Effect of sowing time and weed management practices on direct seeded unpuddled rice (Oryza sativa L.)

Three sowing dates viz.05 June, 20 June and 05 July and five weed management practices viz. pendimethalin 1.5 kg ha⁻¹(PE), pendimethalin 1.0 kg ha⁻¹ + anilophos 0.4 kg ha⁻¹(PE), fenoxaprop-p-ethyl 0.06 kg ha⁻¹(15 DAS) followed by 2,4-D 0.5 kg ha⁻¹ (30 DAS), anilophos 0.4 kg ha⁻¹ (10 DAS) and two hand weedings (20 and 40 DAS) with weed free and weedy check treatments were evaluated in direct seeded unpuddled rice at crop research centre, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, during kharif season of 2006 and 2007. Highest grain yield (2488.5 kg ha⁻¹ during 2006 and 2703.3 kg ha⁻¹ during 2007) was recorded from 20 June sown rice crop which was significantly higher over rest two dates of sowing (05 June and 05 July) in both the years. All weed control treatments caused significantly higher grain yield over non-weeded control in both the years. The grain yield was highest in mechanical two weedings at 20 and 40 DAS (3324.2 kg ha⁻¹ during 2006 and 3436.6 kg ha⁻¹ during 2007) being significantly superior over rest of the treatments. Pendimethalin @ 1.0 kg ha⁻¹ + anilophos @ 0.4 kg ha⁻¹ (pre-emergence) produced significantly higher grain yield (3096.6 kg ha⁻¹ during 2006 and 3288.8 kg ha⁻¹ during 2007) over rest of the herbicidal treatments. Due to less number and dry matter of weeds resulting in better crop growth, reflecting in higher grain yield and economic return in both the years. Reduction in grain yield of rice due to uncontrolled weeds in weedy plots was recorded 70.4% during 2006 and 67.4% during 2007.