Oxidation rate of pyrite in acid sulfate soils: in situ measurements and modelling

• DOI: 10.1071/sr03091
• Publication Date: 2004-09-20T06:45:15Z
• Authors: F. J. Cook; S. K. Dobos; G. D. Carlin; G. E. Millar
• Keywords: Sink (geography); Limiting oxygen concentration

The generation of acidity from oxidation pyrite in acid sulfate soils requires the transport oxygen into soil profile. sink for this will not only be chemical reaction with but biological processes associated both microbial and plant respiration. sinks burning (O2) release CO2. respiratory quotient which is molar volume ratio O2 : CO2 varies between 1.3 0.7 depending on source organic matter being oxidised, generally 1.0. by will, comparison processes, produce minor amounts (if any) intrinsic carbonate minerals. Gas samplers were installed at various depths samples collected these approximately fortnightly intervals. analysed gas chromatography profiles obtained. flux gases was calculated difference attributed to pyrite. varied over period sampling average gave an situ rate 11.5 tonnes H2SO4/ha.year. This considerably more that export site would explain considerable actual storage soils. A model developed steady state exponentially decreasing depth increasing (pyrite) depth. non-dimensional variables, allows relative strengths rates increase or decrease terms explored. does explicitly treat flow macropores. Other models do calculate macropore are compared found give similar results. These results suggest use other near surface could a useful method reducing