Synthesis of a 5-year agroecology research project in Tanzania

Abstract

This synthesis paper evaluates the outcomes of a five-year field research project that examined the impacts of three common agroecological practices applied alone or in combinations (soil amendments, intercropping, biological pest control) on the yields of two Tanzanian staple foods, maize, and cassava. The research has been published in seven peer-reviewed articles and two PhD theses. Here, we brought together all published findings and, additionally, unpublished findings and observations of farmers’ complementary research on their own satellite field plots. These are the main findings: 1) The most reliable yield benefits were achieved through soil amendments, but more for grain crops than cassava and more for non-legume than legume crops. 2) The most significant yield increases were recorded for legume intercropping when it was applied alongside soil amendments rather than on its own. 3) Biocontrol practices are labor-intensive and costly, but the results can be inconsistent and unpredictable. To be effective, they require knowledge of the type and ecology of the pests, but this knowledge is often lacking. Much more must be invested in crop entomology research and consulting to benefit fully from biocontrol practices. Until then, farmers benefit most from the previous two practices, ideally in combination.