Pressure plate extractors
Used to determine - available water capacity, water retentivity, hydraulic conductivity and field capacity.
Applications include - soil classification and survey, optimisation of irrigation and drainage, calibration of soil water and measuring apparatus for field use.
The pressure plate is used to determine soil water retention and suctions greater than 0.4 bar. The apparatus consists of strongly built metal chambers containing one or more ceramic plates, on to which uniform soil samples are placed. Having attained maximum moisture retention (field capacity) the samples within the cells are then subjected to controlled positive air pressures and water is gradually removed. By careful control of pressure, the various equilibrium conditions of pressure and soil water tension or suction are obtained.
The air pressure is provided either from a compressor, compressed air bottle or nitrogen bottle. The air pressure source must always be routed via a pressure regulation manifold.
ELE can supply three types of pressure plate extraction systems, which cover the pressure range 0-15 bar.