98 BULLETIN 757, U. S. DEPARTMENT OF AGRICULTURE. 
It should be noted that in 1900 and 1910 exceptionally low yields 
were made, owing to drought conditions. In 1900 the annual rain- 
fall was about normal in the State (18.6 inches), the shortage of May 
and June being made up during the other months, but 1910 was very 
dry during the whole year, the total rainfall being but 12.4 inches. 
Other data not here presented show that there is only a slight rela- 
tionship between rainfall in April and yield. Neither is there any 
CROP INDEX - WHEAT, OATS, AND BARLEY 
[MAY AND JUNE] 
PRECIPITATION ~ INCHES 
Fic. 17.—Relation of rainfall in May and June to yield per acre. 
marked relation between annual rainfall and yield of these crops. 
May and June are the critical months. With a rainfall of 6 inches 
distributed over the months of May and June, at least normal crops 
may be expected. 
TABLE VI.—Yield per acre for various crops in North Dakota (Bureau of Crop 
Estimates’ figures for 1891-1916, and records of actual yields obtained in this 
imvestigation for 1912-13-14). 
Yield per acre (bushels). 
Source of figures. ——— SSS TSS 
Wheat. Oats. Barley. Flax. Corn. | Potatoes. 
Bureau of Crop Estimates...._..........-- 12.3 28.1 22.4 a8.6 22.8 95 
PTI SHMVeStl Get O Hee ae eee ae 13.2 33.9 PING T/ 7.9 33.8 87 
a Averate 1902-1916 inclusive. 
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