Nitrogen cycling in young mine soils in Southwest Virginia

Deficiency of available nitrogen (N) is one of the major factors limiting the establishment of a long term self-sustaining vegetative community on mine soils. This investigation was conducted to study the nature of N form and dynamics in southwest Virginia mine soils.

Fresh mine spoils contained a large amount of indigenous N, ranging from 650 to 2500 mg/kg soil, which complicated N studies. Most of the indigenous N was "geologic N" which was unavailable to plants. The geologic N came from either 2:1 silicate minerals (fixed NH₄⁺) or coal fragments (nonhydrolyzable organic N). Active N, consisting of hydrolyzable organic N and exchangeable N, comprised the minor fraction of indigenous N available to plants.