Influence of sowing time and weed management practices on weed dynamics and weed control parameters in summer sesame

A field investigation entitled “Effect of dates of sowing and weed management practices on summer sesame in the New Alluvial Zone of West Bengal” was carried out during the summer seasons of 2022 and 2023 at the Instructional Farm, Jaguli, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, West Bengal. The experimental field had a clay loam soil texture, was nearly neutral in soil reaction (pH 6.5), and non-saline in nature with an electrical conductivity of 0.3 dS m⁻¹. The soil contained medium organic carbon (0.68%), low available nitrogen (196.76 kg ha⁻¹), and high levels of available phosphorus (24 kg P₂O₅ ha⁻¹) and potassium (294.5 kg K₂O ha⁻¹). The experiment was conducted using a split-plot design with three replications, where three sowing dates were assigned to the main plots and eight weed management treatments to the sub-plots. The sowing dates consisted of D₁: 21 February, D₂: 7 March, and D₃: 22 March. The weed management treatments included: W₁ – pendimethalin @ 1 kg a.i. ha⁻¹ applied at 2 DAS followed by hand weeding at 30 DAS; W₂ – butachlor @ 1 kg a.i. ha⁻¹ at 2 DAS with hand weeding at 30 DAS; W₃ – hand weeding at 15 DAS followed by quizalofop-ethyl @ 50 g a.i. ha⁻¹ at 30 DAS; W₄ – pendimethalin @ 1 kg a.i. ha⁻¹ at 2 DAS combined with quizalofop-ethyl @ 50 g a.i. ha⁻¹ at 30 DAS; W₅ – butachlor @ 1 kg a.i. ha⁻¹ at 2 DAS along with quizalofop-ethyl @ 50 g a.i. ha⁻¹ at 30 DAS; W₆ – hand weeding twice at 15 and 30 DAS; W₇ – weedy check; and W₈ – weed-free check. The sesame variety ‘Savitri’ was selected for the study. Weed parameters in sesame (weed density, weed dry weight, weed control efficiency and weed index) were significantly influenced by subplot treatments only. Main plots and interaction effects were found to be non-significant. Among the subplot treatments, application of Pendimethalin @ 1 kg a.i. ha-1 (2 DAS) + Hand weeding (30 DAS) i.e. W1 recorded significantly lower total weed density (7.94 m-2), total weed dry weight (6.03 g m-2) and higher weed control efficiency (92.27%) as well as weed index (2.16%).