The purpose of this research was to study the factors affecting soil organic matter (SOM) decomposition such as different temperatures, which represent the common ones in different seasons, available water, and application manure rates, at various periods (2, 4, 8, and 12) months. In order to fulfill this purpose two locations have been selected in Sulaimani Governorate, and then surface soil samples were taken at (0 - 30) cm at two locations {(Kalar (Shirwana castle), and Arbat (Kharajian village)} in Sulaimani area, Iraqi Kurdistan region.