Productivity of sesame as affected by herbicides and nitrogen levels and their residual effects on subsequent chickpea

A field experiment was conducted with an objective to identify effective herbicides and optimum nitrogen level for managing weeds and enhance productivity of sesame (Sesamum indicum L.) and to study their residual effects on succeeding chickpea (Cicer arietinum L.). The study was carried at the Instructional Farm of the College of Agriculture, Swami Keshwanand Rajasthan Agricultural University, situated in Bikaner, during the Kharif seasons of 2022 and 2023 and the Rabi seasons of 2022-23 and 2023-24. There were 20 treatments combinations, with four nitrogen levels (control, 20, 40, and 60 kg/ha) assigned to the main plots and five weed control treatments: weed-free, pre-emergence application (PE) of pendimethalin 750 g/ha, flumioxazin 75 g/ha PE, post-emergence application (PoE) of imazethapyr 50 g/ha PoE and weedy check, designated to the subplots. The highest weed biomass was observed with 60 kg N/ha. Among the herbicidal treatments, pendimethalin 750 g/ha PE, flumioxazin 75 g/ha PE, and imazethapyr 50 g/ha PoE resulted in the lowest density and biomass of grassy weeds, broad-leaved weeds, and sedges. The highest uptake of nitrogen, phosphorus, and potassium by weeds was recorded in the weedy check. The maximum sesame seed yield (770 kg/ha), net return (67,609 ₹/ha), and benefit-cost ratio of 3.28 were recorded with pendimethalin 750 g/ha PE compared to flumioxazin at 75 g/ha and imazethapyr at 50 g/ha. No statistically significant interaction effects were observed between nitrogen levels and weed control measures during both years and in the pooled analysis. Additionally, there was no residual effect of the applied nitrogen and herbicides on the subsequent chickpea crop.