Kurdistan rangelands are located in semi-arid region and conversion of rangelands to dry farming is the most type of land use changes in this areas and then rangelands in this region has been affected by human-induced degradation. The objective of this study was to compare amount of soil organic carbon in two different land uses including rangelands and dry land farm in semi-arid rangelands of Kurdistan province. To compare effect of land use change in soil, every treatment and its control area were next to each other. Slope ranges from 2% to 40% and generally in similar aspect. Soil was sampled by collecting 3 cores in every treatment and its control area from depth of 50 cm in a completely randomized design. Soil samples were air-dried, Gravel and roots were separated and samples were passed through the 2-mm sieve. Gravel was weighed and roots were taken to weigh after drying. The results showed that there is a significant difference of soil’s carbon between dry land farming and rangelands treatments (99%). SOC in this region has greatly declined by changing rangelands to dry farming lands In 9 treatments. Comparison of different treatments using Duncan analysis showed that the highest decrease rate of SOC (44%) was related to dry land farm with 45% slop while the lowest SOC decrease (0%) was obtained in 2-5 % slop.
