Land Application of Solid Waste Compost: Impacts on Groundwater Quality and Uptake of Nutrients and Heavy Metals by Corn
File(s)
Date
1987-12Author
Dyer, Jeffrey M.
Publisher
University of Wisconsin-Stevens Point, College of Natural Resources
Metadata
Show full item recordAbstract
Two solid waste composts and two soils were evaluated for
leaching potential and plant uptake of nutrients and heavy
metals. The soils included a Plano silt loam and Lapeer sandy
loam.
Corn growth response studies were conducted in a greenhouse
pot experiment. Composts were incorporated at several rates (0-
300 T/A) based on lifetime heavy metal loading limits of each
soil. Mature compost released adequate amounts of all nutrients
to sustain corn growth at application rates of 80 tons/acre.
Application of a relatively immature compost resulted in the
immobilization of soil N and severe N deficiency in corn. Plant
concentrations of Cu and Zn increased with increased application
rates of composts. The heavy metals Ni, Cd, Pb, and Cr were not
detected in corn grown on soils amended with either compost. The
liming effect of the compost is believed to be responsible for
limiting metal availability to plants. A combination of compost
and inorganic fertilizer may be necessary for producing optimum
crop yields.
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Soil columns were used in leaching studies. The columns
consisted of compost-amended surface soils underlain by 28 inches
of subsoil. Columns were leached with 60 inches of water for 18
weeks. Results indicate that application of mature solid waste
compost in excess of the N requirements of a crop will leach
significant quantities of nitrate-N. Application of compost at
rates less than 80 tons/acre did not produce nitrate-N in
leachate exceeding fertilized soil background levels. Immature
compost immobilized N and caused reversion of available N to the
unavailable form. Nitrate-N concentrations in immature compost-amended
soils were lower than levels of the control soil.
Chloride, sulfate., boron, potassium, calcium, and magnesium were
readily leached. The concentration of these ions in leachate
increased with increasing compost application. The
concentrations of Cu and Zn in leachate obtained from low
application rate treatments were comparable to the controls. At
high application rates these metals increased in the leachate
compared to the control. The heavy metals Zn and Cu were detected
in subsoil leachate at concentrations slightly higher than the
control soil leachate. The metals Ni, Cr, Pb, and Cd were
effectively tied up in the application zone. A combination of
organic matter, increase in pH, and CEC from compost amendments
may be responsible for immobilizing heavy metals. At
conservative application rates of 40 tons/acre, the impact to
ground water should be negligible for the compounds studied.