Individual study: First-year development of plant communities originating from forest topsoils placed on Southern Appalachian mine soils in the Cumberland Mountains, Tennessee, USA
Farmer Jr. R.E., Cunningham M. & Barnhill M.A. (1982) First-year development of plant communities originating from forest topsoils placed on Southern Appalachian minesoils. Journal of Applied Ecology, 19, 283-294
Surface mining regulations in the USA require removal and storage of topsoil for use in post-mining revegetation. Topsoils may provide site amelioration and a source of local native vegetation. Several investigators in the eastern United States have found large numbers of viable seed in forest soils. In this study, preliminary to field trials, the revegetation potential of using forest topsoil spread on Southern Appalachian minesoils was evaluated.
Soil collection: In early April 1979, forest topsoil was collected from three mixed deciduous stands in the Cumberland Mountains (eastern Tennessee) near a surface coal mining operation, where two samples of surface mine soil were collected. These were slightly acidic (pH 5.7 and 5.9), low in organic matter (1.2%) and phosphorus, and had high to very high levels of magnesium, sulphur, zinc, iron, manganese and copper.
Experimental design: In 27 (1.23 x 1.23 m by 0.62 m deep) plots (three replicates of nine plots), the forest soil was spread over the mine soils to 2-3 cm depth, and fertilized with ammonium nitrate (168 kg/ha) and triple superphosphate (280 kg/ha) broadcast over the surface. Three plots in each replication were filled with one of the two mine soils. Plots were then mulched with 160 g of wheat straw simulating reclamation practice.
Plant monitoring and harvesting: A 10-cm-wide transect through each plot was delineated with string. In mid-May, late June and September, emerging plants were mapped on the transect, heights and survival were recorded, and species identified. During a 2-week period of drought in August, plots were twice irrigated with tap water. In late September, above ground vegetation and roots were harvested, oven-dried, and weighed by species.
An average of 286 plants/m² representing 134 taxa, emerged by late May, no further emergence took place during the study year. Over 90% of these plants survived the growing season (i.e. until the end of September). Total number of plants per plot in the final harvest did not vary significantly with topsoil or mine soil type.
The 1st year plant communities originating from the topsoil seed banks, contained about 1.9 x l06 shoots/ha. At the end of the growing season, dry shoot and root weight was about 8.4 t/ha. Nutrient analysis suggested that most of the added nutrients were retained in biomass. Roots were extensively colonized by endomycorrhizal fungi.
Conclusions: The authors conclud that forest topsoils in areas being surface mined for coal in the southern Appalachians may provide diverse plant communities capable of quick, effective (at least short-term) cover on reclaimed mined areas.