Jan., 1907.] 
Weather and Crop Yield. 
49 
The normal corn yield for these states is 28 bushels per acre, 
and the normal rainfall for July is 4 inches. Whenever the rain¬ 
fall has approximated 5 inches, the corn yield has been over 
32 bushels per acre. On the other hand whenever the rainfall 
has been less than 3 inches the yield has been less than 23 bushels 
per acre. 
By taking the June and July rainfall together the rainfall 
curve and the yield curves agree even more closely than the July 
rainfall and yield curve. 
The normal rainfall for June and July is 8 inches, "while as 
stated above, the normal corn yield is 28 bushels per acre. 
Whenever the rainfall for these two months has averaged over 
9 inches the corn yield has been 32 bushels or more, and when the 
rainfall has been less than 7 inches the yield has been below 25 
bushels. 
The best yield was 34 bushels an acre in 1902, when the June 
and July rainfall was over 11 inches. In 1896 the yeild was 33 
bushels and the rainfall was almost 11 inches. 
The lowest yield was less than 18 bushels per acre in 1901. 
The rainfall in June and July of that year was less than 6 inches 
and for July alone it was about 2 inches. 
Other charts prepared for individual states show that by 
not including western Nebraska and Kansas, and eastern Ohio 
and Kentucky, and by considering carefully the rate of rainfall, 
and the length of periods with little or no rainfall, one can give 
a very close estimate of the yield of corn per acre in the United 
States, by the latter part of July; long before the crop is ready for 
harvesting. 
We believe that a closer analysis of the daily data will show 
that the period during which a good corn yield is assured by good 
rains or seriously lessened by the lack of rain, is less than one 
month. 
In 1904 the writer made a very exhaustive study of the weath¬ 
er and the yield of various corps in Fulton County, Ohio, from 
1874 to 1903 inclusive. 
The data showfing the yield of corps were obtained from the 
records of the Secretary of State, but the weather records, as well 
as many valuable records of farm operations, the advance of 
vegetation, the flight of birds, the blossoming, leafing, etc., of 
trees, shrubs and plants, were obtained of Hon. Thomas Mikesell 
of Wauseon. This gentleman has a most remarkable record of 
phenological observations since 1869—I know of no more com¬ 
plete and exact record in this country than these. 
Charts were made showing the departure of the average tem¬ 
perature and total rainfall from the normals, by months from 
January 1876 to 1904, and the departure of the different crop 
yields from the normal for the same period. 
