OUR GREATEST PLANT FOOD 



785 



PHOSPHATE EXPERIMENTS - RHODE ISLAND STATION 

 DIAGRAM SHOWING INCREASE IN HAY PRODUCTION DUE TO LIMING 



Limed - I ton per acre 



Dissolved Dissolved Dissolved Fine Alyminym Aluminum 



bone black bone phos. rock ground bone Slag meal Floats phos. raw phovi^nJted 



Ha/ per acre 

 Jit. crop 



5700 lbs. 5600 lbs. 5700 lbs. 6000 lbs. 5300 lbs. 6200 lbs. 4400 lbs. 5350 lbs. 



Unlimed 



Dissolved Dissolved Oissofved Fine Aluminum Aluminum 



bone black bone phos. rock ground bone Slag meal ' Floats phos. raw phos. ignited 



ili,ilJ. 



ili„l. 



1 



1 



E5Z0 lbs. 2620 lbs. 2600 lbs. 2300 lbs. 3600 lbs. 2700 lbs. 1750 lbs. I7a5jbs 



All ihe 16 plots fertilized alike, with nitrogenand potash, and each plot had 

 same money value of different forms of phosphoric acid 



HAY CROPS MORE THAN DOUBLED BY USE 01^ PHOSPHATE 



This diagram affords an interesting study. In reality a liming experiment, it shows 

 phosphorus to be a controlling factor in production of the highest importance. It will be noted 

 that "floats," or raw phosphate, gave the largest yield. 



substantial buildings of masonry; when 

 the oil and the natural gas wells run dry, 

 electricity will be gathered from the 

 clouds. We are but in the infancy, on 

 the threshold of discovery and invention. 

 Phosphorus ! Brimstone ! Let the par- 

 lor match become a lost art ; man will 

 strike a light from the sun !" 



So he will, doubtless ; but when the 

 housewife ignites her sun-cooker she 

 must still have bread to bake, meat to 

 roast, and vegetables to boil in plenty, 

 else our people will be illy nourished and 

 our world-pace will slacken and cease. 

 And this is the problem into which the 

 phosphorus supply enters — food. 



There are three necessary elements to 

 the production of plant and therefore 

 human food, and only three ; but all the 

 discovery and invention and genius in 

 the world, added to all the knowledge 

 that may be obtained from the Martians 

 and other beings, cannot supply substi- 

 tutes. They are nitrogen, potash, and 

 phosphorus. And, in supplying the earth 

 with just enough of the last-named, and 

 no more. Nature forgot that she was 

 going to instill into man the spirit of 

 wastefulness ; and so she has, by limiting 

 her supply of phosphorus, in reality fixed 

 the limit of human existence. Man can 

 lessen or extend that limit as he wastes 



