Evaluation of Phosphate Ion-Selective Membranes for Real-time Soil Nutrient Sensing

dc.contributor.author Kim, Hak-Jin
dc.contributor.author Hummel, John
dc.contributor.author Birrell, Stuart
dc.contributor.author Sudduth, Kenneth
dc.contributor.department Agricultural and Biosystems Engineering
dc.date 2018-02-14T16:16:05.000
dc.date.accessioned 2020-06-29T22:34:09Z
dc.date.available 2020-06-29T22:34:09Z
dc.date.embargo 2014-09-19
dc.date.issued 2005-07-01
dc.description.abstract <p>A real-time soil nutrient sensor would allow the efficient collection of data with a fine spatial resolution, to accurately characterize within-field variability for site-specific nutrient application. Our goal was to evaluate the applicability of a phosphate membrane to the measurement of phosphate levels in soil extractants and to determine how previously developed nitrate and potassium membranes would be affected by the presence of phosphate. A type of PVC-based phosphate membrane containing an organotin compound, bis(p-chlorobenzyl)tin dichloride, was evaluated, along with the nitrate and potassium membranes, in pH 7 Tris buffer solution and Kelowna soil extractant for sensitivity and long-term stability. The phosphate membranes in the Tris buffer solution of pH 7 exhibited a response over a range of 10-5 to 10-1 mol/L phosphate concentrations with an average slope of -28.2 +1.5 mV per activity decade of dibasic phosphate. The response speed of tested electrodes containing phosphate, nitrate and potassium membranes was rapid, reaching an equilibrium response in less than 15 s. However, the phosphate membrane in the Kelowna solution of pH 8.5 was almost insensitive to different phosphate levels from 10-6 to 10-2 mol/L due to the presence of a high concentration of fluoride in the solution. In addition, the tin compound-based phosphate membranes had limited lifetimes of less than 14 days. It is not expected that the tested phosphate membranes could be used for phosphate detection in other soil extractants, such as Bray P1 and Mehlich III solutions, because they also contain high concentrations of fluoride.</p>
dc.description.comments <p>Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.</p>
dc.identifier archive/lib.dr.iastate.edu/abe_eng_conf/409/
dc.identifier.articleid 1414
dc.identifier.contextkey 6141854
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath abe_eng_conf/409
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/438
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/abe_eng_conf/409/2005_Kim_EvaluationPhosphate.pdf|||Sat Jan 15 00:08:57 UTC 2022
dc.source.uri 10.13031/2013.18833
dc.subject.disciplines Agriculture
dc.subject.disciplines Bioresource and Agricultural Engineering
dc.subject.disciplines Soil Science
dc.subject.keywords ion-selective membranes
dc.subject.keywords ion-selective electrode (ISE)
dc.subject.keywords soil testing
dc.subject.keywords phosphate
dc.subject.keywords soil extractants
dc.subject.keywords Kelowna
dc.subject.keywords sensitivity
dc.subject.keywords response time
dc.title Evaluation of Phosphate Ion-Selective Membranes for Real-time Soil Nutrient Sensing
dc.type article
dc.type.genre conference
dspace.entity.type Publication
relation.isAuthorOfPublication 1fd6ff71-dbea-4ada-9267-f9ff2ce1caba
relation.isOrgUnitOfPublication 8eb24241-0d92-4baf-ae75-08f716d30801
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