Effect of Faidherbia albida (Delile) A. Chev. based parkland agroforestry on soil physicochemical properties and its socioeconomic benefits: the case of Kenna Woreda, Konso Zone, Southern Ethiopia

Abstract

Faidherbia albida is one of the important parkland agroforestry tree species which have great role in improvement of soil fertility. Thus, the objective of this study was to investigate the effect of Faidherbia albida tree species on some soil physicochemical properties and assess its socioeconomic benefits and management practices in Kenna Woreda, Konso Zone, Southern Ethiopia. A complete block design was used to determine the effect of Faidherbia albida on soil physicochemical properties, while a simple random sampling was used to obtain representative households from purposively selected Fasha and Debena Kebeles. In each block (farmland), three individuals of Faidherbia albida with similar crown height, diameter at breast height, and crown diameter were selected for the study. A total of twenty four composite soil samples were taken at 2.6 m, 5.2 m, 7.8 m, and 23.4 m radial distances under each selected Faidherbia albida tree, in four directions, from 0 - 20 cm and 20 - 40 cm fixed soil depths. Furthermore, open and close ended question, focus group discussion, and face to face interviews were convened to collect socioeconomic data. All model assumptions for normality and homogeneity of variance were checked using Shapiro-Wilk and Levene’s test, respectively, and then soil data were analyzed using one way of analysis of variance and Least Significance Difference for mean separation at P < 0.05. The results showed that sand and clay fraction was not significantly different (P > 0.05) among radial distances and soil depths, while silt fraction was significantly different (P < 0.05). Bulk Density, pH and Electrical Conductivity, Available phosphorus, Soil Organic Carbon, Total Nitrogen, and Cation Exchange Capacity were significantly different (P < 0.05) with distance from the tree trunk and soil depth. Furthermore, the social survey revealed five socioeconomic benefits of Faidherbia albida in the study area including uses for animal fodder, fuel wood, live fence, honey production, and making of household tools. This study also identified numerous tree management practices such as pruning, pollarding, and lopping for managing Faidherbia albida on farmlands. Overall, Faidherbia albida play important role in improving soil fertility and providing valuable benefits to local communities, suggesting the need to sustain and further promote it in the farmlands. Appropriate tree management procedures should be practiced to maximize both agricultural and socioeconomic benefits, which indeed require further investigation.