Contribution of Selected Herbivores’ Dung on the Soil Organic Carbon and Nitrogen in Serengeti National Park, Tanzania

This study was done to determine the contribution of selected herbivores’ dung in the grazed ecosystem of Serengeti National Park, Tanzania. To achieve this Soil Organic Carbon and Nitrogen were determined in four distinct textural soils in three sites, namely Serena with clay and clay loam, Barafu with sandy loam, sandy clay loam, and Seronera with sand clay loam. Thereafter the decomposition of dung pats in terms of weight change and percentage of nutrients in dung pats of four herbivore species (buffalo, zebra, wildebeest and elephant) incorporated into the soil beneath the dung pats were determined. Fresh dung, soil cores beneath the dung pats and control soils 1 m adjacent to the pats were taken for laboratory analysis. Dung pats and soil samples were analysed for initial percentage OC, N, pH and soil particle size distribution. Weight changes of the dung pats after each three weeks period were monitored. Similarly, monthly rainfalls during the study period were recorded from the rain gauges near the sites. The results indicate that the surface soil (0-15 cm depth) pH ranged from 6.0 - 7.5, 7.4 -7.9 and 6.1 - 7.4 for Serena, Barafu and Seronera respectively. While the soil texture was highly significantly different in percentage OC added after 18 weeks, the treatments and texture were both not significant for percentage N increased in the soil after 18 weeks. There was a difference of 1% between the ruminants and non-ruminants in percentage N increase although they were fluctuating over time due to weather changes. The C/N ratios of the controls and the treatments were on average 11 and 15 respectively, being highly significantly different and indicating that, treatments had a potential contribution to the soil OC and N in the ecosystem.