Carbon and nitrogen mineralization characteristics of different types of organic manures

The incubation experiment was used to study carbon (C) and nitrogen (N) mineralization characteristics of 9 organic manures sampled from the bases of sunlight greenhouses in Guanzhong district, Shaanxi Province. The results show that there are significant differences in the C and N mineralization and their mineralization rates (the ratio of C or N mineralization to total organic C or total organic N) among the different manures. The range of C mineralization rates of different manures is from 22.24% to 87.16%, with CV (coefficient of variation) of 90.30%, and the range of N mineralization rates of different manures is from 29.07% to 84.87%, with CV of 67.36%. The mean amounts of C and N mineralization, and mineralization rates of chicken manure are significantly higher than those of pig and cattle manures, and there is no difference between pig and cattle manures. For a same type of organic manure, there are also significant differences in the C and N mineralization and mineralization rates among the manures collected from different places. The amounts of C and N mineralization of organic manure are linearly related with their total N contents, indicating that the N content of organic manure is the key factor affecting the mineralization of C and N from manures.