Aquaflex: Vendor information about a sensor that measures both soil moisture and soil temperature over a large volume of soil.
Earth Systems Solutions: Soil moisture monitoring and sampling instruments for soil science, agricultural, irrigation, and environmental applications.
Kel Instruments Co. Inc.: Specializing in soil pH and salinity test instruments.
Soilmoisture Equipment Corp.: Manufacturer of instruments to measure and extract soil moisture. Products include tensiometers; extractors, compressors and manifolds; plant water status console; salinity sensing equipment; soil permeability equipment; samplers; and related instrumentation and electronic systems.