Value-addition of cereal crop residues for improving the income, nutrition and performance of small-stock of small-scale farmers using low technology oyster mushroom production in Botswana

Grain cereal production gives rise to crop residues in the farm once the grain is harvested or processed. The common residues include straw and husks of small grains such as wheat, barley, rice, sorghum and pearl millet and stalks, husks and cobs of maize. Most of these crop residues are either burnt, ploughed under or processed into animal feed. In Botswana small-scale cereal yields are very low averaging 110kg/ha and the crop residues are normally grazed in situ or ploughed in and are not a source of direct additional income. The use of cereal residues in oyster mushroom (Pleurotus spp.) production is one way of increasing income from a unit of land and improving the diet of farmers since the mushrooms are a high-value crop and nutritious. The spent mushroom substrate can be incorporated into small-stock feed. Botswana’s rain-fed cereal grain yields are expected to decline further as rainfall becomes more erratic and temperatures rise due to climate change. Incorporation of oyster mushroom production into the cereal production system in Botswana can mitigate against food insecurity in that farmers can get additional income from selling mushrooms. The innovation of this study is the value-addition of low quality crop residues through production of high-value mushrooms while the spent mushroom substrate can be a high-value animal feed. The incorporation of mushroom production in cereal production could result in higher income per hectare for small-scale farmers. This paper reviews the potential of adopting oyster mushroom production for enhancing smallholder incomes in Botswana.