摘要
为厘清高寒草地土壤水分动态对降水的响应,利用2015-2017年的降水和不同土层(5、10、20、30和40 cm)土壤水分连续观测数据,分析了高寒草原和沼泽草甸生长季土壤水分变化及入渗对降水事件的响应。结果表明:相比于草原,生长季沼泽草甸降水频次较高,小降水事件占比较大。草原和沼泽草甸土壤水分对降水事件的响应存在较大差异,小降水事件(≤5 mm)仅增加了草原5 cm土层土壤含水量,而对沼泽草甸0~40 cm土壤剖面各层土壤含水量均起到微弱的补充;草原5~10 mm的降水事件明显增加了10 cm土层土壤含水量,而>10 mm的降水事件才可明显补充10 cm以下土层土壤含水量;在沼泽草甸>5 mm的降水事件对40 cm土层土壤含水量的增加较上层(0~30 cm)明显。土壤水分增量不仅受降水事件大小和强度的显著影响(P<0.001),同时受降水前表层(0~10 cm)土壤含水量和降水期间气温的显著影响(P<0.05)。相比草原,沼泽草甸土壤中湿润锋运移较快;小降水事件发生时,沼泽草甸0~40 cm土壤剖面蓄水量增加较多;大降水事件发生时,沼泽草甸0~40 cm土壤剖面蓄水量增加较少。结果表明,草原大降水事件(>10 mm)占比较大的特征对于土壤剖面蓄水具有重要作用,沼泽草甸高频次降水和雨水渗透更快更深的特征,有利于土壤更频繁获取和有效地保持水分资源。该研究结果可为理解高寒草地区域尺度上复合生态系统土壤水分维持对降水格局的响应提供理论基础。
This study investigated the dynamics of soil moisture response to rainfall in alpine grassland on the Tibetan Plateau.Data on soil moisture at five soil depths(5,10,20,30,40 cm)and rainfall were collected from 2015 to 2017 at alpine grassland and marsh meadow sites over the Tibetan Plateau,and were used to analyze the response of soil moisture to rainfall events during the growing season,and explore the rainfall infiltration processes.Compared with grassland sites,the rainfall frequency at marsh meadow sites was higher,and the percentage of small rainfall events during the growing season was higher.The soil moisture responses to rainfall events at the grassland and marsh meadow sites differed greatly.Small rainfall events(≤5 mm)only increased soil moisture in the 0-5 cm soil layer at the grassland sites,but weakly replenished soil moisture in all soil profile layers to 40 cm depth at the swamp meadow sites.Soil moisture to a depth of 10 cm increased significantly after rainfall events of between 5 and 10 mm at the grassland sites.Soil moisture at depths from 10 to 40 cm at grassland sites increased obviously with rainfall events larger than 10 mm.The increase in soil moisture content was more in the 30-40 cm soil layer than in the upper soil layers(0-30 cm)with rainfall events larger than 5 mm at swamp meadow sites.The increase in soil moisture at depths of 0-40 cm after rainfall was significantly positively correlated with the size and intensity of rainfall events at both sites(P<0.001).In addition,the soil moisture for the 0-10 cm depth before rainfall and air temperature obviously influenced the increase of soil moisture at two sites(P<0.05).Compared with the grassland sites,the wetting front moved faster in the marsh meadow soils.When a small rainfall event occurred,there was more water storage in the 0-40 cm soil horizons of the marsh meadow sites than at the grassland sites.When a large rainfall event occurred,the soil profile for the 0-40 cm horizons of marsh meadow sites had less water storage than the grassland sites.These results suggest that the high proportion of large rainfall events(>10 mm)occurring at grassland sites plays a key role in increasing soil water storage in grassland.In contrast,the higher frequency of rainfall events and deeper infiltration in marsh meadows result in those sites exhibiting more frequent and more rapid soil moisture gains and retaining the moisture more efficiently than the grassland sites.These findings provide a theoretical basis for understanding the response patterns of soil moisture following precipitation in these alpine grassland and marsh meadow soils.
作者
石明明
王晓敏
陈奇
韩炳宏
周秉荣
肖建设
肖宏斌
SHI Ming-ming;WANG Xiao-min;CHEN Qi;HAN Bing-hong;ZHOU Bing-rong;XIAO Jian-she;XIAO Hong-bin(Key Laboratory of Disaster Prevention and Mitigation of Qinghai Province,Xining 810001,China;Institute of Meteorological Science of Qinghai Province,Xining 810001,China;Meteorological Bureau of Henan Mongolian Autonomous County,Henan 811599,China;State Key Laboratory of Grassland Agro-ecosystem,College of Pastoral Agriculture Science and Technology,Lanzhou University,Lanzhou 730020,China)
出处
《草业学报》
CSCD
北大核心
2021年第12期49-58,共10页
Acta Prataculturae Sinica
基金
中国科学院青海省人民政府三江源国家公园联合研究专项(LHZX-2020-08)
国家重点研发计划项目(2016YFC0501903)资助。
关键词
土壤水分
入渗
降水事件大小
高寒草地
青藏高原
soil moisture
infiltration
rainfall event size
alpine grassland
Tibetan Plateau