Effect of land cover on soil particle size and organic carbon in the plough layer

Abstract

Physical alteration of soil characteristics of especially the plough layer (0-20cm) is brought about through land culture.The type of land cover, in fact, is an important factor controlling the soil texture, soil organic carbon (SOC) and soil erosion.The objectives of this paper areto analyze soil particle size distribution in the plough layer and quantify the SOC storage in the finer soil separate under native vegetation cover, cultivated land, eucalyptus plantations and barren land.A digital land cover map of the study area has been generated using Resourcesat-2 image.Soil samples from plots under different land cover types have been collected from depths of 0-10 cm and 10-20 cm.Particle size analysis has been done by dry sieving.SOC content of each soil separate - sand, very fine sand, silt + clay, under different land cover, has been done with the help of Walkley and Black method.Analysis of particle size distribution showed that proportion of sand particle is high.However silt+clay proportions have been found to vary with land cover types.SOC was high in silt+clay particles in general; but tended to increase in the sand fractions when particulate organic matter is incorporated.SOC decreased with soil depth under all land cover conditions but showed a reverse trend in some plots of cultivation.