Percolation and Soil Test Guides
- Description on how to perform Percolation and Soil Test.
- http://www.percolationtest.com

Kel Instruments Co. Inc.
- Specializing in soil pH and salinity test instruments.
- http://userweb.cybernex.net/kelway/

Aquaflex
- Vendor information about a sensor that measures both soil moisture and soil temperature over a large volume of soil.
- http://www.streatsahead.com/Pages/Aquaflex%20Menu.html

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 instrume
- http://www.soilmoisture.com

Earth Systems Solutions
- Soil moisture monitoring and sampling instruments for soil science, agricultural, irrigation, and environmental applications.
- http://www.earthsystemssolutions.com/