223-L

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.

The 223 determines soil water potential by measuring electrical resistance. When the 223 is wet, electrical resistance is low. As the 223 dries, resistance increases.

The 223 cylindrical block is 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.