Rangeland cover approximately 85% of Kenya’s land mass and is a major resource for livestock farming with a considerable potential to mitigate climate change, yet these lands are stressed differently by various management. Our study aimed at predicting the long-term changes in Soil Organic Carbon (SOC) in grazing lands of Kenya under different grazing management systems (rotational, continuous and ungrazed), for a 50-year period using RothC 26.3. This research was conducted on a commercial grazing ranch which practices the two grazing management systems. Soil samples were collected at the depths of 0-10, 10-20 and 20-30 cm for the determination of soil organic carbon concentrations and bulk densities, results were later used for running the RothC model. The predicted results showed that the rate of SOC stock [t/ha] was higher under rotational grazing system in comparison to ungrazed and continual grazing system for the modelling period of 2015-2064. In the absence of grazing, the system was predicted to accumulate 19.22 Mg C ha-1 of SOC at the rate of 0.369 Mg C ha-1yr-1, whereas rotational grazing system was predicted to accumulate 30.46 Mg C ha-1 at the rate of 0.61 Mg C ha-1yr-1. The continual grazing management system resulted in the accrual of 18.49 Mg C ha-1 at the rate of 0.37 Mg C ha-1 yr-1 over 50 years. Thus, rotationally grazing management system have the potential of accumulating soil organic carbon in semi-arid grasslands. تفاصيل المقالة

Rangelands ecosystems play a critical role in regulating the emission and uptake of the most important Greenhouse Gases (GHGs) such as CO2, CH4, and N2O. However, the effects of grazing management on GHG fluxes in the semi-arid lands of East Africa remain unclear. The present study compared the effects of three grazing systems on cumulative CO2, CH4, and N2O fluxes in the semi-arid grazing land ecosystem in Yohani ranch Makueni County, Kenya. The study followed a pseudo-replication design in which there were three treatments: 1) Continual grazed, 2) rotational grazed and 3) and ungrazed. Greenhouse gas samples were collected using the static chamber method for a period of three months covering the dry and wet season as well as a transition period. Cumulative soil CO2 fluxes were highest in continual grazing system (2357±123.9 kg ha-1 3 months), followed by rotational grazing (1285±123.9 kg ha-1 3 months) and lowest in the ungrazed (1241±143 CO2 kg ha-1 3 months), respectively. The three month cumulative N2O and CH4 fluxes were also highest in continual grazing and lowest in ungrazed site 677.9±130.1, 208.6±127.3 and 162.2±150.3 (g ha-1 3 months) and CH4, 232.7±126.6, 173.1±126.6 and 80±46.2 (g ha-1 3 months) respectively. The results suggest that the continual livestock grazing system increases emissions of GHGs compared to rotational grazing. تفاصيل المقالة