Closing the cassava yield gap: An analysis from smallholder farms in East Africa

摘要: Cassava yields in Africa are small and it remains unclear which factors most limit yields. Using a series of farm surveys on-farm on-station trials Uganda western Kenya, we evaluated the importance abiotic, biotic associated crop management constraints for cassava production range socio-economic settings as found smallholder farms region. Average under farmer were 8.6 t ha(-1),but these more than doubled to 20.8 ha(-1) by using improved establishment, genotypes 100-22-83 kg single-nutrient N-P-K fertilizers. A survey revealed large yield differences between farms. Less endowed farmers harvested less per unit area better (difference 5.9 9.7 Kenya Uganda, respectively); with access labour, poorer soils, premature harvesting farmers. Analysis 99 6 showed that varied strongly sites years. Poor soil fertility, early water stress sub-optimal weed limited 6.7, 5.4 5.0 ha(-1), respectively, when establishment used. Pests diseases relatively unimportant, while was particularly important fields during dry year (yield gap 11.6 ha(-1)). The use complementary analytical tools such multiple regression boundary line analysis many affected interacting constraints. These should be addressed simultaneously if significant productivity improvements achieved. This will difficult households, since former lack social financial capital improve management. (C) 2009 Elsevier B.V. All rights reserved.