Soil moisture represents the soil moisture content and is one of the important physical properties of the soil. In automatic agricultural production, the detection of soil moisture is a technical link for realizing automatic and precise irrigation, and it is also an important work for studying soil properties. In the method of measuring soil moisture, although the most direct drying method is accurate, it takes time and effort to sample and dry, and it is not suitable for timely measurement of soil moisture in automatic control. The method of measuring soil moisture in the field at a proper time includes: conductance method, heat conduction method (electrothermal method), microwave method, negative pressure gauge method, neutron measurement method, capacitance method and the like. Various methods have their disadvantages: the negative pressure meter method can only measure the water content of the capillary section of the soil; the conductivity method indirectly measures the soil conductivity by measuring the conductivity of the soil, because soil conductivity is not only related to the soil moisture content. It is also related to the species and concentration of ions in the soil. Therefore, the measurement of water quality influenced by irrigation and fertilization have a greater impact; electrothermal and microwave methods also have certain limitations in terms of operation methods, reproducibility, and flexibility; neutron method Wide measuring range, high precision, but relatively high cost, with a certain risk of nuclear radiation, unsuitable for use in general agriculture; Capacitance method utilizes the high permittivity of water and uses the side soil as a dielectric, and the probe (detection The head constitutes a capacitor, which measures the humidity of the soil by measuring the capacitance change of the capacitor. It is also an indirect measurement method. Since the dielectric constant of the soil is not only related to the water content, the measurement accuracy is not high enough. To sum up, in fact, accurate and timely measurement of soil moisture is not a simple matter. Moreover, in the natural situation, the change of soil moisture is a slow process. Even if the problem of the sensing of humidity (sensor problem) is solved, in the circuit, this slowly changing, almost DC electric signal is processed with high precision. It is not easy. The detection technology of soil moisture has extremely important significance in the implementation of automated agriculture, and its products have very broad application prospects. However, there are still few domestic applications in this field. More applications or FDR sensor method, simple operation, good repeatability, low price, suitable for testing all kinds of soil moisture in various regions of the country. Related soil moisture (humidity) testing equipment please see: http://?id=38 Tire Valve Extension,Valve Extensions,Pvc Valve Extension,Flexible Valve Extension Ningbo Kaisheng Auto Parts Co.,Ltd , https://www.valvestemfactory.com