34 



CONTROL SERIES No. 45 



Ground Bone. — Concluded, 

 Ground Bone Adtilterated. 



Brand Showing a Commercial Shortage of $1 or More Per Ton. 



N. Roy & Son 



1 Two analyses. 



' Average steamed ground bone has from 50% to 55% of its phosphoric acid soluble in neutral 

 citrate of ammonia. This sample shows less than 19% of its phosphoric acid soluble in this 

 reagent, in other words, less than one-fifth. This would indicate that two-fifths of the phosphoric 

 acid (10.3%) was derived from bone and the balance (15.45%) from coarsely ground rock phos- 

 phate. The average difference in commercial value between the phosphoric acid in ground bone 

 and ground rock phosphate is about 60 cents per unit, which would lower the ton cost of the product 

 $9.27. The use of hoof meal as an adulterant did not detract from the agricultural value of the 

 nitrogen as hoof meal is a good source of this ingredient, showing both satisfactory nitrogen 

 activity by laboratory methods and availability by vegetation experiment. The water insoluble 

 nitrogen in the adulterated bone sample gave an average activity of 82.05% by the alkaline per- 

 manganate method, thus comparing favorably with the better grades of animal tankage and bone. 

 The use of hoof meal, however, did lower the unit cost of the nitrogen derived from this source 

 about $1.32 per unit. Assuming that three-fifths of the nitrogen was derived from this source 

 and two-fifths from bone, the difference in ton cost would be $2.63. This amount added to the 

 difference in value due to the phosphate rock would make a total rebate of $11.90 per ton. 



' Sample drawn at South Attleboro. It showed a commercial deficiency of $1.13 per ton. 



Wood Ashes. 



Pulverized Animal Manures. 



Farm manures are valued not only for the plant food which they contain, 

 but also for the relatively large amount of partially decomposed organic matter 

 which they furnish and which in turn contributes to the valuable humus content 

 of soils on which the manures are used. The average price paid for pulver- 

 ized manures ($46.44 per ton, in case of 44 samples of pulverized sheep manure 

 inspected during the season) is hardly justified from the standpoint of plant 

 food received. The content of organic matter should therefore be of interest 

 and value. To interpret properly the value of the organic matter supplied, 

 consideration should be given to the extent to which decomposition has taken 

 place and the relative amount of undecomposed straw, hay, or other litter that 

 is present. A well rotted manure will usually produce quicker results in green- 

 house or field than will the undecomposed product containing much litter. 



