12 CIRCULAR NO. 120, BUREAU OF PLANT INDUSTRY. 
SUMMER FALLOWING. 
Three years’ results have now been obtained from the tests in 
summer fallowing land for corn, oats, and cotton. As in 1911, the 
vields of crops on land summer-fallowed the previous season were 
generally low, corn yielding at the rate of 24.7 bushels per acre, as 
compared with the average of 34.1 bushels per acre on the 26 plats 
in the rotation experiments. The corn on the summer-fallowed plat 
yielded the lowest, save one, of any of the 26 plats. 
Cotton on summer-fallowed land yielded at the rate of 448 pounds 
of seed cotton per acre, as compared with an average of 621.5 pounds 
per acre on the 25 plats of cotton, giving the lowest vield of the 25 
plats. 
Fic, 5.—Cotton on plat B 5—5, land continuously cropped and not manured. This plat 
has yielded an average of 397 pounds of seed cotton per acre during the past three 
years. Compare with figure 4. (Photographed June 26, 1912.) 
Oats for grain on a fallowed plat yielded at the rate of 37 bushels 
per acre, the highest yield obtained from the 10 plats of oats. The 
average yleld from 10 plats was 26.75 bushels per acre. While the 
oats on summer-fallowed land yielded somewhat higher than the 
others, the increase was not sufficient to indicate that summer fallow- 
ing is a desirable practice under the conditions at San Antonio, even 
for oats. 
SUBSOILING. 
Subsoiling tests have been a rather important part of the rotation 
and tillage experiments. The results have been summarized and pub- 
lished in Circular No. 114 of the Bureau of Plant Industry. 
[Cir. 120] 
