FARMERS’ SHADE TREE SPECIES PREFERENCE AND EVALUATION OF SELECTED SOIL PHYSICOCHEMICAL PROPERTIES UNDER THE TREE CANOPY IN COFFEE BASED AGROFORESTRY SYSTEMS IN DEDER DISTRICT, EAST HARARGHE ZONE, OROMIA, ETHIOPIA

Abstract

The study was conducted at Deder District, in East Hararghe Zone, Eastern Ethiopia. The aim of the study was to investigate farmers’ shade tree species preference and evaluate selected soil physicochemical properties under and outside shade tree canopy. To address the objectives of this study, all necessary data were collected through key informant interview, questionnaire survey and soil sampling. A total of 15 key informants and 60 households were participated for preference ranking of shade tree species. Based on their selection criteria, sampled households have done preference ranking of tree species used for soil fertility improvement. For soil analysis the representative soil sample was taken in four directions from three different distances; under shade tree canopy at 3m, edge of canopy at 6m and outside a canopy at 15m, then totally 36 soil samples of 18 disturbed and 18 undisturbed bulk soils was taken. The results of this study showed that, farmers’ main selection criteria were based on soil fertility improvement, decomposition rate of litter fall, and growth rate of coffee plants under shade tree canopy. Overall, farmers’ preferences ranking of shade tree species were in the order of Croton macrostachyus 1 st , Cordia africana 2 nd, Ficus sur 3 rd and Acacia abyssinica 4 th . From the known tree species, soil sample was taken under and outside the canopy of Croton macrostachyus with 1 st rank and Cordia africana with 2 nd rank. Based on the finding of this study, silt, clay soil, total porosity, pH, Oc, Ec, TN, Av.P, and Ex.k were significantly (P<0.05) higher under both shade tree canopies than outside shade tree canopy. However, sand soil and Bd were significantly (P<0.05) lower under both shade tree canopies than outside shade tree canopy. The status of soil fertility under the canopy of Croton macrostachyus was significantly (P<0.05) higher than Cordia africana trees. Hence, the soil laboratory analyzed results of soil physicochemical properties are in agreement with farmers’ rank of shade tree species preferences. Generally, under both shade tree species is important to increase soil conservation, litter fall decompositions, improve soil conditions through their ability to provide permanent cover, improve soil porosity, organic matter, total nitrogen, Available Phosphorus and has the potential to raise selected soil physicochemical properties.