CEOP PRODUCTION ON FALLOW LAND AT SAN ANTONIO. 5 
This comparatively light vegetative growth appears to have been 
favorable to the production of grain. In 1912 and 1913, especially 
the latter season, oats on the rotation plats lodged badly, owing to 
excessive vegetative growth. It has been found at San Antonio that 
any treatment which has a tendency to retard the early vegetative 
growth of the oat plant results in increased yields of grain. An 
instance substantiating this statement is afforded by the unfavorable 
results from manuring on land planted to oats to be harvested for 
grain. In a 4-year test with oats, manuring has noticeably decreased 
the yield of grain in two out of the four years, while in the other two 
years the yields were practically the same as those obtained from 
unmanured land. It appears, therefore, that the increase in yield of 
oats on fallowed land has not been due to the fact that conditions 
were more favorable to growth, but rather to a depressing effect on 
the vegetative growth. 
Crops grown on fallowed land have invariably shown irregular and 
slow early development as compared with the same crops on other 
plats. The corn and cotton on the fallowed plats have been notice- 
ably smaller than on the other plats in the rotation experiments, and 
the plants have lacked uniformity in size and appearance. Observa- 
tions on other plats of the experiment farm where cotton has been 
grown on fallowed land corroborate this conclusion. While the 
differences with oats have not been so marked, in 1913 the oats on 
fallowed land were smaller and made slower growth than on land 
continuously cropped or having other treatments. On account of 
the difficulty with the lodging of grain crops, as already indicated, the 
depressing effect of fallowing on the growth of the plants results in 
high yields of oats, while it has the opposite effect on corn and 
cotton. 
SOIL-MOISTURE STUDIES. 
Soil-moisture determinations have been made on the fallowed plats 
considered in this report and also on the continuously cropped plats 
devoted to the same crops. Samples have been taken monthly or 
oftener during the summer throughout the three years. A standard 
soil tube was used for securing the samples. At each sampling two 
cores were taken from different parts of the plat, corresponding foot- 
sections being composited to a single sample. Thus either three or 
six samples were secured from each plat, depending upon the depth 
to which the sampling was done. In most cases samples were taken 
to a depth of 6 feet. 
In figures 2, 3, and 4 the diagram at the top shows the crop, 
stubble, and fallow periods for each plat considered in this report, 
and the curves below show the moisture content of the different 
plats at the time the moisture determinations were made during the 
four years from 1910 to 1913, inclusive. 
