Time Domain Reflectometry Calibration for Typical Upland Soils in Kyushu, Japan

JARQ : Japan Agricultural Research Quarterly
ISSN 00213551
書誌レコードID(総合目録DB) AA0068709X
40-03-05.pdf355.34 KB

Time Domain Reflectometry (TDR) has recently become popular as a method to measure soil water content. An empirical Topp′s equation and some dielectric mixing functions are often used as calibration curves of TDR. This review describes the Topp′s equation and dielectric mixing models. In addition, applicability of Topp′s equation and some dielectric mixing models for the θ-ε relationships for typical upland soils (two types of Ando soils, Red-yellow soils, two types of Brown forest soils, and Toyoura sand) are discussed. Following are several remarks that are stressed on TDR: (1) The empirical Topp′s equation underestimates soil water content for mineral soils of low bulk density. (2) Since dielectric mixing models described the effect of bulk density on the calibration curve, they could be more suitable than the Topp′s equation for the experimented soils. (3) Judging from the fitness of the whole curve, the third-order polynomial regressions and α model were superior to the Maxwell-De Loor model, which has no parameter to be identified. (4) The Maxwell-De Loor model was found to be so flexible that it reasonably fitted with measured data for different types of soil.


dielectric permittivity

electromagnetic wave

mixing model

soil water content

公開者 Japan International Research Center for Agricultural Sciences
国立情報学研究所メタデータ主題語彙集(資源タイプ) Journal Article
開始ページ 225
終了ページ 231
DOI 10.6090/jarq.40.225
権利 Japan International Research Center for Agricultural Sciences
言語 eng