Calculation of Bulk and Solution Electrical Conductivity of Soil Using Time Domain Reflectometry Measurements

TDR을 이용한 토양 총전기전도도 및 용액전기전도도 측정

  • Bae, Byung-Sul (School of Agricultural Biotechnology, Seoul National University) ;
  • Choi, Woo-Jung (School of Agricultural Biotechnology, Seoul National University) ;
  • Han, Gwang-Hyun (School of Agricultural Biotechnology, Seoul National University) ;
  • Han, Kyung-Hwa (School of Agricultural Biotechnology, Seoul National University) ;
  • Yoo, Sun-Ho (School of Agricultural Biotechnology, Seoul National University) ;
  • Ro, Hee-Myong (School of Agricultural Biotechnology, Seoul National University)
  • 배병술 (서울대학교 농생명공학부) ;
  • 최우정 (서울대학교 농생명공학부) ;
  • 한광현 (서울대학교 농생명공학부) ;
  • 한경화 (서울대학교 농생명공학부) ;
  • 류순호 (서울대학교 농생명공학부) ;
  • 노희명 (서울대학교 농생명공학부)
  • Received : 2002.12.17
  • Accepted : 2003.01.03
  • Published : 2003.02.28


Time domain reflectometry (TDR) is a newly developed method for measuring simultaneously solute concentrations and volumetric water content of soil. Bulk electrical conductivity ($EC_a$) of soil is obtained from TDR signal using several equations proposed, and electrical conductivity of soil solution ($EC_w$) can be calculated using the linear relationship $EC_a=EC_w\theta(a\theta+b)+EC_s$ between $EC_a$ and $EC_w$ at constant soil water content. The objectives of this study were to evaluate $EC_a$ proposed by several workers and to obtain the empirical constants (a, b, and $EC_s$) for $EC_w$ of the soils from A, Bl, and B2 horizon of an agricultural field (Coarse loamy, Fluvaquentic Eutrudepts). The $EC_a$ proposed by Yanuka et al. responded most sensitively to the KCl solute concentrations. The empirical constants of a, b, and $EC_s$ for $EC_w$ were -0.249, 1.358, and 0.054 for A horizon, -2.518, 2.708, and 0.097 for Bl horizon, and 2.490, -0.250, and 0.103 for B2 horizon, respectively. Therefore, the results of this study showed that Yanuka et al. equation was most useful one in determining $EC_a$, from TDR signal for agricultural soil with low salinity and that the empirical constants for the calculation of $EC_w$, from $EC_a$ can be obtained through a simple calibration experiment.


Supported by : Korea Science and Engineering Foundation


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