98 
BULLETIX 341, TJ. S. DEPARTMENT OF AGRICULTUEE. 
Table LX. — Value of manure per animal unit determined by comparing two 
groups of Lenawee County {Mich.) farms. 
[The first group includes 75 farms (one-fourth of the entire number) having the least number of animals 
per 100 acres of crops ^average, 19.44). The second group includes 75 farms'" (one-fourth of entire number) 
having the largest number of animals per 100 acres of crops (average, 4S.53). Difference, 29.09.] 
Crops. 
Average yield per acre. 
Acres per 
100 acres of 
crops 
Lowest 
group oi 
75 farms. 
Bushels. 
29. 8 
51.63 
.7 
73.29 
15.9 
20.84 
IS. 4 
38.77 
2.0 
24.79 
Tons. 
33.2 
1.08 1 
Highest 
group of 
75 farms. 
Increase 
in yield 
per acre. 
Increase in 
production 
per 100 
acres of 
crops. 
Prices.** 
Value of 
increased 
production 
per 100 
acres of 
crops. 
Coru 
Potatoes. 
Wheat. . . 
Oats 
Barley. . . 
Hay. 
Bushels. 
56.00 
85.07 
23.54 
44.43 
25.76 
Tons. 
1.18 
Bushels. 
4.37 
11.78 
2.70 
Tons. 
.10 
Bushels. 
130. 23 
8.25 
42.93 
104. 14 
1.94 
Tons. 
3.32 
SO. 63 
.S3 
.98 
.46 
1.00 
IS. 50 
$82. 04 
6.85 
42.07 
47.90 
1.94 
Total. 
242. 22 
Excess of fertilizer used by the second group per 100 acres of crops. 
Increase due to 29.09 animal units 
Increase due to one animal unit 
: 3.00 
239. 22 
8. 22 
a Areas and prices are the averages for the entire 300 farms operated by their owners. These are used 
in order to eliminate factors other than the quantity of manure available. The crop areas given here 
are per 100 acres of six crops mentioned. 
The comparison on which the estimates of value are made is be- 
tween the fourth of the farms having the fewest animal units per 
hundred acres of crops and the fourth having the highest number. 
The farms having most live stock in general had larger acreage of 
corn than did those with less live stock. As a large part of the in- 
crease in crop values per acre was due to the marked increase in the 
yield of this crop, the actual crop values on the more heavily stocked 
farms were somewhat greater than the figures given in the tables in- 
dicate. But this was due to the greater acreage of the more profitable 
crop, and not to greater yield per acre. In order, therefore, to ascer- 
tain the actual effect due to manure alone it was necessary to use the 
average acreage of each crop on the entire number of farms. This 
gives the same relative acreage of each crop on the farms in each 
group. The prices used are also the average for all the farms, for 
such differences in prices as occurred on the groups of farms com- 
pared were not due to the effect of the manure. 
In the Pennsylvania area the increase in crop values due entirely 
to increase in yields on the more heavily stocked farms is seen to 
amount to $15.80 per animal unit per year. In the Michigan area 
the corresponding figure is $8.22. The soils of the Pennsylvania 
area are in the main of granitic origin, and are more in need of 
fertilization than those of the Michigan area, which are of glacial 
origin and contain more lime and soluble mineral matter. Manure 
