18 BULLETIN 218, U. S. DEPARTMENT OF AGRICULTURE. 
Spring plowing has averaged a little better than fall plowing, irre- 
spective of the kind of stubble plowed. The relative merits of the 
two vary from year to year, depending upon the season and the 
condition of the ground at plowing time. Generally, when the 
ground is wet at the time of fall plowing, the better results are ob- 
tained from it. On the other hand, if fall plowing is done when the 
ground is dry, it has not been as good as spring plowing. 
When the cost of production is considered, as in the second part of 
Table VIII, it is seen that the high cost of green manure has caused 
the growth of oats by this method to be done at a loss of $1.16 per 
acre. The high yields and low cost of preparation of disked corn 
ground have combined to make it show the largest profit of any 
method, $9.75 per acre. Intermediate between these are spring 
plowing with $5.23, fall plowing with $4.01, and summer tillage with 
$3.72 profit per acre, respectively. 
EDGELEY FIELD STATION. 
The field station at Edgeley, N. Dak., is located on a soil that is 
derived from the decomposition of shale, which in undecomposed 
particles is found very near the surface. In the third foot the shale, 
while broken and offering fairly free passage to water, is not as yet 
broken down into soil. The depth of feeding of crops is practically 
limited to the first 2 feet. The first foot carries an unduly large sup- 
ply of water available to the crop. The limited depth of soil that 
functions in the storage of water and in the development of the crop, 
however, limits the quantity of available water that can be carried 
in the soil to about half that carried by soils of greater depth. This 
makes the crop practically dependent upon rains that fall while it 
is growing. 
Edgeley offers for study of oat production an unbroken record of 
eight years. Five of the eight years have been productive of heavy 
crops from practically all methods, while three have been years of 
light production from practically all methods. 
The range of yields from different methods of preparation and 
cropping as exhibited in the average of the eight years is compara- 
tively small. This is as might be expected from the soil on which 
the station is located. Its shallowness makes the crop much more 
dependent upon the seasonal precipitation than it is in deeper soils. 
It is, consequently, impossible to realize much benefit from methods 
of cultivation calculated to store water in the lower zone of normal 
crop-feeding depth. 
Oats on land which was summer tilled the previous year have 
produced an average yield of 38.3 bushels per acre, but this is only' 
4.8 bushels more than the average on disked corn ground and 6.4 
bushels more than the average of all crops following small grain. 
