Impacts of Land Use Types on Selected Soil Physico-chemical Properties at Yayu District, Ilu Aba Bora Zone, Southwestern Ethiopia

Abstract

The present study was initiated with aim of investigating the importance of homegarden agroforestry on improving soil properties with specific objective of evaluating selected physico-chemical properties under homegarden agroforestry and to compare with adjacent land use at Yayu district, Southwestern Ethiopia. Representative soil samples were taken from homegarden agroforestry with different age classes; new (Nh), established (Eh) and old homegarden (Oh), and from adjacent land of open cultivated land (Ocl), semiforest (Sf) and natural forest (Nf). Samples were collected in each site of soil sampling in Zigzag method from plot of 20mX20m at each soil depth of 0-30cm and 30-60cm by three replications, totally of thirty six composite soil samples were collected for analysis. Soil data was subjected to analysis of variance using the GLM procedure of the SAS version 9.3 and LSD test were used to compare treatment means at 0.05. The result showed significant difference in soil parameters analyzed.Considering the topsoil, the highest soil pH(6.06), available P(23.17ppm) and exchangeable K(6.53cmol(+)Kg-1 )was obtained inold homegarden agroforestry, whereas the lowest (5.40), (5.81ppm) and (1.45 cmol(+)Kg-1 )was in open cultivated land, in respectively. Regards to subsoil, the highest soil pH(6.18) available P (8.97ppm) and exchangeable (K 2.01 cmol(+)Kg-1 ) in homegarden agroforestry, whereas 5.63, (2.34ppm) and (0.51 cmol(+)Kg-1 ) respectively.Available p and exchangeable k was highly significantly associated with soil pH value at r=0.78** and 0.73** in topsoil, r=0.71**and r=0.87** in subsoil at p<0.05, in respectively. This soils property improvement in the soils of homegardens may perhaps due to house refuses bones and ash, animals manures, contribute of crop residues and litterfall to form SOM; as SOM mineralization form inorganic matter, and humification and buffering capacity of SOM; as it optimizes soil basic cations. Hence it can be concluded that, the soils in the homegarden agroforestry posses the improving trend in soils properties as compared to the adjacent land uses soils. Therefore the homegarden agroforestry practices that has been started and ongoing by the smallholder farmers for ancient time in Yayu district should be considered by NutriHAF and Government to scaling up the practices. Further, detail investigation on soils and plant nutrient analysis is important to clarify the impact of homegarden agroforestry on soil.