Distributive Relationships of the Agricultural Pattern 132 
(e) a mean annual precipitation of 39.55 inches with a late spring and 
early summer maximum, and (g) a growing season which averages 209 
days in length. 
The agricultural pattern is comprised predominantly of fields of 
crops interrupted here and there by sets of improvements. Locally 
differentiated crop combinations permit the resolution of the agricultural 
pattern into sections characterized by different types of economy. The 
Structure of the agricultural pattern depends on (a) interrelationships 
within the pattern, (b) relationships with the natural environment, and 
(c) relationships with other types of cultural phenomena which are in- 
cluded in the areal complex of the American Bottoms. 
