OATS IN THE GREAT PLAINS AREA. 5 
the average appears under the heading "Average," the calculation 
is from the left. The averages of the different methods of treatment 
are the averages of the whole numher of plats that entered into their 
composition. For a rough comparison of seasons the bottom line of 
the first half of the table gives the averages of all plats for each year, 
the average of the yearly average yields appearing in the last column 
to the right. 
As here presented the treatment of the land is specified as fall 
plowed, spring plowed, sod breaking, subsoiled, listed, disked, green 
manured, and summer tilled. Under these headings are subdivisions 
to show the preceding crop. 
Where oats appear following wheat on either fall or spring plowed 
land it has been in rotations of at least 3 years in length. Where oats 
follow oats the system has been that of continuous cropping. 
Fall plowing is done as early as practicable and to a good depth, the 
standard being set at 8 inches. The ground after being plowed may 
be worked down or left rough through the winter, as seems advisable. 
Spring plowing is done as early as practicable in the spring, with the 
exception of one plat at each station, on which oats follow oats. It 
is done to a good depth, about 8 inches, and given sufficient cultiva- 
tion with the harrow, or disk if necessary, to form a good seed bed. 
On one plat which is continuously cropped to oats at each station, 
spring plowing is shallow (only about 4 inches) and is given a mini- 
mum of cultivation. 
Sod is broken in the fall as early as hay production for the year is 
over. 
Subsoiling is done on land continuously cropped to oats. The 
treatment of the plat that appears at some stations under this heading 
is the same as the treatment of the plat that appears under "Fall 
plowed/' except that it is subsoiled. At the time of plowing a sub- 
soiler is run in every other furrow to an additional depth of 6 or 8 
inches, making a total depth of about 14 inches. This is usually done 
two years in succession and then omitted for two years. 
The plat that appears at some stations under the heading " Listed," 
following oats, is a plat continuously cropped to oats. At the time of 
fall plowing this plat is furrowed out with the lister instead of being 
plowed. In the spring it is worked down level and the seed bed 
prepared without the use of the plow. 
The plats on disked corn ground are all in rotation with other crops. 
Both 3-year and 4-year rotations comprise this series. The other crops 
may be winter wheat, spring wheat, barley, green manure, or potatoes. 
In some of the rotations summer tillage replaces one of the crops. 
Where oats are grown after a green-manure crop the system is 
that of a 4-year rotation in which one crop is corn and the other one 
of the small grains. 
