Web Sites:

Natural Resources Conservation Service:

http://www.ngdc.wvu.edu/~hferguson/educationNGDC

http://soils.usda.gov/teachers.html

http://websoilsurvey.nrcs.usda.gov/app/

http://www.usda.gov/news/usdakids/

http://panutrientmgmt.cas.psu.edu/pdf/rp_better_soils_with_noTill.pdf