Managing Crop Residues: Impacts on Soil C:N Ratio and microbial activity with the addition of a decomposition enhancer

Abstract

Crop residue burning poses a substantial concern, as it detrimentally influencing soil microbiota and contributes to atmospheric pollution, underscoring the imperative for precision in crop residue management. An experiment was conducted at Professor Jayashankar Telangana State Agricultural University, College of Agriculture, Rajendranagar to determine the effects of crop residues alone and crop residues combined with decomposition enhancers (Microbial Consortium-MC and Single Super Phosphate-SSP) on the soil C: N ratio and microbial activity during the winter (rabi) season of 2021-22. The pot culture experiment consisted of 13 treatment combinations of crop residues alone and crop residues along with decomposition enhancers in a completely randomized design with 3 replications. The results indicated an initial increase and subsequent decline in carbon content across the treatments, with T5 (Sunhemp residue) showing the highest total carbon. The total nitrogen content increased over time, with T9 (Sunhemp residue + Microbial Consortium @ 1.5%) recording the highest levels. T9 (Sunhemp residue + Microbial Consortium @ 1.5%) exhibited a consistently narrower C:N ratio compared to T4 (Maize Stover). Microbial populations and dehydrogenase enzyme activity were highest in T9 (Sunhemp residue + Microbial Consortium @ 1.5%) at tasselling and T8 (Maize Stover + Microbial Consortium @ 1.5%) at harvest, while the lowest values were observed in the control (T1). Overall, the study highlights the dynamic changes in soil carbon, nitrogen, the C:N ratio and microbial activity in response to crop residue incorporation with decomposition enhancers.