民勤荒漠区不同林龄人工梭梭林土壤水分时间稳定性研究

Study on temporal stability of soil moisture in Haloxylon ammodendron plantations of different ages in the Minqin desert area

摘要

【目的】明确荒漠区梭梭人工林土壤水分的时间稳定性是优化土壤水分监测和预测土壤水分的基础。【方法】基于2023年梭梭生长季土壤含水率的实地观测数据,采用经典统计和时间稳定性分析方法,对5年至25年林龄人工梭梭林0~400 cm土层土壤含水率的时空变异性和时间稳定性进行研究。通过计算Spearman秩相关系数和相对差分,评估土壤水分的时间稳定性。【结果】表层(0~100 cm)土壤含水量随林龄变化较小,保持在6%~9%的较高水平。而100~400 cm土层土壤含水量随林龄增加显著降低,波动范围在2%~9%之间,且深层土壤含水量变化幅度大于浅层。土壤含水率的空间变异性随土层深度增加而增强。对于林龄小于10年的梭梭林,土壤含水率表现出较高的时间稳定性(Spearman秩相关系数> 0.8);而在林龄较高(15 a、20 a、25 a)的梭梭林中,深层土壤的时间稳定性显著降低。【结论】荒漠区人工梭梭林土壤水分动态受植被年龄和土层深度共同影响。随着梭梭种植年限的增加,土壤含水量整体呈现下降趋势,主要是由于研究区域降水稀缺、蒸发强烈以及梭梭蒸腾作用消耗大量水分。在高林龄梭梭林中,应采取适当的水分调控措施,以确保土壤水分的可持续利用。研究成果为理解人工植被对土壤水分平衡及生态系统健康的影响提供了新的视角,也为未来荒漠区植树造林工作提供了重要的科学依据和实践指导。

Abstract

[Objective] The temporal stability of soil moisture in Haloxylon ammodendron plantations in desert regions was elucidated to provide a foundation for optimizing soil moisture monitoring and prediction. [Methods] Field-observed soil moisture content data from the 2023 growing season were analyzed using classical statistical and temporal stability analysis method. The spatiotemporal variability and temporal stability of soil moisture were investigated at depths of 0~400 cm in Haloxylon ammodendron plantations aged 5 to 25 years. Spearman rank correlation coefficients and relative differences were calculated to assess the temporal stability of soil moisture. [Results] Soil moisture content in the surface layer(0~100 cm) remained relatively stable across stand ages, maintaining high levels between 6% and 9%. In contrast, soil moisture content in the 100~400 cm layer significantly decreased with increasing stand age, exhibiting fluctuations ranging from 2% to 9%. Deeper soil layers showed greater variability than shallower layers. The spatial variability of soil moisture content increased with soil depth.Plantations younger than 10 years demonstrated high temporal stability of soil moisture(Spearman rank correlation coefficient >0. 8). Conversely, the temporal stability of soil moisture in deeper layers of older plantations(15 years, 20 years, and 25 years)was significantly reduced. [Conclusion] The dynamics of soil moisture in Haloxylon ammodendron plantations in desert regions are jointly influenced by stand age and soil depth. Overall, soil moisture content decreased with increasing stand age, primarily due to scarce precipitation, intense evaporation, and substantial water consumption through transpiration in the study area.Appropriate water management measures should be implemented in older plantations to ensure sustainable soil moisture use. New insights into the impact of artificial vegetation on soil moisture balance and ecosystem health are provided.

关键词

土壤含水率 / 时空变化 / 人工梭梭林 / 民勤 / 时间稳定性 / 影响因素

Key words

soil water content / spatio-temporal change / Haloxylon ammodendron / temporal stability / Minqin desert / influencing factors

基金资助

国家自然科学基金项目(51969012)

甘肃省水利科研与计划项目(23GSLK044)

甘肃省水利科研与计划项目(23GSLK045)

甘肃省水利科研与计划项目(23GSLK046)