

LLUJU 



NO FERTILIZER. 



KP. 



1*3 



POTASH PHOSPHATE 

 WTHOUT NITROGEN, 



POTASH-PHOSPHATE 

 WITH NITROGEN, 



FIG. 76. Effect of fertilizers. Both oats and peas are helped by potash 

 phosphate. But the pea has much less need for nitrogen than the oat, 

 because the pea can take nitrogen from the air by means of the bacteria 

 in its root tubercles. 



144 



