584 FORAGE PLANTS AND THEIR CULTURE 



Root crops for forage comprise in America but a small 

 portion of the root crops grown. Much the larger part of 

 the " root " crop is grown for vegetables and the acreage of 

 beets for sugar is far greater than that of roots for forage. 



The portion of the plant harvested in " root " crops is 

 truly a thickened root in cassava, chuf as and sweet pota- 

 toes. In beets, carrots, rutabagas and turnips, it is partly 

 root and partly stem which merge insensibly together. 



A root crop may replace any other cultivated crop in a 

 rotation. As a rule four or more years should elapse be- 

 fore the same or a related root crop is grown on the same 

 .piece of land, as otherwise the damage -by insects and 

 disease is apt to be large. 



698. Importance of root crops. Root crops for forage 

 are extensively grown for stock feed in northern Europe, 

 especially Great Britain, Ireland, Germany, Denmark 

 and Scandinavia. In America they have thus far been 

 grown mainly in Canada. In the United States they are 

 nowhere important, but according to the thirteenth census 

 are most largely grown in the states of California, Colo- 

 rado, Utah, New Mexico, Wisconsin, Washington, Oregon, 

 Michigan and New York in order. The large use of 

 forage roots in the first iour states is probably associated 

 with beet culture for sugar. 



On the accompanying map is shown the number of 

 acres of roots for forage in each state, according to the 

 Thirteenth United States Census, and in each province 

 according to the Fifth Canadian Census. 



In a general way the lack of importance of root crops 

 in the United States is correlated with the extensive cul- 

 ture of corn, which supplies a cheap grain feed for live 

 stock. In northern localities, on the Pacific Coast and 

 at high altitudes where corn or other equally cheap grain 



