摘要
干旱、半干旱区植被恢复与重建对降雨具有高度的依赖性,降雨格局的任何细微变化对其生态系统均会产生影响。以宁夏盐池县荒漠草原3种主要覆被类型(浮沙地、天然草地和柠条林地)为研究对象,使用自动气象站、土壤水分仪连续监测2015—2017年降水量和土壤水分数据,分析了3种覆被类型0—250 cm土层的土壤水分动态及其对不同量级降水的响应。结果表明:浮沙地土壤水分从表层至深层为增长趋势,天然草地和柠条林地为增加—减少—增加趋势;水分季节变化分为土壤水分稳定期(12月至翌年2月)、土壤水分积累期(3—5月)、土壤水分消退期(6—8月中旬)和土壤水分恢复期(8月下旬至11月)。5 mm以下的小降水事件对土壤水分几乎无影响;中等降水事件(5~25 mm)和大降水事件(25~40 mm)对0—20 cm或浮沙地0—40 cm土层土壤水分有补给作用;40—100 cm土层的水分补充需要特大降水事件。浮沙地对降水响应最敏感,柠条林地次之,天然草地最滞后。降水量、降水强度、雨前土壤含水量和土壤物理性质均是影响土壤水分入渗的因素,而在降水一致时,土壤类型是决定土壤水分动态的重要因素,植被对土壤剖面水分具有再分配的作用,这在干旱区生态系统中尤为重要,决定了植被类型与土壤类型的对应关系。
Vegetation restoration and reconstruction in arid and semi-arid areas are highly dependent on precipitation,and any slight change in precipitation pattern will have an impact on its ecosystem.Taking three main cover types of desert steppe in Yanchi County of Ningxia,floating sand land,native grassland and Caragana woodland as research objects,the precipitation and soil moisture from 2015 to 2017 were continuously observed by automatic weather station and soil moisture meter,the soil moisture dynamics of 0—250 cm soil layer and the responses to different levels of precipitation were analyzed.The results showed that the soil moisture of floating sand land increased from the surface to the deep layers,and the native grassland and Caragana woodland had the increasing-decreasing-increasing trends;seasonal changes in water content were divided into stable soil moisture period(December to February of the following year),soil moisture accumulation period(March to May),soil moisture decay period(June to mid-August)and soil moisture recovery period(late August to November).Small precipitation events less than 5 mm had almost no effect on soil moisture;moderate precipitation events(5~25 mm)and heavy precipitation events(25~40 mm)could supplement soil moisture in 0—20 cm soil layer or 0—40 cm soil layer in floating sand land.Extra-large precipitation event was needed for the water supplement of 40—100 cm soil layer.Floating sand land was the most sensitive to precipitation,followed by Caragana woodland,and native grassland was the most lagging.Precipitation amount,precipitation intensity,soil water content before precipitation and soil physical properties all affected soil water infiltration.When precipitation was consistent,soil type was the important factor determining soil moisture dynamics.Vegetation could redistribute soil profile moisture,which is particularly important in arid region ecosystem,and determines the corresponding relationship between vegetation types and soil types.
作者
陈娟
宋乃平
陈林
王兴
王启学
CHEN Juan;SONG Naiping;CHEN Lin;WANG Xing;WANG Qixue(School of Agricultural, Ningxia University, Yinchuan 750021;Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwest China of Ministry of Education, Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration of Northwest China, Yinchuan 750021)
出处
《水土保持学报》
CSCD
北大核心
2021年第6期198-206,共9页
Journal of Soil and Water Conservation
基金
宁夏回族自治区重点研发项目(2019BFG02022)
国家自然科学基金项目(31901367)。
关键词
土壤水分
降水格局
覆被类型
荒漠草原
soil moisture
precipitation pattern
cover type
desert steppe
