Status of Selected Soil Properties under Croton macrostachyus Tree at Gemechis District, West Hararghe Zone, Oromia, Ethiopia

Abstract

This study was designed to evaluate the status of some selected soil properties under Croton macrostachyus at Welargi and Hidha Dima kebeles in Gemechis district, West Hararghe Zone. Soil samples were collected from surface layers (0-20cm) at two distances (1 and 3m) under tree canopy and at adjacent open areas (16m) from crop fields. The result of soil analysis revealed that with the exception of soil texture and bulk density, all soil properties increased significantly under Croton macrostachyus canopy than in the open area in both kebeles showing a decreasing trend with increasing distance from the tree trunk, because of the input from Croton macrostachyus, like litter fall for organic carbon and accumulation of organic matter for moisture, nitrogen, available phosphorus, CEC and exchangeable potassium. In addition, the decrement of bulk density under canopy was due accumulation of organic matter. An increase of about  29.9% for organic carbon; 42.4% for total nitrogen; 12.6% for available phosphorus; 7% for CEC; 26.7% for exchangeable potassium; 14.8% for moisture content;  6.1% for soil pH, and a decline by 33.8% in bulk density values were detected under the canopy of Croton macrostachyus. This study demonstrated that Croton macrostachyus tree that was retained on crop fields improve soil properties under its canopy very considerably and this makes its integration into the farming system worthy and promising in the area.

Keywords: Tree-crop based farming, Gemechis, Croton macrostachyus, Hararghe, Soil fertility