Influence of tree species on soil properties under different agri-silviculture systems

Agroforestry on croplands is known to be a simple solution for restoration of soil fertility, especially in drylands. The present investigation was carried out to study the effect of three agroforestry tree species, namely Albizia lebbeck, Grewia optiva and Leucaena leucocephala on physical and chemical properties of soil. Physico-chemical analysis of soil at different depths (0–15, 15–30 and 30–45 cm) revealed significant increase in porosity and decrease in bulk density under the tree canopy when compared to control. There was a slight reduction in soil pH under the tree canopy. Soil electrical conductivity, in general, was observed to be higher under all the tree species as compared to control. Significant build up of soil organic carbon and available N, P and K in the agri-silviculture system was observed. Out of the three tree species, A. lebbeck had more favourable effect on soil physico-chemical properties. Soil moisture was significantly lower under the tree canopy as compared to control. The soil moisture content, bulk density and pH increased, while soil porosity, electrical conductivity, organic carbon, available N, P and K showed decreasing trend with increasing soil depth.