Yearly mineralization rates of soil organic matter, humification coefficients of various organic substances incorporated into the soil, and the decomposition rate of humus formed from corn stalks were studied in the Huang-Huai-Hai Plain. Using 0.3 and 0.2458 as the representative values of humification coefficient of incorporated substances and decomposition rate (r) of the humus formed from them, respectively, the accumulation rates of humus originated from the organic substances incorporated into a field ...