Multi-Purpose Trees and Shrubs in Soil and Water Conservation in the Highlands

Abstract

Two long-term experiments were set up at the National Agricultural Research Centre, Muguga Kenya, to investigate the potential of several multipurpose trees in enhancing soil productivity and controlling soil erosion in the high and medium potential areas of Kenya. One experiment consisted of Sesbania sesban, Leucaena leucocephala, and Leucaena K28 while the other had Calliandra calothyrsus and Leucaena diversifolia grown in alleys. Maize and beans were the test crops. The trees produced varying amounts of dry matter with Sesbania sesban having the fastest growth rate. Prunings constituted between 34 and 79% of the total tree biomass during the first year which accumulated to between 62 and 83% by the end of second year. Neither the trees nor the prunings showed positive effects on crop yield. Other aspects (for example analyses of soil physical and chemical properties) that might shed light on the effect of the trees and prunings on soil productivity have not been completed. Research is. however, still needed to establish quantitative measures for improved soil management under varying environments and assess its potential and limitations.