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.
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References
Balesdent J, Wagner GH & Mariotti A (1988) Soil organic matter turnover in long-term field experiments as revealed by carbon-13 natural abundance. Soil Science Society America Journal 52: 118–124
Balesdent, J (1996) The significance of organic separates to carbon dynamics and its modelling in some cultivated soils. European Journal of Soil Science 47: 485–493
Buyanovsky GA, Aslam M & Wagner GH (1994) Carbon turnover in soil physical fractions. Soil Science Society America Journal 58: 1167–1173
Bonde TA, Christensen BT & Cerri CC (1992) Dynamics of soil organic matter as reflected by natural13C abundance in particle size fractions of forested and cultivated oxisols. Soil Biology and Biochemistry 24: 275–277
Cambardella CA & Elliott ET (1992) Particulate soil organic-matter changes across a grassland cultivation sequence. Soil Science Society America Journal 56: 777–783
Cambardella CA & Elliott ET (1993) Methods for physical separation and characterization of soil organic matter fractions. Geoderma 56: 449–457
Christensen BT (1992) Physical fractionation of soil and organic matter in primary particle size and density separates. In: Stewart BA (Ed) Advances in Soil Science, Vol. 20 (pp 1–90). Springer-Verlag, New York
Christensen BT (1996) Matching measurable soil organic matter fractions with conceptual pools in simulation models of carbon turnover: revision of model structure. In: Powlson DS, Smith P & Smith JU (Eds) Evaluation of Soil Organic Matter Models, NATO ASI Series, Vol. I 38 (pp 143-159). Springer-Verlag, Berlin
Cooter EJ (1998) General circulation model scenarios for the southern United States. In: Mickler RA & Fox S (Eds) The Productivity and Sustainability of Southern Forest Ecosystems in a Changing Environment (pp 15–54). Springer, New York
Elliott ET & Cambardella CA (1991) Physical separation of soil organic matter. Agriculture, Ecosystems, and Environment 34: 407–419
Gee GW & Bauder JW (1986) Particle-size analysis. In: Klute A (Ed) Methods of Soil Analysis, Part I. Physical and Mineralogical Methods (pp 383–411). Soil Science Society of America, Madison, Wisconsin
Gregorich EG, Ellert BH & Monreal CM (1995) Turnover of soil organic matter and storage of corn residue carbon estimated from natural13C abundance. Canadian Journal of Soil Science 75: 161–167
Harrison, KG, Broecker WS & Bonani G (1993) The effect of changing land use on soil radiocarbon. Science 262: 725–726
Harrison KG (1997) Using bulk soil radiocarbon measurements to estimate soil organic matter turnover times. In: Lal R, Kimble JM, Follett RF & Stewart BA (Eds) Soil Processes and the Carbon Cycle (pp 549–559). CRC Press, Boca Raton, Florida
Hendrick RL & Pregitzer KS (1993) The dynamics of fine root length, biomass, and nitrogen content in two northern hardwood ecosystems. Canadian Journal of Forest Research 23: 2507–2520
Hudson RJM, Gherini SA & Goldstein RA (1994) Modeling the global carbon cycle: nitrogen fertilization of the terrestrial biosphere and the “missing” CO2 sink, Global Biogeochemical Cycles 8: 307–333
Insam H (1990) Are the soil microbial biomass and basal respiration governed by the climatic regime? Soil Biology and Biochemistry 22: 525–532
IPCC (The International Panel on Climate Change) (1998) Summary for policymakers — The regional impacts of climate change: An assessment of vulnerability, In: Watson RT, Zinyowera MC & Moss RH (Eds) A Special Report of IPCC Working Group II, International Panel on Climate Change, Geneva, Switzerland
Janzen HH, Campbell CA, Brandt SA, Lafond GP & Townley-Smith L (1992) Light-fraction organic matter in soils from long-term crop rotations. Soil Science Society America Journal 56: 1799–1806
Jastrow, JD (1996) Soil aggregate formation and the accrual of particulate and mineralassociated organic matter. Soil Biology and Biochemistry 28: 656–676
Jenkinson DS 1990. The turnover of organic carbon and nitrogen in soil. Philosophical Transactions of the Royal Society of London, Series B — Biological Sciences 329: 361–368
Jenkinson DS &, Rayner JH (1977) The turnover of soil organic matter in some of the Rothamsted classical experiments. Soil Science 123: 298–305
Johnson DW & Lindberg SE (1992) Atmospheric Deposition and Forest Nutrient Cycling: A Synthesis of the Integrated Forest Study. Springer-Verlag, New York
Johnson DW, Van Miegroet H, Lindberg SE, Todd DE & Harrison RB (1991) Nutrient cycling in red spruce forests of the Great Smoky Mountains. Canadian Journal of Forest Research 21: 769–787
Kirschbaum MUF (1995) The temperature dependence of soil organic matter decomposition, and the effect of global warming on soil organic C storage. Soil Biology and Biochemistry 27: 753–760
Lietzke DA (1994) Soils of Walker Branch Watershed, ORNL/TM-11724. Oak Ridge National Laboratory, Oak Ridge, TN
Lovett GM & Lindberg SE (1993) Atmospheric deposition and canopy interactions of nitrogen in forests. Canadian Journal of Forest Research 23: 1603–1616
Oades JM (1988) The retention of organic matter in soils. Biogeochemistry 5: 35–70
Olson JS (1963) Energy storage and the balance of producers and decomposers in ecological systems. Ecology 44: 322–331
Nadelhoffer KJ & Raich JW (1992) Fine root production estimates and belowground carbon allocation in forest ecosystems. Ecology 73: 1139–1147
Nicholas NS, Zedaker SM & Eagar C (1992) A comparison of overstory community structure in three southern Appalachian spruce-fir forests. Bulletin of the Torrey Botanical Club 119: 316–332
Parton WJ, Schimel DS, Cole CV and Ojima DS (1987) Analysis of factors controlling soil organic matter levels in Great Plains grasslands. Soil Science Society America Journal 51: 1173–1179
Parton WJ, Stewart JWB & Cole CV (1988) Dynamics of C, N, P, and S in grassland soils: a model. Biogeochemistry 5: 109–131
Raich JW & Nadelhoffer KJ (1989) Belowground carbon allocation in forest ecosystems: global trends. Ecology 70: 1346–1354
Schimel DS (1995) Terrestrial ecosystems and the carbon cycle. Global Change Biology 1: 77–91
Schlesinger WH (1990) Evidence from chronosequence studies for a low carbon-storage potential of soils. Nature 348: 232–234
Sharpe DM, Cromack K, Jr., Johnson WC & Ausmus BS (1980) A regional approach to litter dynamics in southern Appalachian forests. Canadian Journal of Forest Research 10: 395–404
Sollins P, Spycher G & Glassman CA (1984) Net nitrogen mineralization from light- and heavy-fraction forest soil organic matter. Soil Biology and Biochemistry 16: 31–37
Spycher G, Sollins P & Rose S (1983) Carbon and nitrogen in the light fraction of a forest soil: vertical distribution and seasonal patterns. Soil Science 135: 79–87
Tom MS, Trumbore SE, Chadwick OA, Vitousek PM & Hendricks DM (1997) Mineral control of soil organic carbon storage and turnover. Nature 389: 170–173
Townsend AR, Vitousek PM & Trumbore SE (1995) Soil organic matter dynamics along gradients in temperature and land use on the island of Hawaii. Ecology 76: 721–733
Trumbore SE, Chadwick OA & Amundson RR (1996) Rapid exchange between soil carbon and atmospheric carbon dioxide driven by temperature change. Science 272: 393–396
Van Dam D, Veldkamp E & Van Breemen N (1997) Soil organic carbon dynamics: variability with depth in forested and deforested soils under pasture in Costa Rica. Biogeochemistry 39: 343–375
Winkler JP, Cherry RS & Schlesinger WH (1996) The Q10 relationship of microbial respiration in a temperate forest soil. Soil Biology and Biochemistry 28: 1067–1072
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Research sponsored by the Terrestrial Carbon Processes Program, Office of Health and Environmental Research, U. S. Department of Energy under contract DE-AC05-96OR22464 with Lockheed Martin Energy Research Corporation.
Publication No. 4807, Environmental Sciences Division, ORNL.
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Garten, C.T., Post, W.M., Hanson, P.J. et al. Forest soil carbon inventories and dynamics along an elevation gradient in the southern Appalachian Mountains. Biogeochemistry 45, 115–145 (1999). https://doi.org/10.1007/BF01106778
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DOI: https://doi.org/10.1007/BF01106778