Tube-pin-type soil moisture content detection method and device based on frequency domain reflectometry

Abstract

The invention discloses a tube-pin-type soil moisture content detection method and device based on frequency domain reflectometry, and relates to the technical field of the detection of the moisture content of the soil. A high-frequency signal is used as an excitation signal, so that a high-frequency attenuation signal amplitude can be measured according to the impedance matching theory in the electromagnetic wave transmission theory, so as to reflect the changes of impedances of the soil to be detected and a probe; meanwhile, the volume density and the temperature of the soil are measured; therefore, the moisture content of the soil can be precisely obtained according to a function relation between the moisture content, and the high-frequency attenuation signal amplitude, the temperature and the volume density or by a correction method for the moisture content based on the temperature and the volume density. The device based on the method comprises a tube-pin-type soil moisture content probe, a 50-ohm coaxial connection wire, a high-frequency signal excitation circuit, a voltage detection circuit, a temperature sensor, a mass sensor, a power module, a micro processing unit and a display module. According to the method and the device, disclosed by the invention, the influence of the temperature and the volume density of the soil on the measurement of the soil moisture content can be eliminated, and the soil moisture content can be accurately and quickly measured; furthermore, the cost is low.

Description

technical field [0001] The invention relates to the technical field of soil moisture content detection, in particular to a needle-type soil moisture content detection method and device based on a frequency reflection method. Background technique [0002] Soil is the basic means of production for agricultural production and also the carrier that provides nutrients for crops. Soil moisture content is very important for the growth of crops. First of all, crops must absorb enough water to meet their own growth needs; secondly, water dissolves nutrients in the soil into a solution, which is exchanged through the concentration of the solution inside and outside the root cells of the plant to complete the absorption of nutrients; finally, the osmosis of water can Bring artificially applied fertilizers into the soil to improve soil fertility. Soil moisture content is an important indicator to understand the condition of the farmland and the growth status of the crops. [0003] At...

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Problems solved by technology

[0008] In view of the problems existing in the existing frequency domain reflectometry (FDR) soil moisture content instruments, the purpose of the present invention is to provide a needle-type soil moisture content detection method based on frequency domain reflectometry

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