Short Term Changes in Soil Chemical Properties under Different Organic Management Protocols

The study assessed how ecological and organic farming practices affect soil chemical properties and nutrient dynamics in the short-term rice-wheat cropping system. A randomized block design with five treatments vis. biochar-based ecological farming (BBEF), climate-resilient organic farming (CROF), low-input natural farming (LINF), phosphorus-potassium fertilization (PK) and nitrogen-phosphorus-potassium fertilization (NPK) was evaluated. Post-harvest soils after 5 crops were analysed for pH, electrical conductivity (EC), soil organic carbon (SOC) and available N, P and K at 0-5, 5-15 and 15-30 cm depths. CROF maintained the highest pH in all layers, showing strong buffering, while NPK had the lowest pH due to urea-induced acidification. EC stayed low across treatments, indicating non-saline soils, with slightly higher values in ecological and organic systems from enhanced organic residue mineralization. SOC was greatest under BBEF followed by CROF at all depths, confirming biochar’s role in long-term carbon storage and the contribution of organic manure in CROF to enhancing soil carbon. Available nitrogen (N) was highest in BBEF and NPK, demonstrating the benefits of biochar and mineral fertilization. Higher available phosphorus (P) in PK and NPK reflected mineral P inputs, while biochar (BBEF) stabilized P availability. Available potassium (K) was highest in PK and in organic systems (BBEF and LINF) due to residue recycling and lower crop removal. Overall, biochar-based ecological and organic practices improved soil fertility and nutrient retention, offering a sustainable strategy to maintain soil health and resilience in intensive rice-wheat systems.