TDR probe for estimating soil water content and bulk electrical conductivity by using multiplexers

Revista Brasileira de Engenharia Agrícola e Ambiental

Coelho Filho, Maurício A.¹  Coelho, Eugênio F.¹  Vellame, Lucas M.² 

[1] Embrapa Mandioca e Fruticultura, Cruz das Almas;UFBA, Cruz das Almas

关键词: calibration;    time domain reflectometry;    soil water content    INTRODUÇÃO A TDR (Reflectometria no Domínio do Tempo) vem sendo cada vez mais utilizada para determinação da umidade do solo em pesquisas de manejo e conservação da água e do solo;   

DOI  :  10.1590/S1415-43662005000400006

学科分类：农业科学（综合）

来源: Universidade Federal de Campina Grande * Centro de Ciencias e Tecnologia

【 摘 要 】

This work had as objective the characterization and the evaluation of TDR probes for estimating soil water content and bulk electrical conductivity. The probes were built to be used directly with the TDR 100 or to be connected to multiplexers. The probes were evaluated for two kinds and various lengths (4 to 19 m) of co-axial cables. The K parameters of Giese-Tieman equation and the probe impedance were determined. The TDR probes were tested for different soil electrical conductivity, under different soil water contents and temperatures. The use of a resistor of 15 W connecting the inner wire to the central rod of the TDR probe is necessary for estimating soil water content and bulk electrical conductivity by TDR. The co-axial cable of larger grounding mesh thickness and larger inner wire diameter was most adequate for use with the TDR probes. The use of multiplexers and co-axial cables up to 13 m length (from TDR to the probe) did not affect significantly water content estimates. The TDR probes of 0.10 and 0.15 m length performed quite well in estimating soil electrical conductivity up to 1.0 dS m-1.

【 授权许可】

CC BY-NC