Measurement of water content in soil not only reflects the demand of crops and other crops for water in soil, but also relates to the dissolution and transfer of nutrients in soil and the activities of microorganisms, and it is the basic condition for plants to survive. Not only in agricultural monitoring, but also in some engineering construction (such as railroads, highways, hydroelectric power stations, channels, houses, etc.), the soil moisture content is also essential information.
Soil moisture transmitter There are many kinds of measurement methods, the common ones are weighing method, tensiometer method, resistance method, neutral law, γ-ray method, optical measurement method, dielectric method and so on. Today we will learn about the differences between each method of soil moisture transmitter.
Weighing method: with a variety of operational inconvenience and other shortcomings, but as a direct measurement of soil moisture content of the only method, in the measurement of accuracy has other methods incomparable advantages, so this principle of soil moisture transmitter as a laboratory measurement method and used for other methods of calibration will be a long time.
Tensiometer method: As the direct object of measurement is the soil matrix potential, it is used to a greater extent in combination with other soil moisture measurement methods for the determination of soil moisture characteristic curves.
Resistance method: Due to the complexity of the calibration and the fact that the calibration results will soon become invalid over time, and for a number of reasons such as limited measuring range and poor accuracy, the resistance method of soil moisture transmitters has been largely phased out.
Based on the principle of radiation neutron method and γ – ray method of soil moisture transmitter, although it has high precision, fast speed and other advantages, but because of their common existence of the fatal defects of human health hazards, in recent years has been abandoned in developed countries, only a small number of experimental research in the country.
Optical measurement method: Although it has the advantage of non-contact, but due to the soil variability, error, adaptability is not strong, optical measurement of soil moisture transmitter research and development prospects are not optimistic.
The characteristics of the dielectric method is to use the dielectric properties of the soil for indirect measurement can realize the rapid and non-destructive measurement of soil moisture, specifically can be divided into time-domain reflection based on the principle of TDR and frequency-domain reflection based on the principle of FDR. The advantages of this type of soil moisture transmitter are fast measurement speed, easy operation, high accuracy, continuous measurement, both for measuring the soil surface moisture, can also be used to measure the profile moisture, can also be used for long-distance multi-point automatic monitoring, the measurement data is easy to process. Moreover, this type of soil moisture transmitter is more convenient and flexible in operation, and can be applied to soil moisture measurement for different purposes. It is a widely used soil moisture measurement method at home and abroad.
Star Meter Manufacturing Co., Ltd. is a high-tech enterprise integrating R&D, production and sales. Specializing in the production of pressure transmitters, level transmitters, temperature transmitters, temperature and humidity transmitters, differential pressure transmitters, soil moisture transmitters, 3051 transmitters and related instrumentation accessories. Many products under the brand of Star Instruments have obtained a number of patents issued by the state, such as CE certification, IS9001 certification, SGS certification, TüV SüD certification, explosion-proof certification and so on.
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