1: System Introduction
Soil water potential(Soil water potential refers to the relativepure waterFree water surface, the property of soil waterpotential energyIt is a form of potential energy. Soil water, like other substances in nature, has various forms of energy. Due to its low flow velocity, its kinetic energy is ignored and the potential energy of soil water is focused on. When water enters the soil pores and is subjected to adsorption forceCapillary forceThe effects of gravity and solute ion attraction generate fundamental potential (including adsorption potential, capillary potential), gravitational potential, solute potential, and pressure potential, respectively. The sum of these energies is calledTotal soil water potential. Each item is called 'Fenshi'. According to the Academic Committee on Soil Physics of the International Society of Soil Sciences (1963), under standard atmospheric pressure, an infinitely small amount of pure water is isothermally and reversibly moved from the free water surface to a certain water absorbing point in the soil, making it the work done by soil water. Its size clearly indicates the effectiveness of soil water on crops, as well as the direction and speed of soil water movement. It is a fundamental concept for studying soil moisture movement and soil vegetation gas continuous systems.
The soil water potential isThe abbreviation for "soil moisture potential energy value", also known as "total soil moisture potential". Due to various forces such as adsorption, meniscus force, and gravity, the potential energy value of soil water generally decreases significantly. Soil water potential is the difference between the potential energy of soil water and pure free water. The unit of pressure is pascals (Pa). Soil water potential reflects the energy state, direction of movement, and effectiveness of soil moisture for plants.
Soil water potential (Water potential is the energy required to extract a unit of water from soil under isothermal conditions, measured in bars (1 bar=100 kPa). Soil water saturation occurs when the water potential is zero; When the moisture content is below saturation, the water potential is negative, and the drier the soil, the greater the negative value. The survival range of general plants is 0 to -15 Pa (-1500 kPa).
2: Composition of Soil Water Potential Monitoring System:
Data collection unit: CR800, CR1000X collector; AM16/32B channel expansion board.
Soil water potential sensor:253
Computer case solar power supply bracket and other auxiliary equipment.
be careful:Collector configuration requirements:data collector(requires configuration)+AM16/32B channel expansion board (configuration required)
3: Introduction to Soil Water Potential Equipment:
253It is very convenient to measure soil water potential, and the measurement range of the sensor is0—2barsSensors can be used toCampbellThe company's collector and,AM16/32Measure on the B expansion board.
The sensor consists of two electrodes implanted in a reference matrix material. The matrix material is wrapped in a synthetic diaphragm to prevent sensor aging. Sensors can be buried in soil for long-term use, but they need to be removed during the winter months to prevent damage.
Technical performance parameters
Range:0—2bars
Size: Long8.26cm, diameter1.91cm
Weight:362.9g
4: Reference:
Research on the Selection and Accuracy of Soil Water Potential Measurement Methods Liu SichunGao Yajun, Wang Yongyi, Ma Aisheng
Study on the Influence of Typical Vegetation on Soil Water Potential Dynamics in Taihang Mountain Area king PengSong Xianfang, Hou Shibin
Study on the hysteresis effect of soil water potential and temperature Wang Guodong Zhang Yiping Zhang Junchang Fu Zhidong
The relationship between soil moisture content and water potential for two types of soils Wu Yanyou Hu Linsheng Gu Ruizhi Wu Yansheng Li Minghong