Using farmers' knowledge of soils in making research results more relevant to field practice: Experiences from Rwanda

In the highlands of Rwanda, soils and climatic conditions vary over short distances in response to relief, parent material and altitude. Soil parameters change in a characteristic way from the hilltop/upper slope to the lower slope and valley bottom. Variations in soil parameters are reflected in crop yields. On average, the lower slopes yield 20-50% less compared with upper slopes, depending on the season and crop rotation. Results of surveys and on-farm studies revealed farmers' detailed knowledge of the soils. Farmers know that soil suitability is closely related to relief. They classify soils by a number of criteria and choose crops according to soil suitability. In order to draw up relevant recommendations, on-station and on-farm trials were set up on toposequences in two agro-ecological zones of southern Rwanda. Even though trial series along a toposequence proved to be a valuable method of experimentation in a highly diverse mountainous environment, it will be impossible for research and extension to fine-tune cropping recommendations. This should be left to farmers by encouraging them to use their local knowledge of soils and soil suitability. Using farmers' terms for soil suitability classes would ease communication and enhance mutual understanding. (C) 1998 Elsevier Science B.V. All rights reserved.