464 SORGHUM. 



and phosphoric acid removed is in reality very gi-eat, and, as is well 

 known, this crop is, especially as regards potash, a very exhausting 

 crop. 



The hay crop, from every consideration, deserves especial attention, 

 occupying as it does so large a portion of our cultivated land (19 percent), 

 constituting one-third the weight of the entire aggregate of our crops, 

 and removing annually from our lauds an amount of potash and phos- 

 phoric acid almost exactly equal to the amount removed l)y all the 

 other crops combined. Its discussion is of the greatest importance. 



Owing to its comparatively cheap production, it is sold at a price in- 

 comparabl}' less than any other crop, and yet, as will be seen by refer- 

 ence to theanalysis given, which represents the average of 34 of our 

 native American grasses, the demand it makes upon the soil is very 

 great. The potash and phosphoric acid present in its ash is, at the 

 prices we have given, equal to 51.5 per cent of the average selling 

 price of the hay itself. 



Fed to the animal, practically all of these two constituents are re- 

 turned to the manure pile ; since in the animal economy but a trifling 

 amount of potash is needed, and only so much of phosphoric acid as 

 will suffice for the production of the bones of tlie growing animal. 



It follows, then, that the manure obtained from the feeding of a 

 ton of hay, having an average composition such as those analyzed, con- 

 tains an amount of potash and phosphoric acid which, at the prices 

 given, is equal to a little more than half the average selling price of hay 

 in the United States, which was in 1879 given at 19.32. This will be 

 readily seen to be true, fir 2,000 pounds hay with 0.74 per cent of ash 

 Avould contain 134.8 pounds of ash. Of this ash 39.8 per cent is pot- 

 ash, or 53.7 pounds; and G.4 percent is phosphoric acid, or 8.6 pounds. 

 Now, 53.7 pounds at 7 cents equals $3.76, and 8.6 pounds at 12 cents 

 equals $1.03, or together S4.79, which equals 51.4 percent of 69.32, 

 the cost of the hay. 



What has been said about tlie feeding of hay to the animal is 

 equally true of the cereals and other feeding crops. Unlike the vege- 

 table world, the animal demands little mineral f )od, mainly phosphoric 

 acid and lime, which comprises the ash obtained by the cremation of 

 the animal. 



We have, then, obviously one solution as to the important question: 

 " How shall exhaustion of our lands be prevented?" The answer the 

 above facts force upon us is : increase so far as possible the home con- 

 sumption of our agricultural products, and carefully preserve and re- 

 turn to our lands such portions of those products as are either not fed 

 to the animal, or, if fed, are not assimilated. 



