Studies on molecular characterization of soil organic carbon (SOC), although critical to understanding SOC dynamics, are relatively scarce for reclaimed minesoils. The aim of this study was to assess the effects of time since reclamation on SOC molecular properties in a reclaimed minesoil chronosequence using different spectroscopic indices. The chronosequence consisted of four minesoils, with similar soil-forming conditions, reclaimed to pasture ecosystem, and distinguished only by time since reclamation varying from 1 to 22 years. Results indicated that the SOC molecules in the older minesoils were comprised of highly humified polyaromatic and polycondensed species with higher proportions of O-containing and N-containing functional groups. In each minesoil, resistant and labile SOC fractions were identified. The resistant SOC fraction constituted >20 and <10 per cent of total SOC (g kg À1 ) in the oldest and youngest minesoil, respectively. Among the spectroscopic indices, the e 285 ultraviolet-visible index, diagnostic of aromatic C, was the most efficient in identifying the intrasite short-term (1-year) changes in SOC molecular properties. Strong positive relationships found between different spectroscopic indices and total SOC (g kg À1 ), with consistently higher r 2 values observed in older minesoils, indicated that SOC molecular characteristics played a key role in overall SOC dynamics, becoming more influential with increasing time since reclamation. In addition, significant relationships between the spectroscopic indices and different soil quality parameters indicated that SOC molecular properties influenced soil quality as well. Overall, the results indicated that SOC molecular properties were useful indicators of both SOC dynamics and soil quality in this minesoil chronosequence.
Current West Virginia coal mining regulations emphasize reforestation as a preferred postmining land use on surface mined areas. Some mined sites reclaimed to pasture are being converted to forests. In the spring of 2001, we compared the establishment and growth of five hardwood tree species on a reclaimed West Virginaia surface mine with compacted soils and a heavy grass groundcover. We planted 1-yr-old seedlings of five species (black cherry [Prunus serotina Ehrh.], red oak [Quercus rubra L.], yellow poplar [Liriodendron tulipifera L.], black walnut [Juglans nigra L.], and white ash [Fraxinus americana L.]) into sites that were mowed and unmowed on north- and south-facing aspects. We applied a ripping treatment, which loosened the compacted soils and disturbed the heavy ground cover. First year results showed >80% survival for all species. After 7 yr black cherry survival averaged 36%, red oak 47%, yellow poplar 66%, black walnut 80%, and white ash 98% across all sites and treatments. Seedling survival was best on north, unmowed, and ripped areas. Average growth (height x diameter(2)) of trees after 7 yr was greatest with white ash (434 cm(3)), followed by yellow poplar (256 cm(3)) and black walnut (138 cm(3)), then by black cherry (31 cm(3)) and red oak (27 cm(3)). Browsing by wildlife had a negative impact on tree growth especially on south aspect sites. Overall, mowing reduced survival of black cherry, red oak, and yellow poplar, but not for black walnut and white ash. Ripping increased survival of black cherry, red oak, and yellow poplar. Growth of all species was improved with ripping. Using inverse linear-quadratic plateau models, the time required for tree survival to stabilize varied from 1 yr for white ash to 6 to 9 yr for the other species.
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