A Laboratory Study On Improvement of Mine Soil Quality for Re-Vegetation Through Various Amendments.

It has been realized recently that the mine soils at abandoned or reclaimed mine sites possess remarkable potential of carbon sequestration and can be a significant sink for atmospheric CO₂ through formation of soil organic matter and through aboveground biomass accumulation. However initial vegetation establishment in a mine soil is difficult due to the poor quality of the  soil such as low soil pH, low soil organic matter, low nutrient content and high toxin level. In this paper, five different amendment materials were researched in the laboratory, intended to improve the mine soil quality to a level which favors vegetation establishments. The materials included natural minerals (zeolite and diatomite) and industrial wastes (flyash, flue gas desulfurization (FGD) gypsum and biosolid). Two mine soils were taken from a reclaimed coal mining site located in central Ohio. The soils were acidic (pH <4.3), sandy, not supportive of vegetations. Incubation of the soils with the amendments at a 10% ratio showed that those materials could effectively improve the soil pH in a period of 5-10 days with FGD showing the highest acid-neutralization capacity. Lettuce seed germination tests exhibited that FGD greatly increased the germinate rate and root length in mine soils, comparable to those growing in the commercial potting media. In contrast, other amendments showed less significant or no effects on promoting lettuce germinations. Those results suggested that FGD is an effective amendment material for the vegetation re-establishments in the mine soils.  Moreover, acid digestion and ICP measurements were applied to reveal the chemical compositions of the soils and the amendments and to identify possible containments in the industrial wastes. Water extraction and ICP were used to evaluate the changes of the plant-available compositions in the mine soils through the amendments and elucidate the effects of the amendments on the lettuce seed germination.