Abstract:
The study was conducted at EL Dilling locality rangeland at South Kordofan State which lies about 165km south east EL Obied town during the years 2010 – 2011. The aim of this study was to assess the impacts of open grazing system on vegetation attributes and biomass productivity. The rangeland was divided into three sites according to utilization degree. Three water points were selected randomly from 25 permanents water points. Three grazed sites were also selected randomly, while the ungrazed site was selected in the middle of two sites. For vegetation measurements the Parker loop method (Parker and Hirris, 1959) have been used, to measure relative plants composition and ground cover of the rangeland.48 transects were delineated using 100 meter tape and a ¾ loop placed at ground level at one meter intervals. In addition to the quadrate method (Wilm et al, 1944) double sample procedure was used to determine relative plants density, plant frequency and biomass productivity. The SAS statistical package and manual calculated formula were used for analysis of the data obtained from vegetation measurements. The results showed very high significant differences in ground cover and significant variation in plant relative composition over the three sites. The study showed that the very sensitive forbs that considered being sensitive for grazing procedure was found in ungrazed site. Also the results showed that there were high variation in plants density and plants frequency between the three sites, in addition to very high significant differences in biomass productivity between the three sites. The study concluded that the open grazing system has affected plants growth, degreased soil stability, changed plants type and decreased rangeland productivity.
