PAPERS ON CHEMISTRY AND PHYSICS 



311 



the maintenance of soil fertility. Notwithstanding the 

 great amount of work that has been done in various parts 

 of the world, the question is far from being solved. The 

 results are often conflicting and not strictly comparable. 



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It was thought advisable, therefore, to compare these 

 two f onns of phosphatic fertilizers in their behavior after 

 they are applied in various types of soil, and also to study 

 some of the factors that influence their behavior. 



