ABSTRACT:
Municipal sewage sludge can be used as a fertilizer for crops but may also introduce undesirable metals into the food chain, especially when used on acid minesoils. In this study, sewage sludge from Morgantown, WV was surface applied to two acid minesoils and a neutral undisturbed soil to evaluate sludge application rates on forage production, nutrient loadings, and on heavy metal accumulation in soils and vegetation. On a reclaimed surf ace mine at Westover, 0, 15, 31, and 64 dry Mg ha−1 of sewage sludge were applied in March 1986 and monitored annually through 1989. These rates of sludge were three to 12 times greater than recommended N rates for pasture on this site. Grass biomass increased and legume biomass decreased with increased sludge application. Weed biomass was increased only during 1986. Minesoil pH was not significantly affected while soil organic carbon four years after treatment increased from 15 to 22 g kg−1 with sludge. Minesoil DPA-extractable Cu, Zn, and heavy metal concentrations also increased with sludge application. Sludge was also applied at up to 27.6 Mg ha−1 at Dellslow (reclaimed surface mine) and Pentress (undisturbed). Vegetative production was 1.5 to 2.8 times greater on sludge-treated vmus control plots during 1989 and 1990 at both sites, but soil pH was unaffected by sludge treatment. No significant differences were found for DPA-extractable Cu, Pb, and Zn in the upper 15 cm (6 in) of soil. Forage tissue analyses revealed greater crude protein, but no deference's in Cu, Pb, and Zn concentrations in treated compared to control plants. Guidelines for land application of sludge in West Virginia have been refined accordingly, and from 1988 to 1990, land applied sludge doubled from 4,150 to 8,520 Mg (4,570 to 9,430 tons).
Footnotes
J. Skousen and C. Clinger are with the Division of Plant and Soil Sciences and the Cooperative Extension Service, West Virginia University, Morgantown, WV 26506–6108. Contribution from the West Virginia Agricultural and Forestry Experiment Station, Mogantown, WV as journal article Number 2287. This research was partially supported with a grant from Anker Enetgy Corporation, Morgantown, WV; the West Virginia Department of Natural Resources, Charleston, WV; and also by funds expatriated under the Hatch Act. The authors express appreciation to John Faltis of Anker Energy Corporation for his cooperation at the Westover site, and to Larry Dumire and Joseph Snyder for allowing access to their farms. Dr. Willem van Eck of the WVU Cooperative Extension Service is gratefully acknowledged for originating the project as part of the statewide demonstration program on recycling of wastewater sludges.
- Copyright 1993 by the Soil and Water Conservation Society
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