EFFECTIVE WEED MANAGEMENT IN DRY DIRECT SEEDED RICE FOR SUSTAINABLE PRODUCTIVITY

A field experiment was conducted at Rice Research Institute, Kala Shah Kaku, Pakistan during 2011 to identify appropriate herbicides for effective weed control in dry direct seeded rice. Randomized Complete Block Design (RCBD) was used with three replications. The major weeds identified with dry direct seeded rice were Echinochloa colona, Echinochloa cruss-galli, Diplachne fusca, Cyperus iria, Cyperus difformis, Scirpus meritimus, Cyperus rotundus, Marsilia minuta and Conyza stricta. Twelve pre and post emergence herbicidal treatments were tested and compared with weedy check. A pre-emergence herbicide was applied just after seeding and the post-emergence herbicides were applied at 21 and 40 days after seeding (DAS). Weed density m^-2 was recorded at 20 and 45 days after seeding. The best weed control (94.8 - 98.1%) was achieved with two sprays (21 40 DAS) of post emergence herbicide (bispyribac sodium) followed by single application (21 DAS) of the same herbicide which gave weed control of 77.5 to 82.3 %. orthosulphuron, phenoxulum and ethoxysulphuron as post emergence herbicides were found more effective against broad leaf weeds and sedges than grasses. As regards paddy yield, it was found to be maximum (3.97 - 4.14 t ha^-1) with the twice application of bispyrabic sodium (Clover 20% SC or Nominee 20% SC) whereas, the lowest paddy yield was recorded in case of weedy check (0.41 t ha^-1). Number of productive tillers m^-2, number of filled grains panicle^-1 and 1000-grain weight (g) were also higher in the plots having twice application of bispyribac sodium than other herbicidal treatments and weedy check.