There is a need to explore management practices that reduce nitrate (NO₃^-) leaching and aid in meeting current greenhouse gas reduction goals. Tile drainage involves using perforated pipes to remove excess subsurface water from agricultural fields, also removing nutrients. The inclusion of cover crops in tile-drained systems in the Midwest has been shown to reduce NO₃^- losses and is potentially a strategy to mitigate soil nitrous oxide (N₂O) emissions. The objectives of this research were to 1) evaluate cumulative soil NO₃^- and soil N₂O losses with and without the inclusion of cover crops in a corn-soybean rotation on a tile-drained landscape and; 2) assess the environmental damage cost (EDC) of N losses with and without the inclusion of cover crops in a corn-soybean rotation on a tile-drained landscape. Corn (Zea mays L.) was grown in 2017, and soybean (Glycine max L.) in 2018. The cover crop used in this experiment was a 92% cereal rye (Secale cereal L.) and 8% daikon radish (Raphanus sativus L.) blend. Treatments included cover crop inclusion, no cover crop inclusion, and a zero control, which did not include cover crops or receive N fertilization. Each treatment was replicated three times in individually tile-drained plots established in Lexington, IL during the 2017 and 2018 growing seasons. In 2017, cover crop inclusion led to a reduction in NO₃^– losses of over 50% when compared to the no cover and zero control. In 2018, total N losses were identical; however, there was an increase in soil N₂O emissions across all treatments compared to 2017. Despite the apparent tradeoff between N loss pathways in 2018, the overall EDC was reduced primarily because of the reduction in NO₃^- loss in the presence of cover crops. The results of this study indicated that the inclusion of a cover crop resulted in a sizeable reduction in N loss during the corn year that equated to a 64% reduction in EDC across a two-year crop rotation.

需要探索减少硝酸盐 (NO ₃ ^- ) 浸出并帮助实现当前温室气体减排目标的管理实践。瓷砖排水涉及使用穿孔管去除农田中多余的地下水，同时去除养分。中西部地区的瓷砖排水系统中包含覆盖作物已被证明可以减少 NO ₃ ^-损失，并且可能是减少土壤一氧化二氮 (N ₂ O) 排放的一种策略。本研究的目的是 1) 评估在瓦片排水景观的玉米-大豆轮作中是否包含覆盖作物的累积土壤 NO ₃ ^-和土壤 N _{2 O 损失；}2) 评估在瓷砖排水景观的玉米-大豆轮作中是否包含覆盖作物时氮素损失的环境损害成本 (EDC)。玉米 (Zea mays L.) 于 2017 年种植，大豆 (Glycine max L.) 于 2018 年种植。本实验中使用的覆盖作物为 92% 的谷物黑麦 (Secaleales L.) 和 8% 的萝卜 (Raphanus sativus) L.) 混合。处理包括覆盖作物、不包括覆盖作物和零对照，即不包括覆盖作物或接受氮肥。2017 年和 2018 年生长季期间，每种处理在伊利诺伊州列克星敦建立的单独瓷砖排水地块中重复 3 次。_{2017 年，覆盖作物的纳入导致 NO 3}减少^——与无覆盖和零控制相比，损失超过 50%。2018 年，总氮损失相同；_{然而，与 2017 年相比，所有处理的土壤 N 2} O 排放量均有所增加。尽管 2018 年氮损失途径之间存在明显的权衡，但总体 EDC 减少主要是因为覆盖存在下NO ₃ ^-损失的减少农作物。这项研究的结果表明，覆盖作物的加入导致玉米年份的氮素损失大幅减少，相当于两年轮作期间 EDC 减少了 64%。