Unfrozen water content:

The TEROS 12 advanced soil moisture/temperature/EC sensor and TEROS 21 Soil Water Potential Sensor from meter group, Inc, USA were used to measure the Volumetric water content and water potential respectively. For TEROS 12, it has range of 0.00-0.70  VWC and accuracy of ±3% VWC (dimension: L X W X H =9.4 X 2.4 X 7.5 cm, needle length=5.5cm). The TEROS 21 has a range of -5 to -100,000kpa and accuracy ±10% of reading +2kPa (dimension: L X W X H=9.6 X 3.5 X 1.5 cm, sensor diameter = 3.2cm).