PROFITABLE FARMING 17 



than it could ever be possible to grind it by 

 mechanical means. Phosphates which are in- 

 soluble in water, such as slag and mineral 

 phosphates, however finely ground, will not 

 compare with the state of chemical division 

 obtained by dissolving phosphates with acid. 

 As the former are incapable of being thoroughly 

 disseminated in the soil, and because of their 

 insolubility, the beneficial action of these phos- 

 phates is comparatively slow. 



Mr. A. D. Hall, on page 150 of his book 

 already cited, states : " The essential condition 

 that should dictate the choice of 

 superphosphate as a fertiliser, is the Extra C08t 

 presence of sufficient carbonate of 

 lime in the soil to ensure the pre- 

 cipitation of the soluble phosphoric justified, 

 acid as a calcium compound. Ex- 

 perience has shown that the extra price of the 

 unit of phosphoric acid in its soluble form in 

 superphosphate is more than justified by its 

 superior effectiveness, which is due to the 

 rapidity with which it becomes disseminated in 

 a finely divided condition in the soil, immediately 

 near the roots of the crops." 



With such a weighty pronouncement as this, 

 is must be perfectly evident that water-soluble 

 phosphate is vastly superior and better value 

 than any other form. All that is needful to 

 obtain the most profitable returns is to see that 

 the soil is not deficient in carbonate of lime, and, 

 if it should need it, to apply it without delay, as 

 described later. 



