90 AMERICAN MANURES. 



The reader will notice the large amount of silica 

 required for the straw. Too little attention has 

 been given to economizing this substance, silica, 

 by wheat growers in this country. In building 

 up the structure of the straw, soluble silica is 

 indispensable. The straw and the roots consti- 

 tute the chemical apparatus for the preparation 

 and assimilation of the different elements re- 

 quired by the grain itself. Hence it is evident, 

 that if there is not enough of soluble silica to 

 give this preliminary structure its proper de- 

 velopment, there will be only a small amount of 

 grain produced, however rich the soil may be 

 in the other elements' required. 



Silica to be available to the plant must be in 

 a soluble condition ; and, as the farmer must 

 wait for the slow formation or liberation of this 

 substance in the soil, the alternating of wheat 

 with other crops that require but little of it, 

 will allow time for it to accumulate in the soil 

 for the raising of wheat crops at proper intervals. 



INDIAN COKN. 



Fifty bushels of corn the estimated crop of an 

 acr e_of 58 Ibs. to the bushel = 2900 Ibs. This 

 weight of corn will require 3000 Ibs. of stalk 

 and cob (when dry), and will contain : 



