Point injected nitrogen application in rice residue mulched wheat: An innovative technology for enhancing productivity and nitrogenuptake

摘要

A field study was conducted to determine the impact of point injected nitrogen (liquid urea) application on nitrogen uptake and crop productivity under straw mulched no-till wheat. The nitrogen application treatments consisted of broadcasting of granular urea as per recommendation of practice (1/2 nitrogen during sowing+1/4th nitrogen after 1st irrigation+1/4thth nitrogen after 2nd irrigation), broadcasting of granular urea on soil surface general practice followed by farmers using 'Happy Seeder' (0+1/2 nitrogen before 1st irrigation+1/2 nitrogen before 2nd irrigation) and point-injected liquid urea placed between every second crop row at 250 mm intervals and 20-40 mm depth using self-propelled nitrogen applicator (0+1/2nitrogen after 1st irrigation+1/2 nitrogen after 2nd irrigation). Nitrogen accumulation and decomposition of straw mulch were observed to be lower under point injected nitrogen application than broadcast methods. The plant density was similar under all treatments but plant nitrogenconcentration and yield attributes were consistently higher with point-injected N compared with broadcast N. Lower plant nitrogen concentration was exhibited at high straw load compared to low straw load suggesting that straw mulch enhanced the nitrogenlosses with broadcasting of nitrogen; which resulted in less availability of nitrogen to the plants. The point injected nitrogen increased the nitrogen uptake and yield about 20% over conventional practice (broadcasting) of nitrogen application.