Promotion of integrated weed management for direct-seeded rice in North West India.

The field studies conducted at farmers’ fields in the North West India (western Uttar Pradesh, India) from 2001 to 2009 showed that complex weed flora caused yield losses in 65–92% direct seeded rice. The success of DSR weeds can be managed by integrated weed management (IWM) approaches, which include stale seedbed techniques, water management, the use of weed-free seed, hand weeding, co-culture of Sesbania, and application of recommended herbicides. Stale seedbed techniques was found to be effective in reducing the density of grassy and froad-leaved weeds.The advantages of direct seeding include more efficient use of water, higher tolerance of water deficit through less soil cracking and percolation and leaching losses upon reflooding, less methane emission, earlier crop maturity (7–15 days) and often higher profit in areas with an assured water supply. The impact of direct seeding of rice on the long-term productivity and sustainability of the system, however, requires careful evaluation within the context of the production system. In DSR the major challenges are effective weed management and appropriate water management for successful crop establishment. Farmers, particularly in north-western India, are keen to grow direct-seeded rice under zero-till or unpuddled conditions provided yields are close to those with conventional transplanting. Good land levelling and integrated weed management are key needs for direct seeding to be widely adopted in the near future.The need to control weeds to protect yields will be paramount, and this project has laid a sound basis for the development and promotion of appropriate weed-management practices. Some herbicides found effective in DSR are pendimethalin, cyhalofopbutyl, fenoxapropethyl, propanil, bispyribac, penoxsulam, carfentrazone, bensulfuron, azimsulfuron, 2,4-D, and chlorimuron + metsulfuron. Continuous monitoring of weed flora is needed to identify shifts in weed flora due to a shift from conventional puddled transplanted rice to DSR and to focus on the emerging problematic new weed species that are even more difficult to control and that are competitive in nature, such as weedy rice.