compounds, as these are always insoluble even in the 

 most fertile soils. Numerous analyses of the "run 

 off" waters show this. The nitrates being always 

 available to the plant, stimulate its feeding powers 

 and force it to act on such insoluble compounds as 

 the phosphates, which, in turn, by yielding slowly, 

 regulate growth and maintain for a longer time the 

 soil's productive power. 



It can readily be seen that the loss would be 

 many times greater if the phosphates and other com- 

 pounds were soluble as well as the nitates. 



The phosphoric acid of soils is practically always 

 insoluble. This is true of new lands, the richest and 

 most productive known. It is nature's method. All 

 fertile soils contain such bases as lime, iron and others 

 that hold phosphorous in insoluble compounds from 

 whence it is released only by the processes of plant 

 growth and the chemical activities of fertile soils. 



THE PURCHASE OF FERTILIZERS. 



Fertilizers should be purchased by the unit of 

 plant food contained, with due consideration of its 

 source, and not simply by the ton or brand, as is 

 usually the case. Each twenty pounds of a ton is 

 called one unit or 1% ; 5% is five units or one hun- 

 dred pounds. Growers often ask, "Can we afford to 

 pay $40 per ton for fertilizer?" It depends entirely 

 upon the amount and source of plant food contained. 



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