Nitrous Oxide and Nitric Oxide Emissions from Lowland Rice Cultivation with Urea Deep Placement and Alternate Wetting and Drying Irrigation
Md. Nayeem Ahmed
Jatish Chandra Biswas
Yam Kanta Gaihre
S. M. Mofijul Islam
Urea deep placement (UDP) and the alternate wetting and drying (AWD) irrigation method are two promising rice production technologies. However, studies on the impact of UDP under AWD irrigation on nitrous oxide (N2O) and nitric oxide (NO) emissions are limited. In this study,the efects of UDP with AWD irrigation on these emissions, nitrogen use efciency (NUE), and rice yields are investigated, compared to conventional broadcast application. N2O and NO emissions from three fertilizer treatments – no nitrogen, UDP, and broadcast application of prilled urea (PU) – were measured. Measurements were taken using an automated gas sampling and analysis system continuously for two consecutive Boro (dry) rice seasons. N2O emission peaks were observed after broadcast application of PU but not after UDP. In contrast, large spikes in N2O emission were observed after UDP, compared to broadcast application, during dry periods. Despite diferences in emission peaks, seasonal cumulative N2O emissions from UDP and broadcast treatments were similar. However, NO emissions were minimal and unafected by UDP orAWD. UDP increased rice yields by 28% and N recovery efciency by 167%, compared to broadcast urea. This study demonstrates that UDP with AWD irrigation can increase yields and NUE withoutincreasing N2O and NO emissions.
Greenhouse gas emissions, Deep placement, Nitrogen-use efficiency, Nitric oxide
Islam, S.M.M., Y.K. Gaihre, J.C. Biswas, U. Singh, Ahmed, Md.N., J. Sanabria, and M.A. Saleque. 2018. “Nitrous Oxide and Nitric Oxide Emissions from Lowland Rice Cultivation with Urea Deep Placement and Alternate Wetting and Drying Irrigation,” Scientific Reports, 17623.