气候变化领域集成服务门户(CCPortal): Divergent controls on carbon concentration and persistence between forests and grasslands of the conterminous US

CCPortal

DOI	10.1007/s10533-020-00725-z
	Divergent controls on carbon concentration and persistence between forests and grasslands of the conterminous US
	Heckman K.A.; Nave L.E.; Bowman M.; Gallo A.; Hatten J.A.; Matosziuk L.M.; Possinger A.R.; SanClements M.; Strahm B.D.; Weiglein T.L.; Rasmussen C.; Swanston C.W.
发表日期	2020
ISSN	0168-2563
英文摘要	Variation in soil organic C (%OC) concentration has been associated with the concentration of reactive Fe- and Al-oxyhydroxide phases and exchangeable Ca, with the relative importance of these two stabilizing components shifting as soil pH moves from acid to alkaline. However, it is currently unknown if this pattern is similar or different with regard to measures of soil C persistence. We sampled soils from 3 horizons (uppermost A, uppermost B, C or lowest B horizons) across a pH gradient of 11 grass-dominated and 13 deciduous/mixed forest-dominated NEON sites to examine similarities and differences in the drivers of C concentration and persistence. Variation in C concentrations in all soils could be linked to abundances of Fe, Al and Ca, but were not significantly linked to variation in soil C persistence. Though pH was related to variation in Δ14OC, higher persistence was associated with more alkaline pH values. In forested soils, depth explained 75% of the variation in Δ14OC (p < 0.0001), with no significant additional correlations with extractable metal phases. In grasslands, soil organic C persistence was not associated with exchangeable Ca concentrations, but instead was explained by depth and inorganic C concentrations (R2 = 0.76, p < 0.0001), implying stabilization of organic C through association with carbonate precipitation. In grasslands, measures of substrate quality suggested greater persistence is also associated with a more advanced degree of decomposition. Results suggest that explanatory variables associated with C concentrations differ from those associated with persistence, and that reactive Fe- and Al-oxyhydroxide phases may not be present in high enough concentrations in most soils to offer any significant protective capacity. These results have significant implications for our understanding of how to model the soil C cycle and may suggest previously unrecognized stabilization mechanisms associated with carbonates and forms of extractable Si. © 2020, This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.
英文关键词	Calcium carbonate; Density fraction; Oxyhydroxides; Radiocarbon; Soil organic matter
语种	英语
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/153165
作者单位	Northern Research Station, USDA Forest Service, Houghton, MI 49931, United States; Biological Station, University of Michigan, Pellston, MI 49769, United States; Dept. of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, United States; Environmental Studies Program, University of Colorado, Boulder, Boulder, CO 80303, United States; INSTAAR University of Colorado, Boulder, Boulder, CO 80303, United States; Forest Engineering, Resources and Management, Oregon State University, Corvallis, OR 97330, United States; Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, VA 24061, United States; National Ecological Observatory Network, Boulder, CO 80301, United States; Department of Environmental Science, University of Arizona, Tucson, AZ 85721, United States
推荐引用方式 GB/T 7714	Heckman K.A.,Nave L.E.,Bowman M.,et al. Divergent controls on carbon concentration and persistence between forests and grasslands of the conterminous US[J],2020.
APA	Heckman K.A..,Nave L.E..,Bowman M..,Gallo A..,Hatten J.A..,...&Swanston C.W..(2020).Divergent controls on carbon concentration and persistence between forests and grasslands of the conterminous US.Biogeochemistry.
MLA	Heckman K.A.,et al."Divergent controls on carbon concentration and persistence between forests and grasslands of the conterminous US".Biogeochemistry (2020).