24 



MAINE AGRICULTURAL EXPERIMENT STATION. 



in the soil at the close of the experiment. In actual field work 

 the good effect of the ground rock would, of course, be far more 

 lasting than that of the acid rock. 



Diagram showing relative weights of dry matter of plants grown with 

 phosphoric acid from different sources. 



Crops 



Phosphate. 



Weight. 



Peas 



Clover , 



Turnips 



Ruta Bagas. 



Barley 



Corn 



Tomatoes... 



Potatoes — 



Turnips, 

 Roots . . 



Ruta Bagas, 

 Roots 



Potatoes, 

 Tubers.. 



Acid Rock. 



Floats. 



Redonda. 



No Phosphate. 



Acid Rock. 



Floats. 



Redonda. 



No Phosphate. 



Acid Rock. 



Floats. 



Redonda. 



No Phosphate. 



( Acid Rock. 

 J Floats. 

 i Redonda. 

 ( No Phosphate. 



( Acid Rock. 

 J Floats. 

 I Redonda. 

 t No Phosphate. 



Acid Rock. 



Floats. 



Redonda. 



No Phosphate. 



I? 



Acid Rock. 



Floats. 



Redonda. 



No Phosphate. 



Acid Rock. 



Floats. 



Redonda. 



No Phosphate. 



Acid Rock. 



Floats. 



Redonda. 



No Phosphate. 



Acid Rock. 



Floats. 



Redonda. 



No Phosphate. 



Acid Rock. 



Floats. 



Redonda. 



No Phosphate. 



Box experiments were made at the New Hampshire Experi- 

 ment Station in 1893 with winter rye, the phosphoric acid being 

 supplied by roasted Redonda, ground bone, and basic slag. 

 The result showed that the rye gave nearly as good returns with 



