The influence of plant growth conditions on rangeland management in Kordofan region

This study was conducted for two consecutive years (2008 and 2009) on the natural rangeland of greater Kordofan region at three sites, the first site was in Urn Nabag (15 km north to Bara), the second site was in (EI-Demokeya) (30 km east of EI Obeid), and the third site was in (Dilling) (160 km south to EI Obeid). These sites were distributed along rainfall isohyets starting from 200 mm in the north (Um Nabag) up to 600mm in the south (Dilling). They represent the major agro-ecological zones in Kordofan region. The main objective was to investigate the variation in rangeland vegetation as indicated by different growth conditions. The field work was carried out at the start of rainy seasons and seed setting stages in the three locations. The samples were taken from three sites; Area of (lxl km2) was selected in each site. Sampling was based on locating randomly three circular plots with radius of 200m as an area previously determined by CARBOAFRlCA project at each location. Within each sampling plot 40 quadrates was selected randomly from the plot in early and late in the rainy season. Results showed that the biomass production at Dilling showed highest values followed by Demokeya and then Bara. Plant composition in Dilling, showed highest values followed by Demokeya and then Bara. Also, the biomass production showed highest values in Dilling followed by Demokeya and then Bara. Litter % in Dilling showed lowest values. Vegetation cover% was lowest in Bara followed by Demokeya and then Dilling. Bare soil incidents were higher in Bara and Demokeya than Dilling. The crude protein content of herbaceous biomass was higher in Bara and Demokeya (sandy soil) than Dilling (clay soil). The crude fiber content (CF) decrease or increase according to the plant age in the three sites. The high ash content was in Dilling compared with Bara and emokeya. However, in time of sampling the differences were recorded in ash but their values decreased by the plant growth. The differences in dry matter between the seasons and among sites were minor. The dominant plants in (Dilling) in the two seasons were Hyparrhenia conifines (Umraggo), Newtonya spp (Newtonya) and Cymbopogon nervatus (Nal). The dominant plants in Bara were Cenchrus biflorus (Haskaneet Khashen), Fimbristylist dichtomo (Umfesaseyat) and Aristida spp (Gaw). The dominant plants in Demokeya were Echinchloa colona (Difra), Eragrostis termula (Bano) and Cenchrus biflorus (Haskaneet Khashen). The similarity index indicated that there was minor similarity recorded between Bara and Damokeya (45%), followed by Damokeya and Dilling (30%) and dissimilarity was between Bara and Dilling (3%). Generally, Dilling recorded the highest biomass quantity, but lowest quality compared with Bara and Demokeya. Consequently, Demokeya was the best site in biomass quality followed by Bara and finally Dilling. The variations investigated by the study justify differential management prescriptions that cater for activities such as seed broadcasting and enrichment of range with certain plant species