10 



FARM AND SCHOOL PROBLEMS. 



increase to the value of $4.50, or enough to pay for cementing 

 a stall each year. 



10. Certain factors effect the value of farm manures. Species of 

 animal, age, character of food, use of animal, bedding, all 

 enter into the problem of determining the value of manure. 



11. No two tables prepared by the best authorities give the same 

 results in determining the value of manure for the reason that 

 conditions, locality, climate, difference in composition of foods, 

 breed of stock, and many other factors may cause a wide 

 variation between the results of two experiments carried on in 

 different places. 



12. A careful study of a few of these tables will serve to show 

 that we can make an estimate that will enable us to know very 

 approximately what we are doing. 



In estimating the difference between the profits of selling 

 corn or hogs, hay or cattle, at the market price of each, there is 

 no mathematical calculation that will show the correct solution 

 that does not include the item of fertility in feeds and manures. 



The following table gives results procured by Roberts : 



Table i. 



MANURE PER I,OOO POUNDS OF LIVE WEIGHT. 



In the above table nitrogen is figured at 20 cents and the other 

 constituents at 5 cents per pound. 



