How does the measurement range of a Jet Fill tensiometer relate to available soil water?
The graph below developed through the use of Soil Moisture Equipment corporation pressure membrane extractors shows the percent of moisture in the soil compared to the force of soil suction with which it is held, for three different types of soils. The “available” moisture for plant growth lies between the “field capacity” and the “wilting point.” In general when 50 percent of the available moisture is used up, irrigation should be started. With the exception of heavy clay soils, tensiometers measure the soil suction value at which 50 percent of the available moisture is used up. In virtually all types of soils and for virtually all commercial crops, if the soil moisture is kept within the operating range of tensiometers, there will be optimum growth conditions and crop yields.
