Paranaíba José R, Struik Quinten, Shendurnikar Saumya, Ma Yinxiao, Quadra Gabrielle R, Kosten Sarian
Department of Ecology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, the Netherlands.
Department of Ecology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, the Netherlands.
J Environ Manage. 2025 Jan;373:123813. doi: 10.1016/j.jenvman.2024.123813. Epub 2024 Dec 24.
Recent studies indicate that greenhouse gas (GHG) emissions from agricultural drainage ditches can be significant on a per-unit area basis, but spatiotemporal investigations are still limited. Additionally, the impact of dredging - a common management in such environments - on ditch GHG emissions is largely unknown. This study presents year-round GHG emissions from nine ditches on a dairy farm in the center of the Netherlands, where each year, approximately half of the ditches are dredged in alternating cycles. We measured monthly diffusive fluxes of carbon dioxide (CO), methane (CH), and nitrous oxide (NO), along with ebullitive CH emissions, supplemented by diel flux measurements (i.e., 24-h measurements) conducted in summer and winter. Our findings indicate that while diffusive GHG fluxes exhibited low spatiotemporal variation, ebullitive CH emissions were significantly higher during warmer periods and marginally elevated at ditch intersections. CH ebullition was the dominant pathway of ditch GHG emissions, accounting for 58% of the total annual emissions, followed by CO (39%), and NO (3%). Approximately 80% of the total CH emissions occurred through ebullition during spring and summer. The average CH emission factor estimated for our ditches (574 kg ha year) is ∼40% higher than the Tier-1 value suggested by the IPCC for ditches on mineral soils (416 kg ha year). Based on two 24-h measurement campaigns, we concluded that neglecting nighttime diffusive CO and CH emissions may lead to inaccurate estimates of annual ditch GHG emissions, with ∼12% underestimation in this study. Although dredging led to subtle increases in water-to-atmosphere GHG emissions immediately after the activity, it reduced overall annual GHG emissions by ∼35%. This study highlights the importance of CH ebullition and of capturing diel cycles of diffusive emissions to accurately assess ditch GHG emissions and underscores the importance of considering seasonal variations and dredging practices when budgeting ditch GHG emissions.
近期研究表明，农业排水沟的温室气体（GHG）排放按单位面积计算可能相当可观，但时空调查仍然有限。此外，疏挖（此类环境中的一种常见管理方式）对排水沟温室气体排放的影响在很大程度上尚不清楚。本研究展示了荷兰中部一个奶牛场九条排水沟的全年温室气体排放情况，每年大约一半的排水沟会交替进行疏挖。我们每月测量二氧化碳（CO）、甲烷（CH）和一氧化二氮（NO）的扩散通量，以及冒泡式CH排放，并辅以夏季和冬季进行的昼夜通量测量（即24小时测量）。我们的研究结果表明，虽然扩散性温室气体通量的时空变化较小，但冒泡式CH排放在温暖时期显著更高，在排水沟交汇处略有升高。CH冒泡是排水沟温室气体排放的主要途径，占年度总排放量的58%，其次是CO（39%）和NO（3%）。春季和夏季约80%的CH排放通过冒泡产生。我们估算的排水沟平均CH排放因子（574千克·公顷⁻¹·年⁻¹）比IPCC针对矿质土壤排水沟建议的一级值（416千克·公顷⁻¹·年⁻¹）高出约40%。基于两次24小时测量活动，我们得出结论，忽略夜间扩散性CO和CH排放可能导致对年度排水沟温室气体排放的估计不准确，本研究中低估了约12%。尽管疏挖活动后立即导致水 - 大气温室气体排放略有增加，但它使年度温室气体总排放量降低了约35%。本研究强调了CH冒泡以及捕捉扩散排放的昼夜循环对于准确评估排水沟温室气体排放的重要性，并强调在计算排水沟温室气体排放预算时考虑季节变化和疏挖做法的重要性。
