10 BULLETIN 151, U. S. DEPARTMENT OF AGRICULTURE. 
SUMMARY. 
(1) Tests of biennial cropping in comparison with annual cropping 
hare been carried on at the San Antonio Experiment Farm for 
three years. 
(2) The yields of corn and cotton have been less on biennially 
cropped land than on annually cropped land. The yields of winter 
oats have been somewhat larger on the biennially cropped land. 
(3) Soil-moisture studies made in connection with these tests do 
not show any important differences in the amount of soil moisture 
present in fallowed land and in continuously cropped land at planting 
and harvest time for corn and cotton. In the plats used for oats 
there was more moisture present at planting and less at harvest time 
on the biennially cropped land than on the annually cropped land. 
In other words, the oats grown biennially used more water and made 
less vegetative growth, but gave larger yields. 
(4) Observations made after heavy rains show that in most cases 
the proportion of run-off from heavy rains was greater on land which 
had been fallow lor several months than on land which had been 
fallow for a comparatively short time. The run-off from an oat plat 
was less than from any of the fallow plats. 
(5) Considering both crop yields and cost of production, the results 
of these experiments indicate that biennial cropping, at least for 
corn, cotton, and oats, is not to be recommended for the San Antonio 
region. 
WASHINGTON: GOVERNMENT PRINTING OFFICE : 1914 
