Technology to Increase Carbon Mineralization Potential of Crop Residues under Cotton-Maize-Pulse Cropping System

Background: Cotton, maize and pulses are widely grown crops in the western zone of Tamil Nadu, resulting in a significant accumulation of crop residues throughout the year. The persistence of these crop residues after harvest can cause problems for farmers and the soil system. Therefore, the goal of the current study is to investigate the carbon mineralization process in these residues to enrich the soil’s nutrient content, turning waste into a valuable resource. Methods: The incubation experiment comprised 13 treatments, each with three replicates. These included a control, surface residue addition, buried residue addition and various combinations of soil, residue, microbial consortia, urea and jaggery, both on the soil surface (S) and incorporated into the soil (I). Result: The incorporation of crop residues into the soil, along with the addition of 1% microbial consortia, 2.0% jaggery and 1% urea, significantly enhanced carbon mineralization. Among the three crop residues, cowpea exhibited the highest performance, followed by cotton and maize, with values of 692, 564 and 522 µg C g-1 soil, respectively. This trend was further supported by the Michaelis-Menten model (V = 951.72 * x/22.13 + x), with a high goodness-of-fit represented by an R2 value of 0.95 for cowpea. The maximum Vmax (951.72 µmol/min) further substantiates the efficient carbon mineralization achieved by utilizing allocated resources in cowpea-incorporated crop residues (CWFI).