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QT-EQ15 Soil water potential meter

Product description: Equilibrium tensiometer is a new revolutionary soil water potential meter which has patent protection. Soil water potential is measured as potential energy per unit quantity of water under isothermal conditions, its unit is bar (1 bar = 100kPa). In the soil, water potential is a major factor in determining the direction and speed of water flow, which is the only index of the effectiveness of soil moisture to plants. The water potential of different soils can be compared with each other directly. Accurate determination of soil water potential has very important significance for the research on the flow of soil water, drought resistance of plants, automatic control of water-saving irrigation, soil moisture monitoring, etc.

 QT-EQ15 Soil water potential meter


EQ15 equilibrium tensiometer consists of two parts: equilibrium sensor and moisture content sensor. The equilibrium sensor is made of a special material which owns two characteristics: stable relationship between water content and water potential, high water permeability. Good permeability can ensure water potential changes simultaneously with soil water content. Moisture content sensor measure the water content of equilibrium sensor all the time. Because the relationship between water content and water potential is known, soil water potential can be calculated based on soil water content. Moisture content sensor is fixed in the equilibrium sensor, thus the changes of ambient environment (Soil density, gravels, root systems, etc.) around the probe have no effect on the measurement results.

Comparison with traditional soil water potential meter

The current soil water potential meters on the market and their measuring principles have several shortcomings in some aspects, such as measurement accuracy, measurement range and stability in measurement. Apparently those soil water potential meters cannot completely meet users’ requirements. The traditional tensiometer usually has a small measurement range (-0.8~0bar), and it can be used only in moist soil and damaged easily; Psychrometer can be heavily affected by the temperature change and its measurement accuracy is low and not suitable for outdoor use. Gypsum blocks has low measurement precision, low stability, and can get significantly affected by soil pH

Equilibrium tensionmeter has irreplaceable advantages

  • Wide measurement range, Including the full spectrum of water potential for plant survival
  • High precision, measurement error is less than 5k Pa
  • Easy to use, no need of any maintenance and repair, completely suitable for long-term outdoor use
  • Measurement accuracy is not affected by soil properties (except alkaline soils)
  • Multiple probe connections to the data logger


  • GPS coordination can be recorded
  • Record data Automatically or manually
  • Wireless data transmission via Wi-Fi
  • Recognize sensors by two-dimensional code
  • Automatically recognize connected sensors
  • Terminal memory card is up to 32G
  • Display real-time data and curve of recorded data
  • Export data to Excel for analysis

Technical parameters


Measurement range

0~ -1500kP(0~-15bar)

Measurement accuracy


±10% Reading(-100~-1500kPa)

Applicable temperature range

Operating temperature: 0~40℃;

Storage temperature: -30~70℃;

Can stay in the permafrost

Applicable soil types

Non-saline soil (EC of soil solution < 1ms/cm)


5~15V DC, maximum consumption: 23 mA x 5s


 100~800 mV


17cm×4cm×2cm; 7.5 cm into the soil


350g (without electrode)


standard 5m, can be extended to 100 meters


Stainless steel housing, sealed


Handheld terminal



Operating system

Android 4.2





Extended memory

up to 32G

Screen size

5.0 In.

Screen resolution


Operation mode

Touch screen

Screen color support

16 million

Origin: China


Beijing Tel: +86-10-62111044 / Fax: +86-10-62114847 / Add: Suite 6B13 Huajie Plaza, 13 Dazhongsi, Haidian District, Beijing 100098, China
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