Abstract:
Eucalyptus globulus is a common smallholder plantation species in Wogera district. The species
is significantly expanding both on marginal and fertile farmlands in the district. This research
analyses the effects of Eucalyptus globules woodlots on selected soil physico-chemical properties
and yield of wheat crop in Wogera district. Three woodlots with similar site condition were
selected for this particular study. Composite Soil samples were taken at soil depth of 0-20 cm in
RCBD design with three replications for analysis of soil physico-chemical properties. Soil samples
were taken in four directions of the selected woodlots at five different horizontal distances from
the woodlots; o m (center of woodlot), 5m, 10m, 15m and 40m both in East, West, South and North
directions. A 1m
2
(1m×1m) quadrate was established at each direction and distances to measure
biomass and grain yield of wheat. Furthermore, 48 households were selected by stratified random
sampling and interviewed using semi structured questionnaire to examine their perception on
Eucalyptus plantation and its effect on soil properties and crop yields. The result showed that soil
bulk density, EC, CEC, soil texture and exchangeable cations (Ca, Mg and K) were not
significantly different across the different directions and distance from the Eucalyptus woodlots,
whereas soil pH, total nitrogen, organic matter and available phosphorus were significantly
different between Eucalyptus plantation and cropland. This could be attributed by 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. The present
experimental results supported farmers’ perception and revealing the impacts of Eucalyptus
plantations on productive lands and reduction in crop productivity. Given the significance of
croplands for food self- sufficiency and food security in Ethiopia, this study recommends
Eucalyptus planting on marginal lands in cluster/block system. Further research required on the
Allelopathy and shading effect of Eucalyptus tree on soil physicochemical properties and crop
yield
