THE ASH CONSTITUENTS OV PLANTS. 



s^5' 



Von Seelhorst' obtuined the following percentages of phosphoric 

 acid and potash in the dry substance of oat kernels: 



I'lioxplioric acid and potash, in. oals groirn with much and little water. 



The content of potash and phosphoric acid in the grain was, there- 

 fore, considerably increased by the presence of an abundant supply of 

 water. 



Recently Langer and von Seelhorst" have made experiments of this 

 kind with oats grown in sterilized sand, and Langer and ToUens have 

 made anah'ses of the resulting crop, with the following results: 



Fertilizing ingredients in oat roots. 



Little water. 



Much water. 



Fertilizer applied. 



^^"21:?- Potash. Nitrogen. ^^IP^ltr Potash. Nitrogen 



ric acid 



Php.«phoric acid 



Phosphoric acid and potash 



Phosphoric acid and nitrogen 



Phosphoric acid, potash, and nitrogen 



Per cent. 

 0. 251 



Per cent. 

 0. 147 



.233 

 .236 



.116 

 .262 



Per cent. 



0.748 



.736 



1.138 



1.154 



Per cent. 



0.165 



.269 



.276 



.237 



Per cent. 



0.142 



.247 



.163 



.189 



Per cent. 



0.678 



.645 



.896 



.919 



It will be seen that the results vary quite widely with the use of the 

 ditiercnt fertilizers and amounts of water. 



RELATION OF THE ASH OF PLANTS TO THE FERTILIZING INGREDIENTS 



OF THE SOIL. 



In view of the fact that the soil and the fertilizer used influence the 

 amount and composition of the ash of plants, it would seem that an 

 examination of the plants grown on a .soil might give an indication of 

 the plant-food constituents of the soil. This point has been studied 

 in a comprehensive manner, first by Heinrich'' and afterwards by 

 Liebschei-, Helmkainpf, Atterberg, and others. According to some 

 of these investigations it appears that the fertility of a soil might be 

 measured by growing plants adapted to the particular soil and analyz- 

 ing the plants, the results indicating a greater or smaller content of 

 assimilable elements in the soil. 



After Hellriegel* had shown that the potash content of barley straw 



iJour. Landw., 46 (1898), pp. 422, 42.S. 



^Ibid., 49 (1901), p. 209. 



^(irundlajren /in- Bctirtheilunjr <ler Ackerkrunie, 1882. 



* Landw. Vers. Stat., 11 (1869), p. 136. 



