Effect of land use on physical and hydrological characteristics of Kabete soils

Abstract

Soil physical and hydrological properties of kabete soils were evaluated at three different land use sites namely forest, grass la n d , and cropland sites. The purpose of this work was to determine the effect of selected land uses on phy si caI and hydrological characteristics of the kabete soils in Kenya. Soil samples for this study were collected from the College of Agriculture and Veterinary Sciences (CAVS), field station. Soil samples for the determination of bulk density, organic matter content, particle size distribution, soil aggregate stability, soil erodibility indices, pore size distribution, soil moisture release characteristics, profile water holding capacity, available water capacity, and saturated hydraulic conductivity, were collected from 0, 10, 30, 60 and 100 soil depth at four different representative areas on each site. Soil samples were then taken for laboratory analysis of physical and hydrologic soil properties using standardized laboratory procedures. The bulk density for the cropland had an average value of 1.16 g -3 em as opposed to forest and grassland sites with average va1ues af 1 .02 and 1 .1 g cm-3 respec t'lve1y. 0rganl.c matt.er con-ten t showed a high value of 4.04% at the forest site, grassland and cropland sites had organic matter content values of 3.51 and 2.77% respectively. Particle size distribution, soil aggregate stability and soil erodibility indices showed significant differences between the three sites. The forest site showed higher readily available water content than the other two sites. The cropland site had the highest amount of non readily available water than grassland and forest sites. The three sites showed different patterns of soil moisture release characteristic curves depending on the soil texture and organic matter content of each site. Field capacity, permanent wilting point, available water capacity, and saturated hydraul ic conductivity for the three sites varied significantly at the soil surface as well as at the 100 cm soil depth.