Abstract
The escalating crisis of freshwater scarcity and the environmental pollution caused by rice straw burning necessitate a transition toward climate-resilient cultivation. This study investigated the interactive effects of irrigation and in-situ straw decomposition on the physiological performance of rice in Tamil Nadu, India. Using a strip-plot design, we evaluated three irrigation regimes and six organic mitigation strategies. Results revealed that incorporating rice straw with dual microbial consortia (Pusa Decomposer and TNAU Biomineralizer) acted as a vital physiological buffer against moisture stress. This treatment (S4) recorded a peak photosynthetic rate of 31.4 μmol CO2 m2 s-1 and optimal stomatal conductance (0.727 mmol H2O m2 s-1), significantly outperforming plots without organic amendments. Notably, alternate Wetting and Drying (AWD) at 10 cm depletion paired with microbial-mediated straw recycling maintained higher chlorophyll retention and gas exchange efficiency than traditional continuous flooding. These results show that 15-30% water savings can be achieved without the usual yield penalty by combining precision irrigation with microbial straw management. In tropical rice ecosystems, this method provides a scalable, beneficial system for water-smart agriculture and sustainable residue recycling.