510 SOILS: PROPERTIES AND MANAGEMENT 



nitrogenous fertilizers. A few such tests, in which nitrate 

 of soda and ammonium sulfate are used as a basis for com- 

 parison, are given in the table below, the statement being 

 in terms of percentage availability when nitrate of soda 

 is taken as one hundred. The experiments quoted were 

 conducted by Wagner and Dorsch,^ by Johnson, Jenkins, 

 and Britton,^ and by Voorhees and Lipman.^ 



Percentage Availability of Fertilizer Nitrogen 



Nitrate of soda 

 Sulfate of ammonia 

 Dried blood . . 

 Bone meal . . . 

 Stable manure . . 

 Tankage .... 

 Horn and boof meal 

 Linseed meal . . 

 Cottonseed meal . 

 Castor pomace 

 Wool waste . . . 

 Leatber meal . . 

 Dry ground fisb 



Wagner 



Johnson 



AND 



AND 



DOKSCH 



Othebs 



100 



100 



90 





70 



73 



60 



17 



45 







49 



70 



68 





69 





65 





65 



30 





20 







64 



Voorhees 



AND 

 LiPMAN 



100 

 70 

 64 



53 



One difficulty in drawing conclusions from these experi- 

 ments is that the substances grouped under the same 

 name are not always identical in the method of their 



^Wagner, P., and Dorsob, F. Die Stiekstoffdiingung der 

 Landw. Kulturpflianzen, Erstes Teil. Berlin. 1892. 



^ Jobnson, S. W., Jenkins, E. H., and Britton, W. E. Experi- 

 ments on tbe Availability of Fertilizer-Nitrogen. Connecticut 

 Agr. Exp. Sta., 21st Annual Rept., Part 4, pp. 257-277. 1897. 



^Voorbees, E. B., and Lipman, J. G. Investigations Rela- 

 tive to tbe Use of Nitrogenous Materials, 1898-1907. New 

 Jersey Agr. Exp. Sta., Bui. 221. 1909. 



