32 



nitrogen amounting to three-tenths of one per cent (0.3%) or more of the weight of 

 the material. In the event of a total nitrogen exceeding the minimum guarantee, 

 accompanied by a low activity of the insoluble nitrogen, the overrun may be taken 

 into consideration in determining the classification of the water-insoluble nitrogen. 

 (&) The water-insoluble nitrogen in mixed fertilizers showing an activity below 

 fifty per cent (50%) by the alkaline method and also below eighty per cent (80%) 

 by the neutral method shall be classed as inferior. This necessitates the use of both 

 methods before classifying as inferior. 



VEGETATION POT EXPERIMENT TO DETERMINE NITROGEN 



AVAILABILITY OF PROCESSED LOW-GRADE MATERIALS AND 



ACTIVATED SEWAGE PRODUCTS. 



In recent years most of the slaughterhouse by-products that formerly were 

 largely absorbed by the fertilizer industry have been diverted to the manufacture 

 of cattle feeds where they command a better price and are more economically 

 utilized. The shortage of the different grades of tankage and dried blood, as well 

 as the normal expansion of the fertilizer industry, has naturally stimulated an 

 effort to produce substitutes for these organic nitrogen-containing substances. 

 By-products of relatively high nitrogen content but low in activity and availability 

 have served for the production of a class of processed organic nitrogen-containing 

 materials now offered to the trade under a variety of trade names and usually with 

 the claim that the plant food which they furnish is available to plant life. Although 

 these products are often bought and sold on their content of active nitrogen as 

 determined by laboratory methods, yet their actual nitrogen availabilitj' in many 

 instances has not been satisfactorily established. It was for this purpose that 

 vegetation experiments were inaugurated in 1925, and have been expanded during 

 1927 to include as many of these products as it was possible to locate through the 

 trade channels. 



Description of the Products Under Experiment 



Agrinite, manufactured by the American Agricultural Chemical Co. at one of 

 their plants at Carteret, N. J. The sample contained 8.88 per cent nitrogen, of 

 which .29 per cent was in ammoniacal, and 2.37 per cent in water soluble organic 

 form. The sample was furnished on request by a representative of the company. 



Tankage, supposed to be animal tankage, representing the product sold by 

 Thomas Hersom & Co., New Bedford, Mass., to the several state institutions in 

 Massachusetts in the spring of 1927. It tested 8.58 per cent nitrogen, of which 

 2.42 per cent was in water soluble form; and 5.23 per cent phosphoric acid. The 

 sample was drawn from stock sold to the Massachusetts Agricultural Experiment 

 Station. 



Avail Tankage, manufactured by the Western Fertilizer Products Co., Granite 

 City, 111. It tested 7.25 per cent total nitrogen, of which .66 per cent was in am- 

 moniacal, .13 per cent in nitric, and 1.08 per cent in water soluble organic form. 

 The sample was procured through trade channels. 



Georgia Tankage, manufactured by Joslin Schmidt Co., St. Bernard, Ohio. 

 The sample was procured through trade channels. It tested 9.13 per cent total 

 nitrogen, of which 1.56 per cent was in water soluble organic form. 



Hynite Tankage, manufactured by United Fertilizer Co., Milwaukee, Wis. 

 One sample, said to represent the product as manufactured in ] 927, was furnished 

 by the manufacturer and one sample was secured through trade channels; a com- 

 posite of the two was used in the experiment. The average nitrogen content was 

 8.92 per cent, of which 1.51 per cent was in water soluble organic form. 



Horn and Hoof Meal. A mixture of processed horn and hoof meal was secured 

 through trade channels. It contained 14.32 per cent nitrogen, of which 2.32 per 

 cent was in water soluble organic form. 



Imhoff Tank Sewage Sludge, from City of Worcester, Mass. The sample, taken 

 from drying bed, was exposed during the winter of 1925. It contained 2.75 per 

 cent nitrogen, of which .62 per cent was in ammoniacal form. 



Milorganite, activated sewage sludge fertilizer, manufactured by the city of 

 Milwaukee. One sample was sent by the manufacturer and one was secured from 

 a carload sold in Massachusetts through trade channels in 1927; a composite of 

 the two was used in the experiment. It contained an average of 5.425 per cent 

 nitrogen, of which .45 per cent was in water soluble organic form. 



