Weed Management in Rice-Wheat Cropping System through Remote Sensing： A Review

The productivity of the flee-wheat rotation of the Indo-Gangetie Plains is critical to India＇s food security. Severe weed competition resulting from the change in morphological characteristics of the modem high yielding varieties （HYV） led to intensive use of herbicides for weed control. Continuous and indiscriminate use of herbicides led to pollution as well as build up of resistant biotypes. This necessitates the need based use of herbicides. Identification of predominant weeds in rice-wheat cropping system through remote sensing and Geographic Information System （GIS） would help in reducing the load of herbicide on agro-eco system by reducing spray volume, application time and non-target spraying. This will help in developing site-specific weed management technique by geating only those areas with herbicide where weed densities exceed the economic threshold and may reduce application rate of herbicides in patches where weed densities are low. This paper reviews the literature on role of remote sensing for