Effect of water regimes and weed-management practices on growth, yield and weed-control efficiency of rice under system of rice intensification

A field experiment was conducted during the rainy (kharif) seasons of 2012 and 2013 at Khudwani, Jammu and Kashmir, to evaluate the effect of water regimes and weed-management practices on growth and yield of rice (Oryza sativa L.) grown on silty clay loam soil. The treatments comprised 3 irrigations schedules, viz. alternate wetting and drying (AWD), saturated conditions (SC) and continuous flooding (FL), and 7 weed-management op tions including 4 herbicidal treatments, viz. pyrazosulfuron ethyl @ 20 g/ha at 3 days after transplanting (DAT, W1 ); cyhalofop butyl @ 80 g/ha at 15 DAT (W2 ); pyrazosulfuron ethyl 20 g followed by (fb) cyhalofop butyl 80 g/ha at 3 and 15 DAT (W3 ); butachlor @ 1.5 kg/ha at 3 DAT (W4 ); 3 cono weeding at 15, 25 and 35 DAT (W5 ) along with weedy check (W6 ) and weed free (W7 ). The experiment was laid out in a split-plot design with 3 replications under SRI. The data revealed that significant higher growth parameters like leaf-area index (LAI), dry-matter accumula tion and tillers/plant and yield attributes, i.e. panicle length, panicles/m2, grains/panicle, panicle weight, grains/ panicles, 1,000-grain weight, and higher grain yield were recorded in saturated water regime. On an average a yield superiority of 2.2 and 5.8% was recorded by saturated water regime over AWD and continuous flooding. Among the herbicides tested, pyrazosulfuron-ethyl @ 20 g/ha (3 DAT) fb cyhalofop-butyl @ 80 g/ha (15 DAT) re sulted in significantly higher panicle length, panicles/m2, panicle weight, grains/panicles, 1,000-grain weight and higher grain yield comparable to the weedy check. The mean yield advantage recorded by the use of pyrazosulfuron-ethyl fb cyhalofop-butyl was 19.3, 14.0 and 10.3% over cyhalofop-butyl, cono-weeding and butachlor, respectively, during both the years of experimentation.