56 



BULLETIN "E. : 



It is thus seen that a change has occurred during the matur- 

 ing of the crop of corn upon these four soils, which has made it 

 possible to recover by the same treatment with distilled water 

 from 17.23 to 54.55 pounds per acre less potash in the three 

 feet of soil occupied by the roots of the corn ; and it is clear that 

 such a rate of decrease in the solubility of potash or in the 

 amount of soluble potash present, could not be maintained 

 through many seasons before the effect would be reflected in the 

 yields of the crops, as, indeed, has been shown to have occurred 

 in the Wisconsin series cited above: 



INFLUENCE OF MANURE UPON THE AMOUNTS OF LIME AND 

 MAGNESIA RECOVERED FROM SOILS BY PLANTS. 



If the amounts of lime and magnesia found in the corn and 

 potato plants are brought together from the general table and 

 grouped under stronger and poorer soils, the results will stand 

 as given in the next table: 



Mean amounts of lime and magnesia recovered from corn and 

 potatoes growing upon manured and unmanured ground. 



From this table it appears that, as an average, the plants 

 growing upon the manured ground, the ones which were mik- 

 ing, at the time of the examination, the most vigorous growth, 

 and the ones which produced, in the end, the largest yields had, 

 in their plant sap or in their tissues, in a form which could 



