GRAIN FARMING IN NORTH DAKOTA. 
YIELDS. 
27 
Success in farming in North Dakota depends very largely upon 
yields, and the factors that affect yield are of interest to every 
farmer. Some of these factors are not under human control, but 
many of them are, and even the uncertain factors may be in some 
degree controlled by the prospective farmer by avoiding localities 
unfavorably situated. 
Fig. 16. — Yield per acre of wheat, oats, barley, and corn (North Dakota, 1891-1916). 
Yields per acre of all crops vary from year to year for various 
causes. The lines in figure 16 show the average yields that have 
been made in the State from 1891 to 1916, inclusive. Wheat, of 
course, is of greatest importance. It generally happens that where 
low yields of this crop are made the production of other crops is 
also low. It is noted that there is a marked parallelism in the lines 
for wheat, oats, and barley; the corn line, however, does not follow 
the general order very closely. 
Within the limits of the growing season, the yield of these crops 
of wheat, oats, and barley are dependent upon rainfall to a greater 
extent than upon any other factor. Corn is dependent upon rainfall 
also, but is affected very greatly by temperature. Its growing season 
is also different from that of the other grain crops. 
The lines in figure 17 show the relation of rainfall to yield. The 
line at the bottom of the figure represents the combined rainfall in 
inches during the months of May and June for each year from 1891 
to 1916, and the upper line is a crop index representing the yields of 
wheat, oats, and barley. It is noted that there is a marked paral- 
lelism in these lines, that is, where the rainfall is greatest the yields 
are uniformly largest. There are two exceptions to this order, one 
for 1896 and another for 1914. In both of these years there was a 
large amount of rainfall during May and June, in each case more 
than 8 inches falling in such short periods that much grain was 
drowned out. Three other years show rainfall during these months 
in excess of 8 inches, but so distributed as to cause increases rather 
than decreases in yields. 
