Soil Science Society America Journal 56: 777–783Ĭambardella CA & Elliott ET (1993) Methods for physical separation and characterization of soil organic matter fractions. Soil Biology and Biochemistry 24: 275–277Ĭambardella CA & Elliott ET (1992) Particulate soil organic-matter changes across a grassland cultivation sequence. Soil Science Society America Journal 58: 1167–1173īonde TA, Christensen BT & Cerri CC (1992) Dynamics of soil organic matter as reflected by natural 13C abundance in particle size fractions of forested and cultivated oxisols. European Journal of Soil Science 47: 485–493īuyanovsky GA, Aslam M & Wagner GH (1994) Carbon turnover in soil physical fractions.
Soil Science Society America Journal 52: 118–124īalesdent, J (1996) The significance of organic separates to carbon dynamics and its modelling in some cultivated soils. 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.īalesdent J, Wagner GH & Mariotti A (1988) Soil organic matter turnover in long-term field experiments as revealed by carbon-13 natural abundance. 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☌ increase in MAT.
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. 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. Total inventories of SOC in the forests (to a depth of 30 cm) ranged from 384 to 1244 mg C/cm 2. 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.
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. Both methods produced results that were qualitatively and quantitatively similar.
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 CaCl 2 (1.4 g/mL) and wet sieving through a 0.053 mm sieve.
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