Continental-scale measurement of the soil organic carbon pool with climatic, edaphic, and biotic controls
Article first published online: 10 FEB 2006
Copyright 2006 by the American Geophysical Union.
Global Biogeochemical Cycles
Volume 20, Issue 1, March 2006
How to Cite
2006), Continental-scale measurement of the soil organic carbon pool with climatic, edaphic, and biotic controls, Global Biogeochem. Cycles, 20, GB1007, doi:10.1029/2005GB002576., , , , , and (
- Issue published online: 10 FEB 2006
- Article first published online: 10 FEB 2006
- Manuscript Accepted: 16 NOV 2005
- Manuscript Revised: 9 NOV 2005
- Manuscript Received: 21 JUN 2005
- soil organic carbon;
- global carbon cycle;
- carbon inventory;
 We present data on soil organic carbon (SOC) inventory for 7050 soil cores collected from a wide range of environmental conditions throughout Australia. The data set is stratified over the spatial distribution of trees and grass to account for variability of SOC inventory with vegetation distribution. We model controls on SOC inventory using an index of water availability and mean annual temperature to represent the climatic control on the rate of C input into the SOC pool and decomposition of SOC, in addition to the fraction of soil particles <63 μm in diameter as a measure of textural control on SOC stabilization. SOC inventories in the top 30 cm of soil increase from 35 mg/cm2 in the driest regions to a modeled plateau with respect to a threshold of water availability at 335 mg/cm2, excluding variables controlling SOC decomposition. Above this threshold, decomposition factors begin to control SOC inventory, which we attribute to energetic control on microbial decomposition rates, and relatively weak stabilization of SOC in association with fine particles. When combined, these relationships provide an overall prediction of SOC inventory that accounts for 89–90% of the variance observed in the measured data set. Deviations from this relationship are most likely due to additional factors that also control decomposition rate such as hydrochemical and soil drainage conditions not accounted for by soil texture. Outliers within this data set are explained with respect to these conditions.