Currently, a Eucalyptus globulus is a common smallholder plantation species in the Wogera district. The species is significantly expanding on marginal and fertile farmlands. The objective is to analyze the effects of Eucalyptus globulus woodlots plantation and their directions on selected soil physicochemical properties and yield of wheat crop. Three woodlots with similar site conditions were selected for this particular study. Soil samples were taken at a soil depth of 20 cm in RCBD design with three replications. Soil samples were taken at four directions (East, West, South, and North) of woodlots plantation at five different horizontal distances from the woodlots; the center of the woodlot, 5 m, 10 m, 15 m, and 40 m. For the wheat yield study: quadrates of 1m2 area at each distance within directions were laid for wheat grain yield measurement. The finding indicated that electric conductivity, available phosphorus, cation exchange capacity, soil texture, and exchangeable cations were not significantly different across the different directions and distances, whereas soil bulk density, pH, total nitrogen, organic matter were significantly different. This could be attributed to the high organic matter addition via litter-fall, root biomass, uptake, and return of nutrients from deeper soil profiles under the tree canopies. The biomass and grain yield of wheat were significantly different across distance and direction from the sampled woodlot in increasing trend in all directions, this study recommends Eucalyptus should planting on marginal lands with appropriate distance from croplands about 20m to minimize its effect on crop yields.
Keywords: Eucalyptus, soil properties, wheat, distance, direction