Investigation the causes of uncertainty in methods for estimating soil organic carbon storage

The purpose of this study was to investigate the causes of uncertainty in different methods of estimating soil carbon and also to evaluate the proposed computational method that eliminated the effect of soil bulk density on carbon calculation and the actual soil carbon content for soils with different bulk densities in terms of the equivalent depth.Therefore, in order to check the accuracy of this proposed method, the amount of carbon in three types of grazing intensity in Golestan province (light grazing, average grazing intensity and severe grazing) was calculated and various methods were tested and analyzed. The results of mean comparison showed that based on first approach (concentration carbon Parameter), amount of carbon in first depth of light grazing area, moderate grazing and intensity grazing have significant differences, and soil concentration are 31.39, 23.57 and 11.5 gr C/kg soil, respectively, However, contradictory results achieved for first depth in case of present the mass soil in per unit area based on constant depth. So that the first depth of the light and medium grazing intensity have more mass carbon, 89.15 and 74.47 ton C/ ha, respectively, and heavy grazing intensity site has the lowest, 42.93 ton C/ ha. There are also these uncertainties between two different depths for different sites. In order to dissolved this conflict in several studies, mass carbon based on equivalent depth was calculated for study area and result show that light and heavy grazing area have the highest and the lowest amount of carbon.