Effects of cover management practices on Runoff and Erosion in Nsukka sandy loam soil

The effects of cover management and non-tillage on runoff and soil loss were investigated in 2004 and 2005 on runoff plots at the University of Nigeria Nsukka farm on a 5% slope of a sandy loam. Grass, legume, coco yam and sorghum were planted as conservation barriers in order to examine their influence on water and sediment transport. After each erosive storm for the two seasons, runoff and sediment yield were determined. The dense effective barriers (Panicum maximum and Centrosema pubescens) slowed down flow, retained water and prevented sediment yield. The less effective barriers with cocoyam, sorghum and control bare fallow allow flow of water and flow velocity was not reduced enough, resulting in water and soil transport. Cumulative runoff was highest in bare fallow (87mm) and lowest in sorghum (41mm). The highest soil loss of 1.13kg/m2 and relatively low loss of 0.55kg/m2 were obtained in cocoyam and sorghum in 2005. Runoff and soil loss were reduced by 100% under grass and legume. Cocoyam and sorghum reduced runoff by 20% and 53% respectively. Sorghum reduced soil loss by 35%, while there was no difference under the bare fallow and cocoyam. Runoff as percentage of rainfall was highest in bare fallow (60.6%) and lowest in sorghum (2.2%) respectively. Erosion rate calculated was lowest in sorghum (0.2kg/m2/month) highest in cocoyam (0.41kg/m2/month) and in bare fallow the value was 0.3kg/m2/month.