2011 Rukshana BFSO 47,51.pdf (461.11 kB)
Model organic compounds differ in their effects on pH changes of two soils differing in initial pH
journal contribution
posted on 2021-01-06, 00:37 authored by F Rukshana, CR Butterly, JA Baldock, Caixian TangCaixian TangThe mechanisms by which organic materials affect soil pH are not fully understood. This study for the first time compared the short-term effect of various model organic compounds on pH change of two soils differing in initial pH (Podosol of pH 4. 4 and Tenosol of pH 6. 1). Eight organic compounds, representing common compounds in plant residues, were selected based on the number and type of chemical functional groups. The addition of organic acids (acetic, malic, citric, and benzoic acid) reduced soil pH immediately due to H+ dissociation. The magnitude of pH decrease depended on the rate of application, degree of dissociation of the acids, and initial soil pH. During a subsequent incubation, pH was slowly restored as these compounds were decomposed. The degree to which pH was restored was reduced with increasing addition rate. The production of H+ ions was increased with increasing rate of acid addition and decreased over time. When potassium citrate (organic anion) was added, soil pH increased due to H+ consumption upon decomposition. Compounds with amine groups (glucosamine hydrochloride) and less easily decomposable compounds (phenol) did not significantly alter pH during 16-day shaking. Changes in pH after glucose addition were relatively small compared with other compounds and were not expected because hydroxyl chemical groups of glucose are neutral. The present study demonstrated that the addition of model organic compounds to soil caused soil pH to increase, decrease, or remains unaffected. The extent and direction of pH change was dependent on the chemical functional group, addition rate, decomposition, and the initial soil pH. © 2010 Springer-Verlag.
Funding
This work was supported by the Australian Research Council (Discovery project DP0877882) and the National Natural Science Foundation of China (40728001). We are grateful to Dr. Helen Hayden for reviewing the manuscript and Ms. Giang Nguyen (Jenny) for technical assistance.
History
Publication Date
2011-01-01Journal
Biology and Fertility of SoilsVolume
47Issue
1Pagination
(p. 51-62)Publisher
SPRINGERISSN
0178-2762Rights Statement
The Author reserves all moral rights over the deposited text and must be credited if any re-use occurs. Documents deposited in OPAL are the Open Access versions of outputs published elsewhere. Changes resulting from the publishing process may therefore not be reflected in this document. The final published version may be obtained via the publisher’s DOI. Please note that additional copyright and access restrictions may apply to the published version.Publisher DOI
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Science & TechnologyLife Sciences & BiomedicineSoil ScienceAgricultureOrganic compoundPlant residues.Association/dissociationInitial soil pHFunctional groupAddition rateDecompositionMICROBIAL BIOMASSRESIDUE DECOMPOSITIONCHEMICAL-COMPOSITIONNITROGENACIDIFICATIONACIDITYMATTERCARBONNEUTRALIZATIONRHIZOSPHEREAgronomy & Agriculture