10 
BULLETIN" 1310, XT. S. DEPARTMENT OF AGRICULTURE 
With the "unfavorable seasons and the failures of winter wheat the 
yields with all methods are low, but marked differences are shown 
between them. 
Table 6. — Annual and average yields of winter wheat 1 obtained with four methods 
of fallow, 1918 to 1923, inclusive 
Plats 
Treatment 
Yields per acre (bushels) 
1918 
1919 
1920 
1921 
1922 
1923 
Average 
Hand I.... 
J and K 
Fall plowed; cultivated immedi- 
ately. 
Fall plowed; left rough first 
winter. 
6.0 
5.5 
7.2 
4.5 
10.3 
15.3 
10.7 

3.8 
8.0 
6.8 
2.7 
13.2 
15.7 
16.8 
7.5 
3.5 
9.5 
13.0 
4.2 




6.1 
9.0 
9.1 
N and 0... 
Summer plowed (early July) 
3.2 
1 In 1920 and 1922 winter wheat winterkilled and was reseeded to Marquis, 
place in 1923, and the plats were reseeded in the spring. 
Some winterkilling took 
Fall plowing which was cultivated after plowing shows 2.9 bushels 
less yield than fall plowing left rough during the first winter. The 
yield from fall plowing left rough is about equal to that of May 
plowing. These two methods show rather consistently higher yields 
than the other two. The most outstanding contrast in methods is 
between the May plowing and the early July plowing, the average 
yield from the latter being only slightly more than one-third that 
from the former. 
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Fig. 5.— *Average yields of winter wheat with four methods of fallow for the 6-year period from 1918 to 
1923, inclusive 
RESULTS OF PLOWING AT DIFFERENT DEPTHS FOR FALLOW 
Depth-of -plowing experiments were started in 1916, and the results 
for seven years of plowing fallow at different depths are here reported. 
The depths of plowing were 4, 8, and 18 inches including subsoiling 
to a depth of 10 inches below the plowed furrow. In the latter case, 
only the surface 8 inches was turned by plowing, the lower 10 inches 
being loosened by means of a subsoiler. 
Oats, barley, and winter wheat have been grown each year on 
fallow plowed to the depths specified. Neither the depths of plow- 
ing nor the crops have been changed during the 7-year period. The 
plowing was done in May and sufficient summer cultivation given to 
control weed growth and maintain a clod mulch. The plats plowed 
to a depth of 8 inches agree in method with the plats L and M in the 
last described experiment. 
