Row crop agriculture is a significant source of two major greenhouse gases (GHGs) (carbon dioxide [CO₂] and nitrous oxide [N₂O]) and the air pollutant precursor ammonia (NH₃). Fluxes of these naturally occurring trace gases are often augmented by agricultural practices, such as fertilizer application and crop systems management. A living mulch system (LMS) maintains a live cover crop year‐round and is an emerging agricultural system that can reduce pesticide and fertilizer use while maintaining yields. Multiple trace gas fluxes of GHGs and NH₃ had not previously been measured together in an LMS of corn (Zea mays L.) and white clover (Trifolium repens L.). This study compared soil gas fluxes in a white clover LMS with two other cover crop systems and a no‐cover‐crop system. Infrared and gas chromatography measurements were taken over 2 yr in northern Georgia. Mean soil CO₂ and N₂O fluxes (159.7 kg ha⁻¹ d⁻¹ and 0.027 kg N ha⁻¹ d⁻¹, respectively) observed in LMS plots exceeded those from other treatments. Soil temperature, moisture, potentially mineralizable nitrogen (N), and nitrate partially explained these differences. Mean soil NH₃ emissions were greater in LMS (0.089 kg N ha⁻¹ d⁻¹) compared with no cover crop (0.038 kg N ha⁻¹ d⁻¹). Increased N₂O and NH₃ fluxes could be from release of N from decomposition of clover and from release of N into the soil as the corn shades the clover. Although LMS plots did not reduce trace gas emissions, labile carbon content was at least 100 mg kg⁻¹ greater than other treatments after 2 yr, improving soil health.

中文翻译：

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地膜和常规农业系统中的土壤微量气体通量

大田作物农业是两种主要温室气体（GHG）（二氧化碳[CO ₂ ]和一氧化二氮[N ₂ O]）和空气污染物前体氨（NH ₃）的重要来源。这些自然产生的微量气体的通量通常通过农业实践（例如施肥和作物系统管理）来增加。直播覆盖系统（LMS）全年保持直播作物覆盖，是一种新兴的农业系统，可以减少农药和化肥的使用，同时保持单产。以前从未在玉米（Zea mays L.）和白三叶草（白三叶（Trifolium repens））的LMS中同时测量到多种痕量的GHGs和NH ₃气体通量。L.）。这项研究将白三叶草LMS中的土壤气体通量与其他两个覆盖作物系统和无盖作物系统进行了比较。红外和气相色谱仪测量是在佐治亚州北部进行的，历时2年。在LMS样地中观测到的平均土壤CO ₂和N ₂ O通量（分别为159.7 kg ha ^-1 d ^-1和0.027 kg N ha ^-1 d ^-1）超过了其他处理的通量。土壤温度，湿度，可能矿化的氮（N）和硝酸盐部分解释了这些差异。与无盖作物（0.038 kg N ha ^-1）相比，LMS中的平均土壤NH ₃排放量更大（0.089 kg N ha ^-1 d ^-1）d ^-1）。N ₂ O和NH _3的通量增加可能是由于三叶草分解产生的N释放和玉米遮盖三叶草时向土壤中释放的N。尽管LMS样地并未减少痕量气体的排放，但2年后的不稳定碳含量至少比其他处理高出100 mg kg ^-1，从而改善了土壤健康。