A Review of Possible Calculation Methods (CMs) for Soil Organic Carbon Stock Estimates and Evaluating Their Methodological Biases

Assessment of soil organic carbon content (SCC), bulk density (BD), rock fragment content (RFC), and depth of specific soil profile/layer are vital to calculate SCS (soil organic carbon stocks). But, different applications of these parameters could produce substantial biases. Four different CMs were studied from 495 publications and explained why three out of four often applied CMs over-estimate SCS. In soils with more RFC (>35%vol.), SCS could be over-estimated by greater than 33.31 t ha−1, as displayed by using northern Ethiopia agricultural soil data. Due to the variation in the RFC, the average methodical over-estimations for these soil samples were varied from 0.46 to 31.3 t ha−1 for three different frequently applied equations. The equation combine as reorganized in this article could aid to unify SCS estimation and evade over-estimation in future uses. Furthermore, the misused CMs of BD and RFC must be modified to estimate precise values of SCS for its future maintainable uses and to alleviate the unprecedented increase in CO2. The miss calculation of SCS will in turn affect the carbon sequestration in the agricultural and natural systems estimation and consideration leading to miss prediction of the soil organic carbon effect on the climate change related studies.