Degradation of soil physical properties in overgrazed rangelands in Laikipia district.

Abstract

Infiltration rate, bulk density, saturated hydraulic conductivity, organic carbon content, particle size distribution and water content, for bush cover, grass cover and bare ground sites within four representative soil types of the overgrazed Mukogodo rangelands in Kenya, were studied. All properties, except particle size distribution, differed significantly among cover types, but rarely among soil types. Surface soil properties differed more often than those of the sub-surface horizon. The infiltration rates of grass and bush cover sites retained 3 to 4 times higher than bare ground. Consistently, bare ground surface soils retained significantly less water than covered sites and also held the least amount of plant-available water. The results indicate that depletion of soil cover due to overgrazing had adversely affected the soil physical properties important for soil water intake, storage and availability to plants.