It is currently unclear how changes to modeled soil water simulations influence key predictions in complex, ecohydrologic models, particularly beyond hydrology. We assessed sensitivity to soil moisture in the Soil and Water Assessment Tool by artificially perturbing simulated soil moisture and analyzing targeted prediction change. Results demonstrated a strong, process-dependent sensitivity of model predictions to perturbations in soil moisture. At the basin scale, the absolute values of differences from a baseline simulation for surface runoff, evapotranspiration, and nitrate loss ranged from 42% to 107%, 29%–76%, and 19%–369%, respectively, for soil moisture changes between 0.5 and 2 standard deviations. Landscape-scale results illustrated the impact of modeled land management actions, notably fertilizer applications, on determining the magnitude of the change. The findings highlight and motivate the need to improve soil moisture simulations, suggesting possible accuracy improvement for key model predictions by more precisely simulating soil moisture.

目前尚不清楚模拟土壤水模拟的变化如何影响复杂的生态水文模型中的关键预测，尤其是水文以外的模型。我们通过人工扰动模拟土壤水分并分析有针对性的预测变化来评估土壤和水分评估工具中对土壤水分的敏感性。结果表明，模型预测对土壤水分扰动具有很强的、依赖于过程的敏感性。在流域尺度上，土壤水分变化的地表径流、蒸散和硝酸盐损失与基线模拟的差异绝对值范围分别为 42% 至 107%、29%–76% 和 19%–369%在 0.5 到 2 个标准偏差之间。景观尺度的结果说明了模拟土地管理行动的影响，特别是施肥，确定变化的幅度。研究结果强调并激发了改进土壤水分模拟的必要性，表明通过更精确地模拟土壤水分可能提高关键模型预测的准确性。