Ecological weed management approaches for wheat under rice–wheat cropping system

Weeds are one of the most important yield limiting factor in wheat cultivation, causing a yield loss of 15–50% depending on relative proportion of weed flora, weed density and period of their infestation. To control the weeds effectively, the farmers of Indo-Gangetic Plains Region (IGPR) are mainly dependent on the chemical herbicides. However, the excessive herbicide use has led to development of resistance in many weed species and shift in weed flora besides negative residual effects on the succeeding crops and food quality as well. Therefore, there is an urgent need to look for alternate methods which are economically viable and ecologically stable. Several approaches like early sowing of wheat, soil solarization, adjustment in row spacing, sowing weed free seeds, adjusting seed rate, planting densities, crop rotations, competitive cultivars, stale seed bed technique, efficient nutrient management, proper irrigation scheduling, mechanical control, mulching, residue retention and tillage methods have been found effective in wheat in numerous field studies. Looking at the potential of such ecological approaches, there is need for in-depth research on various aspects of these methods. This paper reviews the available information on different ecological weed management approaches in wheat under rice–wheat cropping system of Indo-Gangetic plains.