Nutrient Losses from Cropland in the Central Highlands of Kenya due to Surface Runoff and Soil Erosion

Abstract

Soil loss, runoff and nutrient losses were measured on runoff plots during the rainy season from November 1992 to January 1993. Crops grown were maize (Zea mays L.), beans (Phaseolus vulgaris L.) and an intercrop of maize and beans. The control treatment was bare fallow. The total loss of C, N, P, K and plant-available P and K in the eroded soil as well as P and K dissolved in the surface runoff water were not dependent on the nutrient concentration of the eroded soil and water, but rather on the total amount of runoff and eroded soil. Compared to bare fallow, P (and K) losses under maize were reduced to 24.2% (28.3%), under beans to 15.3% (15.4%) and under intercrop to 9.3% (10.7%).