Weed management strategies in Soybean (Glycine max) — A review

Abstract

Soybean (Glycine max L.) being a rainy season crop, faces severe infestation of kharif weeds. Since the crop suppresses weeds due to its dense canopy at later stages of growth, the control of weeds has received very little attention. Weeds offer severe competition to crops during the early stage of growth. The critical crop weed competition period in soybean varies from 15–45 days after sowing (DAS) depending upon location and prevailing environmental conditions. Weeds cause a 26–84% reduction in the yield depending upon the types and intensity of weeds, besides impairing the quality of the produce. Different methods of weed management in field crops include preventive, cultural, mechanical, chemical, biological, and biotechnological means. Weed control through a physical approachachieved by hand weeding at 20 and 40 DAS (twice) is ineffective due to the continuous rainfall and high labour wages. The use of herbicides for the control of weeds has gathered momentum in recent years. Weed control through the integration of herbicides with cultural weeding is a paying proposition. Double knock application of one preemergence herbicide followed by application of post-emergence herbicides, solves the problem of labour scarcity encountered by the farmers. However, the timely application of different weed management tactics has a crucial role in achieving the desired target. Killing one or two flushes before seeding a crop and immediate cultivation of field after harvest to destroy survivors has an added advantage. An effort has been made in this article to review the work done on weed management in soybean