Influence of weed control methods on weeds, yield, energetics and economics of basmati rice (Oryza sativa) under sub-mountaineous conditions of Punjab

A field experiment was conducted during the rainy (kharif) season of 2011–12 and 2012–13 at Krishi Vigyan Kendra, Gurdaspur to assess the effect of various weed control methods on grain yield, weed control efficiency, energy and economics of basmati rice (Oryza sativa L.). The experiment was laid out in randomized block design having 3 replications and comprised of nine treatments, viz. butachlor 50 EC @ 1.5 kg a.i./ha, pretilachlor 50 EC 0.75 kg a.i./ha, pyrazosulfuron ethyl 10 WP @ 15 g a.i./ha, oxadiargyl 80 WP @ 90 g a.i./ha, bispyribac 10 SC @ 25 g a.i./ha, fenoxaprop 6.7 EC @ 67 g a.i./ha, 3 mechanical-weedings with conoweeder (15, 30 and 45 DAT), 2 hand-weedings (15 and 30 DAT) and a weedy check. Mechanical-weeding thrice with conoweeder was significantly superior over all weed control methods for reducing the density and dry-matter accumulation of weeds, increasing the grain yield (3.89 t/ha) and weed control efficiency followed by hand weeding twice. Higher energy productivity (0.44 Kg/MJ) and benefit: cost ratio (1.80) were observed in mechanical weeding thrice with conoweeder. Hand-weeding twice in basmati rice was found to be more energy consuming (9.96 × 103 MJ/ha) over other treatments.