Optimized rice residue management, tillage intensity and nitrogen application enhance soil biological quality and subsequent wheat productivity in rice-wheat system of north-western India

Sustainable residue management and optimum nitrogen (N) fertilization are critical for improving soil biological functioning and crop productivity in cereal-based systems. Particularly, mismanagement of rice residues often leads to burning and which further cause reduction in wheat grain yield and poor soil quality. To address these issues, a two-year field experiment was conducted to study the effect of different in-situ rice residue management practices and N application rates on soil biochemical properties and subsequent wheat productivity. The results from the experiment revealed that soil biochemical activities except peroxidase were significantly ( p < 0.05) increased by rice residue retention/incorporation with 100% recommended dose of nitrogen (N 100 ) as compared to residue burning (CT-RB)/removal (CT-R 0 ) treatments. In-situ residue retention significantly increased soil enzyme activities, with soil oxidative, phosphorus cycling, nitrogen cycling, carbon cycling, and microbial biomass/basal soil respiration enhanced by approximately 1.4, 2.1, 1.7, 1.2, and 3.2-folds, respectively, compared with CT-RB/CT-R 0 treatments. Wheat grain yield under zero tillage with full surface residue retention (ZT+R 100 ) with N 100 was ~15.8-17.3% higher than CT-RB/CT-R 0 treatments. Correlation and cluster analyses demonstrated strong positive linkages among enzyme activities, microbial attributes, and crop productivity under residue retention/incorporation with recommended dose of N, indicating improved microbial functioning and nutrient cycling. Principal component analysis identified peroxidase, fungal biomass and fluoresceine diacetate activity as sensitive soil indicators among different rice residue management and N application rates. Thus, the present experiment pinpoints that in-situ rice residue management combined with optimum nitrogen application can be a robust management strategy for enhancing soil biological quality and wheat productivity in intensively managed agroecosystems.