374 



Assimilation of crops. — M. Isidore Pierre has given to the public, ia a 

 tabulated form, tbe result of an extended series of experiments made for 

 tbe purpose of determining the progress of assimilation during the 

 growth of crops. The objective points of the experiments are thus 

 stated : 



First. At what stage in the life of the plant do fertilizers act most effect- 

 ually in furnishing them the different parts of their substance and at 

 what stage does this action x)ractically cease % 



Secondly. At what stage of its growth does a plant cease to take from 

 the soil, either wholly or in part, the elements which enter into its com- 

 position, and when is it most exhausting to the soil? 



The discussion is given at length in the June number of the Journal 

 d' Agriculture Pratique, and contains much of interest. We can give 

 only the tables exhibiting the results, from which our readers can make 

 their own inferences. Tables Nos. 1 and 2 refer to crops of wheat, and 

 the experiments were mttlo in different years.' No. 3 refers to a crop of 

 colza, and is of value to the American farmer only as illustrating a gen- 

 eral principle, as the crop is not raised in this country. The figures 

 refer to kilograms, per hectare, but, as the reference is really to propor- 

 tions, the reader may call them parts of any measurement he chooses. 



Tabus Ko. 1. 



Table 3n o. 2. 



Table In o. 3. 



March 23. 



Entire croi) , 



^Mineral matter, (ashes) 



Is' itro sen 



Phosphoric acid , 



Limo 



Magnesia and aUcaline salts 



2890. 

 338.7 

 77.0 

 30.8 

 95.0 

 130. 3 



April 2. 



3393. 



393.3 



82.4 



37.0 



112.2 



152.3 



May 0. 



7172. 

 853.9 

 121.7 

 73.0 

 259. 9 

 159. 9 



June 6. 



S035. 

 806.9 

 110.7 

 73.6 

 253.0 

 213. 3 



July 20. 



8005. 

 578.1 

 111.1 

 78.1 

 175. 9 

 209. ti 



