208 



NITROGEN, PHOSPHORUS AND POTASSIUM 



phosphoric acid about two dollars, and " potash" seven dollars 

 and more per unit. 



FIG. 140. Corn responded during early growth to about 100 pounds of a mixed fertilizer 

 (1-8-1) applied in the drill. (See Fig. 141.) 



FIG. 141. No appreciable difference in the yield at harvest time, because the land was 

 well manured. Same field as shown in Figure 140. 



Soils and Crops Determine Kind of Fertilizer to Use. The 

 soil supply of the available plant-food elements and the kind of 



