Weed Management in Conservation Agriculture Systems

Conservation agriculture (CA) does have several advantages over conventional tillage (CT)-based agriculture in terms of soil health parameters. However, weeds are the major biotic constraint in CA, posing as a great challenge towards its adoption. The presence of weed seeds on the upper soil surface, due to no tillage operation, leads to higher weed infestation in CA, and so far, herbicides are the only answer to deal with this problem. Overreliance of herbicide use showed its consequence in terms of environmental pollution, weed shift and herbicide resistance development in weeds. Growing herbicide-tolerant crops using nonselective herbicides could be a broad-spectrum weed management technique to tackle weed shift, but the same is being resulted in the evolution of more problematic ‘super weed’. These observations indicate the need of integrated weed management technologies involving the time tested cultural practices, viz. competitive crop cultivars, mulches, cover crops, intercrops with allelopathic potential, crop diversification, planting geometry, efficient nutrient, water management, etc., along with limited and site-specific herbicide application. The modern seeding equipment, e.g. ‘Happy Seeder’ technology, that helps in managing weeds through retention of crop residues as mulches, besides providing efficient seeding and fertilizer placement, shows the promise of becoming an integral part of CA system.