MULCHING AND WEED MANAGEMENT EFFECTS ON THE PERFORMANCE OF RICE (ORYZA SATIVA L.) TRANSPLANTED IN NON-PUDDLED SOIL

Abstract

Labour shortage is pushing the smallholder farms to seek for labour saving strategies for planting and weed control. With this point of view, this study was undertaken to determine the effectiveness of mulching from previous crop relative to herbicides and hand weeding on weed control and grain yield of rice transplanted in non-puddled soil after mustard in the northern Bangladesh during January to May in 2014 and 2015. Rice cv. BRRI dhan28 was transplanted with a combination of six weed control practices [Conventional tillage (CT)+3 hand weeding (HW) (Control); Glyphosate (Gly)+strip tillage (ST)+1HW; Gly+ST+pre-emergence (PE) herbicide (pendimethalin); Gly+ST+post-emergence (PO) herbicide (Ethoxysulfuron-ethyl); Gly+ST+PE+PO; and Gly+ST+weed-free (WF)], and two levels mulch of previous mustard [M0: no mulch and M50: 50% mulch (875 kg ha-1). Over the two years, CT produced 30% higher weed density and 40% higher weed biomass than ST. Spraying herbicides at PE followed by at PO in ST reduced weed density by 45% and weed biomass by 70%. Retention of 50% mulch reduced weed density by 20% and biomass by 34%. The combination of applied glyphosate, ST, followed by sequential application of PE and PO herbicides and the retention of 50% mulch achieved the highest weed control efficacy. Furthermore, this practice produced the 12% higher yield and 47% higher economic returns relative to manual weed control in conventional tillage. These results demonstrate the value of mulch integrated with pre-plant, PE and PO herbicides in controlling weeds and improving grain yield and return of rice transplanted in a non-puddled soil.