FOURTEENTH ANNUAL YEAR BOOK— PART YIII. 573 



cubic feet of space or to a volume of concentrated human food only 

 1/25 6 as large. As stated above a dairy cow will confeume about three 

 tons of hay and one ton of grain or an amount of field crop equal to 

 about four tons. This the dairy cow changes into about 300 pounds of 

 the most concentrated human food known. The heavy field crop is re- 

 duced to a weight eqiial to one-twenty-sixth as much. 



While these calculations cannot be accurate for all cows and for all 

 conditions, they are considered conservative, and point with a great 

 deal of significance to what the dairy cow is able to do in the way of 

 changing bulky and weighty field crops into concentrated human foods, 

 for which there is always a ready demand at high prices. 



PRESEKVES AXD INCREASES KICHXESS OF LAXD. 



The land in the central west is rich and productive. There is. how- 

 ever, evidence on every hand that land which has raised a crop for 

 several successive years Is not so productive as it formerly was. The 

 average wheat yield is not now so large as it was a few years ago. 

 Those interested in agriculture have learned and are realizing the 

 danger arising from an exhausted soil. The dairyman does not worry 

 about a decrease in the productivity of his land. Instead his land 

 is increasing in richness. Instead of a less productive soil his soil pro- 

 duction continues to improve. 



The dairy farms of Illinois, Iowa, South Dakota and other states 

 amply emphasize this. By dairy farming the little countrj- of Den- 

 mark doubled the yield of their lands in twenty years. Why? Be- 

 cause of the cow. Instead of hauling their grain, hay and straw 

 away from the farm to market, these products were fed to the dairy 

 cow. She transformed these field crops into butter-fat. skim-milk 

 and manure. The manure was hauled to the land, the skim-milk fed 

 to calves and hogs, and the butter sold as a concentrated expensive 

 human food. The land was thus left richer than before and the farm- 

 ers' pocketbook was fattened, two essentials in the economics of life. 

 When $1,000 worth of hay is hauled from the farm about $(iOO worth 

 of soil fertility or plant food is lost. In $1,000 worth of wheat sold, 

 the farmer loses about $250 worth of plant food. In $1,000 worth 

 of butter sold the farmer loses less than one dollar's worth of soil 

 fertility. 



In addition to the feed raised aaid fed. the dairy farmer usually 

 buys some concentrated feeds rich in nitrogen and minerals, such as 

 bran, oil meal and cottonseed meal. The products and by-products of 

 these feeds add to the fertility of the land. So the dairy farmer not 

 only maintains the fertility of his soil, but he actually increases it. 



This work of the dairy cow then has a much greater significance 

 than just to provide a profit and daily living. The keeping up of the 

 soil fertility is a work of the dairy cow. from which future generations, 

 as well as the present one, will reap benefits. The dairy cow should 

 therefore have an important place in any scheme of permanent agri- 

 culture. 



