Soil moisture is an important physical parameter of soil. It has extremely important significance for plant growth, survival, and net growth. At the same time, soil moisture status is a comprehensive reflection of natural conditions such as climate, vegetation, topography, and soil factors. Evapotranspiration (vegetation transpiration and soil evaporation) have important effects. Therefore, the monitoring of soil moisture and its changes is the basis for research on ecology, agriculture, water, environment, and water and soil conservation. Farmland soil moisture is an important parameter for agriculture, meteorology and hydrology. It not only affects the agricultural production, quality and irrigation system, but also affects the distribution and management of water resources such as runoff and infiltration, and the distribution of net solar radiation. Therefore, regular monitoring of soil moisture content is indispensable and very important for the research and application of these fields. There are many ways to measure soil moisture. One is to directly measure the soil moisture content and volumetric moisture content, such as drying and weighing method, neutron meter method, etc. The other is to measure the soil matrix potential, such as the tension meter. Method, resistance block method, moisture meter method, etc. There are many ways to monitor soil moisture in the field, but it can be summed up in two major categories, direct and indirect. With the widespread use of computer technology, ancient direct assays are being replaced by a variety of indirect assays that are highly automated. The following is a brief introduction to the methods and principles that have been widely used. The empirical method The empirical method is also called the perception method. It is a method to determine the moisture content of a sample based on experience by observing and touching samples collected by an earth drill or sampler. This method can control the error to within 10%-15%. In many cases, this accuracy is sufficient to meet the needs. Advantages: Simple and fast. Disadvantages: The accuracy is low and requires some skill. Soil sampling method Sampling method is the only method to directly measure soil moisture content. Because of its high precision, it is often used to calibrate other methods. In addition, there are soil moisture measuring instrument measurement technology, moisture measurement technology, nuclear technology methods, electromagnetic technology, remote sensing technology, etc., which will not be elaborated. According to the needs of different professions for soil moisture determination, they can be divided into three categories: one is the regular monitoring, one is the root layer (l~2m) moisture assessment, and the third is the regional soil moisture change. evaluation of. From the various methods and principles for determining soil moisture content described above, they have their own advantages and disadvantages. At present, there is no single method that can fully meet the above three requirements and become a common measurement method for each specialty. According to their own measurement purposes and existing conditions, the selection of 2-3 kinds of measurement techniques used in combination, to avoid weaknesses, will be a positive approach. Among the various methods mentioned above, which method is more accurate or more applicable, it is difficult to make a comprehensive measurement. In general, neutron soil moisture measuring instruments and time domain reflectometers are relatively moderate in terms of investment, installation, use, maintenance, measurement accuracy, and data automation, and are suitable for use; negative pressure gauges and resistance blocks are more suitable. For cheaper, the current domestic users are more. Each time specific monitoring is implemented. One or more measurement techniques should be selected based on the purpose of measurement, the conditions available, etc., so that the purpose of doing more with less can be achieved. Get satisfactory results. It Is One Of The Most Important Accessories For Cleaning Machine Cleaning Equipment, As Long As A Good Water Gun To Achieve The Performance Of Cleaning Equipment. Whether It Is The Car Washing Industry, Industry, Commerce, And Other Fields Spray Guns,spray Gun, Ultra High Pressure Gun, Pressure Gun,Water Spray Gun ZHEJIANG BOTUOLINI MECHANICAL CO.,LTD , https://www.botuopump.com
By heating the soil sample and evaporating the water, the method can calculate the moisture content of the sample based on the lost moisture and multiply the soil bulk density by the volumetric moisture content of the sample. The methods of heating generally include a constant temperature oven method, an alcohol burning method, and an infrared lamp irradiation method.
Advantages: High accuracy, simple tools, easy sampling, easy calculation.
Disadvantages: It takes a long time to determine, a low degree of automation, labor intensity, can not be long-term sampling and measurement of the same site.