18 



FIELD CROPS 



10. Tubers. The only important tuber crop is the 

 potato, sometimes locally known as the Irish or white potato 

 to distinguish it from the sweet potato, which is a root, not 

 a tuber. This is one of our important food crops, the pro- 

 duction in 1909 being 389,195,000 bushels, valued at $210,- 

 667,000. It occupies 0.77 per cent of the area of improved 

 farm land, and ranks sixth in value among our field crops. 



11. Roots. The principal root crop of the United States 

 is the sweet potato, which was grown on 641,000 acres in 



Fig. 3. There are br 



beets. 



most important root crop. 



1909, with a production of 59,222,000 bushels. Other root 

 crops are grown principally for stock feeding, as the mangel, 

 carrot, turnip, and rutabaga. This class of crops occupied 

 only 18,916 acres in 1909, with a production of 254,533 tons. 

 The sugar beet is a root crop which is grown for the pro- 

 duction of sugar. It is discussed under the heading of 

 sugar crops. 



12. Sugar Crops. Two important sugar crops are grown 

 in the United States, the sugar cane and the sugar beet. 



