Dryland cereal crop environments range from the dry savannas (barley, finger millet, pearl millet and sorghum) to the desert margins (pearl millet). Food and feed resources often dwindle to critically-low levels during the long dry seasons (6-8 months). In the developing world, dryland cereals are almost entirely cultivated under rainfed conditions; they must perform reliably despite scanty and unpredictable rainfall.
Mixed crop-livestock systems
Along the dry-to-very dry agro-ecological spectrum, low forest vegetation gives way to brush and grasslands suitable for herding and grazing, so livestock become an increasing part of the agricultural mix. Strong interdependencies arise between the crop and the livestock components. Crop farmers depend on livestock manure to improve soil fertility, and livestock herders depend on crop straw and grain as feed sources for their animals.
The diversity provided by both cultivating crops and raising livestock reduces livelihood risk and raises incomes for poor agriculturalists and herders. Sustainability requires the continued vitality of both components. Dryland Cereals therefore works to increase both the food and feed productivity of its focus crops, developing ‘multi-purpose‘ varieties that exhibit high straw digestibility and nutrient content as well as micronutrient-dense grains for human consumption.
Combating land degradation
Because drought limits productivity, the content of organic matter in dryland soils is often insufficient to support high-yield cereal production. This yield gap is expected to widen as the demand for meat and dairy products continues to grow strongly. Manure supplies are insufficient to raise soil organic matter to the extent required, and fallow periods that could help restore soil fertility are shortening or disappearing altogether due to increasing population pressure. These trends towards soil impoverishment expose the topsoil to rain and wind erosion during the strong storms that buffet these areas.
To reduce the risk of land degradation while also increasing agricultural productivity, appropriate soil-water-nutrient management practices are needed, such as the increased cultivation of nitrogen-fixing legumes – a strategy evidenced by farmers for example in the pearl millet-cowpea systems of West Africa. Conservation agriculture (minimum tillage and related innovations) is also gaining momentum, such as the zaï pit system used in Sahelian West Africa and shallow basins in Southern Africa. In addition, judicious increases in the use of fertilizer are needed, as for example with the ‘microdosing‘ system that is expanding in both of these regions, with careful attention to sustainability issues such as soil acidification (often a risk in soils with low organic matter content).