There are 2 basic parameters that describe the state of water in soil: one is soil water content, or the amount of water per unit of soil, and the other is soil water potential, or the energy state of water in the soil. Although water content is useful when trying to describe the water balance of a soil, i.e. how much water is moving in, out, or being stored, water potential is often preferred over water content because it determines how water moves in a soil or from the soil to the plant. In addition, you can use water potential to determine plant availability of water, schedule irrigation, or determine the mechanical stress state of soil.
The Soil water potential sensor probe measures the water potential and temperature of a wide range of soil and other porous materials without user maintenance and factory calibration. Its extended range makes this sensor ideal for measuring the water potential in natural systems or other drier systems. The added temperature measurements can be used to determine approximate soil water potential in frozen soils.
Specifications
General specifications
Operating temperature: -40 to 60 ºC (no water potential measurement below 0 ºC)
Operation humidity: 0 ~ 100% RH
Dielectric measurement frequency: 70 MHz
Measurement time: 150 ms
Dimensions: 9.6 cm (L) x 3.5 cm (W) x 1.5 cm (D)
Sensor diameter: 3.2 cm
Cable length: 5 m
Water potential
• Range: −9 to −100,000 kPa (pF 1.96 to pF 6.01)
Resolution: 0.1 kPa
Accuracy: ±(10% of reading + 2 kPa) from −9 to −100 kPa
Temperature
Range: −40 to 60 ºC
Resolution: 0.1 ºC
Accuracy: ±1 ºC