Sustained accelerated soil erosion alters key soil properties such as nutrient availability, water holding capacity, soil depth and texture, which in turn have detrimental effects on crop productivity and therefore reduce C input to soils. In this study, we applied a 1-D soil profile model that links soil organic carbon (SOC) turnover, soil erosion and biomass production. We used observational data to constrain the relationship between soil erosion and crop productivity. Assuming no change in effort, we evaluated the model performance in terms of SOC stock evolution using published observational data from 10 catchments across Europe and the USA. Model simulations showed that accounting for erosion-induced productivity decline (i) increased SOC losses by 37 % on average compared to a scenario where these effects were excluded, and (ii) improved the prediction of SOC losses when substantial soil truncation takes place. Furthermore, erosion-induced productivity decline reduced soil–atmosphere C exchanges by up to 30 % after 200 years of transient simulation. The results are thus relevant for longer-term assessments and they stress the need for integrated soil–plant models that operate at the landscape scale to better constrain the overall SOC budget.

中文翻译：

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使用基于模型的方法评估土壤侵蚀和生产力下降对土壤碳动态的影响

持续的加速土壤侵蚀会改变关键的土壤特性，例如养分利用率，持水量，土壤深度和质地，进而对作物生产力产生不利影响，从而减少土壤中的碳输入量。在这项研究中，我们应用了一维土壤剖面模型，该模型将土壤有机碳（SOC）转换，土壤侵蚀和生物量生产联系在一起。我们使用观测数据来约束土壤侵蚀与作物生产力之间的关系。假设工作量不变，我们使用来自欧洲和美国10个流域的公开观测数据，根据SOC储量演变评估了模型性能。模型仿真表明，与排除腐蚀造成的生产率下降（i）相比，考虑到这些影响的情形，SOC损失平均增加了37％，（ii）改进了土壤被截断时SOC损失的预测。此外，经过200年的瞬态模拟，侵蚀引起的生产力下降使土壤-大气C交换减少了30％。因此，结果与长期评估有关，并且强调需要在景观尺度上运行的土壤-植物集成模型，以更好地约束总体SOC预算。