PROCEEDINGS OF THE OHIO ACADEMY OF SCIENCE. 247 



60 years is 34.5 bushels per acre. In figure 1 two curves have 

 been charted showing the variations of the corn yield and the 

 July rainfall from the normal for each year from 1854 to 191 3. 



An inspection of this chart will show that while in a few 

 cases the curves do not run together, in general there is a marked 

 relation between them. This is especially true when there is 

 much variation from the normal. 



If the 60 years be grouped by different rainfall amounts the 

 yield figures show some interesting results. This is brought out 

 in table i where the July rainfall amounts are grouped for each 

 variation of one-fourth inch, one-half inch, and one inch. 



Table 1. Effects of Variations in July Rainfall in Ohio, on the 

 Yield of Corn. 1854 to 1913. 



For each increase in the Tliere has been an increase in 

 rainfall of the corn yield of 



Per Acre. Total Bush. Value. 



% inch from 1.75 to 8.0 in 0.8 bush. 2,800,000 $1,400,000 



Ya. inch from 2.0 to 4.0 in 1.4 bush. 5,900,000 2,950,000 



y2 inch from 1.75 to 8.0 in 1.2 bush. 4,200,000 2.100,000 



J^ inch from 2.5 to 3.5 in 4.3 bush. 15,050,000 7.525,000 



1.0 inch from 1.75 to 8.0 in 2.3 bush. 8,050,000 4,025,000 



Below 3.0 in. to 5.0 or more 7.8 bush. 27,300,000 13,650,000 



The total amount of land devoted to corn in Ohio averages 3,500,000 

 acres. The average farm price of corn on December 1 is 50c per bushel. 



One of the most important facts brought out in this table 

 is that there is a critical July rainfall value of close to 3.00 

 inches. For example the first item in the table shows that the 

 average increase in the yield of corn with each increase in the 

 rainfall of one-fourth inch from 1.75 inches to 8.00 inches, is 

 0.8 bushels per acre, but between 2.00 inches and 4.00 inches, each 

 increase in the rainfall of one-fourth inch causes an increase in 

 the yield of 1.4 bushels per acre. 



Again in the 3rd and 4th items the figures show that with 

 each increase of one-half inch in the July rainfall the yield 

 averages to increase at the rate of 1.2 bushels per acre, but when 



' Figure 1 is omitted because of the size of the chart. 



