TILLAGE AND ROTATION EXPERIMENTS, NORTH DAKOTA 13 
system is practiced, the acreage of corn should be less than if live- 
stock is grown. With the more general use of adapted seed, better 
yields of corn can be expected. 
RESULTS ON FALLOW COMPARED WITH THOSE ON DISKED POTATO GROUND 
Two four-year rotations at Hettinger offer comparisons of both 
wheat and oats following potatoes and following fallow. Rotation 
No. To is manured fallow, wheat, potatoes, and oats, and rotation 
No. 76 is manured fallow, oats, potatoes, and wheat. Wheat on 
potato ground averaged 0.3 bushel more than on fallow, and oats 
following potatoes averaged 0.1 bushel less than on fallow. Potatoes 
averaged 82.8 bushels in rotation No. 75 and 82.1 bushels in rotation 
No. 76, indicating that the two were about equal in yielding power. 
Since the two rotations differed so little in the yields of both wheat 
and oats the conclusion is that potato ground is equal to fallow 
as a preparation for grain. These rotations were arranged to deter- 
mine the relative effects of potatoes and of fallow on succeeding 
grain crops and not to study the method of growing potatoes. Dur- 
ing dry years potatoes will yield more on fallow, but in years with 
low temperatures and heavy rainfall potatoes, like corn, may yield 
less after fallow than following grains. In 1923 some experiments 
were added at Dickinson to determine the relative values of grain 
stubble and of fallow for the production of potatoes. It is too early 
to draw conclusions from the results. 
RESULTS ON MANURED FALLOW COMPARED WITH THOSE ON UNMANURED 
FALLOW 
Four rotations at Hettinger included fallow which received an 
application of manure just before plowing in the spring of the 
fallow year. Two of these may be compared with similar rotations 
containing fallow without manure. Rotations Nos. 19 and 71 are 
fallow, oats, corn, and wheat, with manure applied at the rate of 10 
tons per acre before the fallow in rotation No. 71. A comparison 
of the yields of oats in these two rotations shows that there was a 
decrease of 1 bushel per acre following the use of manure. The an- 
nual differences in yield were marked by wide variations in favor 
of both the manured and the unmanured fallow. In 1913 oats in 
rotation No. 19 yielded 41.9 bushels and in rotation No. 71 only 15 
bushels, or 26.9 bushels in favor of the unmanured fallow. In 1915 
rotation No. 19 yielded 83.4 bushels and rotation No. 71 105 bushels, 
or 21.6 bushels in favor of the manured fallow. The average weight 
of straw was 275 pounds heavier in rotation No. 19 than in No. 71. 
Wheat following corn in these rotations averaged 2.7 bushels more 
in the unmanured than in the manured rotation. Manure induces 
a rank early growth, and these experiments indicate that the yield 
is increased in wet years, when there is ample moisture to carry the 
vigorous early growth to maturity. 
Rotations Nos. 18 and 72 are similar to the above rotations except 
that wheat instead of oats immediately follows the fallow. The 
wheat averaged 17.4 bushels after ordinary fallow and 15.4 bushels 
after manured fallow, a decrease of 2 bushels following manure. 
The weight of straw was 129 pounds heavier on the manured fallow. 
In all of these rotations corn was the second crop after the fallow 
and was harvested for silage. The green weight of corn harvested 
for silage averaged 587 pounds per acre less following wheat in the 
