CROP PRODUCTION ON FALLOW LAND AT SAN ANTONIO. 9 
Table II. — Absorption and run-off from rains in February, 1912, San Antonio Experi- 
ment Farm — Continued. 
Fallow period 
or crop. 
Samples taken on Feb. 26, one day after a 2.9-inch rain, when 
the soil was already wet. 
Plat No. 
Average moisture, 
content in 6 feet. 
Increase.. 
Run-off. 
7 days 
before 
rain. 
1 day 
after 
rain. 
Per cent. 
Inches. 
Inches. 
Percent- 
age of 
rainfall. 
A-l-1 - 
3 months 
Per cent. 
15.2 
16.8 
15.3 
16.7 
15.5 
16.3 
Per cent. 
16.6 
17.2 
16.8 
17.8 
16.2 
18.4 
1.4 
.4 
1.5 
1.1 
.7 
2.1 
1.3 
.37 
1.4 
1.03 
.66 
1.96 
1.61 
2.54 
1.51 
1.88 
2.25 
.95 
55.3 
A4-2.... 
15 months... 
87.1 
A 4-3 
5 months 
51.7 
A-l-1 
18 months. . . . 
64.6 
A4-5 
6 months 
77.3 
A !-(i 
Oats 
32.6 
Table II shows that the run-off from land that had been fallow for 
several months was greater than from land plowed a comparatively 
short time before the heavy rains. The proportion of run-off from 
the second rain was somewhat greater than that following the first 
rain, and the difference in run-off from plats fallowed for a short time 
and from those which had been fallow for a longer time was more 
marked. The run-off from the oat plat was materially less following- 
bo th rains than that from any of the fallow plats. 
ECONOMIC CONSIDERATIONS. 
The question of whether it is desirable to make a practice of 
biennial cropping for certain crops must be considered from two 
standpoints: (1) The effect upon the crop and (2) the cost of pro- 
duction as compared with annual cropping. It must be remembered 
that in the first case only one crop is grown in two years and that 
fixed costs, such as the interest on the investment in land for two 
years, must be charged against one crop. Under the conditions at 
San Antonio, where plant growth continues practically the entire 
year, making necessary the cultivation of the fallow to kill weeds 
and maintain a mulch, the expense of f allowing is nearly, if not quite, 
as much as that of growing a crop on the land. Other items, such as 
the depletion of the humus and the possible ultimate effect on fertility, 
are matters deserving consideration in connection with the practice 
of biennial cropping. It must be concluded, then, that even though 
biennial cropping gave increased yields of winter oats at San Antonio 
it is not necessarily desirable as a farm practice in growing that crop 
there. In other words, the results of these experiments indicate 
that biennial cropping is not to be recommended for the San Antonio 
region, at least for cotton, corn, and oats. 
