180 AGRICULTURE 



than by mature fattening beasts, so that 

 nearly all becomes available for the use of 

 crops. The larger proportion of the potash 

 appears in the urine, while the most of the 

 phosphates are voided as undigested residues 

 in the dung. 



It is possible by means of a calculation to 

 indicate the difference in the quality and 

 value of farmyard manure produced in 

 the one case by fattening steers and in the 

 other case by milk cows. In the case of a 

 cow yielding 700 gallons of milk in the course 

 of the year, the following approximate 

 quantities of fertilizing materials will be 

 removed from the food and diverted to the 



milk : 



s. d. 



42 lb. of nitrogen at 6id. per Ib. .129 



16 lb. of phosphoric acid at l^d. per Ib. 2 

 14 lb. of potash at 2d. per lb. . .024 



171 



Assuming that the cow stands in a byre for 

 half the year, producing during that time 

 6 tons of farmyard manure, the above figure 

 would be reduced by one-half, which means 

 that each ton of farmyard manure is dim- 

 inished in value by about 2s. 3d. A steer 

 weighing 7 to 9 cwt., in passing from 



