Soil erosion poses a significant threat to agricultural production worldwide, with a still-debated impact on the current increase in atmospheric CO₂. Whether erosion acts as a net carbon (C) source or sink also depends on how it influences greenhouse gas (GHG) emissions via its impact on crop yield and nutrient loss. These effects on the environmental impacts of crops remain to be considered. To fill this gap, we combined watershed-scale erosion modeling with life cycle assessment to evaluate the influence of soil erosion on environmental impacts of wheat production in the Ebro River basin in Spain. This study is the very first to address the full GHG balance of erosion including its impact on soil fertility and its feedback on crop yields. Two scenarios were simulated from 1860 to 2005: an eroded basin involving conventional agricultural practices, and a non-eroded basin involving conservation practices such as no-till. Life cycle assessment followed a cradle-to-farm-gate approach with a focus on recent decades (1985–2005). The mean simulated soil erosion of the eroded basin was 2.6 t ha⁻¹ year⁻¹ compared to the non-eroded basin. Simulated soils in both eroded and non-eroded basins lost organic C over time, with the former emitting an additional 55 kg CO₂ ha⁻¹ year⁻¹. This net C source represented only 3% of the overall life cycle GHG emissions of wheat grain, while the emissions related to the increase of fertilizer inputs to compensate for N and P losses contributed a similar percentage. Wheat yield was the most influential parameter, being up to 61% higher when implementing conservation practices. Even at the basin scale, erosion did not emerge as a net C sink and increased GHG emissions of wheat by 7–70%. Nonetheless, controlling erosion through soil conservation practices is strongly recommended to preserve soils, increase crop yields, and mitigate GHG emissions.

土壤侵蚀对全球农业生产构成重大威胁，其对当前大气中CO ₂增加的影响仍存在争议。侵蚀是否充当净碳（C）源或汇还取决于它如何通过对作物产量和养分损失的影响来影响温室气体（GHG）排放。这些对作物环境影响的影响仍有待考虑。为了填补这一空白，我们将流域规模侵蚀模型与生命周期评估相结合，评估土壤侵蚀对西班牙埃布罗河流域小麦生产的环境影响。这项研究首次全面解决了侵蚀的温室气体平衡问题，包括其对土壤肥力的影响及其对作物产量的反馈。从 1860 年到 2005 年，模拟了两种情景：一个涉及传统农业实践的侵蚀盆地，另一个涉及免耕等保护实践的非侵蚀盆地。生命周期评估遵循从摇篮到农场大门的方法，重点关注近几十年（1985-2005）。与非侵蚀盆地相比，侵蚀盆地的平均模拟土壤侵蚀量为 2.6 t ha ^-1年^-1 。随着时间的推移，侵蚀盆地和非侵蚀盆地的模拟土壤都会失去有机碳，前者额外排放 55 kg CO ₂ ha ^-1年^-1。该净碳源仅占小麦籽粒整个生命周期温室气体排放量的 3%，而与增加化肥投入以补偿氮和磷损失相关的排放量则贡献了类似的百分比。小麦产量是最有影响力的参数，实施保护措施后产量提高了 61%。即使在流域范围内，侵蚀也没有作为净碳汇出现，并使小麦的温室气体排放量增加了 7-70%。尽管如此，强烈建议通过土壤保护措施控制侵蚀，以保护土壤、提高作物产量并减少温室气体排放。