Influence of puddling intensity and water-management practices on weed dynamics and yield of transplanted rice (Oryza sativa)

A field experiment was conducted at Tirupati during winter (rabi) season of 2003 and 2004 to evaluate the ef- ficiency of low-dose herbicides under different puddling and water-management practices on yield attributes and yield of transplanted rice (Oryza sativa L.). Intensive puddling with continuous submergence (IPCS) recorded the lowest weed density and dry weight, highest stature of yield attributes (panicles/m2, length of the panicle and filled grainslpanicle), higher grain and straw yields and higher economic returns, but it was comparable with in- tensive puddling with irrigation a day after disappearance of ponded water (IPDDPW) treatment. The increase in grain yield was 40.1, 31.2 and 13.6% in IPCS, IPDDPW and normal puddling with continuous submergence (NPCS) respectively over normal puddling with irrigation a day after disappearance of ponded water (NPDDPW). Significantly lowest water requirement and highest water-use efficiency (WUE) was registered with IPDDPW fol- lowed by IPCS. Among the weed-management practices, oxadiargyl 75 glha + hand-weeding (HW) at 40 days after transplanting (DAT) recorded the highest values of all the yield attributes, yield and econpmic returns with lesser weed density and dry weight over the unweeded check, which was on a par with HW twice (20 and 40 DAT). On an average, the increase in grain yield was 39.5 and 34.2% in oxadiargyl 75 glha + HW (40 DAT) and HW twice (20 and 40 DAT) respectively over the unweeded check. The highest WUE was registered with oxadiargyl 75 g/ha + HW (40 DAT), followed by HW twice (20 and 40 DAT); however the difference in water re- quirement of rice due to different weed-management practices was not statistically evident.