Zhou Dongmeng, Si Jianhua, He Xiaohui, Jia Bing, Zhao Chunyan, Wang Chunlin, Qin Jie, Zhu Xinglin, Liu Zijin
Key Laboratory of Eco-Hydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China.
University of Chinese Academy of Sciences, Beijing, China.
Front Plant Sci. 2023 Jan 24;14:1099217. doi: 10.3389/fpls.2023.1099217. eCollection 2023.
Afforestation as an effective measure for wind and sand control has achieved remarkable results in northern China, and has also greatly changed the land use and vegetation characteristics of the region. It is important to study the spatial and temporal dynamics of soil water content (SWC) in different afforestation years and its temporal stability to understand the dynamic characteristics of SWC during afforestation. In order to reveal the spatiotemporal dynamic characteristics of SWC in desert area plantations, in this study, five restorative-aged plantations in desert areas were selected and their SWC was measured in stratified layers for the 0-400 cm soil profile; we also analyzed the spatiotemporal dynamics and temporal stability of the SWC. The results showed that the SWC of plantations decreased with the increase in planting age in the measurement period, and the SWC of deep layers increased by more than that of shallow layers with planting age. Spearman's rank correlation coefficients for SWC of 0-400 cm in both 5- and 11-year-old HA plantations reached above 0.8 and were highly significantly correlated; the temporal stability of SWC tends to increase as the depth of the soil layer deepens. In contrast, the temporal stability of SWC in deeper layers (200-400 cm) of 22-, 34- and 46-year-old stands showed a decreasing trend with depth. Based on the relative difference analysis, representative sampling points can be selected to monitor the regional average SWC, but for older plantations, the uncertainty factor of stand age should be considered in the regional moisture simulation. This study verified that it is feasible to simulate large-scale SWC in fewer observations for plantations younger than 11 years old, while large errors exist for older stands, especially for deeper soils. This will help soil moisture management in plantations in arid desert areas.
造林作为防风固沙的有效措施，在中国北方取得了显著成效，也极大地改变了该地区的土地利用和植被特征。研究不同造林年份土壤含水量（SWC）的时空动态及其时间稳定性，对于了解造林过程中SWC的动态特征具有重要意义。为揭示沙漠地区人工林土壤含水量的时空动态特征，本研究选取了5个不同恢复年龄的沙漠地区人工林，对其0 - 400 cm土壤剖面进行分层测量土壤含水量；同时分析了土壤含水量的时空动态及时间稳定性。结果表明，在测量期内，人工林土壤含水量随造林年龄的增加而降低，且深层土壤含水量随造林年龄的增加幅度大于浅层。5年生和11年生HA人工林0 - 400 cm土壤含水量的Spearman秩相关系数均达到0.8以上，呈极显著相关；土壤含水量的时间稳定性随土层深度的增加而增强。相反，22年生、34年生和46年生林分深层（200 - 400 cm）土壤含水量的时间稳定性随深度增加呈下降趋势。基于相对差异分析，可选取代表性采样点监测区域平均土壤含水量，但对于老龄人工林，在区域水分模拟中应考虑林分年龄的不确定性因素。本研究验证了对11年生以下的人工林，用较少观测值模拟大面积土壤含水量是可行的，而对于老龄林分，尤其是深层土壤，存在较大误差。这将有助于干旱沙漠地区人工林的土壤水分管理。
