SPRING WHEAT IN THE GREAT PLAINS AREA. 17 
is used at this station and is plowed under at the same time as peas. 
This is done in early summer, and the land is then handled as an 
intensively cultivated bare fallow until seeding time. While results 
have fluctuated between the two crops used for green manure from 
year to year, the variations have probably been within the limits of 
e \ i >erimental error. 
As to the relative merits of fall and spring plowing and disking as 
a means of preparation for wheat, the yields show such lack of con- 
sistency from year to year that it would be unwise to attempt to draw 
general conclusions from the data at hand, unless it were that the 
results attending these practices will vary with the season and that 
no particular one is essential to success. 
Wheat, on both spring and fall plowing after oats, appears on the 
average to yield better than wheat after wheat. 
When the cost of production is figured, it is found that the average 
yields of the five years under study have been sufficient to allow a 
profit from all methods except that of green manure. While the 
yield from this method was next to the highest, it was not enough to 
offset the heavy cost of production. 
The greatest profit, '$6. 59 per acre, was obtained from disked corn 
ground, and the least, $2.64 per acre, from summer tillage. 
DICKINSON FIELD STATION. 
The soil at the Dickinson Field Station, in North Dakota, is somewhat 
lacking in uniformity. In general, however, it is characterized as a 
sandy loam to a depth of approximately 5 feet. Below this depth 
is a lighter soil, which in some cases becomes very sandy or pure sand. 
The soil has the capacity to retain a large proportion of water and to 
give up to the crop a large share of what is retained. This feature, 
in connection with the depth to which a crop may feed, makes it 
possible to store in this soil an exceptionally large quantity of water 
that can be recovered by the crop. 
While records for the Dickinson station are available for study 
since and including 1908, the yields and averages are made up from 
the results of six years, as the crop of 1912 was destroyed by hail 
shortly after heading. As the fall plowing that year was done 
exceptionally early, on account of the opportunity offered by the 
early removal of the crop, it shows up relatively much better than 
usual in 1913. On this account it approached summer tillage and 
green manure both in opportunity and in results. 
Four of the years studied have been years of heavy wheat produc- 
tion from all methods. The year 1911 was one of low general average, 
but of exceptional differences between methods. It was a year of 
drought during the late stages of growth, which, made it possible to 
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