喀斯特林地冬季土壤水分对降雨的响应特征

Response of soil moisture to rainfall in forest land in a karst region during winter season

在湿润喀斯特地区,冬季土壤水分变化是水文过程的重要环节,并影响着植被恢复和生态重建。以次生林地为研究样地,使用HOBO H21_USB土壤水分自动监测系统对不同土层(0—20 cm)土壤水分进行连续监测,进而分析降雨前后不同土层土壤水分动态变化及土壤水分对降雨的响应特征。结果表明:(1)0.3 mm降雨量对土壤水分几乎没有影响, 4 mm降雨量只对0—5 cm土层土壤水分产生影响, 7 mm和10 mm的降雨对10 cm以上土层土壤水分有影响, 12 mm降雨量主要影响20 cm以上土层土壤水分,25 mm降雨量主要影响15 cm以上土层土壤水分。(2)林地冬季各土层土壤水分对降雨的最快响应时间均为0.1 h。

In humid karst area,the change of soil moisture in winter is an important part of hydrological process,which affects vegetation restoration and ecological reconstruction.Taking secondary forest land as the research sample plot,the HOBO H21_USB automatic soil moisture monitoring system was used to continuously monitor soil moisture in different soil layers(0-20 cm).the dynamic changes of soil moisture in different soil layers before and after rainfall and the response of soil moisture to rainfall were analyzed.The results show that:(1)The rainfall of 0.3 mm has almost no effect on the soil moisture.The rainfall of 4 mm only affects the soil moisture of the 0-5 cm soil layer.The rainfall of 7 mm and 10 mm has an effect on the soil moisture of the soil layer above 10 cm.The rainfall of 12 mm mainly affects the soil moisture of the soil layer above 20 cm,and the rainfall of 25 mm mainly affects the soil moisture of the soil layer above 15 cm.(2)The fastest response time of soil moisture in each soil layer of forest land to rainfall in winter is 0.1 h.