In cold humid temperate regions, peak nitrous oxide (N₂O) fluxes from agricultural soils occur during spring freeze-thaw periods. Fall-applied manure that adds water-soluble nutrients to the soil prior to freeze-up could contribute to spring N₂O emissions. The objective of our field experiment was to evaluate the relationship between water-soluble nutrients and N₂O emissions during the spring freeze-thaw period in a sandy-loam soil with fall-applied manure and fall-sown cover crops in Québec, Canada. Dairy cattle manure (solid or liquid form) was applied in September, then 100% ryegrass (Lolium multiflorum Lam.) and 50% ryegrass and 50% hairy vetch (Vicia villosa Roth) were sown. In the following spring (March–April), soil N₂O fluxes were measured in non-steady-state closed chambers, and soil samples were analyzed for soil reactive nitrogen (ammonium, NH₄⁺ and nitrate NO₃⁻), dissolved organic carbon and nitrogen, soil moisture (water-filled pore space), and denitrification activity. Spring N₂O fluxes were not related to the fall-applied manure and cover crop treatments, possibly due to nitrogen transformations or loss from soil after manure application. The NH₄⁺ concentration, water-filled pore space, and denitrification activity were significant predictors of soil N₂O emissions during the spring freeze-thaw period, but only explained about 24% of the variation in these N₂O emissions. This suggests that N₂O was produced by biological processes such as nitrifier denitrification. N₂O emission may be the result of stochastic diffusion processes through pores with ice-water mixtures, as well as through cracks that form during freezing-thawing processes. Therefore, water-soluble soil nutrients may be poor predictors of spring N₂O emissions from manure-amended soils in our region.

在寒冷潮湿的温带地区，春季冻融期间会出现来自农业土壤的一氧化二氮（N ₂ O）峰值通量。秋季施用的肥料会在冻结之前向土壤中添加水溶性养分，这可能会导致春季N ₂ O排放。我们的田间试验的目的是评估加拿大魁北克含肥料和秋播覆盖作物的沙壤土春季冻融期水溶性养分与N ₂ O排放之间的关系。九月份施用了乳牛粪便（固体或液体形式），然后施用了100％的黑麦草（黑麦草）和50％的黑麦草和50％的毛v子（野豌豆）罗斯）。在下面的弹簧（3月4月）土壤氮素₂在非稳定状态下关闭室中测量的氧气通量，以及土壤分析样品的土壤活性氮（铵，NH ₄ ⁺和硝酸NO ₃ ^- ），溶解的有机碳和氮，土壤水分（充满水的孔隙空间）和反硝化活性。春季N ₂ O通量与秋季施肥和覆盖作物的处理无关，这可能是由于施肥后氮素转化或土壤流失造成的。NH ₄ ⁺浓度，充满水的孔隙空间和反硝化活性是土壤N _2的重要预测因子春季冻融期的O排放量，但仅解释了这些N ₂ O排放量变化的约24％。这表明N ₂ O是通过诸如硝化器反硝化的生物过程产生的。N ₂ O的排放可能是通过冰水混合物的孔隙以及在冻融过程中形成的裂纹而随机扩散的结果。因此，水溶性土壤养分可能不能很好地预测我们地区粪便改良土壤中春季N ₂ O的排放。