11. Microdosing of Mineral Fertilizer and Conservation Agriculture for Sustainable Agricultural Intensification in Sub-Saharan Africa

Microdosing of mineral fertilizer and conservation agriculture (CA) have been identified as promising approaches for sustainable agricultural intensification. Microdosing has been found to give a very good economic return for a small investment in fertilizer. Microdosing has created a demand for fertilizer in rural areas of Mali, and the local business community has responded by providing fertilizer in their shops. The agro-ecological advantages of microdosing are connected to adaption to climate change, highly efficient use of water, inhibition of the parasitic weed Striga hermonthica and earlier harvest. The possible problem that microdosing can lead to nutrient mining is exaggerated. The effect of CA on yield and soil properties is dependent on how it is practiced. Mulching has been identified as the key ecological component of CA, as it reduces soil surface temperature, improves water infiltration and helps control weeds. The major problem associated with mulching is the free roaming of animals in the dry season, which removes all the crop residues left on the soil surface. Grazing management must therefore go hand in hand with development of CA. It is concluded that microdosing and CA can be combined. Microdosing can give short-term benefits in terms of yield increase, while CA will build soil quality, which is of vital importance for the long-term sustainability of agricultural systems.