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Phosphorus speciation in biosolids-amended soils : correlating phosphorus desorption, sequential chemical extractions, and phosphorus-xanes spectroscopy

dc.contributor.advisorPeak, J. Dereken_US
dc.contributor.committeeMemberNiu, Catherineen_US
dc.contributor.committeeMemberde Freitas, Renatoen_US
dc.contributor.committeeMemberBelanger, Nicolasen_US
dc.contributor.committeeMemberSchoenau, Jeffrey J. (Jeff)en_US
dc.creatorKar, Gourangoen_US
dc.date.accessioned2007-11-21T16:52:31Zen_US
dc.date.accessioned2013-01-04T05:08:54Z
dc.date.available2008-12-03T08:00:00Zen_US
dc.date.available2013-01-04T05:08:54Z
dc.date.created2007en_US
dc.date.issued2007en_US
dc.date.submitted2007en_US
dc.description.abstractThis study was conducted to compare the speciation and behavior of P in soils receiving either different biosolids or inorganic fertilizer, as assessed by sequential chemical extractions, phosphate desorption, and synchrotron X-ray absorption near edge structure (XANES) spectroscopy. The objectives of this study were to i) measure the total amount of organic and inorganic phosphorus removed by chemical extraction method ii) investigate how P desorption kinetics are influenced in biosolids amended soils compared to inorganic fertilizer amended soils; and iii) perform solid state speciation of soil samples before and after chemical extraction and desorption with P K-edge XANES spectroscopy. Soil samples were analyzed that received three different rates of biosolids (16.8, 33.6, and 67.2 Mg ha-1 yr-1) and one inorganic fertilizer application (336 kg N, 224 kg P, and 112 kg K ha-1 yr-1) for 32 years. Both sequential chemical extraction and XANES analysis showed that total amount of P increased in biosolids amended soils (from 5292 to 10945 mg P kg-1) and that it increased with increasing application rate. Sequential chemical extractions showed that the labile portion of total P in inorganic fertilized soil (40 %) was larger than in biosolids applied soils (39 to 27 %). Results from both sequential chemical extraction and XANES analysis showed that NaOH extraction removed the highest amount of P from all biosolids applied soils (from 1857 to 2600 mg P kg-1). The amount of desorbed P decreased as the soil:solution ratio increased from 0.005 to 100 g L-1 for both soils and the desorption was typically higher in inorganic fertilizer applied soil than in biosolids applied soil. The effect of pH on P desorption was pronounced, and desorption was higher at pH 5 than pH 7.5 for both soils. A continuous flow desorption method was also used to measure cumulative P desorption over time. Cumulative P desorption in inorganic fertilizer applied soil (894.5 mg P kg-1) was higher than in the biosolids amended soils (572.9 mg P kg-1) over 20 hr period time. First-order and parabolic diffusion kinetic equations were used to model the desorption data from the continuous flow technique. This revealed that the P desorption rate was faster (and chemically-controlled) at initial stages and slower (and diffusion-limited) at later stages. The desorption rate was much faster in inorganic fertilizer applied soil than in biosolids applied soil.XANES analysis of the fractions removed in sequential chemical extractions suggested that the predominant form of P was poorly crystalline dicalcium phosphate in biosolids applied soils, and labile, sorbed forms as well as some apatite-type calcium phosphate was present in inorganic fertilizer applied soil. The combined results from sequential chemical extraction and XANES analysis indicate that P in inorganic fertilizer and biosolids-applied soils behave differently. There were larger amounts of low crystallinity phosphates in the biosolids samples, and much higher apatite content in the inorganic fertilizer amended soil.en_US
dc.identifier.urihttp://hdl.handle.net/10388/etd-11212007-165231en_US
dc.language.isoen_USen_US
dc.subjectBiosolidsen_US
dc.subjectP XANES spectroscopyen_US
dc.titlePhosphorus speciation in biosolids-amended soils : correlating phosphorus desorption, sequential chemical extractions, and phosphorus-xanes spectroscopyen_US
dc.type.genreThesisen_US
dc.type.materialtexten_US
thesis.degree.departmentSoil Scienceen_US
thesis.degree.disciplineSoil Scienceen_US
thesis.degree.grantorUniversity of Saskatchewanen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Science (M.Sc.)en_US

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