Models for moisture estimation in different horizons of yellow argisol using TDR

Authors

  • Karla Silva Santos Alvares de Almeida Universidade Federal do Recôncavo da Bahia
  • Luciano da Silva Souza Universidade Federal do Recôncavo da Bahia
  • Vital Pedro da Silva Paz Universidade Federal do Recôncavo da Bahia
  • Maurício Antônio Coelho Filho Empresa Brasileira de Pesquisa Agropecuária
  • Eduardo Holzapfel Hoces Universidad de Concepción

DOI:

https://doi.org/10.5433/1679-0359.2017v38n4p1727

Keywords:

Apparent dielectric constant, Soil water content, TDR calibration.

Abstract

The determination of soil moisture is very important because it is the property with the most influence on the dielectric constant of the medium. Time-domain reflectometry (TDR) is an indirect technique used to estimate the water content of the soil (?) based on its dielectric constant (Ka). Like any other technique, it has advantages and disadvantages. Among the major disadvantages is the need for calibration, which requires consideration of the soil characteristics. This study aimed to perform the calibration of a TDR100 device to estimate the volumetric water content of four horizons of a Yellow Argisol. Calibration was performed under laboratory conditions using disturbed soil samples contained in PVC columns. The three rods of the handcrafted probes were vertically installed in the soil columns. Weight measurements with digital scales and daily readings of the dielectric constant with the TDR device were taken. For all soil horizons evaluated, the best fits between the dielectric constant and the volumetric water content were related to the cubic polynomial model. The Ledieu model overestimated by approximately 68 % the volumetric water content in the A and AB horizons, and underestimating by 69 % in Bt2, in relation to volumetric water content obtained by gravimetry. The underestimation by linear, Topp, Roth, and Malicki models ranged from 50 % to 85 % for all horizons.

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Author Biographies

Karla Silva Santos Alvares de Almeida, Universidade Federal do Recôncavo da Bahia

Drª em Engenharia Agrícola, Universidade Federal do Recôncavo da Bahia, UFRB, Cruz das Almas, BA, Brasil.

Luciano da Silva Souza, Universidade Federal do Recôncavo da Bahia

Prof., UFRB, Cruz das Almas, BA, Brasil.

Vital Pedro da Silva Paz, Universidade Federal do Recôncavo da Bahia

Prof., UFRB, Cruz das Almas, BA, Brasil.

Maurício Antônio Coelho Filho, Empresa Brasileira de Pesquisa Agropecuária

Pesquisador, Empresa Brasileira de Pesquisa Agropecuária, Embrapa Mandioca e Fruticultura, Cruz das Almas, BA, Brasil.

Eduardo Holzapfel Hoces, Universidad de Concepción

Prof., Universidad de Concepción, UDEC, Chillán, CL, Chile.

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Published

2017-08-04

How to Cite

Almeida, K. S. S. A. de, Souza, L. da S., Paz, V. P. da S., Coelho Filho, M. A., & Hoces, E. H. (2017). Models for moisture estimation in different horizons of yellow argisol using TDR. Semina: Ciências Agrárias, 38(4), 1727–1736. https://doi.org/10.5433/1679-0359.2017v38n4p1727

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