Integrated Weed Management in Bt-Cotton Under Semi Arid Conditions – A Review

Abstract

Cotton is one the major Kharif cash crop of India and is also known as ‘White Gold’ or ‘King of fibres’. Being a rainy season, long duration, wide spaced and slow growing crop at initial stage, it is highly sensitive to weed competition. The critical period of crop-weed competition is 15 to 60 days after sowing and during this period the crop suffers from heavy losses in seed cotton yield. Weeds are the major constraints that reduce the crop yields since they compete for the nutrients, moisture, light and space. The losses caused by weeds in cotton ranges from 50 to 85 percent depending upon the nature and intensity of weeds in the field. The most common practices adopted by the farmers are manual weeding and inter-culture operation. But during critical period of crop-weed competition, the non-availability of labour, high wages of labour and wet field conditions, leads to ambiguous conditions for cotton growers. Due to delay in inter-culture operations in the crop, ineffectual results produced are clearly reflected in final yield. Thus, timely management of weeds through physical, mechanical, biological and chemical means needs to be ensured for achieving the higher cotton productivity. Physical and mechanical methods are widely used but in case of biological weed control, limited options are available. Chemical weed management is the better choice of the farmer being economical, quick responsive and suitable to the prevailing conditions. Chemical weed control in cotton by using suitable pre and post emergence herbicides during critical period of crop-weed competition gives a way out to handle the situation and to realise higher productivity. Further, the integration of all the weed management practices in the form of IWM needs to be explored more and more being economically viable, ecologically sustainable and locally available and user friendly techniques. Realization of higher cotton yield and fetching better remunerations mainly depends on an integrated weed management approach that also recognizes the adoption of location specific cultivar.