SPRING WHEAT IN THE GREAT PLAINS AREA. 21 
are not exhibited at this station in cither the good or the poor years. 
The reason for this is to be found in the shallowness of the soil that 
functions for the growth of the crop and for the storage of water that 
can be recovered by the crop. This shallowness makes the crop 
dependent for its growth upon seasonal rains that fall while the crop 
is growing. It may be that this shallowness makes it possible to 
realize quicker results from the cumulative effect of the use of manure 
than would be realized on deeper soils. 
The relative merits of fall or spring plowing of either wheat or oat 
stubble seem to be a matter of season. In no case does it make 
a great difference, and on the average the difference has been neg- 
ligible. It should be noted that the result from the one plat of wheat 
on spring-plowed wheat land deserves but little consideration. On 
account of its location and of continual spring plowing, it has accu- 
mulated blowing soil until it is now built up several inches above its 
original level, or the present level of other plats. 
Fall-plowed corn ground has apparently had an advantage over 
corn ground, either spring plowed or disked, in preparation for wheat. 
The results are determined from 1 plat of fall-plowed corn as against 
12 plats of disked corn ground, which are distributed over the whole 
field; the advantage, therefore, may be due to a particularly favor- 
able location of the one plat. 
With the exception of the high yield of wheat in 1914 on peas used 
as green manure, there is little choice between them and rye similarly 
used. Both have been better than sweet clover plowed under. The 
average yield of wheat following peas as green manure is exactly 
the same as the average on summer tillage. 
Summer tillage has given an average yield of 17.9 bushels per acre 
for the eight years. This is exceeded only by the yield on fall-plowed 
corn ground. When this is compared with a similar average yield 
of 17.7 bushels per acre from disked corn ground and 14.2 bushels 
from wheat under all methods following small-grain crops, it is seen 
that summer tillage is an unnecessary practice and one not to be 
recommended for this section. This is brought out strongly by Table 
IX, which shows the cost of production and the resultant profit or 
loss from each method. Disked corn ground shows an average 
8-year profit of $7.64 per acre, spring plowing $4.76, and fall plowing 
$4.15, while the cost of summer tillage has reduced the profit to $1.03. 
The average loss for the green manures has been $2.92 per acre. 
HETTINGER FIELD STATION. 
The soil at the Hettinger (N. Dak.) station is a heavy clay loam. 
The seasons during which the work has been carried on have been 
such that the results of soil-moisture study are not yet conclusive 
in determining the proportion of water that can be stored in the soil 
