Vegetative Potential to Reduce Total Dissolved Solid Nutrient Ions Generated from Reclaimed Mine Lands in Central Appalachia
One of the major issues in surface coal mine land reclamation is the impact of total dissolved solids (TDS) on water quality. To address this issue, this study assessed whether vegetation could reduce TDS nutrient ion movement from the rooting zone in early reclamation stages when TDS generation is often highest. Vegetated and un-vegetated paired plots were established across eight sites with gradients in age, spoil material, and vegetative productivity. Ion exchange resin lysimeters were used to compare nutrient ion fluxes in soil solution that contribute to TDS between paired plots. Soil and vegetation properties (used as proxies for evapotranspiration and plant uptake) were characterized at each site and correlated with log ratios of common TDS contributing ions [i.e., base cations Ca2+, Mg2+, Na+, K+ (RBC), sulfate (RSO42-), and total Ca2+, Mg2+, Na+, K+, SO42- (Rtotal)] between un-vegetated and vegetated plots. Strong Spearman correlations were found between RTotal, RBC, and RSO42- during the peak growing season, and were weakened overall during vegetative dormancy. Soil organic matter was shown to be a strong correlate through dormant periods. Correlations between TDS nutrient ions and vegetation suggest evapotranspiration in the growing season, and interception during dormant periods, exert an influence on nutrient ion fluxes. These findings indicate that aggrading forests may reduce TDS nutrient ion loading, through solute retention mechanisms driven by organic matter inputs and plant uptake.