Natural Revegation of Acid Coal Spoils in Southeast Iowa

摘要

Iowa is in the center of the former tall-grass prairie formation, and now is the center of a region of intensive agriculture. An abundant supply of Iowa coal has been subjected to only a modest amount of strip-mining because of high sulfur content of the coal and over-burden, and an uncertainty about the geologic continuity of the deposits. As one part of the environmental studies of the state-funded Iowa Coal Project, natural revegetation of orphan spoils in Iowa was analyzed. For six sets of differently-aged spoils, 108 vegetation transects were recorded by soil condition, topographic moisture and age. Ordination analysis indicates that vegetation redevelopment has resulted in a complex of vegetation characteristics rather than a uniform successional sequence. Substrate acidity is important for initial colonization; roughly 40 to 50% of even the oldest spoils remain unvegetated because of substrate acidity. On spoils with a higher pH, moisture, age, seed source and other factors influence the present vegetation. (ERA citation 03:046375)