Long-term effects of integrated organic and inorganic fertilization on soil properties, nutrient use efficiency, and crop yield in a rice–wheat system

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Understanding the role of integrated nutrient management (INM) practices under intensive farming is essential for restoring soil health, enhancing system resilience to climate variability, and sustaining crop productivity. The present experiment was laid out in a randomized complete block design with seven treatments and three replications, as follows: CT, absolute control (no fertilizer, no organic amendment); NPK 50 , 50% recommended dose of NPK through fertilizers; NPK 100 , 100% recommended dose of NPK through fertilizers; NPK 50 +FYM, 50% recommended dose of NPK through fertilizers + 50% N through farmyard manure; NPK 50 +WCS, 50% recommended dose of NPK through fertilizers + 50% N through wheat cut straw; NPK 50 +GM, 50% recommended dose of NPK through fertilizers + 50% N through green manure ( Sesbania aculeata ); and NPK 100 +FYM, 100% recommended dose of NPK through fertilizers + 50% N through farmyard manure to rice, while wheat received 100% recommended dose of NPK through fertilizer in all treatments except CT. The results of the present investigation revealed that the inclusion of organic amendments with inorganic fertilizer in the rice crop significantly increased soil properties relative to NPK 100 . Furthermore, the succeeding wheat crop exhibited significantly higher nutrient uptake and nutrient use efficiency (NUE) under INM compared with inorganic fertilization, reflecting the residual effects of the organic amendments applied to rice in combination with the recommended NPK fertilizer applied directly to wheat. INM treatments showed increase of ~7%–10%, ~6.6%–9.5%, and ~6.5%–9.6% in agronomic efficiency of N, P, and K as compared to NPK 100 , respectively. Principal component analysis identified microbial biomass carbon, available water content, and cation exchange capacity as the most sensitive soil quality indicators. These findings highlight that long-term substitution of 50% N with organics has a promising effect on sustaining crop yield by improving soil properties and nutrient use efficiency.