摘要 Water erosion is the major reason for the loss of soil organic carbon in the Northeast China, which leads to the soil quality deterioration and adjacent water pollution. In this study, the effect of extraction temperature, pH value, and salt on the water extractable organic matter (WEOM) was determined by means of the UV absorbance, fluorescence excitationemission matrix, and derived fluorescence indexes. In general, the carbon content and aromaticity of WEOM increased with the increasing of extraction temperature, with the exception that there was no significant difference in the amount at 0 and 20°C. More fluorophores, especially microbially-derived organic matter were extracted at high temperature. The pH values of extractant, including 5, 7, and 10, showed no effect on the carbon amount of WEOM, whereas the aromaticity and microbially-derived component gradually increased with the increasing of pH values. The fluorescence intensity of humic acid-like fluorophore was stronger in neutral and alkali condition than that in acidic condition. The addition of 10 mmol L-1 CaCl2 significantly decreased the carbon amount of recovered WEOM. Moreover, it significantly decreased the aromaticity of WEOM and the quantity of fulvic acid-like and humic acid-like fluorophores, whereas increased the percentage of tyrosine-like and tryptophan-like fluorophores in the total fluorophores and the amount of microbially-derived organic matter. Generally, 10 mmol L-1 KCl showed the same influence trend, but with low influence degree.
Abstract Water erosion is the major reason for the loss of soil organic carbon in the Northeast China, which leads to the soil quality deterioration and adjacent water pollution. In this study, the effect of extraction temperature, pH value, and salt on the water extractable organic matter (WEOM) was determined by means of the UV absorbance, fluorescence excitationemission matrix, and derived fluorescence indexes. In general, the carbon content and aromaticity of WEOM increased with the increasing of extraction temperature, with the exception that there was no significant difference in the amount at 0 and 20°C. More fluorophores, especially microbially-derived organic matter were extracted at high temperature. The pH values of extractant, including 5, 7, and 10, showed no effect on the carbon amount of WEOM, whereas the aromaticity and microbially-derived component gradually increased with the increasing of pH values. The fluorescence intensity of humic acid-like fluorophore was stronger in neutral and alkali condition than that in acidic condition. The addition of 10 mmol L-1 CaCl2 significantly decreased the carbon amount of recovered WEOM. Moreover, it significantly decreased the aromaticity of WEOM and the quantity of fulvic acid-like and humic acid-like fluorophores, whereas increased the percentage of tyrosine-like and tryptophan-like fluorophores in the total fluorophores and the amount of microbially-derived organic matter. Generally, 10 mmol L-1 KCl showed the same influence trend, but with low influence degree.
LI Ming-tang, ZHAO Lan-po , ZHANG Jin-jing.
2013.
Effect of Temperature, pH and Salt on Fluorescent Quality of Water Extractable Organic Matter in Black Soil. Journal of Integrative Agriculture, 12(7): 1251-1257.
[1]Abraham T. 2002. Effects of divalent salt on adsorptionkinetics of a hydrophobically modified polyelectrolyteat the neutral surface-aqueous solution interface.Polymer, 43, 849-855
[2]Akagi J, Zsolnay A. 2008. Effects of long-term devegetationon the quantity and quality of waterextractable organic matter (WEOM): biogeochemicalimplications. Chemosphere, 72, 1462-1466
[3]Chantigny M H. 2003. Dissolved and water-extractableorganic matter in soils: a review on the influence ofland use and management practices. Geoderma, 113,357-380
[4]Chen W, Westerhoff P L, Leenheer J A, Booksh K. 2003.Fluorescence excitation-emission matrix regionalintegration to quantify spectra for dissolved organicmatter. Environmental Science & Technology, 37,5701-5710
[5]Dudal Y, Hologado R, Maestri G, Guillon E, Dupont L. 2006.Rapid screening of DOM’s metal-binding ability usinga fluorescence-based microplate assay. Science of theTotal Environment, 354, 286-291
[6]Fontaine S, Barot S, Barré P, Bdioui N, Mary B, Rumpel C.2007. Stability of organic carbon in deep soil layerscontrolled by fresh carbon supply. Nature, 450, 277-281
[7]Guggenberger G, Zech W, Shulten H R. 1994. Formationand mobilization pathways of dissolved organic matter:evidence from chemical structural studies of organicmatter fractions in acid forest floor solutions. OrganicGeochemistry, 21, 51-66
[8]Hassouna M, Massiani C, Dudal Y, Pech N, Theraulaz F.2010. Changes in water extractable organic matter(WEOM) in a calcareous soil under field conditionswith time and soil depth. Geoderma, 155, 75-85
[9]Kalbitz K. 2001. Properties of organic matter in soil solutionin a German fen area as dependent on land use anddepth. Geoderma, 104, 203-214
[10]Huguet A, Vacher L, Relexans S, Saubusse S, Froidefond JM, Parlanti E. 2009. Properties of fluorescent dissolvedorganic matter in the Gironde estuary. OrganicGeochemistry, 40, 706-719
[11]Landgraf D, Leinweber P, Makeschin F. 2006. Cold andhot-water-extractable organic matter as indicators oflitter decomposition in forest soils. Journal of PlantNutrition and Soil Science, 169, 76-82
[12]Li F S, Yuasa A, Ebie K, Azuma Y, Hagishita T, Matsui Y.2002. Factors affecting the adsorption capacity ofdissolved organic matter onto activated carbon: modifiedisotherm analysis. Water Research, 36, 4592-4604
[13]Marschner B, Kalbitz K. 2003. Controls of bioavailabilityand biodegradability of dissolved organic matter insoils. Geoderma, 113, 211-235
[14]McKnight D M, Boyer E W, Westerhoff P K, Doran P T,Kulbe T, Andersen D T. 2001. Spectrofluorometriccharacterization of dissolved organic matter forindication of precursor organic material and aromaticity.Limnology & Oceanography, 46, 38-48
[15]Mikutta R, Mikutta C, Kalbitz K, Scheel T, Kaiser K, JahnR. 2007. Biodegradation of forest floor organic matterbound to minerals via different binding mechanisms.Geochimica et Cosmochimica Acta, 71, 2569-2590
[16]Peng J M, Headley J V, Barbour S L. 2002. Adsorption ofsingle-ring model naphthenic acids on soils. CanadianGeotechnical Journal, 39, 1419-1426
[17]Römkens P F A M, Dolfing J. 1998. Effect of Ca on thesolubility and molecular size distribution of DOC andCu binding in soil solution samples. EnvironmentalScience and Technology, 32, 363-369
[18]Seremesic S, Milosev D, Djalovic I, Zeremski T, Ninkov J.2011. Management of soil organic carbon in maintainingsoil productivity and yield stability of winter wheat.Plant, Soil and Environment, 57, 216-221
[19]Sierra M M D, Giovanela M , Parlanti E, Soriano-Sierra E J.2005. Fluorescence fingerprint of fulvic and humic acidsfrom varied origins as viewed by single-scan andexcitation/emission matrix techniques. Chemosphere,58, 715-733
[20]Wu Q Y, Hu H Y, Zhao X, Li Y. 2010. Effects of chlorinationon the properties of dissolved organic matter and itsgenotoxicity in secondary sewage effluent under twodifferent ammonium concentrations. Chemosphere, 80,941-946
[21]Zhang J J, Dou S, Song X Y. 2009. Effect of long-termcombined nitrogen and phosphorus fertilizer applicationon 13C CPMAS NMR spectra of humin in a TypicHapludoll of northeast China. European Journal of SoilScience, 60, 966-973.
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