18 
BULLETIN 1211, U. S. DEPARTMENT OF AGRICULTURE 
Table 17. — Net increase in yield of potatoes due to successive increments of 
manure and fertilizer 
Value of manure and fertilizer applied 
Total 
Incre- 
increase 
ment 
Bushels 
Bushels 
8 
8 
15.5 
7.5 
22 
6.5 
27 
5 
30 
3 
32 
2 
33 
1 
Bushels 
per 
dollar's 
input of 
fertilizer 
and 
$2.50.. 
$5.00.. 
$7.50.. 
$10.00. 
$12.50. 
$15.00. 
$17.50. 
3.2 
3.1 
2.9 
2.7 
2.4 
2.1 
1.9 
Table 18. — Relation between depth of plowing and yield of potatoes 
Depth of plowing 
Yield after 
eliminating 
effects of 
other 
factors 
Depth of plowing 
Yield after 
eliminating 
effects of 
other 
factors 
6.0 inches . . . ... 
Bushels 
122.5 
125.0 
126.7 
127.0 ! 
8.0 
Inches 
Bushels 
126.0 
8.5. 
123.0 
7.0 inches. . . . 
9.0 ,. 
120.0 
Table 19. — Relation between seed planted and yield of potatoes per acre 
Increase 
in vield 
Seed planted per acre 
Adjusted 
potato 
due to 
increase 
ofl 
bushel in 
yield 
seed 
input 
Bushels 
Bushels 
10 bushels. 
100 
118 
132 
143 
152 
12bushels . 
9 
14 bushels.. .. . . 
7.5 
16bushels .. . 
5. 5 
18 bushels . . .... 
4 5 
BEEF PRODUCTION ANALYSIS 
The data on beef production were more complete, and an analysis 
covering more factors was made. Taking into consideration the 
daily inputs of grain, roughage, and protein concentrates per head, 
the weight of the animals at the beginning of the feeding period, and 
the length of the feeding period, it was possible to determine the net 
effect of each factor upon the gains made. The net gain accompany- 
ing an increase of 1 pound in protein concentrates was 0.07 pound 
of beef. As few droves were fed any protein concentrates, this 
determination of the relation of protein concentrates to the gain in 
weight did not have a particularly good basis. For each of the other 
factors, however, it was possible to determine rather accurately not 
only the average gain due to it, but the gain due to each individual 
