Vegetation restoration has been widely implemented as an effective approach to the control of soil erosion. However, severe soil desiccation is likely to occur if vegetation types and local precipitation conditions are not accounted for. In this study, an abandoned farmland and three typical vegetation types, including a natural shrubland, a plantation of black locust, and a natural oak secondary forest, were investigated to determine the characteristics of soil moisture in different hydrological years. The responses of soil moisture to precipitation were analysed at different timescales. Higher soil water contents were observed either in wet years or for natural vegetation types. The temporal response of soil moisture to precipitation was largely dependent on the timescale. At monthly scale, shallow soil moisture (0–100 cm) varied consistently with precipitation, whereas on interannual scale, precipitation is positively related to soil moisture along the whole profiles. Black locust and oak lands consumed more soil moisture than the shrubland, and severe soil desiccation developed in deep soil layers in the black locust plantation. The shrubland showed steeper regression slopes than other types for both the changes in soil water storage over time (ΔSWS_t) versus the growing season precipitation and the difference in soil water storage with the abandoned farmland (ΔSWS_v) versus the growing season precipitation, suggesting its higher adaptability to precipitation changes in this region. The results indicate that the shrubland develops optimal water use strategies through coevolution with local conditions and should be given precedence in vegetation restoration initiatives in this region.

中文翻译：

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黄土丘陵区土壤水分变化对不同植被类型降水的响应

植被恢复已被广泛用作控制土壤侵蚀的有效方法。但是，如果不考虑植被类型和当地降水条件，则很可能发生严重的土壤干燥。在这项研究中，调查了一个废弃的农田和三种典型的植被类型，包括天然灌木林，刺槐人工林和天然橡树次生林，以确定不同水文年中土壤水分的特征。在不同的时间尺度上分析了土壤水分对降水的响应。在潮湿的年份或自然植被类型中都观察到较高的土壤水分含量。土壤水分对降水的时间响应在很大程度上取决于时间尺度。以每月的规模 浅层土壤水分（0–100 cm）随降水变化而变化，而在年际尺度上，降水与整个剖面上的土壤水分呈正相关。刺槐和橡树地比灌木丛消耗更多的土壤水分，在刺槐人工林的深层土壤中形成了严重的土壤干燥。对于土壤水储量随时间的变化，灌木丛显示出比其他类型更陡的回归斜率（ΔSWS_吨）对生长季节沉淀和废弃农田（ΔSWS在土壤蓄水的差_v）相对于生长季节沉淀，表明其较高的适应性在该区域中沉淀的变化。结果表明，灌木林通过与当地条件的共同发展来制定最佳的用水策略，在该地区的植被恢复计划中应优先考虑。