INSPECTION OF COMMERCIAL FERTILIZERS 55 



Description of Phosphates Included in the Experiment. 



Ammoniated Superphosphate. This is the product of the Davison Chemi- 

 cal Co., Baltimore, Md. It is made by adding liquid or anhydrous ammonia to 

 superi)hosphate. As ordinarily carried out, the jn-ocess results in somewhat 

 lowering the availability of the phosphoric acid originally contained in the super- 

 phosphate, as measured by laboratory methods. The process appears to be a 

 very economical method of ammonifying fertilizer mixtures and is of much in- 

 terest to the fertilizer industry at present. The product usually contains from 

 17 to 19 per cent total, and from 12 to 14 per cent citrate-soluble phosphoric acid. 



Ammo-Phos (13-4G grade). This is the jiroduct of the American Cyanamid 

 Co., New York, N. Y. It is known to be a very reliable source of available 

 l^hosphoric acid as well as anuxionia and was included in the experiment as an- 

 other standard or check with which to compare some of the other ])hosi)hates. 



Basic Slag Phosphate. Two grades were employed, both having been 

 drawn by our insjjectors from stock imported from Belgium or Germany during 

 the season of 1929. These slags are said to differ from the basic phosphatic slags 

 of pre-war times in that less lime and more sand is used in slagging the iron 

 ore. 



Calcined Phosphate. The two jiroducts under this name were developed by 

 the Mellon Institute of Industrial Research, Pittsburgh, Penn. They are of 

 recent origin and are not ]iroduced commercially at present. 



Colloidal Phosphate. This is a fine, silty, natural phosi)hate, a by-jiroduct 

 in mining Florida ])hosphate It is sold rather widely, in experimental amounts, 

 in Massachusetts and other New England States by the Colloidal Phosjihate 

 Sales Co. of New England. A description of this product is given on i)age 51, 

 Bulletin No. 51, Control Series, ])ublished by this station in 1929. 



Fused Phosphate and Potash. This jn-oduct is manufactured by the Kreiss 

 Potassium Phosphate Co., Tampa, Fla. It is not a true chemical compound of 

 potassium phosphate. Claims are made by the producers that both the phos- 

 phoric acid and the potash are readily available to-ijlants. It is not, to the 

 writer's knowledge, sold in this locality. 



High Grade Residue. This is a by-product, largely iron and aluminum 

 l)lios])liate, made I)y the Grasselli Chemical Co., Cleveland, Ohio, and used largely 

 in mixed fertilizers. 



Ober Residue. These materials were jirepared under the direction of Dr. 

 W. H. Ross, of the Bureau of Chemistry and Soils, United States Department of 

 Agriculture, from the so-called insoluble phosphoric acid found in ammoniated 

 superphosphates. The water soluble phosphoric acid is first extracted from the 

 ammoniated superphosphate (anhydrous ammonia process), and the residue is 

 then treated with neutral citrate of ammonia solution as in the determination of 

 citrate-soluble or reverted phosjihoric acid described in the book of methods of 

 the Association of Official Agricultural Chemists. Residue A is made by treating 

 2 grams of the water insoluble residue of the ammoniated superphosphate with 

 100 c.c. of the neutral citrate solution; Residue B, by treating Jo gnvm of the 

 residue with 100 c.c. of the solution. 



Precipitated Bone. In the production of this i)roduct the mineral part of 

 bones is dissolved in a solution of hydrochloric acid, permitting the recovery of 

 the organic portion of the bone for the manufacture of glue. The phosphoric acid 

 is precipitated from the acid solution by neutralizing with milk of lime, and is 

 largely in the form of di-calciiun phosphate, a white amorphous powder when dry. 

 Precipitated bone has a high content of citrate-soluble or so-called reverted 

 phosphoric acid. There is a lack of experimental data as to its availability by 

 vegetation tests. 



