EVALUATION OF SELECTED SOIL PHYSIOCHEMICAL PROPERTIES AND MAIZE YIELD UNDER BALANITES AEGYPTIACA IN PARK LAND AGROFORESTRY SYSTEM IN KAMBA DISTRICT, GAMO ZONE, ETHIOPIA.

Abstract

Dispersed or park land agroforestry trees such as Balanites aegyptiaca which is maintained or planted on farmland provide a significant contribution to soil fertility improvement and Maize yields. However, there was no quantitative information on the level of soil nutrient additions of this tree to the soil system. A 5 × 1ha of land of entirely the same biophysical setting was delineated. Five trees of relatively the same diameter at breast height (DBH), canopy diameter and height were selected to study the effect of the tree on soil properties and Maize yields. In total, 40 composite soil samples collected from four directions at four distances were collected from each tree, that is 1/3m, 2/3m,perperial and away from tree trunk at two soil depths of 0 - 20 and 21 - 40 cm. The experiment design followed RCBD factorial arrangement with five replication. Soil parameters tested were soil texture, bulk density(BD) , soil organic carbon(SOC) , soil organic matte (SOM), moisture content (MC),soil reaction (pH), total nitrogen (TN), available phosphorus (Av.P), electrical conductivity (EC) and cation exchange capacity (CEC). In addition, maize crop yield and growth performance were assessed under Balanityes agypitica in park land agroforestry from the three canopy distances and the one control plots away from tree canopy. The result of soil analysis showed that except the soil textural class and bulk density all were increased significantly under Balanityes agypitica canopy. For the maize yield performance, except the harvest index the maize growth and yield parameters showed highly significant different between under Balanityes agypitica tree canopy influence and away from tree canopy. In general, B. agypitica added a significant amount of nutrients to the soil. Thus, retaining this important tree species on farmland played a positive role in replenishing soil fertility and maize growth and yield parameters for resource-constrained households so as to reduce chemical fertilizer amendments. For this we can recommend traditional agro forestry practice for improving physical and chemical properties of soil and increases maize crop yield.