Long-term tillage and cover cropping differentially influenced soil nitrous oxide emissions from cotton cropping system

Climate-smart agricultural practices, such as no-tillage (NT) and cover cropping, have been widely adopted and are anticipated to yield multiple benefits, including soil carbon sequestration, enhancing soil health, and crop yield stability. However, their influence on nitrous oxide (N2O) emissions varies, with the potential of both increasing and decreasing N2O emissions. Increasing N2O emissions under these practices may potentially offset the climate mitigation benefits from increased soil carbon sequestration. We investigated N2O emissions in response to 42 years of long-term adoption of NT and legume cover crop, under nitrogen rates of 0 and 67 kg N ha-1, in a continuous cotton system in the Southeastern US. Intensive manual chamber-based measurements were conducted over two growing seasons (2021-2022 and 2022-2023). Long-term NT did not significantly (p > 0.05) affect cumulative N2O emissions during the study period. Hairy vetch cover crop-grown plots emitted 2-3 times more N2O ..., , , # Long-term Tillage and Cover Cropping Differentially Influenced Soil Nitrous Oxide Emissions from Cotton Cropping System [https://doi.org/10.5061/dryad.0vt4b8h75](https://doi.org/10.5061/dryad.0vt4b8h75) ## Description of the data and file structure This study aimed to evaluate the long-term impact of no-till (NT) practices and cover crops on nitrous oxide (N₂O) emissions in interaction with nitrogen (N) fertilization in a continuous cotton cropping system in the Southeast US. The experiment was designed using a split-split plot layout, with selected experimental levels including two N rates (0, NF; 67 kg N ha⁻¹, F), two cover crop treatments (hairy vetch, HV; no cover crop, NC) in the sub-plot, and two tillage methods (conventional tillage, CT; no-till, NT) in the sub-sub plot, replicated four times. N₂O emissions and soil data were collected from November 2021 to October 2023. Soil samples from a 0-10 cm depth were periodically collected and analyzed for ammonium (NH₄⁺), nitrate (...气候智能型农业实践（Climate-smart agricultural practices），如免耕（no-tillage, NT）与覆盖种植，已得到广泛推广应用，预计可带来多重效益，包括土壤固碳、提升土壤健康水平以及维持作物产量稳定性。然而，此类实践对氧化亚氮（nitrous oxide, N₂O）排放的影响存在显著差异，既可能增加也可能减少N₂O排放。若这类实践导致N₂O排放升高，则可能抵消土壤固碳提升所带来的气候减缓效益。本研究针对美国东南部连作棉田体系，探究了施氮量为0与67 kg N·ha⁻¹条件下，长期采用免耕与豆科覆盖作物种植42年后对N₂O排放的影响。本研究在两个生长季（2021-2022年与2022-2023年）内开展了密集的手动箱法观测。研究期间，长期免耕对累积N₂O排放量无显著影响（p > 0.05）。种植毛叶苕子覆盖作物的样地N₂O排放量较对照高2~3倍…… # 长期耕作与覆盖作物对棉田土壤氧化亚氮排放的差异化影响 [https://doi.org/10.5061/dryad.0vt4b8h75] ## 数据与文件结构描述 本研究旨在评估美国东南部连作棉田体系中，免耕（NT）与覆盖作物措施及其与氮肥施用的交互作用对N₂O排放的长期影响。试验采用裂裂区试验设计，设置的试验因子水平如下：两个施氮水平（0 kg N·ha⁻¹，记为NF；67 kg N·ha⁻¹，记为F）；副区设置两种覆盖作物处理（毛叶苕子，HV；无覆盖作物，NC）；副副区设置两种耕作方式（常规耕作，CT；免耕，NT），所有处理均重复4次。N₂O排放数据与土壤样品数据的采集周期为2021年11月至2023年10月。定期采集0~10 cm土层的土壤样品，分析其铵态氮（NH₄⁺）、硝态氮（……