YOU Xianhui1,2 , YANG Yan1,2, XU Gang1,2, ZOU Xiaogang1,2, HE Zhili1,2, TIAN Ning1,2, TIAN Hongming3, ZENG Zhuzhou3
(1. Chongqing Key Laboratory of Karst Environment, School of Geographical Sciences, Southwest University, Chongqing 400715, China;
2. Field Scientific Observation & Research Base of Karst Eco-environments at Nanchuan in Chongqing, Ministry of Land and Resources of China, Chongqing 408435, China;
3. Harmo Trust Agriculture Development Co., Ltd, Chongqing 409800, China)
Abstract: It had been reported that the rock exposure ratio and the vegetation coverage rate in the sloping and reversed slopes on both sides of the Longtan karst trough valley were different remarkably. This study conducted the dynamic high-resolution monitoring of CO2 concentration in soils on both sides of the Longtan karst trough valley, and monitored temperature and moisture of soils simultaneously using solid CO2 sensors during the period of from June 2017 to May 2018. The results showed that: (1) During heavy rainfalls, the overall soil CO2 concentration was promoted by rainfall events, except a short decrease in the early stage of rainfalls (within 1 hour). (2) The concentration of CO2 in soil was higher in the day than in the night, the concentration of CO2 in soil was more sensitive to the air temperature than the soil temperature did, and the daily fluctuation of CO2 concentration in soil followed an order of summer> autumn> spring> winter. (3) In terms of short-term weather conditions, the rock exposure and vegetation coverage rate have important influences on CO2 concentration of soil, the higher is the rock exposure rate, the higher is the fluctuation of CO2 concentrations in soil under heavy rainfalls, and the higher is the correlation of the CO2 concentrations in soil and the soil temperature.
Key words: Karst trough valley area; soil CO2 concentration; heavy rainfall; soil temperature; soil moisture
EARTH AND ENVIRONMENT Vol.47, No.1, Tot No.327, 2019, Page 16-25