Effect of Pre- and Post-Emergence Herbicides on Weed Biomass, Nutrient Depletion, and Growth of Soybean in Humid South-Eastern Plains of Rajasthan

Field experiment was conducted during the kharif season of 2019 at the Agricultural Research Station, Ummedganj, Kota (Rajasthan), to evaluate the effect of various herbicide treatments on nutrient depletion and growth of soybean (Glycine max L. Merrill). The experiment comprised eight treatments, including pre- and post-emergence herbicides and hand weeding, laid out in a randomized block design with three replications. The herbicide application significantly reduced weed density and dry weight, thereby reducing nutrient depletion by weeds and improving crop growth and yield attributes. Maximum nutrient depletion by weeds with losses of 50.2 kg nitrogen, 3.58 kg phosphorus, and 41.4 kg ha^-1 potassium was under the weedy check, indicating the severity of nutrient loss in untreated plots. In contrast, minimum nutrient removal by weeds under two hand weeding at 20 and 40 days after sowing, followed by the application of sodium acifluorfen + clodinafop-propargyl @ 165 + 80 g a.i. ha^-1 at 20 days after sowing, also resulted in improved crop growth.