State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, Hubei, China.
Research Institute of Rice Industrial Engineering Technology, Yangzhou University, Yangzhou, 225009, China.
Chemosphere. 2023 Dec;344:140326. doi: 10.1016/j.chemosphere.2023.140326. Epub 2023 Sep 28.
Optimizing water and nitrogen management to minimize NH volatilization from paddy fields has been extensively studied. However, there is limited research on the combined effect of different rates of organic fertilizer substitution (OFS) and irrigation methods in rice cultivation, exploring an effective water and nitrogen combination is beneficial to mitigate NH volatilization. To address this gap, we conducted a two-year field experiment to investigate NH volatilization under different OFS rates (0%, 25%, and 50%) combined with continuous flooding irrigation (CF) and alternate wet and dry irrigation (AWD). Our findings revealed that NH fluxes exhibited similar emission patterns after each fertilization event and significantly decreased with increasing rates of OFS during the basal stage. Compared to no substitution (ON0), the low (ON25) and high (ON50) rates of OFS reduced cumulative NH emissions by 18.9% and 16.6%, and lowed NH emission factors (EFs) by 26.7% and 23.3%, respectively. Although OFS resulted in a slight reduction in rice yield, yield-scaled NH emissions were significantly reduced by 11.9% and 6.5% under the low and high substitution rates, respectively. This reduction was mainly attributed to the slight yield reduction observed at the low substitution rate. Furthermore, when combined with ON0, AWD irrigation had the potential to increase NH volatilization. However, this increase was not observed when combined with ON25 and ON50. During each fertilization stage, floodwater concentration emerged as the prominent environmental factor influencing NH volatilization, showing a stronger and more positive correlation compared to other factors such as floodwater pH, soil pH, and NH concentration. Based on our findings, we recommend implementing effective water and nitrogen management strategies to minimize NH volatilization in rice cultivation. This involves applying a lower rate of organic fertilizer substitution during the basal stage, maintaining high water levels during fertilization, and implementing mild AWD irrigation during non-fertilization periods.
优化水氮管理以最大限度减少稻田 NH 挥发已有广泛研究。然而，在水稻种植中，不同有机肥料替代率（OFS）和灌溉方式的综合影响研究有限，探索有效的水氮组合有利于减轻 NH 挥发。为解决这一差距，我们进行了为期两年的田间试验，研究不同 OFS 率（0%、25%和 50%）与连续淹灌（CF）和干湿交替灌溉（AWD）相结合下 NH 挥发。我们的研究结果表明，每次施肥后 NH 通量表现出相似的排放模式，在基肥阶段随着 OFS 率的增加而显著降低。与不替代（ON0）相比，低（ON25）和高（ON50）OFS 替代率分别降低了 18.9%和 16.6%的累积 NH 排放量，降低了 26.7%和 23.3%的 NH 排放因子（EF）。尽管 OFS 导致水稻产量略有降低，但低（ON25）和高（ON50）替代率下的产量标准化 NH 排放量分别显著降低了 11.9%和 6.5%。这种减少主要归因于低替代率下观察到的产量轻微减少。此外，当与 ON0 结合时，AWD 灌溉有可能增加 NH 挥发。然而，当与 ON25 和 ON50 结合时，并未观察到这种增加。在每个施肥阶段，淹水浓度是影响 NH 挥发的主要环境因素，与其他因素（如淹水 pH 值、土壤 pH 值和 NH 浓度）相比，其相关性更强且更呈正相关。根据我们的研究结果，我们建议在水稻种植中实施有效的水氮管理策略，以最大限度减少 NH 挥发。这包括在基肥阶段应用较低的有机肥料替代率，在施肥期间保持高水位，以及在非施肥期间实施温和的 AWD 灌溉。
