provides both productivity and environmental benefits: greater yield stability under changing conditions particularly drought, lowering the need for inorganic fertiliser input, and averting further soil degradation through enhancing soil structure. Firstly, we will translate and build on our existing knowledge of abilities of different maize varieties to source nutrients from organic matter through establishment of demonstration and trial sites across an existing network of smallholder farms in NE Zimbabwe and S Malawi. We will discuss with farmers our approach, strategies to increase soil organic matter and expected impacts on maize yield in the context of local environmental and soil conditions. On-site findings will form the basis for environmental and economic assessments of this technology, and for soil organic matter considerations to be embedded into existing guidelines for conservation agriculture. Finally, we will work with plant breeders to move towards integrating environmental sustainability criteria into maize breeding programmes. Potential applications and benefits:Conservation agriculture, based on reduced soil inversion, crop residue retention and diversification is best suited to be practised under degraded, low fertile soils under drought conditions. Some drought tolerant maize varieties are excellent utilisers of soil organic matter replenished during conservation agriculture, which is anticipated to incur both economic and environmental benefits. Embedding this into variety selection criteria, takes us towards future breeding for sustainability that is best suited to the local context in southern Africa. This is an important step for improving food and nutritional security, environmental sustainability, reducing poverty, and enhancing the production environment of smallholder farmers and rural populations, in particular women, in southern Africa.