Role of crop competition in managing weeds in rice, wheat, and maize in India: a review

In India, the three staple food crops viz., rice, wheat, and maize, contribute more than four-fifths of the total food grain production. Among the several factors limiting their productivity, weeds account for about 40%. In order to meet the requirements of growing population, it is essential to improve productivity by reducing such unwarranted losses. Managing weeds with crop competition is an eco-friendly approach. Once the mechanisms of competition are understood, further improvements in weed control could be gained by manipulating other agronomic practices. The choice of cultivars, crop density, seeding rate, direction of planting, and intercropping could be exploited to enhance crop competitiveness against weeds. The variation in competitiveness and weed suppression among cultivars has been documented in rice, and to a lesser extent in wheat and maize. Research has demonstrated that the integration of crop competitiveness with other methods, such as the use of herbicides and manual weeding, is successful in managing weeds. However, in India, greater efforts are needed to exploit crop competitiveness for managing weeds in rice, wheat and maize. The success of these approaches relies on proper understanding of the biology and ecology of weeds, to identify weak points in their life cycle.