Optimum Seed Rate of Vigna sun-hum (Tagtaga) for Rangeland Rehabilitation in Sandy Soil of North Kordofan

In order to determine the optimum rate of Vigna sun-hum seed sowing for rangeland rehabilitation in sandy soil of North Kordofan, Sudan, two trials were conducted separately under managed and unmanaged conditions at El-obeid Agricultural Research Farm in Sheikan locality of North Kordofan State in 2015 and 2016. Seed rates were 1, 2, 3, 4 and 5 Kg/feddan (4200m) and arranged by a Completely Randomized Block Design with three replications. The species in both trials was established under rain-fed conditions by broadcasting seeds on prepared seed beds early in the rainy season. In the managed trial, seeds were broadcasted on a clean seed bed. The first and second weeding was carried out after two and four weeks from seed broadcasting. In the un-managed trial, a bare area or an area with scatter occurrence and low density of herbaceous species was selected annually and weeding was not done. Vegetation cover, density and forage dry weights were obtained using (50x50 cm²) quadrate. MSTAT-C statistical software package was used for the statistical analysis. In both managed and un- managed trials, the results revealed that there were significant (P≤0.001) differences in most measured variables. In the managed trial of 2015 cropping season, the seed rate of 3 kg/feddan recorded the highest vegetation cover (33.3%) and the highest dry weight (260.3 g/m²) whereas the one kg/feddan had the least vegetation cover (10%) and dry weight (52.1 g/m²). In un-managed trial of 2016 cropping season, the seed rate of 4 kg/feddan recorded the highest density (98 plant/m²) and the highest dry weight (100.3 g/m²) whereas the third seed rate recorded the least density (37 plant/m²) and dry weight (33.6 g/m²). Results of combined analysis indicated that there were significant (P<0.001) differences among the five seed rates in most studied parameters. For Vigna sun-hum as endangered leguminous range species, two optimum seed rates of 3 and 4 kg/feddan were recommended for ranches and natural rangeland rehabilitation in the managed and un-managed areas, respectively.