DEVELOPMENT AND APPRAISAL OF MECHANICAL WEED MANAGEMENT STRATEGIES IN DIRECT SEEDED AEROBIC RICE (Oryza sativa L.)

Water scarcity is an annihilating threat to sustainability of transplanted rice. Weeds are notorious competitor of rice and major constraint in adaptation of direct seeding. Although a number of mechanisms have been introduced for weed control but still a huge gap is present for a solid innovation and its practical implementation. A two years study was conducted to develop sustainable mechanical methods for managing weeds in aerobic rice grown by dry direct-seeding at Students' Farm, Department of Agronomy, University of Agriculture, Faisalabad, during 2008 and 2009. Experiment was laid out in RCBD with split plot arrangement (inter row cultivation implements in main plots and inter row cultivation frequencies in sub plots). Experiment was replicated thrice for both years with net plot size 3.0 m x 6.0 m. The results revealed that Tine Cultivator significantly reduced the weed dry weight consistently for all inter row frequencies whereas Spike Hoe and Plug Weeder provided minimum weed control. Inter row cultivation frequencies statistically had no differences at 15 days after sowing (DAS) for weed dry weight while at 45 DAS F-4 (15, 25, 35 and 45 DAS) and F-3 (15, 25 and 35 DAS) significantly reduced the weeds dry weight when combined with Tine Cultivator. Tine Cultivator significantly increased the plant height, number of productive tillers, panicle length, number of kernels per panicle, 1000-grain weight and paddy yield for both growing seasons. Similar increases in above yield components were also observed in F-4 inter row cultivation frequency. Tine Cultivator combined with F-4 was proved to be the best interaction and that was followed by Tine Cultivator and F-3 frequency. Weed control by Tine Cultivator proved to be the most viable and economical method.