ISSN:
1573-515X
Keywords:
climate
;
C/N ratios
;
light-fraction organic matter
;
particulate organic matter
;
soil C turnover
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Geosciences
Notes:
Abstract Soil organic carbon (SOC) was partitioned between unprotected and protected pools in six forests along an elevation gradient in the southern Appalachian Mountains using two physical methods: flotation in aqueous CaCl2 (1.4 g/mL) and wet sieving through a 0.053 mm sieve. Both methods produced results that were qualitatively and quantitatively similar. Along the elevation gradient, 28 to 53% of the SOC was associated with an unprotected pool that included forest floor O-layers and other labile soil organic matter (SOM) in various stages of decomposition. Most (71 to 83%) of the C in the mineral soil at the six forest sites was identified as protected because of its association with a heavy soil fraction (〉1.4 g/mL) or a silt-clay soil fraction. Total inventories of SOC in the forests (to a depth of 30 cm) ranged from 384 to 1244 mg C/cm2. The turnover time of the unprotected SOC was negatively correlated (r=−0.95, p〈0.05) with mean annual air temperature (MAT) across the elevation gradient. Measured SOC inventories, annual C returns to the forest floor, and estimates of C turnover associated with the protected soil pool were used to parameterize a simple model of SOC dynamics. Steady-state predictions with the model indicated that, with no change in C inputs, the low-(235–335 m), mid-(940–1000 m), and high-(1650–1670 m) elevation forests under study might surrender ≈ 40 to 45% of their current SOC inventory following a 4°C increase in MAT. Substantial losses of unprotected SOM as a result of a warmer climate could have longterm impacts on hydrology, soil quality, and plant nutrition in forest ecosystems throughout the southern Appalachian Mountains.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01106778
