Revegetation of unreclaimed coal strip-mines in Oklahoma. I. Vegetation structure and soil properties.
An investigation of 49 unreclaimed coal strip-mines between 10 and 70-yr old revealed that definite soil horizons had not yet formed but that chemical and physical weathering was occurring rapidly in the soft sedimentary rocks of the spoils. The soils were slightly acid gravelly clay loams. Concentrations of Ca, K, P and N were approx. twice as high as in surrounding upland forests, and Zn concentrations were markedly higher than in forest soils, while concentrations of Fe, Mn and Cu were similar in mine and forest soils. Soil on older sites had greater vegetation cover, higher contents of sand, clay, Ca, K and N, and lower Fe and gravel contents, than on younger sites. Biomass-related measures of vegetation structure on older sites approached values found in surrounding upland forests and were significantly correlated with soil properties, especially N and Ca. The sites were classified into four groups on the basis of soil properties. The groups differed with respect to some vegetation structural properties.