208 



NITROGEN, PHOSPHORUS AND POTASSIUM 



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

 and more per unit. 



Fig. 140. — Corn responded uumiy, vnny gruwtu uu uuuul ±uu 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 



