Weed Management in Transplanted Paddy in Wetlands under Water Shortage with Alternate Wetting and Drying System of Irrigation

A field experiment was conducted during the Rabi season of 2023-2024 in the farm of Karunya Institute of Technology and Sciences, Coimbatore, Tamil Nadu to find out an effective weed management system in transplanted paddy under alternate wetting and drying. The experiment was laid out in randomized block design with thirteen treatments and two replications.The results showed that at all stages of observations tallest paddy crop was produced in T13 (continuous submergence in paddy field). The height of paddy crop at harvest was 14.3 % more in T13 than in unweeded control under alternate wetting and drying (T12). Highest number of tillers per plant (16.5) were recorded in T8 which received early post emergence application of Bispyribac sodium @ 0.03 kg ai/ha at 15 DAT + roto weeding at 35 DAT. By 90 DAT highest leaf area index was recorded by pre emergence application of Pyrazosulfuron ethyl along with one hand weeding at 35 DAT(T6), early post emergence spray of Bispyribac sodium alone (T7), and Bispyribac sodium with one roto weeding at 35 DAT (T8) and Bispyribac sodium and one hand weeding at 35 DAT (T9). By harvest the dry matter production was the highest in T8 (Bispyribac sodium with one roto weeding at 35 DAT) followed by T9 (Bispyribac sodium with one hand weeding at 35 DAT).Highest production of grains and straw (7362 and 15280 kg ha-1) were also recorded in T8 (early post emergence application of Bispyribac sodium @ 0.03 kg ai/ha at 15 DAT + roto weeding at 35 DAT) closely followed by T9 (early post emergence application of Bispyribac sodium @ 0.03 kg ai/ha at 15 DAT + hand weeding at 35 DAT).