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Increased Denitrification in Soils by Additions of Sulfur as an Energy Source
Author(s) -
Mann L. D.,
Focht D. D.,
Joseph H. A.,
Stolzy L. H.
Publication year - 1972
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/jeq1972.00472425000100030030x
Subject(s) - loam , denitrification , nitrate , soil water , chemistry , sulfur , environmental chemistry , nitrite , anoxic waters , nitrogen , soil science , environmental science , organic chemistry
Abstract Denitrification rates were studied in four large soil columns using Hanford sandy loam and Moreno silty clay loam soils. One column of each soil was amended with sulfur to serve as an energy source for the bacterium Thiobacillus denitrificans. Limestone was also added as a pH buffer. The other column of each soil was left untreated to serve as a control. A solution of Ca(NO 3 ) 2 containing 425 ppm NO 3 ‐N was perfused continuously through the columns. The columns were monitored periodically at depths of 10, 30, 50, 70, and 90 cm for nitrate, nitrite, redox potential (E h ) and microbial numbers. Highly anaerobic conditions developed in all columns as was evidenced by low E h values at each depth. All of the nitrate was reduced in each column, and nitrates penetrated to lower depths in the untreated columns. Nitrite concentrations were found to be negligible. Denitrification rate constants were established as 0.174, 0.520, 0.186, and 1.426 days −1 , for the Hanford‐untreated, Hanford‐treated, Morneo‐untreated, and Moreno‐treated columns, respectively. Sulfur additions to field soils which are low in microbial energy sources could be an effective method of reducing the nitrate level in waters percolating through the profile.