scholarly journals Determination of soil water content using time domain reflectometer (TDR) for clayey soil

Author(s):  
N. H. H. Abdullah ◽  
N. W. Kuan ◽  
A. Ibrahim ◽  
B. N. Ismail ◽  
M. R. A. Majid ◽  
...  
1989 ◽  
Vol 69 (3) ◽  
pp. 701-704 ◽  
Author(s):  
G. C. TOPP ◽  
J. L. B. CULLEY

Determination of volumetric soil water content (θ) using time domain reflectometry (TDR) is well established. A commercially available instrument (IRAMS) (the IRAMS (Instrument for Reflectometry Analysis of Moisture in Soils) is a trademark registered by Foundation Instruments Inc. of Ottawa) is now available which incorporates computer software, thus providing direct readouts of θ. A field study of the operation of the IRAMS showed that it operates consistently and repeatedly. The IRAMS values were higher but related linearly to those obtained using a TDR cable tester and manual calculations of travel times. A linear correction of the IRAMS readings is proposed and possible causes are suggested for the observed deviations from expected values. Key words: Time domain, reflectometry, soil water content, field


1997 ◽  
Vol 7 (1) ◽  
pp. 17-22 ◽  
Author(s):  
P. Parchomchuk ◽  
R.G. Berard ◽  
C.S. Tan

We have found time domain reflectrometry (TDR) to be a rapid and effective method of measuring soil water content (SWC) in microirrigated orchards, particularly in applications where many sites are monitored frequently. With simple modifications to commercially available systems, it has been possible to measure up to 100 sites per hour. TDR SWC measurements have been successfully applied for scheduling irrigation and for in situ determination of SWC characteristics. The determination of plant water use from changes in SWC of microirrigated trees, however, requires that a sufficient number of probes be used to detect the spatial distribution of water within the root zone. Due to water redistribution in the soil following an irrigation, measurements made near drip emitters depend highly on the time after irrigation that the measurement is made. It is therefore important to be consistent in the timing of SWC measurements relative to irrigation events if the effects on SWC of different irrigation management practices are to be compared.


Soil Science ◽  
2010 ◽  
Vol 175 (10) ◽  
pp. 469-473 ◽  
Author(s):  
Zhaoqiang Ju ◽  
Xiaona Liu ◽  
Tusheng Ren ◽  
Chunsheng Hu

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