10 SOILS OF THE EASTERN UNITED STATES. 



southward to South Carolina. This " thermal zone " exists only 

 where the orchard sites are protected from the strong winds and 

 the heavy storms, coming chiefly from a western direction. Thus 

 upon the eastern flanks of the Blue Eidge, in altitudes ranging 

 from 1,200 to 1,500 feet or somewhat higher in Virginia, and at 

 altitudes ranging from 1,400 feet to 2,000 feet above sea level in 

 western North Carolina and western South Carolina, there exists 

 a belt of territory within which unseasonable frosts rarely occur. 

 It is between these elevations that the best quality of fruit is pro- 

 duced and the Porters black loam is the dominant orchard soil of 

 the section. In fact, in Virginia, the adaptation of this type to the 

 production of a certain variety of apples has caused it to be known as 

 the " pippin land " of this section. 



There is a further restriction placed upon the planting of apple 

 orchards through the direction of exposure or the aspect of the 

 orchard site. Thus in general it may be said that the pippins will 

 be of the very best quality only in the sheltered coves within the 

 " thermal belt " which have a northern or northeastern exposure, 

 while the red varieties of apples and practically all varieties of 

 peaches are grown to best advantage within this belt upon eastern 

 or southeastern exposures. In all cases the slope must be such as to 

 give adequate air and water drainage, thus preventing largely the 

 ravages of fungous diseases which would otherwise interfere with the 

 orcharding operations. 



This climatic limitation, which is so pronounced in the case of 

 orchard fruits, is also noticeable in the case of practically all other 

 crops. It has already been noted that practically no agricultural 

 crops may be grown above an altitude of 3,500 or 4,000 feet in this 

 general section and that even the timber growth becomes stunted or 

 lacking at the highest altitudes. It is also a fact that from 2,500 

 feet to 4,000 feet above tide level the crops of northern latitudes alone 

 may be cultivated to advantage, and even corn is not fully successful 

 at the upper limit of this zone. Wheat, rye, oats, buckwheat, and 

 timothy are the crops best suited to the highest altitudes, while corn, 

 wheat, and mixed timothy and clover are suited to the intermediate 

 altitudes. Irish potatoes do fairly well even to the upper limits of 

 cultivation and seem to have a wider range in altitude than any 

 other special crop which may be grown upon these two types. Cot- 

 ton, sweet potatoes, and similar crops are', of course, successful only 

 at the lowest altitudes and in the more southern locations. Thus the 

 existence of climatic zones due to differences in altitudes is very 

 marked in the case of the region occupied by the Porters loam and 

 black loam. 



There is another limitation even upon the most valuable special 

 crops which may be produced upon these two types; it is the limita- 



