258 



PROCEEDINGS OF THE OHIO ACADEMY OF SCIENCE. 



The second column in this table shows that there is no 

 appreciable relation between the variations in rainfall in Ohio 

 and the yield of winter wheat. The rainfall is neither too heavy 

 nor too light often enough to have an appreciable effect upon 

 the yield. This is true of individual months as well as for the 

 fall, winter, and spring seasons. 



The first column of table 9 also shows that neither the mean 

 temperature for the fall, winter, and spring seasons nor that for 

 individual months except February and March, has a controlling 

 eft'ect upon the yield of wheat. The value of r for March is 

 slightly more than seven times the probable error and as this 

 is preceded by the plUs sign it shows that warm weather in March 

 is very important for a good yield. 



Figure 5 brings out the influence of the temperature for 

 March upon the winter wheat in Ohio. An inspection of the 

 chart will show that March has been warmer than the normal 



Figure 5. Dot chart showing the relation between the mean tem- 

 perature for March and the yield of winter wheat in Ohio. 1860 to 1913. 



