Surface Hydrology and Erosion Group, Institute of Environmental Assessment and Water Research (IDAEA), CSIC, Barcelona, Spain.
Surface Hydrology and Erosion Group, Institute of Environmental Assessment and Water Research (IDAEA), CSIC, Barcelona, Spain.
Sci Total Environ. 2019 Jan 10;647:1421-1432. doi: 10.1016/j.scitotenv.2018.08.020. Epub 2018 Aug 3.
Soil water-content (SWC) variability in forest ecosystems is affected by complex interactions between climate, topography, forest structure and soil factors. However, detailed studies taking into account the combined effects of these factors are scarce. This study's main aims were to examine the control that throughfall exerts on local spatial variation of near-surface soil water-content and to combine this information with forest structure and soil characteristics, in order to analyze all their effects together. Two stands located in the Vallcebre Research Catchments (NE Spain) were studied: one dominated by Quercus pubescens and the other by Pinus sylvestris. Throughfall and the related shallow SWC were monitored in each plot in 20 selected locations. The main characteristics of the nearest tree and soil parameters were also measured. The results indicated that mean SWC increment at the rainfall event scale showed a strong linear relationship with mean throughfall amount in both forest plots. The % of locations with SWC increments increased in a similar way to throughfall amount in both forest plots. The analyses considering all the effects together indicated again that throughfall had a significant positive effect in both forest plots, while soil litter depth showed a significant negative effect for the oak plot but lower statistical significance for the pine plot, showing a comparable -although more erratic- influence of the organic forest floor for this plot. These results, together with lower responses of SWC to throughfall than expected in rainfall events characterized by low preceding soil water-condition and high rainfall intensity, suggest that litter layer is playing an important role in controlling the soil water-content dynamics. The biometric characteristics of the nearest trees showed significant but very weak relationships with soil water-content increment, suggesting that stemflow and throughfall may act at lower distances from tree trunk than those presented in our study.
森林生态系统中的土壤水分（SWC）变化受到气候、地形、森林结构和土壤因素之间复杂相互作用的影响。然而，考虑到这些因素的综合影响的详细研究很少。本研究的主要目的是研究穿透雨对近地表土壤水分局部空间变化的控制作用，并将这些信息与森林结构和土壤特性相结合，以便一起分析它们的所有影响。在位于西班牙东北部 Vallcebre 研究集水区的两个林分中进行了研究：一个以 Quercus pubescens 为主，另一个以 Pinus sylvestris 为主。在每个林分的 20 个选定地点的每个样地中监测穿透雨和相关的浅层 SWC。还测量了最近树木的主要特征和土壤参数。结果表明，在降雨事件尺度上，平均 SWC 增量与两个林分的平均穿透雨呈强线性关系。在两个林分中，具有 SWC 增量的位置百分比以与穿透雨相似的方式增加。同时考虑所有影响的分析再次表明，穿透雨对两个林分都有显著的积极影响，而土壤凋落物深度对橡树林分表现出显著的负影响，但对松林分的影响较低，这表明有机林地板对该林分的影响具有可比性-尽管更不稳定。这些结果，以及在先前土壤水分状况低和降雨强度高的降雨事件中 SWC 对穿透雨的响应低于预期，表明凋落物层在控制土壤水分动态方面起着重要作用。最近树木的生物计量特征与土壤水分增量之间存在显著但非常弱的关系，这表明茎流和穿透雨可能比我们研究中提出的距离树干更近地作用。
