In late summer and fall, soil drying can slow the rate of residue decomposition. During late fall and winter, soil temperatures again limit decomposition. Factors such as size of residue, placement and mixing of residue within the soil and, as previously stated, residue composition also affect decomposition. The rate of decomposition is most rapid when residue is broken into small fragments and well mixed with soil. Decomposition in the laboratory is typically studied by incubating known amounts of residue and measuring carbon dioxide evolution over time.
Microbes convert carbon in residue to gaseous carbon dioxide.
In the field, decomposition has been studied by placing known amounts of residue in, on or above the soil and measuring weight loss over time. The rotation was annual crop, no-till winter wheat. He recorded the weight loss of these bundles periodically over the next year. These placements approximated standing stubble, chopped or matted residue and incorporated residue. The rotation was winter wheat-spring green peas.