| Abstrakt: |
The effects of sewage sludge, lime, and gypsum on the revegetation of acidic coal refuse material were studied at a Fulton County, IL, land reclamation site. Treatments consisted of a control, 542 dry Mg ha−1anaerobically digested sewage sludge, 89.6 Mg ha−1lime, 112 Mg ha−1gypsum, and combinations of these amendments. The experimental plots were seeded with a mixture of bromegrass (Bromus inermisLeyss.), tall fescue (Festuca arundinaceaL.), and alfalfa (Medicago sativaL.). Yearly analysis of coal refuse material (0–15 cm) showed that the concentrations of NH+4‐N, [NO−3+ NO−2]‐N, available P, and water‐soluble K were the highest in sludge‐amended treatments, but they decreased with time. Plant yields increased each year from 1978 to 1980 in treatments receiving lime, sewage sludge, or both amendments. The highest yield of 6.00 Mg ha−1occurred in the 1980 sludge + lime treatment. In 1980, the order of dry matter plant yields by treatments was sewage sludge + lime > gypsum + sewage sludge + lime > lime > sewage sludge > gypsum + sewage sludge > gypsum + lime > gypsum = control. Coal refuse and tissue K levels indicated that supplemental K would be desirable for long‐term maintenance of a vegetative cover. The better survival of bromegrass and tall fescue, as compared to alfalfa, reflected the coal refuse pH and the shorter root system of the more acid‐tolerant grasses. Concentrations of Al, Fe, Pb, and Zn in composite plant samples from some treatments exceeded the phytotoxic limits for these metals in plants. Potential plant toxicity from metals in the coal refuse material was most likely reduced by reactions with the applied sewage sludge and lime. |
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