Presentations

Permanent URI for this collection

https://hub.ifdc.org/handle/20.500.14297/1435

Browse

Browse by

Author
Collection
Date
Topics
Titles

Browsing Presentations by Subject "Nitric oxide"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Impacts of Urea Deep Placement with Intermittent Irrigation on Nitrous Oxide and Nitric Oxide Emissions and Nitrogen Use Efficiency from Lowland Rice Cultivation
    (2018-10) S.M. Mofijul Islam; Yam Kanta Gaihre; Upendra Singh; Jatish Chandra Biswas; Md. Nayeem Ahmed; Joaquin Sanabria; Bjoern Ole Sander; Mohammad Saleque
    Urea deep placement (UDP) and alternate wetting and drying (AWD) irrigation method are two promising rice production technologies. However, studies on the impacts of UDP under AWD irrigation on nitrous oxide (N2O) nitric oxide (NO) emissions are still limited. We investigated the effects of UDP on N2O and NO emissions, nitrogen use efficiency (NUE) and rice yields compared with conventional broadcast application of prilled urea (PU) under AWD irrigation. Emissions were measured from three fertilizer treatments — no N, UDP and PU using an automated gas sampling and analysis system continuously for two consecutive Boro (dry) rice seasons in Bangladesh. For UDP, urea briquettes were placed in 7-10 cm below soil surface between four hills of rice at each alternate row after ten days of transplanting, while PU was applied as broadcast in three equal splits. Treatments were arranged in a randomized complete block design with three replications and emissions were measured at every three-hour interval. N2O emissions were irregular and event specific. Fertilizer induced emission peaks were observed after broadcast application of prilled urea (PU), but they were not observed in UDP. However, emissions peaks during dry period were more prominent in UDP compared to PU. Nevertheless, seasonal cumulative N2O emissions were similar between UDP and PU treatments. Across the season, UDP and PU showed yield-scaled N2O emission 96.3 and 88.7 g t–1 grain and emission factors were 0.49 and 0.23%, respectively. In contrast to N2O emission, NO fluxes were small and not affected by either fertilizer or water management. Across the season, UDP significantly increased rice yield, agronomic use efficiency and recovery efficiency of N by 29%, 109% and 167%, respectively compared to broadcast PU. Since UDP significantly increased grain yield and NUE compared to broadcast PU, and maintained similar emissions of N2O with PU, UDP could be equally effective under AWD irrigation as with continuous flooding condition. Therefore, UDP might be considered an eco-friendly technology for improving rice yields and reducing GHG emissions, particularly N2O emissions in both water regimes.
  • Thumbnail Image
    Item
    Quantifying Nitric Oxide Emissions under Rice-Wheat Cropping Systems
    (2019-07) Yam Kanta Gaihre; Wendie D. Bible; Upendra Singh; Joaquin Sanabria
    Urea deep placement (UDP) increases nitrogen use efficiency (NUE) and crop yields while reducing nitrogen (N) losses to the environment. However, studies on its environmental impacts on nitric oxide (NO) emissions are still limited. Therefore, we conducted a greenhouse experiment to quantify the NO emissions from a rice-wheat system. NO emissions were measured from three N fertilizer treatments – control (no N), UDP, and broadcast prilled urea (PU) – using an automated gas sampling and analysis system continuously for a rice-wheat cropping cycle. In rice, UDP was tested under two water regimes – continuous flooding (CF) and alternate wetting and drying (AWD). Fertilizer treatments had significant effects (p<0.05) on NO emissions. UDP with AWD irrigation increased NO emissions (3.41g N ha-1 ) (p<0.05) by 2.5- times compared to UDP with CF (1.35g N ha-1 ). But emissions were similar between UDP and 31 broadcast PU under the CF water regime. In wheat, the application of N fertilizer – regardless of application methods – increased NO emissions (615g N ha-1 , average across application methods) by 10-times over control (62.52 g N ha-1 ). However, emissions were not significantly (P>0.05) different among the treatments. Fertilizer induced emission factors (EFs) were not affected by N placement methods in either rice or wheat. On average, EFs in the rice were very low (<0.002%) compared to the wheat (0.5%). This study reveals that (regardless of treatments), the contribution of rice (<4 g N ha-1) on total annual NO emissions (433 g N ha-1 ) was very small 38(<0.5%) compared to emissions from wheat.