52 TALKS ON MANURES. 



I do not say that these are the only ingredients of any value in 

 a ton of manure. Nearly all the other ingredients are indispen- 

 sable to the growth of plants, and if we should use manures con- 

 taining nothing but nitrogen, phosphoric acid, and potash, the 

 time would come when the crops would fail, from lack of a 

 sufficient quantity of, perhaps, magnesia, or lime, sulphuric acid, or 

 soluble silica, or iron. But it is not necessary to make provision 

 for such a contingency. It would be a very exceptional case. 

 Farmers who depend mainly on barn-yard manure, or on plowing 

 under green crops for keeping up the fertility of the land, may 

 safely calculate that the value of the manure is in proportion to 

 the amount of nitrogen, phosphoric acid, and potash, it contains. 



"We draw out a ton of fresh manure and spread it on the land, 

 therefore, in order to furnish the growing crops with 12f Ibs. of 

 nitrogen, G Ibs. of phosphoric acid, and 13J Ibs. of potash. 

 Less than 33 Ibs. in all ! 



We cannot dispense with farm-yard manure. We can seldom 

 buy nitrogen, phosphoric acid, and potash, as cheaply as we can 

 get them in home-made manures. But we should clearly under- 

 stand the fact that we draw out 2,000 Ibs. of matter in order to 

 get 33 Ibs. of thcs3 fertilizing ingredients. We should try to 

 make richer manure. A ton of manure containing GO Ibs. of 

 nitrogen, phosphoric acid, and potash, costs no more to draw out 

 and spread, than a ton containing only 30 Ibs., and it would be 

 worth nearly or quite double the money. 



How to make richer manure we will not discuss at this time. It 

 is a question of food. But it is worth while to enquire if we can 

 not take such manure as we have, and reduce its weight and bulk 

 without losing any of its nitrogen, phosphoric acid, and potash. 



CHAPTER XIV. 



FERMENTING MANURE. 



Dr. Yoelcker placed 2,838 Ibs. of fresh mixed manure in a heap 

 Nov. 3, 1854, and the next spring, April 30, it weighed 2,026 Ibs., 

 a shrinkage in weight of 28.6 per cent. In other words 100 tons 

 of such manure would be reduced to less than 71 tons. 



The heap was weighed again, August 23d, and contained 1,904 

 Ibs. It was again weighed Nov. 15, and contained 1,97-1 Ibs. 



