Modern Business Geography 
40 
Cer 10 Inche. 
to 7J Inches 
+10 30 Inches 
vt040 Inches 
to 50 Inches 
110 60 Inches 
J10 80 Inches 
010100 Inches 
Jveri00Inches 
pin 
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Fic. 6. By comparing Figures 5 and 6, we see that the heaviest production of cotton comes in 
regions that have an average annual rainfall of 30 to 50 inches. Without irrigation cotton pro- 
duction is not possible at all in regions of less than 20 inches of rainfall. More than 50 inches 
means too many cloudy days for the plants to produce large. firm bolls. 
seven months of weather free from frost. This limits cotton 
raising in the United States to the part south of a line drawn from 
Norfolk, Virginia, to Cairo, Illinois (Fig. 5). The plant also needs 
ample water in the summer. Hence it cannot be grown in the region 
of light rains in Texas, New Mexico, and Arizona, except where irri- 
gation is practiced. Since the cotton plant must have much bright 
sunshine, it does not grow well in the coastal region of North and 
South Carolina, Georgia, and Florida, where there is a great deal of 
rain and of cloudy weather. If the rainfall is too heavy, the plant 
produces luxuriant leaves rather than cotton. An exception is a 
variety of the plant called sea-island cotton, which produces a valuable 
long fiber in spite of the moisture that prevents the best results with 
other varieties. This variety gets its name from the low, sandy 
islands near the coast of Georgia and South Carolina, where it was 
first grown in this country. 
Another important condition in cotton growing is the character of 
the soil. The plant grows best in limy soils or in the deep, rich soils 
in the valley floors along rivers. 
Other conditions also help to determine where cotton shall be 
grown. Until the picking machine is perfected, cotton growing must