Declining soil fertility and unsustainable residue management are major challenges in the rice–wheat cropping system of the Indo-Gangetic Plains. This study evaluated the effects of rice straw biochar integrated with organic and inorganic nutrient sources on soil physicochemical and biological properties, with implications for sustainable agricultural intensification. A two-year field experiment (2018–19 and 2019–20) was conducted using a randomized block design with nine treatments, including an unfertilized control, soil treatment receiving the recommended dose of NPK fertilizers (RDF), and combinations of 50% RDF with biochar and organic amendments (farmyard manure, vermicompost, and poultry manure at 25% and 50% substitution levels). The treatment 50% RDF + 50% poultry manure + biochar showed the greatest improvement in soil properties, increasing soil organic carbon (1.16–1.20% vs. 0.58–0.60% in control), available nitrogen (~ 560 vs. ~ 276 kg ha⁻¹), phosphorus (~ 25 vs. ~ 6.4 kg ha⁻¹), and potassium (~ 360 vs. ~ 245 kg ha⁻¹). Soil enzymatic activities (urease, dehydrogenase, and phosphatases) were significantly enhanced under integrated treatments, indicating improved biological functioning. Bulk density decreased (1.70–1.75 g cm⁻³) compared to the control (1.82–1.86 g cm⁻³), reflecting improved soil structure. Overall, biochar-based integrated nutrient management significantly enhanced soil fertility, nutrient use efficiency, and biological activity compared to sole fertilizer or control treatments. The recycling of rice residues into biochar offers an environmentally sustainable alternative to residue burning while improving soil health. These findings support sustainable agricultural practices by improving soil fertility, nutrient efficiency, and residue recycling, with implications for SDG 2, SDG 12, and SDG 13.
Jaswal et al. (Sun,) studied this question.