PRINCIPLES OF MANURING. 



65 



Percentages of the valuable manurial ingredients 



(if thu cattio foods that pass into the inanuro 

 they produce, determined for the common farm 

 animals. 



Nitrogen 



Average. 



Per ct. 

 49.1 

 34 

 83.1 

 68.4 

 3.^.1 

 *103.5 



It is seen that diflereut species of farm animals do not make 

 equally- valuable manure from the same kind of food. Other things 

 being equal, a growing animal makes poorer manure than one full 

 grown, because of the demands made upon the food for the forma- 

 tion of bone and muscle. With the same feed a cow giving milk 

 makes less valuable manure than one that does not, for the milk 

 takes up quite an amount of nitrogen and mineral substances. The 

 cattle withdrawing the least manurial value from the food they eat 

 are fattening animals, and those standing still and making no growth 

 or producing nothing. 



We are quite safe in assuming that on the average 80 per cent, of 

 the nitrogen and 95 per cent, of the phosphoric acid and potash 

 that are fed to farm animals pass into the solid and liquid excre- 

 ments. Taking these figures as a basis, and knowing the composi- 

 tion of any cattle food, we can easily calculate the relative money 

 value of the manure it is capable of producing, provided one can 

 settle upon a fair price per pound for the valuable ingredients. 

 Now we have a list of prices from which commercial manures are 

 valued, that is, it costs so much to ol^tain a pound of nitrogen 

 according to the form in which it exists, and the same for phosphoric 

 acid and potasli. The nitrogen of fish can be bought for twenty 

 cents per pound, and probably has about the same value as that of 

 stable manure. The real value of the nitrogen in manure depends 

 somewhat upon the digestibility of the food from which it came. 

 All the nitrogen that is contained in the digested nitrogenous com- 

 pounds and not used b}^ the animal passes out in the urine, while 

 the undigested nitrogen passes into the solid excrements. The 

 nitrogenous compounds of the urine arc nuich more easil}' decom- 



* More than 100 per cent, because of the mineral substances in the water drank, 

 and that accidentally get into the food. 



