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Elevated CO 2 and moisture effects on soil carbon storage and cycling in temperate grasslands
Author(s) -
TATE K.R.,
ROSS D.J.
Publication year - 1997
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1046/j.1365-2486.1997.00094.x
Subject(s) - environmental science , grassland , soil carbon , soil water , cycling , ecosystem , nutrient cycle , temperate climate , water content , climate change , agronomy , soil science , ecology , forestry , geography , geology , biology , geotechnical engineering
In grassland ecosystems, most of the carbon (C) occurs below‐ground. Understanding changes in soil fluxes induced by elevated atmospheric CO 2 is critical for balancing the global C budget and for managing grassland ecosystems sustainably. In this review, we use the results of short‐term (1–2 years) studies of below‐ground processes in grassland communities under elevated CO 2 to assess future prospects for longer‐term increases in soil C storage. Results are broadly consistent with those from other plant communities and include: increases in below‐ground net primary productivity and an increase in soil C cycling rate, changes in soil faunal community, and generally no increase in soil C storage. Based on other experimental data, future C storage could be favoured in soils of moderate nutrient status, moderate‐to‐high clay content, and low (or moderateIy high) soil moisture status. Some support for these suggestions is provided by preliminary results from direct measurements of soil C concentrations near a New Zealand natural CO 2 ‐venting spring, and by simulations of future changes in grassland soils under the combined effects of CO 2 fertilization and regional climate change. Early detection of any increase in soil C storage appears unlikely in complex grassland communities because of (a) the difficulty of separating an elevated CO 2 effect from the effects of soil factors including moisture status, (b) the high spatial variability of soil C and (c) the effects of global warming. Several research imperatives are identified for reducing the uncertainties in the effects of elevated atmospheric CO 2 on soil C.