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concerned, the insoluble phosphoric acid from animal 

 sources being much more readily appropriated by the plant 

 than the same form when of mineral origin. 



The phosphoretic slag obtained by dephosphorizing pig 

 iron in the Thomas-Gilchrist process for steel-making, has 

 recently become an important factor in the world's supply 

 of phosphoric acid, but has been met with but little in 

 southern fertilizer markets. 



Should the basic process of steel making be introduced in 

 this State, an additional valuable source of phosphoric acid 

 will be furnished to the farmers of Alabama. 



The attention of this office has been called to circulars 

 distributed by manufacturers and dealers in non-acidulated 

 phosphates, in which a claim is advanced in favor of the 

 natural phosphate and against the acid phosphate, to the 

 elfect that the free sulphuric acid of the latter is highly de- 

 trimental to vegetation, and therefore constitutes a valid 

 objection to its use for fertilizing purposes. 

 , As a matter of fact, however, the proportion of sulphuric 

 acid used in the treatment of phosphate rock is, as stated 

 above, very rarely sufficient to give even a slight excess of 

 free sulphuric acid in the product and farmers need appre- 

 hend no trouble from this source. 



(2.) NITROGEN MANUEES. 



Nitrogen is supplied in commercial fertilizers in three 

 forms, these several forms being designated by the sources 

 from which they are derived : 



(1) Vegetable nitrogen. 



(2) Animal nitrogen. 



(3) Mineral nitrogen. 



Among the chief forms of vegetable nitrogen may be 

 mentioned cotton seed, cotton seed meal, and the cakes and 

 meal resulting from the extraction of oils from various 

 vegetable sources. 



Cotton seed and its product, cotton seed meal, is the best 

 known of any of the vegetable fertilizers to the southern 



