Y ray method moisture sensor and TDR method moisture sensor use the difference

Y ray method moisture sensor and TDR method moisture sensor use the difference

Soil moisture sensor also known as: soil moisture sensor, soil moisture sensor, soil water content sensor, mainly used to measure the soil volume water content. To do soil moisture monitoring and agricultural irrigation and forestry protection currently commonly used to soil moisture sensors are FDR type and TDR type, that is, frequency domain type and time domain type. At present, the more popular is FDR type, FDR frequency domain reflectometer is a kind of instrument used to measure soil moisture, it has the advantages of easy and safe, fast and accurate, fixed point continuous, automation, wide range, less calibration, etc..

At present, there are many kinds of soil moisture measurement methods at home and abroad, and thus different soil moisture sensors. For example: Time Domain Reflection (TDR), Gypsum, Infrared Remote Sensing, Frequency Domain Reflection/Frequency Domain (FDR/FD), Titration, Capacitance, Resistance, Microwave, Neutron, Karl Fischer, Y-Ray and Nuclear Magnetic Resonance methods. Here we introduce the working principle of each sensor.

1, TDR method moisture sensor.

TDR is a system similar to radar system, with strong independence, and its results are basically independent of soil type, density and temperature. And there is also a very important point is that TDR can determine soil moisture under icing, which is incomparable to other methods. In addition, TDR can monitor soil water and salt content simultaneously, and there is almost no difference between the results of the two measurements before and after.

2, FDR and FD method moisture sensor.

FDR and FD method is not only cheaper than TDR, and the measurement time is shorter, after specific soil calibration, the measurement accuracy is high, and the shape of the probe is not limited, can be measured simultaneously at multiple depths, and data acquisition is easier to achieve.

3, the resistance method moisture sensor.

The resistance method uses the resistance of gypsum, nylon, glass fiber, etc. and their water content. When these intermediates plus electrodes are placed in moist soil, then after a period of time, the water content of these things reach equilibrium. Because of the relationship between resistance and moisture content, we previously calibrated a certain correspondence between resistance and percentage, and then we can get the moisture reading in the range of 1 to 15 atm suction by these components.

4, neutron scattering (neutron scattering) method moisture sensor.

The neutron method is suitable for determining soil moisture in the field. It is based on the principle that hydrogen sharply reduces the velocity of fast neutrons and scatters them away, and now there are neutron moisture meters on the market for measuring soil moisture. Neutron moisture meter has many aspects of the advantages, but there are considerable restrictions on organic soil, and it is not suitable for the determination of soil moisture content of 0-15cm.

V. Y-ray method moisture sensor.

Similar to the neutron meter, the ray transmission method uses the radioactive source 137Cs to radiate a line, with a probe to receive a ray through the soil after the energy, and soil moisture content conversion to get.