Fertilizer N management can mitigate N₂O emissions but complex soil-weather conditions modulate the mitigation potential. Conditional inference tree (CIT) is a machine learning method able to untangle complex interactions while providing an interpretable model. The goals of this study were (a) to assess the effect of N fertilizer on N₂O emissions, and to use CIT to identify (b) the main soil-weather drivers of daily N₂O hot moments and (c) fertilizer management options to mitigate them. The study was conducted in 2 yr in no-till corn (Zea mays L.) with seven combinations of N source and placement tested. Daily N₂O emissions were measured with vented chambers, and soil temperature and water-filled pore space (WFPS) were measured near the chambers on the same days of gas sampling. Overall, 2013 was drier with lower N₂O emissions than 2014. Cumulative N₂O losses differed across treatments and years, with broadcast emitting more in 2014 than in 2013, and only subsurface-banded fertilizer with a nitrification inhibitor (NI) consistently abated N₂O losses. The main hot moment conditions were within ∼80 d of fertilizer application when soil temperature >15 °C and WFPS >57%. Under these conditions, NI abated losses by 50% compared with fertilizer alone. The machine learning approach used here could be used in larger datasets to elucidate environment-specific drivers of N₂O hot moments and potential fertilizer mitigation practices under different soil, weather, and management conditions.

中文翻译：

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解开免耕玉米每日 N2O 排放的土壤-天气驱动因素和肥料管理缓解策略

肥料 N 管理可以减少 N ₂ O 排放，但复杂的土壤天气条件会调节缓解潜力。条件推理树 (CIT) 是一种机器学习方法，能够在提供可解释模型的同时解开复杂的交互。本研究的目标是 (a) 评估氮肥对 N ₂ O 排放的影响，并使用 CIT 确定 (b) 每日 N ₂ O 炎热时刻的主要土壤-天气驱动因素和 (c) 肥料管理减轻它们的选择。该研究在免耕玉米 ( Zea mays L.)中进行了 2 年，测试了七种氮源和种植位置的组合。每日 N ₂在气体采样的同一天，使用通风室测量 O 排放，并在室附近测量土壤温度和充满水的孔隙空间 (WFPS)。总体而言，2013 年更干燥，N ₂ O 排放量低于 2014 年。N ₂ O 的累积损失因处理和年份而异，2014 年的广播排放量高于 2013 年，只有含有硝化抑制剂 (NI) 的地下带状肥料持续减少N ₂ O损失。当土壤温度 > 15 °C 和 WFPS > 57% 时，主要的热矩条件在施肥后 80 d 内。在这些条件下，与单独施肥相比，NI 减少了 50% 的损失。这里使用的机器学习方法可用于更大的数据集，以阐明 N 的特定环境驱动因素不同土壤、天气和管理条件下的₂ O 热点时刻和潜在的化肥缓解措施。