Research

http://www.soiltestinglab.colostate.edu/documents/Garden%20Center%20list%20soil%20sample%20kits-addresses.pdf

http://www.soiltestinglab.colostate.edu/

http://www.ext.colostate.edu/pubs/crops/00520.html

http://www.colostate.edu/Dept/CoopExt/4DMG/Soil/soiltest.htm