Controlling the Infestation of Johnsongrass (Sorghum halepense) in Sweet Corn through Different Weed Management Practices

Abstract

With the aim of evaluating the efficacy of different weed management practices on weed control in sweet corn, an experiment was conducted at Agronomy Research Farm, Faculty of Agriculture, SKUAST-Kashmir, Wadura, Sopore during the Kharif seasons of 2023 and 2024. The experiment was laid out in Randomized Complete Block Design and consisted of nine treatments which were replicated thrice. The treatments included T1: use of cowpea as an intercrop (1:1), T2:  Cowpea as intercrop (1:1) + Pendimethalin @ 0.750 kg ha-1 (P.E), T3: Cowpea as intercrop (1:2), T4: Cowpea as intercrop (1:2) + Pendimethalin @ 0.750 kg ha-1 (P.E), T5: Pendimethalin @ 0.750 kg ha-1 (P.E) fb tembotrione @ 120 g ha-1 (PoE) at 30 DAS, T6: Pendimethalin @ 0.750 kg ha-1 (P.E) fb topramezone @ 25 g ha-1 (PoE) at 30 DAS, T7: Pendimethalin @ 0.750 kg ha-1 (P.E) fb hand weeding at 20 & 40 DAS, T8: weed free treatment  and T9: weedy check. The weeds recorded from the experimental plot included grasses, broadleaf weeds as well as sedges. Broadleaf weeds constituted 55% and 57% (2023 & 2024 resp) of the total weed density and the dominant broadleaf weeds included Portulacea oleracea, Amaranthus viridis, Datura stramonium, Hibiscus trionum, Convolvulus arvensis and Hypericum perforatum. Sedges were less in number and constituted only 5% & 4% (2023 & 2024 resp.) of the total weed density, Cyperus rotundus was the only sedge identified from the field. Grasses constituted the rest 40 % & 41 % (2023 & 2024 resp.) of the total weed density and the dominant grasses identified from the experimental plot were Sorghum halepense, Cynodon dactylon and Digitaria sanguinalis. Sorghum halepense was the most prominent grassy weed that formed 70% & 45% (2023 & 2024 resp) of the total density of grasses. The data pertaining to weed density at 60 DAS revealed that during both years, after the weed-free treatment (T8), the lowest weed and Sorghum halepense density was recorded under T7 (Pendimethalin + Hand Weeding at 20 & 40 DAS), whereas the highest was observed under the weedy check (T9). Among other treatments T5 (Pendimethalin + Tem) recorded lowest density of sorghum which was statistically similar to that of T5 and was followed by T6 (Pendimethalin + Top). Although T8 and T7 showed lower density of sorghum and showed more weed control efficiency (pertaining to sorghum) than T5 but T5 showed superior economics. Hence, integration of pre-emergence and post-emergence herbicides with hand weeding proved most effective against Johnsongrass infestation in sweet corn.