Impacts Assessment of Open Grazing System on Some Rangeland Enviromental Comonents

Abstract

The study was conducted at EL Dilling locality rangeland at South Kordofan state which lies about 165km Southwest EL Obied town during the years 2010 – 2011. The aim of this study was to assess the impacts of open grazing system on some rangeland environmental components. The rangeland was divided into three sites according to utilization degree. Three water points were selected randomly from 24 permanents water points. Three grazed sites were also selected randomly, while the un-grazed site was selected in 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.almost48 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. For seed bank analysis, 72 soil samples were taken from the three sites to assess seed bank. Almost12 soil samples of 10×10 cm with a two different depths (0 – 10 cm) and (10 – 20 cm) were taken from each site (four from each transect). The point’s center quarter method (Cottam and Acurtis, 1956) had been used to measure trees density. To analyze and assess the socio- economic and social dimensions of open grazing system and its impacts, descriptive statistical analysis had been used. Questionnaire was designed to collect information from the animal owners at the seasonal grazing land users. A total of 120 randomly selected respondents represented 6% of total number on herders that used seasonal grazing land at the study area. The SAS statistical package and manual calculated formula were used for analysis of data obtained from vegetation measurements. And the socio- economic aspects data were analyzed using the SPSS computer programme. 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 to be sensitive for grazing procedure was found in un-grazed site. Also the results showed that plant density and plant frequency showed high variation between the three sites, in addition to very high significant differences in biomass productivity between the three sites. Also the results showed that, native tall grass species like Sorghum purpureosercim, , Andropogon gayanyus, and Pennisetum pedicellatum, and forbs such as Blepharis linariifolia, Asteraceae hyperhernia ofrun, Demodium dichotomum, and Impomea cordofana had disappeared around water points and grazing sites, while those plants represented high frequency at un-grazed site. The study conclude that the open grazing system has affected plants growth, decreased soil stability, changing plant types, seed bank and decreased rangeland productivity. Also the study showed that, many populations were affected by open grazing system, as results of degradation of rangeland, and the high demand of rangeland resources. And these led to conflicts among stakeholders. The study recommended that, new methods of animal production system should be tried. Hence to protect rangeland environmental components deterioration, such as farm for beef production can be established in large areas at Dilling locality. Rangeland conservation through introduction of native forbs such as Blepharis linariifolia, Asteraceae hyperhernia ofrun, Demodium dichotomum, and Impomea cordofana and native grasses like Chloris gyana, Sorghum purpureosercim Andropogon gayanyus should be introduced in rangeland.