This study summarizes a large diverse dataset of methane (CH₄) fluxes measured from agricultural sites across the British Isles. A total of 53,976 manual static chamber measurements from 27 different sites were investigated to determine the magnitude of CH₄ fluxes from a variety of agricultural fields across the UK and Ireland. Our study shows that contrary to some studies, agricultural soils (both arable and grassland) are small net emitters of CH₄ rather than sinks. Mean fluxes measured from arable and grassland sites (excluding fertiliser and tillage events) were 0.11 ± 0.06 and 0.19 ± 0.09 nmol m⁻² s⁻¹, respectively, and were not found to be significantly different (Welch t-test, p = 0.17). Using the values reported in this study, we estimate that an annual emission of 0.16 and 0.09 Mt of CO₂-eq is expected from arable and grassland agricultural soils in the UK and Ireland (comparable to 0.3 and 0.7% of the current annual CH₄ emission inventories, respectively). Where CH₄ uptake occurs in soils, it is negligible compared to expected emissions of the application of animal manures and tillage events, which were both found to significantly increase CH₄ emissions in the immediate few days to months after events. Our study highlights that there are significant differences in CH₄ uptake and emissions between sites, and that these differences are partially the result of the moisture content of the soil (i.e., the aerobic status of the soil). We expect uptake of CH₄ to be more prevalent in drier soils where volumetric water content does not exceed 35% and emissions to be exponentially greater where agricultural fields become waterlogged.

中文翻译：

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农业土壤：不列颠群岛的甲烷汇还是源？

本研究总结了从不列颠群岛各农业地点测量的甲烷 (CH ₄ ) 通量的大型多样化数据集。对来自 27 个不同地点的总共 53,976 次手动静态室测量进行了调查，以确定来自英国和爱尔兰各种农田的 CH ₄通量的大小。我们的研究表明，与一些研究相反，农业土壤（耕地和草地）是 CH _{4 的}小型净排放源，而不是汇。从耕地和草地（不包括肥料和耕作事件）测量的平均通量分别为 0.11 ± 0.06 和 0.19 ± 0.09 nmol m ^-2  s ^-1，并且没有发现显着差异（Welch t- 测试，p  = 0.17）。使用本研究中报告的值，我们估计英国和爱尔兰的耕地和草地农业土壤的 CO ₂ -eq年排放量预计为 0.16 和 0.09 Mt （相当于当前年度 CH ₄排放量的0.3% 和 0.7%）排放清单）。在土壤中发生CH ₄吸收的情况下，与施用动物粪便和耕作事件的预期排放相比，可以忽略不计，发现这两种情况都会在事件发生后的几天到几个月内显着增加 CH ₄排放。我们的研究强调，CH ₄存在显着差异站点之间的吸收和排放，并且这些差异部分是土壤水分含量（即土壤的有氧状态）的结果。我们预计 CH _{4 的}吸收在体积含水量不超过 35% 的干燥土壤中更为普遍，并且在农田积水的地方排放量呈指数增长。