6 DAIRYING. 



change. In many grain-growing sections of the country where for- 

 merly the uncertainty of the crop each year made the farmer's 

 income somewhat precarious, the fertility of the land has been im- 

 proved, and the general prosperity of the farmer has been increased 

 by the introduction of dairying. 



7. Soil exhaustion from constant cropping of the land is an 

 important matter in- all lines of farming ; and the advantages which 

 dairying has over other lines of farming in this respect are worthy 

 of consideration. "When only butter is sold from the farm there is 

 very little fertility removed from the soil. The carbon, oxygen, and 

 hydrogen of which butter fat is composed are taken from the air 

 and from water by the aid of sunlight, and so these elements are 

 maxle to contribute to the food of man without exhausting the soil 

 to the extent that grasses and grains extract its fertility. 



a. Fertilizing Materials in Dairy Products and in Farm Crops. 



8. One ton of butter contains about 1,688 pounds of fat, 272 

 pounds of water, and 20 pounds of milk sugar, and lactic acid, and 

 20 pounds of casein and mineral matter.* The first two sub- 

 stances, fat and water, comprise 1,960 pounds of the ton ; and their 

 formation does not impoverish the soil to any great extent. This 

 leaves only the 20 pounds of casein and mineral matter as the 

 fertilizing ingredients taken from the soil. This is a comparatively 

 small part of the ton, and no other farm crop removes so little 

 fertility from the land. 



9. In a ton of mixed hay there are about 220 pounds of ash 

 (mineral matter) and protein; in a ton of corn 240 pounds; and of 

 wheat 275 pounds. These constituents are similar to the ash and 

 casein of butter, and a comparison of the figures shows that the 

 hay, the corn, and the wheat are 11 to 15 times more exhaustive 

 to the soil than is butter, when one ton or about $400 worth of 

 butter is compared with one ton of hay. 



10. The case is somewhat different with milk. A ton of whole 

 milk removes from the soil about 88 pounds, or over four times as 

 much fertility as does butter. This difference between milk and 

 butter is largely due to the casein in milk, but the fertility which it 



*Exclusive of salt added. 



