WEED CONTROL AND NUTRIENT PROMOTION IN ZERO-TILLAGE WHEAT THROUGH RICE STRAW MULCH

Field trials were conducted to study the allelopathic potential of rice straw mulching at different doses for weed control and nutrients status improvement of soil in zero-till wheat at the Adaptive Research Farm, Gujranwala, Punjab, Pakistan during Rabi season 2008-09 and 2010-11. Rice straw mulch was used at the rate of 7.5, 10.0, 12.5, 15.0, 17.5 and 20.0 t ha^-1 the next day after sowing (DAS). A control plot was kept without rice straw mulch for comparison. It was observed that rice straw mulch had significantly increased the soil organic matter content, the available P, K and decreased the soil pH. Minimum broad leaved weeds (9.89, 11.22, and 12.11 plants m^-2), narrow leaved weeds (15.45, 18.89 and 21.22 plants m^-2) and dry weed biomass (45.73, 58.01 and 65.68 g m^-2) were recorded in plots treated with 20.0, 17.5 and 15.0 t ha^-1 rice straw mulch, respectively. Reduction in plant population was observed with increasing rate of rice mulch. However, number of tillers m^-2, grains spike^-1, 1000-grain weight and grain yield were all significantly higher in the treated plots as compared to the control plots. Maximum grain yield (4.58 t ha^-1) was recorded for 15.0 t ha^-1 rice straw mulch plots followed by 17.5 t ha^-1 of rice straw mulch (4.37 t ha^-1) plots. It can be concluded that using rice straw mulch may be a good alternate source of weed management, soil fertility supplement and a source of bio-herbicide.