Disentangling the combined impacts of flooding intensity and land use types on soil nitrous oxide emissions in the riparian zone of Three-Gorges Reservoir(Original data))

This study provides unprecedented insights into the interactive effects of flooding intensity and land use on soil N₂O emissions in the riparian ecotone of the Three Gorges Reservoir (TGR) – a critical global hotspot for greenhouse gas research. While land use and hydrology individually influence N₂O fluxes, their combined impacts remain poorly quantified, especially in dynamic reservoir ecosystems. Through long-term field measurements across three flooding gradients and four land uses, we reveal that anthropogenic land use (e.g., cornfields) amplifies N₂O emissions irrespective of flooding intensity, whereas natural grassland exhibits resilience with minimal flux variations. Crucially, we demonstrate that flooding intensity alone does not dictate emissions; instead, interactions with land management dominate N₂O dynamics. Our identification of ammonium, nitrate, soil moisture, and temperature as key drivers offers mechanistic clarity for predictive models. These findings challenge assumptions about hydrological controls and underscore that reducing anthropogenic disturbance (e.g., maintaining grasslands) is the most effective strategy for mitigating N₂O emissions in managed riparian zones.

本研究针对三峡水库（Three Gorges Reservoir, TGR）河岸交错带的土壤氧化亚氮（N₂O）排放，就淹水强度与土地利用的交互影响提供了前所未有的深入认知；该区域亦是全球温室气体研究的关键热点区域。尽管土地利用与水文过程各自均可对N₂O通量产生调控作用，但二者的协同效应仍未得到充分量化，在动态变化的水库生态系统中这一局限尤为显著。本研究通过针对三种淹水梯度与四种土地利用类型开展的长期野外原位监测，发现人为土地利用（例如玉米田）无论淹水强度如何，均会加剧N₂O排放；而天然草地则展现出较强恢复力，其N₂O通量变化幅度极小。尤为关键的是，本研究证实，单一的淹水强度并不能决定N₂O排放水平，相反，土地管理模式的交互作用才是调控N₂O动态变化的主导因素。本研究明确了铵态氮、硝态氮、土壤含水率与土壤温度为关键驱动因子，可为相关预测模型提供清晰的机制阐释。本研究结果挑战了现有关于水文调控作用的既有认知，并强调，在人工管理的河岸带区域，减少人为干扰（例如维持草地生态）是缓解N₂O排放的最有效策略。