Optimizing soil properties, water use efficiency, and crop yield through biochar and organic manure integration in organic soil.

Speedy decomposition of organic manure and efficient utilization of rice husk waste are two critical challenges for sustainable environment and soil health management. However, understanding the synergistic effects of rice husk biochar (B) and organic manure (OM) on soil properties and crop growth in subtropical conditions remains unclear. A field study was conducted to investigate the impact of sole and combined application of rice husk biochar (0 t ha^-1, 3 t ha^-1), farmyard manure (FYM), and vermicompost (VC) on soil aggregation, aggregate-associated carbon, water use efficiency (WUE), economic benefits, and yield of radish crop in sandy clay loam organic soil. Biochar application enhanced the macroaggregate stability and aggregate associated C contents. Soil moisture, infiltration rate (IR) and WUE were significantly improved by 9.2%, 20.8% and 13.6%, respectively, with addition of biochar, which might be related to improved aggregate-associated carbon and water retention in the soil. Similarly, improved soil properties, WUE were noticed in the treatment receiving combination of FYM + VC over the control. 16% and 30.9% higher radish yield was observed with biochar and FYM + VC amended treatments compared without B0 and manure OM0, respectively. The integrated use of biochar (3 t ha^-1) and OM (FYM + VC) resulted in highest economic benefits of net return (₹ 138,325 ha^-1) and B:C (1:5) ratio and least in control plots. These results indicate that adding biochar in organic management practices considerably improved the soil properties, WUE which resulted in increased organic radish production.