TILLAGE AND ROTATION EXPERIMENTS, NORTH DAKOTA 9 
bushels. In the continuously cropped wheat series the spring- 
plowed plat averaged 11.8 bushels and the fall-plowed plat 879 
bushels per acre for the 11 years from 1912 to 1922. Plats given 
similar treatment at Dickinson averaged 12.8 and 12.5 bushels, re- 
spectively, for a 15-year period. 
Oats at Hettinger averaged 29 bushels on spring plowing and 25.6 
bushels on fall plowing, an increase of 3.4 bushels with spring plow- 
ing. Barley averaged 21 bushels on spring plowing and 20.6 bushels 
on fall plowing, a difference of only 0.4 bushel. Corn averaged 
higher on fall plowing, but this method was represented by only a 
single plat. On plats cropped continuously to corn one that was 
spring plowed averaged 6,396 pounds and one that was fall plowed 
7,021 pounds of silage per acre, an increase of 625 pounds, or almost 
10 per cent, on fall plowing. 
All crops at Williston except corn yielded slightly better on spring- 
plowing than on fall plowing. The average yield of wheat was 14.1 
bushels on spring plowing and 13.9 bushels on fall plowing. Oats 
averaged 31.4 bushels on spring plowing and 28.2 bushels on fall 
plowing. Barley averaged 14.2 bushels on spring plowing and 12.7 
bushels on fall plowing. With corn, however, the yields of both 
grain and fodder were slightly heavier on fall plowing. Ear corn 
averaged 13.8 bushels on fall plowing and 13.2 bushels on spring 
plowing. Fodder averaged 3,542 pounds on fall plowing and 3,514 
pounds on spring plowing. 
The results are slightly in favor of spring plowing except for 
corn at Hettinger and Williston, where some increases have followed 
fall plowing. As a practice it is desirable to plow as much land in 
the fall as possible, in order that seeding may be done early in the 
spring. One of the most important factors in crop production in 
this area is the early seeding of grain. When the soil in the fall is 
wet enough to permit a good job of plowing, it is desirable to do it 
at that time. When the ground in the fall is so dry that plowing is 
difficult and the soil breaks up very rough, the succeeding yields are 
usually lower than on spring plowing. Usually the upper soil is 
wet enough in the spring to make a good job of plowing possible at 
that time. 
RESULTS ON FALLOW AND FOLLOWING SMALL GRAINS COMPARED 
At each of the stations fallow appears in a number of rotations 
and also in the continuous-cropping series with the principal crops. 
In the latter group of experiments fallow alternates with the several 
crops in two-year combinations. These rotations and cultural series 
give opportunity to study fallow with several crops and in several 
relations. 
During the early years of the experiments the grain stubble was 
plowed in the fall in preparation for fallow and replowed during 
the summer of the fallow season. A series of tests of methods of 
fallow at several stations showed that fall plowing did not increase 
the yields. The present practice is to plow as early in the summer 
as practicable, usually between May 20 and June 15, and subse- 
quently work the land only enough to prevent weed growth. Plow- 
ing is done to a depth of from 6 to 8 inches. Shallower plowing is 
practiced in the area but the best farmers plow to about this depth. 
18519—25 2 
