Assessment of The Environmental Impact of Natural Rangeland Management Interventions In Wad Omer Agricultural Scheme - Khartoum State

Abstract

This study was conducted in Wad Omer agricultural scheme, Omdurman locality which was located between 16º 19ʹ 37ʺ -16º 27ʹ N and 31º 43ʹ- 31º 47ʹ E, in Khartoum state, during the period 2017and 2018. The study aimed to assess the environmental impacts of natural Rangeland management interventions in Khartoum State at Wad Omar Agricultural Scheme. Two range sites were selected in the study area; (sand soil and rock soil) 500m×500m plot was marked based on the criteria set .Eight transects of 100 m length were randomly distributed for vegetation measurements. Parker loop method were used to measure relative plants cover, of the rangeland using ¾ loop placed at ground level at one meter intervals, also quadrate of 1×1m was used to determine plant density, frequency and biomass production across line transect with interval of 20m between each other. The nearest individual method was used in each site to determine trees density. For soil seed bank and organic matter determination, 30 soil samples were taken in both range sites, collected from three soil depth (0-10, 11-20 and 21-30 cm) within area of 10×10 cm. All samples of the same depth were mixed of subsamples (250 gm). These subsamples were washed to separate the seeds, and also water and calcium chloride were used to separate dead and live seed. A questionnaire was designed to collect information from three villages which were randomly selected, represent 10% of total people. The standard equations of vegetation measurement were used for plant attributes and also SAS statistical program was used to analyze vegetation measurements and soil seed bank. The statistical package for social sciences (SPSS) was used to analyze socio-economic data. The results showed the average percentage of plant cover in the sandy soil was higher than the rocky soil site also the result showed that the plant density in sandy soil was 45/plant/m2 and 35/plant/m2 in rocky soil. The productivity of the biomass had not affected by the soil types in grazing sites. The study found the dominate species composition at the sandy site were Corchorus spp (Khudra Baria) 61.1%, Dactyloctenium aegyptium(Abusabe) 59.2%, Aristida adscensionis (Gaw)53.7% and Panicum turgidum(Tummam)53.4%. While the dominated species composition of the rocky site were Aristida adscensionis (Gaw) 55.2%, Eragrostis termula (Banw) 54.3%, Trinthema spp (Rabaa) 48.5% and Panicum turgidum (Tummam) 44.2%. The study found that, the seed bank density decreases with the increase of soil depth and the lowest seed number in sandy soil. The study found that the main interventions of range and pasture Administration (RPA) to improve the rangeland status included broadcasting of seeds, planting forage, drilling wells, provide herbside and fertilizers and grow shelterbelts. The study concluded that the range management interventions in Wad Omer agricultural scheme had positive effects on crops protection and soil conservation. More interventions from Range and Pasture Administration in Khartoum State should be done. The seed bank, organic matter and vegetation attribute were good indicators can to be used to assess the impact of range improvement activities.