Influence of various doses of Herbicides on weed flora population, yield attributes and yield of Transplanted Rice (Oryza sativa)

An experiment was undertaken to study the response of different doses of herbicides on weed flora population, yield attributes and yield of transplanted rice. The investigation was carried out at Students' Farm of College of Agriculture, Chaudhary Charan Singh Haryana Agricultural University; Kaul (Kaithal). The experiment laid out in randomized block design replicated three times during the kharif season of 2008 consisting 15 treatments combinations viz., T1- 25 g/ha dose of Bispyribac sodium 10 SC at 20 DAT; T2- 25 g/ha dose of Bispyribac sodium 10 SC at 25 DAT; T3- 30 g/ha dose of Bispyribac sodium 10 SC at 20 DAT; T4- 30 g/ha dose of Bispyribac sodium 10 SC at 25 DAT; T5- 30 g/ha dose of Azimsulfuron 50 DF at 20 DAT; T6- 30 g/ha dose of Azimsulfuron 50 DF at 25 DAT; T7- 40 g/ha dose of Azimsulfuron 50 DF at 20 DAT; T8- 40 g/ha dose of Azimsulfuron 50 DF at 25 DAT; T9- 750 g/ha dose of Pretilachlor 50 EC at 3 DAT; T10- 1500 g/ha dose of Butachlor 50 EC at 3 DAT; T11- 100 g/ha dose of Oxadiargyl 80 WP (Top Star) at 3 DAT; T12- 20 g/ha dose of Pyrazosulfuron 10 WP at 3 DAT; T13- 56.25 g/ha dose of Fenoxaprop-p-ethyl 9 EC (Whip Super) at 25 DAT; T14- Weed Check; T15- Weed Free. Findings of the experiment revealed that among POE treatments, T3 recorded significantly lowest grassy weed population i.e. 3.1, 3.5 and 3.2/m2 at 40, 60 and 80 days after transplanting respectively, in comparison to rest of the other treatments except treatment T1 (3.2, 4.4 and 3.9/m2 respectively) to which it is statically at par. Among POE treatments, highest broad leaf weed control was observed in treatment T7 i.e. 3.4, 4.0 and 3.5/m2 at 40, 60 and 80 days after transplanting respectively, which was statistically at par with treatments T1, T3, T5 and T8. Performance of Bispyribac sodium @ 30g/ha at 20 DAT in controlling grassy weed and Azimsulfuron @ 30 g/ha at 20 DAT and Azimsulfuron 40 g/ha at 20 DAT in controlling broad leaf weeds at 40, 60 and 80 days after transplanting which were statically at par with Pretilachlor @ 750 g/ha at 3 DAT (PRE) which was best among all treatments except weed free in terms of highest effective tillers/m2, highest filled grains/panicle, lowest unfilled grains/panicle, boldest grain and productivity of rice crop. So using Pretilachlor (PRE) @ 750 g/ha at 3 DAT and Bispyribac sodium (POE) @ 30 g/ha at 20 DAT are the best options in transplanted rice in terms of weed control as well as productivity of rice.