Influence of Organic and Inorganic Nitrogen on Rice Grain Yields and Nitrogen Use Efficiency in the Non-Calcareous Soils of Bangladesh

Increasing use of nitrogen fertilizers along with its inappropriate application method resulting in higher N losses and low N use efficiency (NUE), is an important concern to sustain soil fertility and crop productivity in Bangladesh. Urea Deep Placement (UDP) technology, which reduces fertilizer use, increase NUE and crop productivity, is a proven technology in lowland rice cultivation. Moreover, use of organic fertilizer combined with chemical fertilizer helps to increase soil organic matter and increase crop yield. Therefore, cropping pattern-based field experiments were conducted at Bangladesh Agricultural University farm to determine the effects of different forms of nitrogen fertilizer in combination with organic manures on rice yield and NUE in Non-Calcareous soils (AEZ 9). Eight fertilizer treatments including broadcast urea, deep placement of granular urea and urea briquette and combined use of organic manure with broadcast urea were laid out in randomized complete block design with three replications. Results show that deep placement either urea or urea briquette increased grain yields and NUE significantly compared to broadcast PU. Moreover, addition of organic manure with broadcasted urea significantly increased both grain and straw yields compared to without organic manure. No significant grain yields difference observed among the deep placement and organic manure with broadcasted urea treated plot, but addition of organic manure improves and sustains the physical, chemical and biological functioning of soil. The NUE among the fertilizer treatments decreased with increasing N rates. The highest NUE observed at deep placed treatment (65-72%), which was significantly higher than broadcast PU (28-45%), suggesting an effective technology to attain food and environmental security.
Islam, M.R., H. Akter, M.R. Islam, M.A. Ali, Y.K. Gaihre, A.A. Mahmud, and M.M.H. Talukder. 2018. “Influence of Organic and Inorganic Nitrogen on Rice Grain Yields and Nitrogen Use Efficiency in the Non-Calcareous Soils of Bangladesh,” presented at the First International Conference on Challenges for Future Agriculture 2018, January 27-28, Bangladesh Agricultural University (BAU), Bangladesh.