Instrument for measuring soil moisture and conductivity based on phase detection and measuring method thereof

Abstract

The invention provides an instrument for measuring the soil moisture and conductivity based on phase detection, comprising a signal generator, a circulator, a delayer, a phase detector, a wave detector and a microprocessor. The invention adopts sinusoidal signals with single frequency to substitute phase step signals, converts the phase difference between incidence signals and reflection signals into direct-current voltage signals in direct proportion by adopting the phase detector; the broadcast time of electromagnetic wave on a probe can be obtained by measuring the direct-current voltage signal; the wave detector rectifies the reference signals and reflection signals to obtain the voltage amplitude and transmit the voltage amplitude to an analog-digital converter and further obtain the soil moisture and the conductivity by calibration. As expensive rapid phase step signal generators and high-frequency sampling osilloscopes are not adopted, the invention greatly reduces the cost and lowers the technical difficulty. The technical performance is equivalent to the similar instrument abroad while the cost is only 50 percent of the foreign products. In addition, the invention also provides a method for measuring the soil moisture and / or the conductivity by using the measuring instrument.

Description

technical field [0001] The invention relates to the field of measurement technology, in particular to a soil moisture and conductivity measuring instrument based on the principle of phase detection and a measuring method thereof. Background technique [0002] The research results of soil science in recent years show that the parameter of soil electrical conductivity itself contains a wealth of information reflecting soil quality and physical properties. For example, the content of salinity, water and organic matter in the soil, soil compaction, texture structure and porosity all affect the change of soil electrical conductivity to varying degrees. Among the above factors, the influence of soil salinity and water content on electrical conductivity is significantly greater than that of other factors. It is one of the hot spots of precision farming research in developed countries to evaluate the growth environment of crops by means of measuring soil electrical conductivity. Al...

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Problems solved by technology

[0018] The technical problem to be solved by the present invention is to overcome the difficulties in research and development and the high cost of measurement equipment caused by the difficulty in accurately measuring the time of electromagnetic waves propagating on the sensor probe in the existing TDR soil moisture measurement technology.

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