气候变化领域集成服务门户(CCPortal): Differential effects of wetting and drying on soil CO2 concentration and flux in near-surface vs. deep soil layers

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DOI	10.1007/s10533-020-00658-7
	Differential effects of wetting and drying on soil CO2 concentration and flux in near-surface vs. deep soil layers
	Min K.; Berhe A.A.; Khoi C.M.; van Asperen H.; Gillabel J.; Six J.
发表日期	2020
ISSN	0168-2563
起始页码	255
结束页码	269
卷号	148 期号:3
英文摘要	Soil stores over 2500 Pg carbon (C), with the majority of C stored in deep soil layers (> 30 cm). Soil C can be lost to the atmosphere when organic compounds are mineralized to carbon dioxide (CO2, via oxidative decay or respiration) and moved upward through the soil profile (via diffusion). Soil moisture status can influence the balance between respiration and diffusion, thereby altering the soil CO2 concentration and flux. However, it is unclear how wetting and drying influence soil CO2 dynamics in surface vs. deep soil layers. Thus, we irrigated three soil profiles in Mediterranean arable land and continuously monitored soil CO2 concentration at 15, 30, 50, 70 and 90 cm during wetting and drying phases under ambient temperature conditions. We estimated gas diffusivity, CO2 flux, and temperature responses of soil CO2 concentration during the experiment. Decreases in gas diffusivity during the wetting period coincided with increases in soil CO2 concentrations. However, the negative gas diffusivity-soil CO2 concentration relationship did not hold true all the time, implying that CO2 production was the driving factor for the apparent soil CO2 concentration. We observed hysteretic responses of soil CO2 concentration to temperature as soil moisture varied, with deeper soil CO2 concentration being more sensitive to temperature than surface soil CO2 concentration, especially during the drying phase. The movement of CO2 was upward at all depths during the ambient phase, but the direction and the magnitude of CO2 fluxes varied across the depth gradient during the wetting and drying phases. This study highlights that the relative contribution of gas diffusivity vs. CO2 production to soil CO2 concentration changes with wetting and drying, and that the responses of soil CO2 concentration to temperature are dependent on the antecedent environmental conditions. Also, the downward movement of CO2 during the wetting and drying phases suggests that quantifying surface soil CO2 efflux may underestimate dynamic C processes in deeper soils. © 2020, Springer Nature Switzerland AG.
英文关键词	Deep soil carbon; Gas diffusivity; Hysteresis; Soil organic matter decomposition; Temperature sensitivity
语种	英语
scopus关键词	air-soil interaction; arable land; carbon flux; carbon sequestration; soil carbon; soil profile; wetting-drying cycle
来源期刊	Biogeochemistry
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/153155
作者单位	Life and Environmental Sciences, School of Natural Sciences, University of California-Merced, 5200 N. Lake Rd, Merced, CA 95343, United States; College of Agriculture, Can Tho University, Can Tho, Viet Nam; Wageningen University, Wageningen, Netherlands; Institute of Environmental Physics, University of Bremen, Bremen, Germany; Flemish Institute for Technological Research (VITO), Mol, Belgium; Department of Environmental Systems Science, Swiss Federal Institute of Technology, ETH-Zurich, Zurich, Switzerland
推荐引用方式 GB/T 7714	Min K.,Berhe A.A.,Khoi C.M.,et al. Differential effects of wetting and drying on soil CO2 concentration and flux in near-surface vs. deep soil layers[J],2020,148(3).
APA	Min K.,Berhe A.A.,Khoi C.M.,van Asperen H.,Gillabel J.,&Six J..(2020).Differential effects of wetting and drying on soil CO2 concentration and flux in near-surface vs. deep soil layers.Biogeochemistry,148(3).
MLA	Min K.,et al."Differential effects of wetting and drying on soil CO2 concentration and flux in near-surface vs. deep soil layers".Biogeochemistry 148.3(2020).