Effect of Zero Tillage and Different Weed Management Practices in Direct Seeded Rice (Oryza sativa L.) in Indo Gangetic Plains: A Review

Millions of rural and urban residents depend on the rice-wheat cropping system of the Indo-Gangetic plains (IGP) for their food security and means of subsistence. About 18 million hectares (m ha) of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) are rotated across Asia, of which 13.5 m ha are in the Indo-Gangetic Plains (IGP) of India. This agricultural system’s viability is currently in jeopardy due to static yields of both wheat and rice and a decline in total factor productivity. The North West IGP's high input crop culture has allowed weeds to dominate the weed flora, including P. minor in wheat and Echinochloa crus-galli L. in rice. Farmers in North West India have largely used zero tillage for growing wheat, and recently, farmers in the eastern IGP have done the same. Perennial weeds in the Eastern Indo-Gangetic Plain, such Cynodon dactylon L. and Cyperus rotundus L. can occasionally be a nuisance under zero tillage. As an alternative to puddled transplanted rice, the focus is currently on dry direct-seeded rice and machine transplanting of non-puddled rice. As a result of changes in tillage, crop establishment techniques, water use, and weed control brought on by the switch from transplanted rice to direct seeded rice, weed composition and diversity frequently vary. In nations where DSR is frequently used, weedy rice has become a significant concern. Using the Zero Tillage DSR system, certified seed, cultivars that are weed-competitive, stale seedbed procedures, living mulches, and chemical and biological weed control might change weed-crop competition in the crop's favour. However, more research on emergence characteristics and mulching effects of different crop residues on key weeds under zero tillage, cover cropping, and breeding crops for weed suppression will strengthen nonchemical weed management programs. In this review, we examine the extent of weed infestation, weed flora shift and the non-chemical alternative weed management in DSR.