10 
BULLETIN ^3, U. S. DEPARTMENT OF AGRICULTURE. 
No summer-fallow land was found in the winter-wheat districts, 
and in the spring- wheat areas only a small percentage of the crop 
area was summer-fallowed. 
The area devoted to flax production was also limited. 
The miscellaneous crops consisted principally of potatoes, millet, 
spelt, and clover and timothy seed. 
CLIMATE. 
Although wheat is grown in localities in the United States having 
widely different climates, it is a cool-weather crop, and produces the 
largest yield of best quality where cool, moderately wet weather 
prevails during the growing season and dry, sunny weather during 
the ripening period. Wheat is not generally a safe crop where the 
mean annual precipitation is less than 15 inches. In the districts 
of densest production (North Dakota and Kansas) the annual pre- 
cipitation ranges from 18 to 32 inches. Where the rainfall exceeds 
45 inches a year wheat does not thrive, principally because rust and 
fungus diseases are more prevalent there than in less humid districts. 
The distribution of the rainfall is as important as the total amount. 
For instance, in Ford County, Kans., in 1918, the total rainfall was 
normal, but the average yield of wheat for the county was only 3 
bushels per acre. This low yield was due mainly to the small amount 
of rainfall during the months of April, May, and June; in June it 
was only one-fourth inch; and for the three months but 4.5 inches, 
as compared with a normal rainfall of about 8 inches for these months. 
Table IV shows the average yearly precipitation for all districts 
\nsited, as compared with the total rainfall for the year 1919: 
Table IV. — Mean annual rainfall for districts visited. 
Region. 
Weather station. 
Annual average. 
1919 
SPRING WHEAT. 
North Dakota: 
Grand Forks County 
Morton County 
South Dakota; 
Spink County 
Minnesota: 
clay County 
Traverse County 
WINTER WHEAT. 
Kansas: 
Ford County 
Pawnee County 
McPherson County 
Missouri: 
Saline County 
Jasper County 
St. Charles County 
Nebraska: 
Phelps County 
Saline County 
Keith County 
o No record taken after 1914, 
Larimore... 
New Salem 
Melette 
Moorhead.. 
"WTieaton... 
Dodge City 
Lamed 
McPherson 
Marshall... 
Joplin 
St. Charles. 
Holdredge.. 
Crete 
Lodgepole.. 
From 1910 to 1918. 
From 1909 to 1918. 
From 1892 to 1918. 
From 1881 to 1918. 
From 1915 to 1918. 
From 1896 to 1918. 
From lS60tol918.. 
From 1889 to 1918. 
From 1890 to 1918., 
From 1878 to 1914 a 
From 1890 to 1918.. 
From 1891 to 1918.. 
From 1880 to 1918.. 
From 1890 to 1918.. 
Inches. Inches. 
20. 20 25. 32 
17.87 13.68 
23.65 I 
18.47 
26 
23.75 
21.18 
13.70 
19.88 
31.46 
36.12 
35.11 
25.83 
33.42 
18.95 
