The 223 determines soil water potential by measuring electrical resistance. When the 223 is wet, the electrical resistance is low. As the 223 dries, resistance increases.
The 223 cylindrical blocks are composed of gypsum cast around two concentric electrodes, which confine current flow to the interior of the block, greatly reducing potential ground loops. Gypsum located between the outer electrode and the soil creates a buffer against salts that may affect the electrical conductivity.
The 223 connects to a data logger via an AM16/32-series multiplexer. Because the multiplexer contacts close only during measurement, electrical currents leading to premature degradation of the 223 are eliminated.
Campbell Scientific recommends removing the 223 during winter.
The 223, manufactured by Delmhorst, is a cylindrical gypsum block that estimates soil water potential from -10 to -1000 kPa. It connects to a data logger via an AM16/32-series multiplexer.
Benefits and Features
- Compatible with AM16/32-series multiplexers, allowing measurement of multiple sensors
- Multiplexer connection prevents electrolysis from prematurely destroying the probe
- Measures a wide range of matric potential
- Buffers salts in the soil
- No maintenance required
- Compatible with most Campbell Scientific data loggers
- Uses electrical resistance method for soil water matric potential measurement
- Measurement range: -1000 kPa to -10 kPa
- 223-L Delmhorst Soil Matric Potential Block for Multiple used with a multiplexer connected between the data logger and the sensor
| Material | Gypsum |
| Measurement Range | -10 to -1000 kPa |
| Calibration | Individual calibrations are required for accurate measurements. Refer to the sensor manual for more information. |
| Operating Temperature | Soil temperatures above freezing |
| Life Expectancy | Two freeze-thaw cycles |
| Electrode Description | Concentric cylinders |
| Center Electrode | Excitation |
| Outer Electrode | Ground |
| Cylinder Diameter | ~2.25 cm (0.88 in.) |
| Cylinder Length | ~2.86 cm (1.25 in.) |
| Weight | 180 g (0.4 lb) |
