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Kinetics of Sulfate Desorption from Soil
Author(s) -
Sharpley Andrew N.
Publication year - 1990
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1990.03615995005400060010x
Subject(s) - desorption , surface runoff , soil water , chemistry , sulfate , soil science , environmental chemistry , environmental science , hydrology (agriculture) , adsorption , geology , ecology , geotechnical engineering , organic chemistry , biology
Sulfate desorption and mobility in soil can be of both environmental and agronomic importance. This study was conducted to describe the desorption of SO 4 from agricultural soils under experimental conditions applicable to the movement of SO 4 in overland flow and runoff waters. The kinetics of SO 4 desorption from soil were investigated at five different water/soil ratios (10:1–400:1), five time periods (5–180 min), and four SO 4 additions (0–200 mg kg −1 ). Sulfate desorption (S d ) was logarithmically related to contact time ( t ) and water/soil ratio ( W ) and was a linear function of the initial extractable SO 4 content of soil ( S e ). The kinetics of SO 4 desorption was described by the equation S d = K S e t α W β , where K , α, and β are constants for a given soil. This equation has previously been shown to describe desorption of soil P and K. The kinetic constants, K ( r 2 = 0.88), α ( r 2 = 0.83), and β ( r 2 = 0.88), were related to extractable soil Al content for 107 U.S. soils. The uniformity of equation constants for a given soil and the ease with which they can be estimated from extractable soil Al indicate the potential use of the equation in modeling SO 4 desorption from soil and subsequent movement in surface runoff water.