Efficient management of fertilizer nitrogen in wet direct-seeded rice (Oryza sativa) in northwest India

A field experiment was conducted during 2000-02 and 2004 to study the optimum rate, source and schedule of N application for wet-direct seeded rice (Oryza sativa L.) on a Typic Ustrochrept during the summer monsoon (June-October) rainy seasons. The N-response of wet-direct seeded rice ranged from 80-120 kg /ha, beyond which the yields leveled off. Response to applied N was not influenced by farmyard manure application. Application of 120 kg N/ha in 3 equal split doses at 20, 40 and 60 days after seeding gave maximum grain yield and N use efficiency of wet-direct seeded rice. Performance of polymer-coated urea applied in a single dose at seeding in wet-direct seeded rice was as good as urea applied in 4 split doses. Total N uptake and, the recovery and agronomic efficiencies of applied N were maximum at 80 kg N/ha. Grain yield of wet-direct seeded rice was on a par with that of transplanted rice.