14 



Yearbook of the Department of Agriculture. 



previous 5 years is 14 per cent. In the year 1917 these same 

 12 markets received more than 14,000,000 cattle. 



THE SILO AND THE CORN CROP. 



No single agricultural step in marking the advance of 

 methods of utilizing corn has been so important as the 

 preservation of the crop in the green state in the silo. Be- 

 tween 1860 and 1870 the first silos for corn were used in 

 Europe. The first record of silo construction in this country 

 was in 1875, when two were built and used in Michigan. 

 The days of experimentation with silage have now passed. 

 Because it is an economical means of utilizing green feeds, 

 especially corn, silage construction and the use of the silo 

 are increasing rapidly, particularly in the dairy States. 

 The following table shows the States leading in the number 

 of silos: 



Number of silos in the United States. 



[From the Monthly Crop Report, August, 1917, of the Bureau of Crop Estimates.] 



State. 



Number 

 of silos. 



Capacity (tons). 



Average.' 



Total. 





55,000 

 24,000 

 25,000 

 27,000 

 30,000 

 33,000 

 55,000 

 15,000 

 16,000 

 13,000 

 11,000 

 10,000 

 35,000 

 55,000 



75 

 65 

 67 

 70 

 79 

 70 

 87 

 95 



105 

 90 



106 

 80 

 67 

 77 



4,125,000 





1,560,000 

 1,675,000 



Ohio. ." 





1,890,000 

 2,370,000 

 2,310,000 









4,785,000 





1,425,000 





1,680,000 





1,170,000 





1,166,000 

 800, 000 







2,345,000 



All other. 



4,235,000 







404,000 



78 



31,536,000 







The average number of milch cows in the United States in 

 the decade 1908 to 1917 was 20 per cent more than in the pre- 

 vious decade. A large part of this increase is no doubt due to 

 the growing popularity of the silo as a cheap means of pre- 

 serving green feeds. 



VARIATIONS OF THE CORN PLANT. 



Whatever may have been the origin of corn, the fact re- 

 mains that in its distribution over the United States it has 

 undergone many and diverse modifications. Sturtevant re- 



