15 



A study of the table suggests the follo\\dng conchisions: 



1. With reference to the Poultry Manure: 



(a) Although the activity of the total nitrogen by the alkaline permanganate 

 method was actually higher, and by the neutral permanganate method almost 

 as high as for dried blood, yet when measured by its crop producing power (yield 

 of dry matter) it showed an availability of 46.25 per cent where the sub-optimum, 

 or smaller amount of nitrogen was used, and under 40 per cent when the optimum 

 or larger amount was used, as compared with dried blood at 80. In other words, 

 on the basis of dry matter recovered, the Poultry Manure gave only 58 per cent as 

 great a yield as did dried blood, where the smaller amount was used, and less than 

 half the yield shown by dried blood where the larger amount was used. 



(b) On the basis of nitrogen recovered, it showed an availability of 50.38 per 

 cent with the smaller, and less than 42 per cent with the larger nitrogen application, 

 as compared with dried blood at 80. 



(c) In the studies with the water insoluble nitrogen (the washed product) the 

 alkaline permanganate method classed the insoluble nitrogen as inferior, while the 

 neutral method passed the product as satisfactory. The availabilit}'' of the water 

 insoluble nitrogen on the basis of dry matter recovered was less than 37 per cent, 

 and by nitrogen recovered about 41 per cent, as compared with dried blood at 80. 



(d) It appears from this test that the high nitrogen availability claimed for this 

 product by the distributors was not fully substantiated. 



2. With reference to the Rehmsdorf Tankage: 



(a) The activity'- of the total nitrogen as measured by the laboratory methods 

 was about 78 per cent by the alkaline and 90.5 per cent by the neutral, as compared 

 with 76.5 per cent and 98.25 per cent for dried blood. The actual availability of 

 the total nitrogen as established by the vegetation test, on the basis of dry matter 

 recovered, was about 51 per cent where the smaller amount of nitrogen was used, 

 and about 37 per cent where the larger amount was used, as compared with dried 

 blood at 80. 



(b) On the basis of nitrogen recovered it showed an availability of about 54 per 

 cent with the smaller, and about 36 per cent with the larger nitrogen application, 

 as compared with dried blood at 80. 



(c) In the studies with the water insoluble portion of the product, both laboratory 

 methods passed the product as satisfactory. The actual availability of the Water 

 insoluble nitrogen on the basis of dry matter recovered was about 42 per cent; and 

 on the basis of nitrogen recovered, about 43.4 per cent, as compared with dried 

 blood at 80. 



(d) It appears from results secured by this experiment that the quality of the 

 nitrogen furnished by this product was not only very much inferior to that derived 

 from dried blood, but also that it did not measure up to the high quality claimed 

 for the material in the literature put out by the company. 



Explanation of Tables of Analyses. 



The column headed "Grade of Fertilizer" gives the minimum guarantee of 

 ammonia, available phosphoric acid and potash, always stated in this order. To 

 convert ammonia to equivalent nitrogen, multiply by the factor .82. 



In the table headed "Mixtures Showing a Commercial Shortage of $1 or More 

 per Ton," under the heading "Approximate Commercial Valuation per Ton," is 

 found the sum of the valuation of each plant food element calculated on the basis 

 of analysis and trade values adopted for 1925, which appear on a preceding page of 

 the bulletin. 



In the same table, under "Approximate Commercial Shortage per Ton," is shown 

 the commercial valuation of the deficiencies or tests found below the guarantee, 

 per ton of fertilizer, the value of overruns being used in all cases to offset valuation 

 of shortages. 



Under "Nitrogen" the column headed "Proportion in Water Soluble Form" 

 includes both the mineral and the water soluble part of the organic nitrogen, both 

 of which are readily available. Under "Quality of Insoluble Nitrogen" in aU of 

 the tables of mixed fertilizers, passed indicates an acti\'ity of 50 or over by the 

 alkahne and 80 or over by the neutral permanganate method; inferior indicates 

 an activity below 50 and below 80 by the two laboratory methods. All samples are 



