Excessive depletion of soil moisture by artificial forests in the vegetation restoration areas of the Loess Plateau has attracted widespread attention. To assess potential risks of soil moisture deficit, we needed on-site vegetation and soil sampling data, as well as UAV images from the Chaigou Watershed for three-dimensional analysis, combining both sampling and raster data. Three-dimensional surfaces for assessment of trade-off were established innovatively by the local regression and interpolation methods. The results indicated that soil moisture benefits at 20–40 cm depth are lower than at 0–20 cm due to infiltration and surface disturbance. In some areas of the Chaigou Watershed, grass and shrub-grass vegetation are facing risks of soil moisture deficit based on trade-off values (RSMD) and multiparameter evaluations. Analysis of deep soil water content variability revealed the moisture decreases significantly with the deepening of the soil layer in some plots. R (Richness), H (Shannon’s Diversity), Margalef, COHESION, and CONTAG were applicable in interpolation and fitted with the local regression model (R2 > 0.6) corresponding to the trade-off, but SPLIT was proven to be inapplicable in this study area. The zero trade-off inflection points were 6 %–8 %, while the trend inflection points were 7.5 %–9 % for soil moisture and vegetation indices of vegetation and landscape in typical sampling sites of the Chaigou Watershed. Three-dimensional fitting model is more comprehensive and effective in assessing deep soil moisture conditions and grass plots on shady slopes generally had the best trade-off status in this region.

中文翻译：

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黄土高原丘陵区深层土壤水分与植被恢复权衡建模


黄土高原植被恢复区人工林对土壤水分的过度消耗引起了广泛关注。为了评估土壤水分不足的潜在风险，我们需要现场植被和土壤采样数据，以及来自柴沟流域的无人机图像进行三维分析，结合采样和栅格数据。通过局部回归和插值方法创新性地建立了用于评估权衡的三维表面。结果表明，由于渗透和表面干扰，20-40 cm 深度的土壤水分效益低于 0-20 cm 深度的土壤水分效益。在柴沟流域的一些地区，基于权衡值 （RSMD） 和多参数评估，草和灌木-草植被面临土壤水分不足的风险。深部土壤含水量变化分析表明，随着土层的加深，部分样地水分显著减少。R （Richness） 、 H （Shannon's Diversity ）、 Margalef 、 COHESION 和 CONTAG 适用于插值，并拟合了对应于权衡的局部回归模型 （R2 > 0.6），但 SPLIT 被证明不适用于该研究领域。柴沟流域典型采样点土壤水分和植被植被植被指数的零权衡拐点为 6 %–8 %，而趋势拐点为 7.5 %–9 %。三维拟合模型在评估深部土壤水分条件方面更加全面有效，阴坡上的草地通常具有最佳的权衡状态。