
According to Wikipedia:
The top twenty agricultural products of the United States by value as reported by the FAO in 2003 (ranked in order of value with mass in metric tons):
1. Corn 256,904,992
2. Cattle meat 11,736,300
3. Cow's milk, whole, fresh 78,155,000
4. Chicken meat 15,006,000
5. Soybeans 65,795,300
6. Pig meat 8,574,290
7. Wheat 63,589,820
8. Cotton lint 3,967,810
9. Hen eggs 5,141,000
10. Turkey meat 2,584,200
11. Tomatoes 12,275,000
12. Potatoes 20,821,930
13. Grapes 6,125,670
14. Oranges 10,473,450
15. Rice, paddy 9,033,610
16. Apples 4,241,810
17. Sorghum 10,445,900
18. Lettuce 4,490,000
19. Cottonseed 6,072,690
20. Sugar beets 27,764,390
The only other crops to ever appear in the top twenty in the last 40 years were, commonly, tobacco, barley, and oats, and, rarely, peanuts, almonds, and sunflower seeds (in all, only 26 of the 188 crops the FAO tracks worldwide). Alfalfa and hay would both be in the top ten in 2003 if they were tracked by FAO.
Not quite a "staple food," but... according to ABC News:
Marijuana Called Top U.S. Cash Crop
Marijuana Takes the Pot as Most Valuable Cash Crop in the Country. Marijuana is the top cash crop in 12 states and among the top three cash crops in 30, according to a new study. http://abcnews.go.com/Business/story?id=2735017
Ha!



