The effects of cultivation upon some physical and chemical properties of three Kenya soils

Abstract

Studies to evaluate some chemical and physical properties of cultivated and adjacent uncultivated (virgin or grassland) soils of three Kenyan soils (Andoso1, Luviso1 and Nitoso1 from Kiambu, Machakos and Kisii, respectively) were undertaken. The data indicate that considerable adverse changes had taken place in two of the soils (Andoso1 and Luviso1) due to their continuous use. The observed changes mainly with organic carbon, total nitrogen and bulk density had mostly occurred in the upper 0-10 cm layer and rarely below 20 cm depth. In general, tillage of land appears to have adversely affected some soil properties (organic carbon, total nitrogen and bu1 k dens ity) whi ch are inportant in good crop production. The data from Nitoso1 however indicate that these adverse changes can be slowed or reversed if appropriate farming methods are employed. In many instances, the site under minimum tillage showed slightly superior soil properties than the adjacent grassland sites. The deterioration in soil properties due to cultivation were therefore found to be particularly severe with the Luviso1 than with the Andoso1 and Nitoso1 soils. The vulnerability of this soil to deterioration was associated to the soil management (i.e. harsh treatment both cultural and environmental) it receives