Impacts of Bush Encroachment Control on Rangeland Vegetation in the Southeast Ethiopian Rangelands

This study was conducted to examine impacts of bush encroachment control on rangeland vegetation in the south east Ethiopia. The study targeted two main and dominant encroaching woody plant species, Acacia bussie and Acacia aerfota, and their effects on rangeland vegetation attributes dynamics in Raitu district of Bale zone, southeastern Ethiopia for two consecutive years. Rangeland site encroached by these two acacia species was replicated/divided into three plots, and each plot was subdivided into five sub-plots receive five treatments: cutting at 0.5 m above ground alone (T1), cutting at 0.5 m above ground and dissecting the stumps (T2), cutting at 0.5 m above ground and pouring chemicals on stumps (T3), cutting at 0.5 m above ground and debarking the stumps down into the soil surface (T4) and control (T5). Data on biomass, species richness, basal and litter covers, soil erosion and compaction, dead and re-sprouted encroaching tree/shrub species were collected. The applied treatments significantly influenced (P<0.05) basal cover, dry matter and the two encroaching tree species. The results of this study showed that T1 and T4 were good in controlling A. aerfota in that order. T4 and T3 had a significant effect in controlling A. bussie in their order. The most dominant grass and non-grass species observed after the control actions were Cenchrus ciliaris, Bothriochloa radicans, Hebiscus aponerus, Pennisetum mezianum, Lintonia nutans, Chrysopogon plumulosus and Eragrostis papposa. Therefore, controlling encroaching tree/shrub species had created a conducive grazing area with palatable herbaceous species for the livestock. The management of bush encroachment, if sustained, will contribute to stabilizing rangelands and help to minimize the negative effects of feed and food crises in the future.