北京山区侧柏林坡面土壤水分时空动态及其影响因素

研究基于自然坡面土壤水分高密度观测方法，明确北京山区侧柏林自然坡面土壤水分动态变化特征、时间稳定性及其影响因素，提升对北京山区坡面土壤水分时空动态及其影响因素的认识，为华北土石山区生态恢复对水文水资源影响评估提供依据。研究以北京鹫峰国家森林公园人工侧柏林地坡面（40 m×50 m）为研究对象，用Diviner 2000测量该自然坡面中30个测点，于2014年8月至2016年3月对坡面观测砾石层以上的土壤含水量（SWC）进行了观测。结果表明：观测期间土壤蓄水量（SWS）具有明显的季节变化特征且与降水量的变化趋势基本保持一致；不同土层SWC均处于中等变异，SWC较高时，SWC的变异性较低；研究区的土壤水分在整个观测期间都具有较高的时间稳定性，位于上坡水平阶的2号测点最能代表研究区的平均土壤水分；随着离树距离的增加SWS逐渐增加，春、夏、秋季离树距离0.5 m与1.5 m处SWS差异显著（P<0.05）；水平阶SWS显著大于陡坎（P<0.05），夏、秋季下坡位土壤SWS显著低于上坡位（P<0.05），水土保持工程措施对坡面SWC的分布格局有重要的影响。

Spatial and temporal dynamics of soil moisture and its influencing factors on the slope of Platycladus orientalis in Beijing mountain area

Based on the high-density observation method of soil moisture on natural slopes, this study clarifies the dynamic characteristics, spatial and temporal stability, and influencing factors of soil moisture on the natural slopes of Platycladus orientalis in Beijing mountainous areas. It is necessary to provide a basis for the assessment of the impact of ecological restoration on hydrology and water resources in the earth-rock mountainous area of northern China. Taking the slope (40 m×50 m) of Platycladus orientalis forest land in Beijing Jiufeng National Forest Park as the research object, 30 measuring points in the natural slope were measured by Diviner 2000 and the soil water content (SWC) above gravel layer was observed from August 2014 to March 2016. The results show that the soil water storage (SWS) has visibly seasonal variation characteristics and is consistent with the quantitative value change trend; the average SWC of different soil layers is in intermediate variability and the SWC variability decreases with increase in SWC. Soil moisture has a high time stability during the entire observation period. The No.2 measuring point located on the horizontal slope is the most representative of the average soil moisture in the study area. With the increase of the distance from the tree, the SWS gradually increase. In spring, summer, and autumn, the SWS at the distance of 0.5 m and 1.5 m from the tree is significantly different (P<0.05). SWS of the horizontal level is significantly greater than SWS of the steep slope (P<0.05), and the SWS on the downslope in summer and autumn is significantly lower than that of the upslope (P<0.05). Soil and water conservation engineering measures have important influence on the SWC distribution pattern on the slope.