98 



BULLETIN 341, U. S. DEPARTMENT OE AGRICULTURE. 



Table LX. 



-Yalue 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, 48.53). Difference, 29.09.] 





Acres per 



100 acres of 



crops." 



Average yield per acre. 



Increase 

 in yield 

 per acre. 



Increase in 



production 



per 100 



acres of 



crops. 



Prices." 



Value of 

 increased 



Crops. 



Lowest 

 group of 

 75 farms. 



Highest 

 group of 

 75 farms. , 



production 

 per 100 

 acres of 

 crops. 





29.8 

 .7 

 15.9 

 18.4 

 2.0 



33.2 



Bushels. 

 51.63 

 73.29 

 20.84 

 ' 38. 77 

 24. 79 



Tons. 

 1.08 



Bushels. 

 56.00 

 85.07 

 23.54 

 44. 43 

 25.76 



Tons. 

 1.18 



Bushels. 

 4.37 

 11.78 

 2.70 

 5.66 

 .97 



Tons. 

 .10 



Bushels. 



130. 23 



8.25 



42.93 



104. 14 



1.94 



Tons. 

 3.32 



$0.63 



.83 



.98 



.46 



1.00 



18.50 



$82. 04 





6.85 



Wheat 



42.07 





47.90 





1.94 



Hay 



61.42 







Total 















242.22 



















Excess of fertilizer used by the second group per 100 acres of crops 3. 00 



Increase due to 29.09 animal units : 239. 22 



Increase due to one animal unit 8.22 



o 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 



