Stressmeter

摘要

An apparatus for determining a critical level of soil humidity for plants including an external body, a soil recipient container hermetically sealed to the external body so as to receive a soil sample therein, a well positioned within the external body and containing water therein, a pressure cell connected to the well so as to controllably pass water from the well to the soil recipient container, and an air admitting pipe in sealed relationship with the external body. The pressure cell has a preestablished resistance to the passage of water. The soil recipient container has a collecting pipe thereon for passing water into the soil. The air admitting pipe has an end which opens exterior of the external body so as to allow air to pass into the external body. The air admitting pipe communicates with the pressure cell. The air admitting pipe serves to transmit air into the pressure cell when energy in the soil recipient container is higher than the resistance of the pressure cell. The pressure cell then urges water from the well into the collecting pipe of the soil recipient container.