CLASSIFICATION OF CROPS 13 



extensive rather than intensive methods are used in the culti- 

 vation of field crops. This rule does not always hold true; 

 the most careful and intensive methods are used in the 

 culture of sugar beets and of some types of tobacco, while 

 fruits and vegetables are sometimes grown in large areas 

 by extensive or field methods. 



5. Classification of Field Crops. It is rather difficult to 

 make a definite classification of field crops, for certain uses 

 may be made of a given crop under one set of conditions 

 and other and very different uses under another. New 

 uses are continually being made of the various crops, so that 

 a classification made now might be materially wrong in a 

 few years. The principal field crops can, however, be 

 included in some one of the following classes: Grain, hay 

 and forage, fiber, tuber, root, sugar plants, and stimulant. 

 This classification is based in part on the portions of the 

 plants which are used, and in part on the uses to which 

 they are put. Medicinal plants and a few others of a mis- 

 cellaneous nature are not grown to any considerable extent 

 and need not be considered at length. 



6. Relative Importance. The 1910 census reports show 

 that the total area in field and garden crops in the United 

 States was, in 1909, 311,000,000 acres, of which all but about 

 10,000,000 acres were in field crops. These 10,000,000 

 acres were devoted to garden and orchard crops. The to- 

 tal area of improved farm land was more than 478,000,000 

 acres, leaving something like 167,000,000 acres in pastures 



VALUE _ AREA 



BHHBMBDBHHHHEBBKH GRAIN ^^EOSBOOBSSaan 



FIBRE mm 



\ALLOTHERSm 



Fig. 1. Relative areas and values of the important classes of farm crops. 



