Nitrous oxide (N2 O) emission from agricultural soils represents a significant source of greenhouse gas to the atmosphere. We evaluated the suitability of a modified Soil and Water Assessment Tool (SWAT) model to estimate the N2 O flux from the application of solid manure at two grassland sites (North Wyke [NW] and Pwllpeiran [PW]) in the United Kingdom. The simulated N2 O emissions were validated against field observations measured in 2011 and 2012 for model calibration and validation, respectively. The SWAT model predicts water-filled pore space (WFPS) very well with Nash-Sutcliffe efficiency (NSE), R2 , RMSE, and percentage bias (PBIAS) values of 0.67, .72, 0.06, and 3.64, respectively, during the calibration period for NW site, whereas it gives 0.68, .69, 0.07, and 3.04, respectively during the validation period. At PW, the model predicted the NSE, R2 , RMSE, and PBIAS of 0.55, .69, 0.04, and -4.5, respectively, during calibration and 0.63, .71, 0.05, and -2.6, respectively, during the validation period. Compared with WFPS, the model resulted in a slightly lower fit for N2 O emissions for NW (NSE = 0.47, R2 = .63 during calibration, and NSE = 0.55, R2 = .58 during validation) and for PW (NSE = 0.54, R2 = .71 for calibration, and NSE = 0.47, R2 = .69 for validation). Results revealed that the SWAT model performed reasonably well in representing the dynamics of N2 O emissions after solid manure application to grassland.

中文翻译：

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预测英国草地施肥后的一氧化二氮排放量

农业土壤中的一氧化二氮 (N2 O) 排放是大气中温室气体的重要来源。我们评估了改进的土壤和水评估工具 (SWAT) 模型的适用性，以估计在英国两个草地场地（North Wyke [NW] 和 Pwllpeiran [PW]）施用固体肥料所产生的 N2 O 通量。模拟的 N2 O 排放根据 2011 年和 2012 年测量的现场观测值分别进行了验证，用于模型校准和验证。在校准期间，SWAT 模型非常好地预测了充水孔隙空间 (WFPS)，纳什-萨特克利夫效率 (NSE)、R2、RMSE 和百分比偏差 (PBIAS) 值分别为 0.67、0.72、0.06 和 3.64 NW 站点的周期，而在验证期间分别给出 0.68、0.69、0.07 和 3.04。在 PW，该模型预测的 NSE、R2、RMSE 和 PBIAS 在校准期间分别为 0.55、0.69、0.04 和 -4.5，在验证期间分别为 0.63、0.71、0.05 和 -2.6。与 WFPS 相比，该模型对 NW（校准期间 NSE = 0.47，R2 = .63，验证期间 NSE = 0.55，R2 = .58）和 PW（NSE = 0.54， R2 = .71 用于校准，NSE = 0.47，R2 = .69 用于验证）。结果表明，SWAT 模型在表示固体肥料施用于草地后 N2 O 排放的动态方面表现得相当好。该模型导致 NW（校准期间 NSE = 0.47，R2 = .63，验证期间 NSE = 0.55，R2 = .58）和 PW（NSE = 0.54，R2 = .71）的 N2 O 排放拟合略低用于校准，NSE = 0.47，R2 = .69 用于验证）。结果表明，SWAT 模型在表示将固体肥料施用于草地后 N2 O 排放的动态方面表现得相当好。该模型导致 NW（校准期间 NSE = 0.47，R2 = .63，验证期间 NSE = 0.55，R2 = .58）和 PW（NSE = 0.54，R2 = .71）的 N2 O 排放拟合略低用于校准，NSE = 0.47，R2 = .69 用于验证）。结果表明，SWAT 模型在表示将固体肥料施用于草地后 N2 O 排放的动态方面表现得相当好。