Understanding soil and ecosystem respiration in a dune-meadow cascade ecosystem  

作　　者：Xueer Kang Tingxi Liu Lina Hao Limin Duan Rong Wu Xin Tong Yongzhi Bao Yixuan Wang Yu Gong Wenmei Cao 

机构地区：[1]Inner Mongolia Agricultural University Water Conservancy and Civil Engineering College,Hohhot 010018,China [2]Inner Mongolia Key Laboratory of Protection and Utilization of Water Resources,Hohhot 010018,China [3]Autonomous Region Collaborative Innovation Center for Integrated Management of Water Resources and Water Environment in the Inner Mongolia Reaches of the Yellow River,Hohhot 010018,China [4]North China University of Science and Technology Architectural Engineering College,Tangshan 063210,China [5]Grassland Research Institute,Chinese Academy of Agricultural Sciences,Hohhot 010010,China

出　　处：《Ecological Processes》2024年第4期279-294,共16页生态过程(英文)

基　　金：supported by the National Natural Science Foundation of China(the Yellow River Water Science Research Joint Fund)(U2243234);the National Natural Science Foundation of China(51939006);the National Natural Science Foundation of China(52109022,52169002);the Inner Mongolia Autonomous Region Science and Technology Leading Talent Team(2022LJRC0007);the Ministry of Education of China Innovative Research Team(Grant IRT_17R60);the Chinese Ministry of Science and Technology Innovative Research Team in Priority Areas(Grant 2015RA4013);the Inner Mongolia Agricultural University Basic Research Project(BR22-12-04,BR221012);the Inner Mongolia Industrial Innovative Research Team(Grant 2012);frst-class Academic Subjects Special Research Project of the Education Department of Inner Mongolia Autonomous Region(No.YLXKZX-NND-010).

摘　　要：Arid and semi-arid regions,which account for more than 30%of the Earth’s land area,increasingly dominate the spatiotemporal trends in global carbon fuxes.The Horqin Sandy Land is a typical semi-arid fragile ecosystem in northern China.Understanding the components of the carbon budget in ecosystems under conditions of extreme soil moisture limitations provides a foundation for comprehending the carbon balance in semi-arid ecosystems.The seasonal and diurnal variations in soil respiration(R_(s))in semi-mobile dune(SD)and meadow wetland(MW)ecosystems of the Horqin Sandy Land were examined,and the sources of CO_(2)emissions from Rs were identifed using stable carbon isotopes.The responses of Rs and ecosystem respiration(R_(eco))to environmental temperature,moisture and leaf area index(LAI)were revealed.The results showed that on a seasonal scale,in SD with soil moisture content(M_(s))below feld capacity(FC),M_(s) had a greater infuence on Rs than soil temperature(T_(s))during the growing season.Changes in the LAI during the middle and late growth period afected R_(s) by altering root carbon supply.In MW,the most favorable M_(s) for R_(s) was near FC.The increase in LAI before mowing could efectively promote root and soil microbial respiration,and the decomposition of litter driven by T_(s) was the main form of R_(s) at this time.After mowing,root respiration and soil microbial respiration were the main processes contributing to CO_(2)emissions.On a daily scale,relative humidity(RH)dominated the R_(s) variation under dry conditions,whereas in other conditions,the R_(s) was adequately explained by temperature in SD and MW.The overall R_(eco)was larger than R_(s),but occasionally R_(s) was greater than R_(eco).The efects of temperature,moisture and LAI on R_(eco)and R_(s) varied with growing season.Adding factors,such as ecosystem type,vegetation growth,water,and heat,to the carbon cycle model can improve predictions of carbon emissions,and aid in further management decisions in arid and semi-arid areas.

关 键 词：Arid and semi-arid area Carbon emission Stable carbon isotope Carbon pool 

分 类 号：S15[农业科学—土壤学]