88 FOOD FOR PLANTS 



most profitable amount of available Nitrogen re- 

 quired for individual locations. In the last analysis 

 a practical trial in the field is what counts. The 

 grower must check for himself and constantly study 

 his condition like a business man. 



Looking at the Nitrogen subject broadly, we find 

 that during the last quarter century the agricultural 

 use of Chilean Nitrate has increased in this country 

 many times faster tfian the use of mixed fertilizers. 



Although the Chilean Nitrate industry is now 

 nearly 100 years old, Nitrate having been first ex- 

 ported in 1820, there is still enough, it is estimated, 

 to last 300 years. The fact that the use of this Ail- 

 American product has increased many times faster 

 here in our country, namely, from 16,000 tons per an- 

 num in 1899 to nearly 650,000 tons at present, whilst 

 ordinary fertilizer consumption has not much more 

 than doubled in the same period, is not without sig- 

 nificance as is also the fact that in 1919 the U. S. 

 Department of Agriculture distributed 150,000 tons 

 of Chilean Nitrate for Agriculture use as such. This 

 did not include what was sold to growers through the 

 regular channels of original trade. 



The production and consumption of different forms 

 of commercial Nitrogen has increased faster than the 

 production of phosphorus and potash during that 

 period. From the practical side, therefore, we regard 

 the possibilities of increased crop production from the 

 increased use of Nitrogen as very real and very 

 promising. 



In Hawaii where more Nitrogen is used per acre 

 than in any other part of the world, in the growing 

 of sugar cane, the average production per acre is the 



