140-5 Organic Matter Pools in Reclaimed Soils: Quantification Using Biological, Chemical and Physical Fractionation Methods.

See more from this Division: S06 Soil & Water Management & Conservation
See more from this Session: Impact of Soil Management On Soil Quality
Monday, October 22, 2012: 2:15 PM
Duke Energy Convention Center, Room 235, Level 2
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Abbey F. Wick1, Brian Strahm2, Rebecca Phillips3, Sarah Waldron3, Kevan Minick4 and Walter Lee Daniels1, (1)Department of Crop and Soil Environmental Sciences, Virginia Tech, Blacksburg, VA
(2)Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, VA
(3)Northern Great Plains Research Laboratory, USDA-ARS, Mandan, ND
(4)Virginia Tech, Blacksburg, VA
Long-term assessment of soil amendments used to enhance not only soil properties, but also carbon (C) storage in reclaimed mine soils is of interest.  Furthermore, the stability of C associated with various amendments is important for estimating C storage potential.  To evaluate these dynamics, long-term experimental plots were sampled where a series of treatments (control, topsoil, biosolids and sawdust) were applied over a mixture of sandstone and siltstone overburden in southwest Virginia.   As a second component to this study, samples from these four treatments were analyzed using different laboratory fractionation methods for C stability to illustrate the impact of sample preparation and method selection on interpretation of results.  Labile and recalcitrant C concentrations were similar across soil treatments after 28 yrs when using physical and chemical fractionation methods. However, differences were observed when using a biological method for separation (incubation), where pool sizes among treatments varied and the mineralization rate for the recalcitrant pool was higher under the biosolids and topsoil treatments.  When using a physical fractionation technique (density floatation), labile C constituted a greater portion of total C (67-72%) than the recalcitrant fraction.  This was similar regardless of sample preparation (sieving to 2 mm or 8 mm).  Chemical fractionation (acid hydrolysis) indicated 30 - 38% of total C in the labile fraction with the remainder in the recalcitrant pool.  The selection of fractionation technique for assessing soil C pools in various reclamation treatments is vital for the interpretation of treatment effects, where the proportion of pools and differences among treatments may vary greatly depending on the method used.
See more from this Division: S06 Soil & Water Management & Conservation
See more from this Session: Impact of Soil Management On Soil Quality