Effect of establishment methods and irrigation scheduling on growth indices of wet season rice

Abstract

Rice cultivation plays a crucial role in global food security but is increasingly challenged by labor shortages and water scarcity. Traditional methods such as puddled transplanted rice (TPR) are highly resource-intensive, necessitating the adoption of efficient establishment methods and optimized irrigation strategies. This study aimed to evaluate the effect of different establishment methods and irrigation scheduling on key growth indices-crop growth rate (CGR), relative growth rate (RGR) and net assimilation rate (NAR) during the wet season. The experiment was conducted at the Indian Institute of Rice Research (IIRR), Hyderabad, using a strip plot design with four replications, comprising nine treatment combinations. Three rice establishment methods were assigned to horizontal strips: normal transplanting (NTP-M1), mechanized SRI (MSRI-M2), and direct-seeded rice in raised beds (DSR-M3). Three irrigation scheduling treatments were assigned to vertical strips: AWD with 10 cm depletion (I1), AWD with 5 cm depletion (I2), and continuous submergence (±5 cm) (I3). Results revealed that MSRI (M2) significantly improved CGR, RGR and NAR due to better seedling establishment, enhanced canopy expansion, and improved tillering efficiency. Among irrigation treatments, AWD with 5 cm depletion (I2) optimized water use without compromising growth, demonstrating its potential for sustainable water management. The findings highlight that mechanized transplanting (MSRI) combined with precision irrigation (AWD-5 cm) enhances water use efficiency, maintains growth indices and improves overall crop productivity. This study underscores the importance of integrating mechanized establishment methods with precise irrigation scheduling to enhance growth indices and ensure sustainable rice production in water-limited environments.