Desempenho metrológico de TDR para medição da concentração de potássio na solução do solo

Translated title of the contribution: Metrological assessment of TDR performance for measurement of potassium concentration in soil solution

Isaac de M. Ponciano, Jarbas H.D. de Miranda, Richard A. Cooke, Vanessa de F. Grah, Alisson J.P. da Silva

Research output: Contribution to journalArticlepeer-review

Abstract

Despite the growing use of the time domain reflectometry (TDR) technique to monitoring ions in the soil solution, there are few studies that provide insight into measurement error. To overcome this lack of information, a methodology, based on the central limit theorem error, was used to quantify the uncertainty associated with using the technique to estimate potassium ion concentration in two soil types. Mathematical models based on electrical conductivity and soil moisture derived from TDR readings were used to estimate potassium concentration, and the results were compared to potassium concentration determined by flame spectrophotometry. It was possible to correct for random and systematic errors associated with TDR readings, significantly increasing the accuracy of the potassium estimation methodology. However, a single TDR reading can lead to an error of up to ± 18.84 mg L-1K+in soil solution (0 to 3 dS m-1), with a 95.42% degree of confidence, for a loamy sand soil; and an error of up to ± 12.50 mg L-1of K+ (0 to 2.5 dS m-1) in soil solution, with a 95.06% degree of confidence, for a sandy clay soil.

Translated title of the contributionMetrological assessment of TDR performance for measurement of potassium concentration in soil solution
Original languagePortuguese
Pages (from-to)343-349
Number of pages7
JournalRevista Brasileira de Engenharia Agricola e Ambiental
Volume20
Issue number4
DOIs
StatePublished - Apr 2016

Keywords

  • Central limit theorem
  • Electrical conductivity
  • Instrumentation

ASJC Scopus subject areas

  • Environmental Engineering
  • Agronomy and Crop Science

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