A significant proportion of the global carbon emissions to the atmosphere originate from agriculture. Therefore, continuous long-term monitoring of CO₂ fluxes is essential to understand the carbon dynamics and balances of different agricultural sites. Here we present results from a new eddy covariance flux measurement site located in southern Finland. We measured CO₂ and H₂O fluxes at this agricultural grassland site for 2 years, from May 2018 to May 2020. In particular the first summer experienced prolonged dry periods, which affected the CO₂ fluxes, and substantially larger fluxes were observed in the second summer. During the dry summer, leaf area index (LAI) was notably lower than in the second summer. Water use efficiency increased with LAI in a similar manner in both years, but photosynthetic capacity per leaf area was lower during the dry summer. The annual carbon balance was calculated based on the CO₂ fluxes and management measures, which included input of carbon as organic fertilizers and output as yield. The carbon balance of the field was −57 ± 10 and −86 ± 12 g C m⁻² yr⁻¹ in the first and second study years, respectively.

中文翻译：

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芬兰南部农业草地的二氧化碳通量和碳平衡

全球向大气排放的碳排放中有很大一部分来自农业。因此，连续长期监测 CO ₂通量对于了解不同农业地点的碳动态和平衡至关重要。在这里，我们展示了位于芬兰南部的一个新的涡流协方差通量测量站点的结果。从 2018 年 5 月到 2020 年 5 月，我们在该农业草地场地测量了 2 年的CO ₂和 H ₂ O 通量。特别是第一个夏季经历了长时间的干旱期，这影响了 CO ₂通量，并且在第二个夏天观察到了更大的通量。在干燥的夏季，叶面积指数（LAI）明显低于第二个夏季。在这两年中，LAI 的水分利用效率以类似的方式增加，但在干燥的夏季，每叶面积的光合能力较低。年度碳平衡根据CO ₂通量和管理措施计算，其中包括作为有机肥料的碳输入和作为产量的输出。在第一个和第二个研究年中，该田地的碳平衡分别为 -57  ±  10 和-86  ±  12 g C m ^-2  yr ^-1。