Chemical weed control in puddle-seeded rice

摘要

Field experiments were conducted at Cuttack during the dry season of 1990 and 1991 in coastal alluvial soil to find out an effective pre-emergence herbicide comparable to hand weeding for puddle-seeded rice (cv, Kalinga III and Annada). For the variety Kalinga III of 85 days duration and semi-tall plant type, the promising herbicides were pyrazosulfuron-ethyl at 0.01 kg ha~(-1) and oxadiazon 0.4 kg ha~(-1) during 1991 and pretilachlor (1.0 kg ha~(-1)), anilofos (0.4 kg ha~(-1)), anilofos + 2,4-D (0.3+ 0.4 kg ha~(-1)), thiobencarb (1.0 kg ha~(-1)) and butachlor (1.5 kg ha~(-1)) in 1992, For the semi-dwarf variety Annada of 105 days duration, the lower dose of anilofos (0,4 kg ha~(-1)) in both EC and granular formulations and a new herbicide cinmethylin at a lower dose of 0.05 kg ha~(-1) were found effective in controlling the weeds and increasing the yield. Among the herbicides, 2,4-D Na showed the highest phytotoxicity on rice seedlings and, hence, adversely affected the plant growth and yield,