Microbial consortia: Sustainable alternative to maize residue burning and way to enhance nitrogen in calcareous soil

Crop residue burning is a major environmental problem that causes air pollution and greenhouse gas emissions. This study aimed to evaluate the effect of microbial consortia and nutrient boosters (urea and jaggery) on maize residue decomposition and nitrogen mineralization in calcareous soil. Thirteen treatments with different combinations of microbial consortia, urea, jaggery and residue application methods (surface or incorporation) were compared with a control (soil only) in a laboratory incubation experiment. The microbial consortia and nutrient boosters significantly increased the available nitrogen content in soil compared to the control and treatments with only residue. The highest increase (21.9%) was in the treatment with incorporated residue, 1% consortia, 1% urea, and 2% jaggery. This treatment also achieved the highest rate of nitrogen mineralization. Incorporation of residue and amendments generally resulted in higher nitrogen availability than surface application. Meanwhile, microbial consortia degraded the high carbon and nitrogen (C:N) ratio maize residue and released mineral nitrogen to the soil. Furthermore, urea and jaggery provided nitrogen and carbon sources for the microbes, boosting nitrogen availability. Therefore, these findings suggest that microbial consortia, urea, and jaggery are effective amendments for enhancing nitrogen availability from maize residue in soil, and can provide a sustainable alternative to residue burning by accelerating decomposition and nutrient mineralization.