INORGANIC MANURE. 195 



The following rotation is adopted in Alscce, as Deing the most 

 advantageous ; it extends over a period of five years, during 

 which the land is only once manured : — 



1st Year. 2d Year. 3d Year. 4th Year. 5th Year. 6th Year. 



Manured. Manured. 



Oats, or 



Wheat with Rye, or Potatoes 



Potatoes or Wheat Clover Fallow turnips Barley. 



Beet 

 Potash Silica Lime Silica > p Silica ) „ 



Plants. Plant. Plant. Potash 5 ^ LANTS Lime > ^ LANTS - 



Now, if we suppose that the action of the manure depends 

 upon its ammonia, or amount of nitrogen, then it is obvious that 

 a progressive diminution must ensue ; that the nitrogen in the 

 crops of the first and second years must amount to more than 

 that contained in the crops of the fourth and fifth years. But 

 this opinion is completely opposed to the following proportions, as 

 indicated by analysis : — 



1st Year. 2d Year. 3d Year. 4th Year. 5th Year. 

 Nitrogen in the crop - - 46 35*4 84*6 560 2S"4 



Thus, in the third and fourth years the nitrogen in the crops 

 amounted to much more than the quantity contained in the crops 

 of the first and second years ; and in the fifth year the quantity 

 was only one-fourth less than it was in the second year. Now, 

 is it possible or conceivable that the ammonia given in the first 

 year, being a body of great volatility and very apt to evaporate 

 along with water, could be present in greater quantity in the soil 

 during the fourth year than it was in the first and second years ; 

 or that it could yield to the oats of the fifth year the necessary 

 quantity of nitrogen for their growth ? 



But let us admit that the nitrogen conveyed to the soil by 

 strong manuring was actually exhausted in the fifth year by the 

 different plants cultivated upon it ; and let us then compare the 

 rotation employed in Alsace, with that adopted on one of the 

 most fertile districts of the Rhine. In Bingen there is a nine- 

 years' rotation followed, the plants succeeding each other in the 

 following order : — 



