TILLAGE AXD ROTATION EXPERIMENTS, NORTH DAKOTA 21 
Dickinson, where the experiments have run longest, a marked reduc- 
tion in the yield of wheat was noted but not in the yield of ear corn. 
From the A plat at this station an average of 762 pounds of wheat 
and 1,189 pounds of straw, a total of 1,951 pounds, was removed 
annually by the wheat crop. In the corn series 3,343 pounds of 
fodder was removed annually, or more material than was removed 
from the wheat plats if the two weights were adjusted to a dry basis. 
Since the corn plat is free from weeds and the wheat plat is badly 
infested, it is inferred that weeds are responsible for the decreased 
yield of wheat. 
The plats alternately cropped to small grains and fallowed have 
remained relatively free from weeds, and the yields of these plats 
have not decreased in comparison with those of similar ones in 
rotations. 
SUMMARY 
This bulletin summarizes the results of the tillage experiments 
and crop rotations in western North Dakota during 16 years at 
Dickinson and 11 years each at Hettinger and Williston. 
Climatic conditions at the three stations are very similar, the 
precipitation being a little greater at Dickinson and slightly better 
distributed at Hettinger, and the frost-free period longer at Wil- 
liston. 
The results of most of the experiments agree very closely at the 
three stations and also agree with the results of similar work at 
other stations in the northern Great Plains. 
Spring grains and corn have produced slightly higher yields with 
spring plowing than with fall plowing. Exceptions to this are noted 
with wheat at Dickinson, corn silage at Hettinger, and both ear corn 
and fodder at Williston. 
At each of the stations the highest average yields of all crops, 
except barley and corn fodder at Dickinson and corn silage at Het- 
tinger, were obtained on fallow. The increases over other methods 
were not sufficiently great, however, to pay directly for the use of the 
land for a season and for the tillage necessary to keep the fallow 
clean. As a factor in keeping land free from weeds and as an aid to 
early seeding, fallow has a value not directly estimable. 
Disking corn ground is more economical than either spring plow- 
ing or fall plowing it in preparation for small-grain crops and has 
given higher yields. 
The value of corn in a rotation is far greater than the value of the 
feed produced. Yields of wheat, oats, and barley were greater on 
disked corn ground than on spring-plowed or fall-plowed grain 
stubble and not far below those on fallow. Wheat at the three 
stations averaged 18.8 bushels on fallow and 16.5 bushels on disked 
corn ground, oats averaged 40.3 bushels on fallow and 35.1 bushels 
on disked corn ground, and barley averaged 28 bushels on fallow and 
25.7 bushels on corn ground. 
Growing corn on fallow has resulted in an increase of mature ear 
corn, but a reduction in the quantity of fodder at Dickinson, a reduc- 
tion in the silage at Hettinger, and an increase in the fodder at 
Williston. Corn on fallow tends to mature later than when grown 
on grain stubble plowed either in the fall or in the spring. 
