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CO 2 enrichment increases carbon and nitrogen input from fine roots in a deciduous forest
Author(s) -
Iversen Colleen M.,
Ledford Joanne,
Norby Richard J.
Publication year - 2008
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2008.02516.x
Subject(s) - liquidambar styraciflua , mineralization (soil science) , nitrogen , deciduous , nitrogen cycle , biomass (ecology) , agronomy , soil horizon , soil carbon , environmental science , root system , soil water , ecosystem , chemistry , botany , soil science , biology , ecology , organic chemistry
Summary• Greater fine‐root production under elevated [CO 2 ] may increase the input of carbon (C) and nitrogen (N) to the soil profile because fine root populations turn over quickly in forested ecosystems. • Here, the effect of elevated [CO 2 ] was assessed on root biomass and N inputs at several soil depths by combining a long‐term minirhizotron dataset with continuous, root‐specific measurements of root mass and [N]. The experiment was conducted in a CO 2 ‐enriched sweetgum ( Liquidambar styraciflua ) plantation. • CO 2 enrichment had no effect on root tissue density or [N] within a given diameter class. Root biomass production and standing crop were doubled under elevated [CO 2 ]. Though fine‐root turnover declined under elevated [CO 2 ], fine‐root mortality was also nearly doubled under CO 2 enrichment. Over 9 yr, root mortality resulted in 681 g m −2 of extra C and 9 g m −2 of extra N input to the soil system under elevated [CO 2 ]. At least half of these inputs were below 30 cm soil depth. • Increased C and N input to the soil under CO 2 enrichment, especially below 30 cm depth, might alter soil C storage and N mineralization. Future research should focus on quantifying root decomposition dynamics and C and N mineralization deeper in the soil.