THIRTY-SEVENTH ANNUAL CONVENTION. 113 



she will consume. For the purpose of illustrating what I wish 

 to bring out, I have not permitted the cow any pasture, but have 

 fed her prepared feeds and it is fair to say that the amount of 

 feed she would need in a year would be about 6 tons of silage, 

 2 tons of clover hay, 1,000 pounds of corn stover, 1,500 pounds 

 of corn chop, 1,000 pounds of bran and 300 pounds of oil meal.. 

 It is common knowledge that a certain amount of fertility has 

 been taken from the soil to produce these feeds and that the 

 soil does not contain an unlimited supply of some of these ele- 

 ments. 



Dr. Hopkins of the University of Illinois, the best soil au- 

 thority in the country, says that most Illinois soils lack in phos- 

 phorus and nitrogen, but that they are well supplied with all the 

 other elements. It is generally held that there are three im- 

 portant elements of plant food, namely, nitrogen, phosphorus 

 and potash. It will be interesting, I am sure, to know just how 

 much of these elements is required to produce the amount of 

 feed that I have assumed the cow would eat in producing 8,000 

 pounds of milk testing 3.8 per cent and maintaining her body. 

 It is not difficult now to obtain tables showing the amount of 

 fertilizing elements in 1,000 pounds of the different feed stuffs 

 and so I have calculated to give in the following table the 

 amount of nitrogen, phosphorus and potash taken from the soil 

 to produce the feed which a cow will consume in a year. The 

 following table shows the different amounts of elements in the 

 different amounts of feeds : 



Lbs. Lbs. Lbs. 



Name and Amt. of Feed. Nitrogen. Phosphorus. Potash 



6 tons corn silage 52 13 44 



2 tons clover hay 80 22 75 



1,000 lbs. corn stover 6 4 11 



1,500 lbs. corn chop 24 10 8 



1,000 lbs. bran 25 27 15 



300 lbs. oil meal 20 6 4 



Total 207 82 157 



