Initial Efficiency of Commonly Used Practices to Control Soil, Runoff and Nutrient Losses from Maize and Banana Based Systems in the Lake Kivu Basin

This study was carried out to determine the initial efficiency of commonly used practices to control soil erosion from Maize and Banana based cropping systems in Lwiro micro catchment in the Lake Kivu basin. Soil, runoff and nutrient losses were determined using runoff plot approach. Instrumentalised runoff plots of 2X15m were installed on maize intercropped with beans and banana gardens. Two soil erosion management practices, namely; Tithonia and contour bunds were tested on Maize intercrop with Beans and mulch for Banana. The experiment included a control practice for each crop. Each treatment and control was replicated four times. Runoff and soil loss were estimated for each rainfall event and aggregated on seasonal basis. Nutrient (N, P and K) losses were estimated per season. Results of the long and short rains of the first year of experimentation show that soil and runoff losses did not significantly change with practices and seasons (P>0.05) for both banana and maize based systems. Soil and runoff losses ranged from 15.73 to 32.93 Mg/ha, and from 168.14 to 322.17 m3; respectively. Nutrient losses varied with practices and seasons (P<0.05) and ranged from 54.68 to 112.34 Kg/ha, 87.7 to 409.4 Kg/ha; 24.5 to 94.22 Kg/ha for K, N and P; respectively. Soil and runoff losses ranged from 8.99 to 20.6 t/ha, and from 85 to 152 m3; respectively. Only K losses changed significantly with season (P<0.05) and ranged from 17.8 to 53.9 Kg/ha under Banana cropping system.