InThe soil moisture sensor in agricultural meteorology is expressed by the following methods and units.
Methods for detecting soil moisture with agricultural sensors
①Weight percentage. That is, the weight of soil water accounts for the percentage (%) of its dry soil weight. This method is widely used, but the soil types are different. And the same soil moisture has different availability of soil moisture, which is not convenient for comparison between different soils.
② Percentage of field water holding capacity. That is the soil moisture accounts for the percentage of the field water holding capacity of this type of soil. Conducive to comparison between different soils, but can not give the concept of specific water.
③The amount of soil moisture storage. Refers to the absolute amount of water in a certain depth of soil. Usually in millimeters, which is convenient for comparison with precipitation and evaporation. The calculation formula of soil moisture storage W (mm) is: W = 0.1·h·d·w. In the formula, h is the thickness of the soil layer, d is the bulk density of the soil (g/cm3). 0.1 is the unit conversion factor, and w is the soil moisture (weight percentage).
④Soil water potential or water potential is the soil moisture content expressed in energy. Its unit is atmospheric pressure or joule/g. For the convenience of use, the ordinary logarithm of the value can be taken. And the abbreviation symbol is pF, which is called the pF value of soil water.
Soil moisture sensor agricultural testing method
① Weight method. Take the soil sample and dry it weigh its dry soil weight and moisture content to calculate.
② Negative pressure meter method. Use a negative pressure gauge to measure. When the unsaturated soil water absorption is balanced with the negative pressure in the device. The negative pressure indicated by the pressure gauge is the soil water absorption. And then the soil water content can be calculated based on it.
③ Resistance method. Use resistance type soil moisture meter to measure. Determine the soil moisture according to the relationship between the conductivity of the soil solution and the soil moisture content.
Accurate and convenient instrument for detecting soil moisture
Agricultural instrument used to detect soil moisture sensor agriculture. The soil moisture sensor (transmitter) is a high-precision, high-sensitivity soil moisture measuring instrument. This sensor uses the principle of electromagnetic pulse to measure the soil. Thereby obtaining the true soil moisture content. It is fast, accurate, stable and reliable, and is not affected by chemical fertilizers and metal ions in the soil. This instrument can be widely used in agriculture, forestry, geology, construction and other industries.