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Heavy Applications of Liquid‐Digested Sludge on Three Ultisols: I. Effects on Soil Chemistry
Author(s) -
Robertson W. K.,
Lutrick M. C.,
Yuan T. L.
Publication year - 1982
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1982.00472425001100020026x
Subject(s) - organic matter , loam , ultisol , chemistry , environmental chemistry , soil organic matter , extraction (chemistry) , soil water , soil test , sewage sludge , dry matter , environmental science , soil science , zoology , sewage treatment , environmental engineering , chromatography , organic chemistry , biology
The quantities of municipal wastes are so large that croplands have been considered as possible sinks for their disposal. In this study large amounts of liquid‐digested sludge were applied to the soil. The accumulation and distribution of its constituents in the soil profile were studied. The sludge contained 2.6 and 3.0% dry matter and very little Cd and other toxic metals. Liquid sludge equivalent to 0, 87, 174, 241, 288, and 335 metric tons/ha of dry matter was applied to each of three Paleudults (Orangeburg fine sand loam [fsl], Lucy fsl, and Troup fsl) over a 6‐year period. Soil samples, to a depth of 150 cm, were obtained 1 year after the last sludge application to determine nutrient and organic matter movement. Sludge applications increased soil organic matter to a depth of 90 cm in Orangeburg fsl and Troup fsl, but had no consistent effect on Lucy fsl. About 50% of the applied organic matter was oxidized, forming acids that lowered the soil pH. Double acid extraction of Orangeburg fsl indicated that Ca, Mg, and to some extent K, moved below the 90‐cm depth of the soil profile. Lesser amounts leached from the 90‐ to 120‐cm layer, and no detectable amounts leached from the 120‐ to 150‐cm layer. Extractable Fe and Al increased to the 90‐cm depth. Extractable Cu remained in the top 30 cm and Zn in the top 90 cm of the profile. Similar results were found in a 5 N HCl digest except that P was significantly increased by sludge application and accumulated largely in the surface soil.