Distributive Relationships of the Agricultural Pattern 118 
the relative importance of precipitation deficiency and drainage ditches 
in bringing about this result. Since 1930, when a cycle of relatively 
low precipitation began, the cultivated areas have been expanded to 
include former swamp land and even some lake floors (Figs. 24 and 25). 
The newly reclaimed land during these dry years has given larger yields 
of wheat and corn than those from much of the older agricultural land. 
The increasing dependence of farmers on marginal land suggests the 
Probability of economic distress in a wet cycle. 
Months for 1933 
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F Temperatures during 1933 _—————-_ Normals............. 
1G. 21—Mean monthly temperatures fo 
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Months for 1934 
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See 2222 2 522 
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Precipitation during Sk a ROE ess es aes 
Fic. 22—Monthly precipi 
