52 TALKS ON MANURES. 



I do not say that these arc tlie 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 shouKl 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 conting^'ncy. I' would be a very exceptional case. 

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

 under green crops for keejjiug 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 lbs. of 

 nitrogen, Gi los. of phosphoric acid, and 13J lbs. of potash. 

 Less than 33 lbs. 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 lbs. of matter in order to 

 get 33 lbs. of these fertilizing ingredients. We should try to 

 iruike rirfwr manvrc. A ton of manure containing GO lbs. of 

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

 and spread, than a ton containing only 30 lbs., 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. 



CHAPTEE XIV. 



FERMENTING [MANURE. 



Dr. VoRlcker placed 2,838 lbs. of fresh mi.xed manure in a heap 

 Nov. 3, 1854, and the next spring, April 30, it weighed 2,020 lbs., 

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

 of sach manure wouM bo reduced to less than 7U tons. 



Tlie heap was weig^ied again, August 231, and contained 1,994 

 lbs. It was again weighed Nov. 15, and contained 1,974 lbs 



