368 



ANNUAL. REPORT OF THE 



Off. Doc. 



roughage produced on the farm, and the manure is carefully saved 

 and restored, at least seventy-five per cent, of the fertilizing con- 

 stituents removed in such crops will be restored to the land. A 

 small part of the remaining twenty-live per cent, will be added to 

 the available fertility through the disintegration of the insoluble 

 compounds of the mineral elements of fertility, due to the operation 

 of this decaying vegetable matter and the admission of air by fre- 

 quent cultivation. Still, at best, there will remain a deficiency to 

 be made up. In so far as the grain and roughage may be sold from 

 the farm, instead of being consumed thereon, and the manure re- 

 turned, of course, this deficiency will be augmented. To what ex- 

 tent the soil is depleted in the removal of some of the common farm 

 crops, the following statement will show: 



Fertilizing Constituents Removed. 



Pounds per Ton. 



Thus, if a clover field produces two and one-half tons of hay per 

 acre, we remove from that acre 103.5 pounds of nitrogen, worth 

 515.45, 19 pounds of phosphoric acid, worth 95 cents, 110 pounds of 

 potash, worth |5.50, or a total value of |21.90. If this were sold at 

 $10 per ton and the value of the fertilizing constituents removed 

 were deducted, there would remain |3.10 for the work of harvesting 

 and marketing. But if fed to the dairy cow the protein alone in 

 that two and one-half tons, at seven cents per pound, would be worth 

 •125.69, and the manure returned would be worth |16.47. Of course, 

 in the removal of the nitrogen contained in that two and one-half 

 tons of clover hay we do not take the 103.5 pounds wholly out of the 

 soil, since a large portion of this had been taken from the atmos- 

 phere, and in leaving the stubble and roots of the clover plant we 

 probably leave the soil as rich in nitrogen as it was before the crop 

 was grown; but we remove so much that might have been added 

 to the soil. The real loss to the soil is probably to be measured by 

 the value of the phosphoric acid and potash removed in the hay, 

 namely, |6.45. But by feeding the hay and returning the manure to 

 that acre, seventy-five per cent, of the total fertilizing value of the 

 two and a half tons of clover hay, or |1G.47 as stated, would be 

 restored to the soil. 



From the tabulated statement given, the results of removing any 



