Laboratory and field measurements with a fiber optic soil moisture sensor

A novel design of a fiber-optic soil moisture sensor is described together with its performance under laboratory and field conditions. The sensor utilizes total internal reflection of light in a right-angled glass prism. The sensor-head can be buried at any depth below the soil surface and is linked to a remotely operated light source. The sensor is tested for several days of continuous operation using different soil types and drying conditions.