Each type of organism has slightly different requirements for optimal growth and activity, so the particular species that are active, and their population levels, will vary during the season and by the method used for straw incorporation. Aeration, temperature, nutrients, and moisture are factors that affect the rate and degree of rice straw decomposition. Aeration Straw decays most readily when oxygen is present. This aerobic decomposition process may be quite rapid given the right temperature and moisture levels. Under these conditions, microbes decompose straw into organic matter, minerals, and carbon dioxide.
Different microbes are at work under anaerobic and aerobic conditions.
Temperature Straw decomposition is dependent on temperature. It is most rapid in the warmer part of the fall and spring and continues into the next cropping season. Cold winter temperatures slow down the process. Nutrients Microorganisms need carbon, nitrogen, and other nutrients, which they obtain from the soil, crop residues they decompose, and nutrients released by the microbes that die during decomposition. The initial nitrogen content of the residue is particularly important because low nitrogen may limit decomposition.