An automatic time domain reflectometry device to measure and store soil moisture contents for stand-alone held use
H.G.M. van 1
J. Kokot 2
W. Skierucha 2
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DLO Winand Staring Centre for Integrated Land, Soil and Water Research, Soil Physics Laboratory P.O. Box 125, NL-6700 AC Wageningen, The Netherlands
Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4,20-236 Lublin, Poland
Int. Agrophys. 1995, 9(3): 235–241
A field setup was developed to measure soil moisture content on ten different positions using the Time Domain Reflectometry (TDR) technique. The setup has been designed to meet specific field demands, such as a complete independency of an external power source, a low power consumption, long-term use without the need for maintenance, and compact dimensions. The system consists of a microprocessor driven TDR instrument connected to a palmtop computer through a serial RS232 communications line. The system is controlled from the palmtop computer incorporated in the design. Type of measurement, such as water content, dielectric constant or pulse travel time can be chosen. Also, the measuring interval can be selected between one minute and twenty-four hours in one minute intervals. Data retrieval from the system is reduced to simply exchanging the PCMCIA memory-card from the palmtop computer. The system is powered by a 12V battery/solar panel system. During the first tests a number of errors in the software were found and a problem with the power supply was detected and was subsequently put right.