Influence of crop-establishment methods and weed-management practices on weeding efficiency and productivity of basmati rice (Oryza sativa)

Abstract

A field experiment was conducted on sandy clay loam soil at the research farm of Sher-e-Kashmir University of Agricultural Sciences and Technology, Jammu, Chatha, Jammu and Kashmir during the rainy (kharif) season of 2016 and 2017, to study the response of different establishment methods and weed management practices on basmati rice (Oryza sativa L.). The experiment comprising 3 establishment methods and 5 weed-management practices with 3 replications was laid in split-plot design. Among establishment methods, system of rice intensification (SRI) though at par with conventional transplanted rice (CTR) showed significant reduction in weed population, weed dry weight and nutrient uptake by weeds at 40 and 60 days after transplanting (DAT) over direct seeded rice (DSR). Likewise, for weed-management practices, application of pendimethalin 1 kg a.i./ha as preemergence (for DSR) or butachlor 1.5 kg/ha as pre-emergence (for CTR) followed by (fb) bispyribac sodium at 25 g a.i./ha at 25 DAS/DAT recorded significantly lower weed density (no./m2 ), weed biomass (g/m2 ) at 40 and 60 DAS/DAT and weed nutrient uptake at 60 DAS/DAT. However, this treatment was at par with pendimethalin 1 kg a.i./ha as pre-emergence (for DSR) or butachlor 1.5 kg/ha as pre-emergence (for CTR) fb 2 mechanical weedings at 20 and 40 DAS/DAT. The same treatment recorded the highest weed-control efficiency (75.28%). Plant height and number of tillers at 60 DAS/DAT and at harvesting effective tillers/m2 , filled grains/panicle, 1,000ˆgrain weight (g) as well as grain and straw yields were significantly higher in SRI over DSR, but at par with CTR. Pendimethalin 1 kg a.i./ha as pre-emergence (for DSR) or butachlor 1.5 kg/ha as pre-emergence (for CTR) fb 2 mechanical weedings at 20 and 40 DAS/DAT recorded significantly higher values over other treatments but at par with pendimethalin 1 kg a.i./ha as pre-emergence (for DSR) or butachlor 1.5 kg/ha as pre-emergence (for CTR) fb bispyribac sodium at 25 g a.i./ha at 25 DAS/DAT for plant height at 60 DAS/DAT, and at harvesting for effective tillers/m2, filled grains/panicle, 1,000-grain weight (g) as well as grain and straw yields. The SRI resulted in the highest net returns (`74,810/ha) and benefit: cost (B:C) ratio (1.63) among the establishment methods, whereas pendimethalin 1 kg a.i./ha as pre-emergence (for DSR) or butachlor 1.5 kg/ha as pre-emergence (for CTR) fb 2 mechanical weedings at 20 and 40 DAS/DAT among the weed-management methods fetched the highest net returns (`60,639/ha) and B : C ratio (1.36).