2.1. Study sites
We chose an open-pit coal mine, designated site 289 by the
Indiana Department of Natural Resources, Reclamation Division,
as our source site for plant seeds and AM fungi adapted to postmine
conditions. Site 289 is two miles east of Midland, Indiana, in
Greene County. It was mined for three years and then abandoned in
1993. It covered an area of 2.5 acres and had a small (approximately
0.5 acres) pond that was dominated by cattails (Typha). The pond
was heavily polluted. The water was typical of the acid mine runoff
known as yellow boy. The mine soil had a pH of 3.83. Aluminum
goes into solution when the pH drops below 5.0. Aluminum toxicity
inhibits root development at exposure levels as low as 200M
Al (Cumming and Ning, 2003; Matsumoto, 2000). Low pH and aluminum
toxicity are common problems associated with coal mine
restoration.