EVALUATION OF SOIL PHYSIO-CHEMICAL PROPERTIES UNDER A YOUNG ALBIZIA LEBBECK (RATTLE TREE) PLANTATION IN A SAVANNA ECOSYSTEM

Abstract

The use of agroforestry practice as a source of improving soil quality was studied with the aim of assessing the effect of six-year-old Albizia lebbeck on soil. The experiment was laid out on a randomised complete block design comprising of five treatments and three replicates at 0–15cm and 15–30 cm depths. The soil physio-chemical properties were estimated using standard analytical procedures. The result revealed increase in clay and decrease in silt and sand contents, down the depth. The silt clay ratio indicated young soil with high weathering potential. The control favoured macro-aggregate (0.881), while A. lebbeck and 10 t ha-1 green manure favoured micro-aggregate. Mean weight diameter showed that the control (0.910) was more stable than other treatments. Organic carbon, organic matter, total nitrogen and carbon to nitrogen ratio were not significantly influenced, while phosphorus was at 15–30 cm depth, influenced by A. lebbeck. Soil pH was slightly acidic but suitable for plant production, and change in pH was negative indicating the exchangeable capacity of the soil. All the soil quality indicators studied were low. Therefore, in choosing A. lebbeck as an alternative source of improving soil quality production, the factors evaluated should be tree age, incorporation method, soil stability and other cultural practices like tillage operation.