摘要 |
<p>A matric potential responder which includes a liquid absorbing swellable nonliquid material (115) held within a housing (114) of a ceramic material environ such as soil, to the material (115), being subject to a compressive force such as a spring (116). This uses balance of compressive force as compared to tension of the soil matric potential being used to control a position of a valve (119) which is arranged to effect an output such as control of a mains water valve (110).</p> |