The sensitivity of chemical weathering to climatic and erosional forcing is well established at regional scales. However, soil formation is known to vary strongly along catenas where topography, hydrology, and vegetation cause differences in soil properties and, possibly, chemical weathering. This study applies the SoilGen model to evaluate the link between the topographic position and hydrology with the chemical weathering of soil profiles on a north–south catena in southern Spain.We simulated soil formation in seven selected locations over a 20 000-year period and compared it against field measurements. There was good agreement between simulated and measured chemical depletion fraction (CDF; R²=0.47). An important variation in CDF values along the catena was observed that is better explained by the hydrological variables than by the position along the catena alone or by the slope gradient. A positive trend between CDF data and soil moisture and infiltration and a negative trend with water residence time was found. This implies that these hydrological variables are good predictors of the variability in soil properties.The model sensitivity was evaluated with a large precipitation gradient (200–1200 mm yr⁻¹). The model results show an increase in the chemical weathering of the profiles up to a mean annual precipitation value of 800 mm yr⁻¹, after which it drops again. A marked depth gradient was obtained for CDF up to 800 mm yr⁻¹, and a uniform depth distribution was obtained with precipitation above this threshold. This threshold reflects a change in behaviour, where the higher soil moisture and infiltration lead to shorter water transit times and decreased weathering. Interestingly, this corroborates similar findings on the relation of other soil properties to precipitation and should be explored in further research.

中文翻译：

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模拟链位置和水文对土壤化学风化的影响

化学风化对气候和侵蚀强迫的敏感性在区域尺度上得到了很好的证实。然而，众所周知，土壤形成在地形、水文和植被导致土壤性质差异和可能的化学风化的连环中变化很大。本研究应用 SoilGen 模型评估地形位置和水文与西班牙南部南北链状土壤剖面化学风化之间的联系。我们模拟了 2 万年期间七个选定地点的土壤形成，并比较了它反对现场测量。模拟和测量的化学消耗分数 (CDF; R ² =0.47）。观察到沿链的 CDF 值的一个重要变化，这可以更好地由水文变量解释，而不是仅通过沿链的位置或坡度梯度来解释。发现CDF数据与土壤水分和入渗呈正趋势，而与水停留时间呈负趋势。这意味着这些水文变量是土壤特性可变性的良好预测指标。模型敏感性是用大降水梯度（200-1200 mm yr ^-1）评估的。模型结果显示剖面的化学风化作用增加，达到年平均降水量 800 mm yr ^-1，之后又下降。对于高达 800 mm yr ^{-1的 CDF，获得了显着的深度梯度}，并且在高于该阈值的降水量下获得了均匀的深度分布。该阈值反映了行为的变化，其中较高的土壤水分和渗透导致更短的水通过时间和减少的风化。有趣的是，这证实了其他土壤性质与降水关系的类似发现，应在进一步的研究中进行探索。