Estimating soil organic carbon using pedotransfer functions in Damavand Rangelands

In our country, regardless of a limited area, soil organic carbon is very low in most areas of production such as agriculture and rangeland. This fact suggests that slight change in the amount of organic carbon can have high impact on soil properties and thus its quality in arid and semi-arid conditions. Determination of soil organic carbon (SOC) is of great importance because of its role in physical, chemical and biological properties. This research was aimed to estimate soil organic carbon using pedotransfer functions and the independent variables of soil physical and chemical properties in Damavand Rangelands. For this purpose, 60 soil samples were taken systematically at a soil depth of 0-30 cm in Damavand rangelands and soil organic carbon, pH, lime, nitrogen, sand, silt and clay were determined. Results showed that the average percentage of organic carbon was 0.49 percent and the minimum and maximum were 0.1% and 0.92%, respectively with a normal distribution. According to the obtained results, soil organic carbon was significantly positively correlated with clay and then with the nitrogen. One of the methods used to estimate soil organic carbon is a multivariate linear regression model where the dependent variables (clay, nitrogen, sand, silt, soil pH, bulk density and the percentage of gravel) are used, having a high correlation coefficient with organic carbon.