Agricultural ditches and stream networks are overlooked hotspots of carbon emissions

作者：Lei Zhou, Yongqiang Zhou, José R. Paranaíba, Mike Peacock, Erik Jeppesen, David P. Hamilton · 发表于：National Science Review · 年份：2025 · DOI：10.1093/nsr/nwaf111 · 被引用次数：9 · 研究领域：Water-Energy-Food Nexus Studies、Environmental Impact and Sustainability、Soil and Water Nutrient Dynamics

In many agricultural regions, ditch-stream networks play a critical role in preventing waterlogging, enhancing soil aeration, and channeling water to crops in areas with insufficient rainfall, promoting productivity. These networks facilitate the lateral transfer of water, energy, and materials between upstream agricultural lands and downstream rivers or lakes (Fig. 1a). Ditches typically form a dense network across agricultural landscapes, and cover an area of ∼5.4 × 104 km2 [1], which accounts for <2% of the total global lake area (3.2 × 106 km2). Ditches generally occupy 3%–5% of the agricultural landscape and contribute 15%–50% of annual carbon emissions [2,3]. For example, in Great Britain, the total length of ditches is estimated at 60 400 km—more than twice the combined length of streams and rivers (26 700 km) [1]. Similarly, the Netherlands has a high density of agricultural ditches (∼300 000 km) [4], while Sweden's ditch network is even more extensive, spanning 756 000 km and covering ∼690 km2 [5], which is <2% of Sweden's lake area (∼38 000 km2). Moreover, ditches account for 84% of Sweden's national methane (CH4) emissions from flooded lands (34 000 t CH4 yr−1), including reservoirs and ponds [5]. However, the mechanisms driving organic carbon transformation and carbon emissions in intensively managed ditch-stream systems remain underexplored and are often poorly quantified, particularly regarding internal transformation processes. Agricultural ditches and streams ...