ORGANIZATION AND MANAGEMENT OF FAEMS IN PENNSYLVANIA. 
29 
Acid phosphate was used by many farmers. Some, however, used 
more expensive fertilizers. Mixing acid phosphate with stable 
manure in the barn was not practiced to any extent. 
In order to show the effect upon crop yields of increasing the 
amount of fertilizer and manure used per 100 acres of crops, the. 
349 farms were grouped as shown in Table XV. 
Table XV. — The effect upon crop yields of applying different amounts of fertilizer and 
of live stock Jcept on 349 farms, Grove City, Pa., area. 
Fertilizer per acre. 
Animal units per 100 
None. 
100 pounds or under. 
Over 100 pounds. 
acres of crops. 
Animal 
units per 
100 acres 
of crops. 
Fertil- 
izer per 
acre. 
Crop in- 
dex. 
Animal 
units per 
100 acres 
of crops. 
Fertil- 
izer per 
acre. 
Crop in- 
dex. 
Animal 
units per 
100 acres 
of crops. 
Fertil- 
izer per 
acre. 
Crop 
index. 
25 
Pounds. 


82 
100 
28 
45 
Pounds. 
55 
63 
92 
107 
Pounds. 
28 174 
44 
98 
Over 35 
43 
109 
Farmers using over 100 pounds of fertilizer per acre of crops and 
keeping less than 35 animal units per 100 acres of crops failed to pro- 
duce as high crop yields as the farmers who used no fertilizer but had 
-. - 
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eBBHbB&sl - , - . »..-*■- 
Fig. 8.— Limestone prepared for burning. Either coal or wood may be used. 
over 35 (or an average of 43) animal units per 100 acres of crops. 
The highest crop yields were obtained by the group using over 100 
pounds of fertilizer per acre and keeping over 35 animal units per 100 
acres of crops. The crop yields on these farms were 9 per cent above 
the average of all the farms. The lowest crop yields were on the group 
