Physical characteristics of the poonthalpadam soils of Kerala

Abstract

An appraisal of tha physical characteristics of the Poonthalpadam soils reveals that the texture of the profile samples varies from sandy clay to clay. The highest clay content is found to be in the surface layers which may be either due To impeded drainage which does not permit cJay migration or due to deposition of clay by flood waters on to the surface of the original soil. The apparent specific gravity ranges from 1 .20 to 1 .80 and the absolute specific gravity varies from 2.25 and 2.51 . There exists a negative correlation between clay content and apparent specific gravity. The porespace as well as volume of expansion show a decrease down the profile except in the profiles from Valiavallampathy and Kuttippallam. The upper and the lower plastic limit and sticky point moisture are found to be the highest in the surface layer of the profiles. These limits are of importance to the tillage operation since plastic limit represents the minimum moisture percentage at which the soil can be puddled and these fimitsare affected by ctay content, nature of clay minerals, organic matter and nature of exchangeable cations. Improving the physical condition of these soils would result in increased productivity of these soils.