228 Fertilizers 



A gain of fertility by the rotation system. 



Assuming that the increased yield of corn is 20 

 bushels, with accompanying stalks, of wheat 10 bushels 

 per acre, of oats 15 bushels, of clover J ton and of 

 timothy J ton, the amounts applied will be practically 

 sufficient to furnish all of the potash contained in this 

 increase, and more than sufficient to meet the demands 

 for phosphoric acid. That is, by this system there has 

 been applied in the materials 30 pounds of nitrogen, 64 

 of phosphoric acid and 80 of potash. While, if this in- 

 creased crop was secured, the following amounts would 

 be required: 71 pounds of nitrogen, 31 of phosphoric 

 acid and 79 of potash. The considerable amounts of 

 plant-food contained in the yard manure, and the gain 

 from the roots and stubble of the clover, serve to supply 

 the balance of nitrogen required, and to provide a store 

 of unused residue for future crops. 



The method, if adopted, would be more rational, and 

 likely to result in more satisfactory returns than the 

 one now generally practiced, namely, to purchase with- 

 out particular regard to the character of the materials 

 furnishing the constituents, or their proportions, and 

 to apply, on the average, even less per acre than is 

 here recommended. Assuming that 200 pounds to the 

 acre of the average corn fertilizer, showing a composi- 

 tion of 2.5 per cent nitrogen, 8 of phosphoric acid and 

 5 of potash, were applied only to the crops corn, oats 

 and wheat, omitting both clover and timothy, there 

 would have been added 15 pounds of nitrogen, 48 of 

 phosphoric acid and 30 of potash, amounts of each too 

 small to provide for a large increase in crop, provided all 

 were needed. 



