Soil moisture determines the consistency of organic matter decomposition in field and lab test patterns
Description
We proposed the following hypothesis: (1) Since the precipitation in China is decreasing from east to west on a large scale, and the original soil moisture is retained, the decomposition rates of both S. nigrum and cotton strips generally exhibited a decreasing trend from east to west across large scale. (2) Since soil is the substrate and habitat for litter decomposition, it has the greatest influence on the decomposition. (3) Since the S. nigrum stems contain lignin, the decomposition rate of S. nigrum is lower than cotton strips. (4) Since Cd was unevenly distributed, the Cd concentrations in both S. nigrum and cotton strips gradually increased as decomposition progressed. Our data showed that the lab test of organic matter decomposition is consistent with the decomposition pattern in the field. Additionally, the high concentrations of heavy metal Cd resulted in a lower decomposition rate of cotton strips compared to S. nigrum. Cd is released slowly during decomposition and the release rate is regulated by the initial binding method. Notably, the highest SMMUE in mid-latitude regions indicates the adaptability of microorganisms. This study enhances our understanding of the importance of soil moisture in determining patterns of organic matter decomposition and the differences in decomposition between standardized and conventional litter.