IMPACT OF COVER CROPS IN IMPROVING AGRO-ECOSYTEMS INCLUDING SUSTAINABLE WEED SUPPRESSION – A REVIEW
Weeds are always considered as one of the serious pests that compete for their growth and development and decline the production in of major crops. Weeds occur in abundance in every cropping system i.e. wheat-rice, wheat- maize and wheat- cotton cropping systems. Herbicides are used in order to minimizet weed infestation, but the use of herbicides or inorganic chemicals against weeds is also developing resistance in weeds to herbicides. Despite that herbicides are also affecting the environment especially human health. Pesticides not only damage the human health but also pollute the air, soil, water and becoming part of food chain. One of the options to minimize weed infestation is intercropping of cover crops between cash crops to reduce the weed suppression. Cover crops are the plants grown inn field in such a way that these plants give soil cover despite it may be incorporated in field or not and also facilities weed suppression, control soil erosion, improve soil fertility and also manage diseases and pests present in that field. Cover crops normally comprise of legumes and grasses. Cover crops lead to be one of the better options that reduce the dose of herbicides and these are harmonious with the objectives of conservation agriculture. Regardless of much importance of cover crops and their worth in agricultural systems, cover crops have certain negative aspects as well. They compete with cash crops for moisture, solar radiation and nutrients which ultimately decrease the return of cash crops. Farmers are still hesitating to grow cover crops in their farming systems due to lack of knowledge about these crops. According to Daily Times, in Pakistan soil erosion is 20% and organic matter is less than 1%. So, cultivation of cover crops helps to minimize the adverse effect of erosion and enhances the organic matter content in soil. Cover crops may decline the yields but cover crops are one of the steps that leads to a sustainable or conservation agriculture.