Below are several sites that can be used as supplemental or extension lessons.  The website is listed with a short explanation of what can be found in each.

http://ambassador.maca.org/
MACA Crop Life Ambassador has volunteers working in the agricultural industry available to speak about the methods of modern American farming.  This program brings FREE speakers to schools and civic groups across the Midwest.  Programs include; America’s Abundance, Today’s Agriculture, Careers Across the Spectrum”, Farm Fueled, Biofuels, Farmers Stewards of the Land, Feeding Planet Earth, War of the Weeds, The Water Issue, Agriculture And Food Safety, and Biotechnology In Agriculture.

http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/nedc/training/soil/?cid=nrcs142p2_053588/
This printable poster shows the different colors and horizons of the 12 orders of soils.

http://www.nal.usda.gov/educational-resources-children-parents-andteachersThis site, maintained by the United States Department of Agriculture’s National Agriculture Library, spotlights kids and teens’ roles within agriculture.  The wide variety of topics will change when updates are made.

http://www.yourchildlearns.com/farm.htm
If your technology is slow, or you have young learners, this free educational software allows you to print a farm house, barn, silo and other buildings to make a farm, all on regular paper on your PC printer.  Have your students arrange the buildings, make pens and fields, plan what animals, and crops to grow.

http://agclassroom.org/teacher/agknow.htm
Regardless of the grade level you teach, this website provides a vast amount of resources, lesson plans, webquests, career information, and quizzes.  The “Student Center” is designed especially for kids and can be an independent activity if needed.

http://agclassroom.org/kids/ag_facts.htm might be a great place to start if you want to compare and contrast different states’ agriculture products.

http://www.epa.gov/region6/6pd/bingo/
This site is great for Pesticide Safety Bingo.  You will need to print the card, but everything is included that you need to play.

http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/sis5219
While this webpage is based in Canada, it has great maps of food produced in the United States.  Corn, soybeans, wheat, barley, are the crop maps included- this would make great overlay transparencies to compare and contrast.

http://www.pbs.org/wgbh/harvest/
Depending on the level of your students, you can choose to introduce genetically modified foods.  The PBS presentation is fantastic for older students and can easily be broken down into sections.