Effect of Post Bush Clearing Management Practice on Herbaceous Species Productivity and Soil Status of Rangelands in Hammer District of South Omo Zone

Abstract

Bush encroachment is one of the factors that cause rangeland degradation in most pastoral areas of east Africa. A study on effects of post bush clearing management practice on rangeland productivity and soil status was conducted in Hammer district of South Omo zone, Southern Ethiopia with the objective of assessing effect post bush clearing management practice on the vegetation composition and soil status. A hectare of rangeland encroached by different acacia species was fenced and replicated/divided into three plots, and each plot was subdivided into four sub-plots to receive four treatments: un cleared woody vegetation (control) T1, cutting at above ground and leave as it is in the field (T2), cutting above ground and remove from field (T3), cutting above ground and burn right in the field (T4). Data on species composition indicated that almost all species present in all treatment groups with exception of two grass species Cenchrus ciliaris and Chloris pycnotrix dominated in plots which has received T2. Data on total herbaceous biomass, total grass biomass, total non grass biomass, soil erosion and soil compaction were collected after treatment applications. The applied treatments significantly influenced at (p<0.05) total herbaceous biomass, total grass biomass, total non grass biomass production, soil erosion and soil compaction. The results of this study showed that better biomass yield was harvested from treatment T2 which is highly significant at (p<0.05) followed by T3. There was no significant difference at (p<0.05) between T1 and T4 in all parameters.  On top that pastoralists perceived T2 in terms of lesser labor cost relative to T3 to remove cut materials from the field, even though it was in accessible to harvest and utilize at final stage. Therefore, controlling encroaching tree/shrub species through mechanical control and leaving the cleared material as it had increased the total herbaceous biomass for the livestock. The management of bush encroachment in such a way if sustained will contribute in stabilizing rangelands productivity and help to minimize the shortage of feed.

Keywords: Biomass yield, Bush clearing, herbaceous layer, soil compaction