THE ORGANIC MATTEE OF THE SOIL 117 



range from .73 per cent, to 15.14 per cent., while similar fig- 

 ures on the Russian Tschernozen^ vary from 3.45 to 16.72 

 with an average of 8.07 per cent. The subsoil of course runs 

 lower in every case. The following figures, while far from 

 representative, are suggestive : 



Table XXII 



PERCENTAGE OP ORGANIC MATTER (0 X 1.724) IN CERTAIN 

 REPRESENTATIVE SOILS OP THE UNITED STATES. 



Description 



8 Residual soils — Robinson ^ 



3 Glacial and loessial soils — Robin- 

 son ^ 



2 Kansas till soils — Call ^ 



6 Nebraska loess soils — ^Alway *. . . 

 30 Minnesota till soils — Rost and 

 Always 



Subsoil 

 .64 



1.44 

 1.98 

 1.96 



1.88 



As the soil nitrogen is carried almost wholly by the organic 

 matter, and is a true organic constituent of the soil, its con- 

 sideration at this point is opportune. The nitrogen ® of soils 

 varies with the organic matter and may range in surface 

 mineral soils from .01 to .60 per cent. West Virginia ^ soils, 



^ Kossowitsch, P., Die Schwarzerde ; Internat. Mitt. f. Bodenkimde, 

 Band I, Heft 3-4, S. 316, 1912. 



^Eobmson, W. 0., The Inorganic Composition of Some Important 

 American Soils; IT. ^ Bept. Agr., Bui. 122, 1914. 



®Call, L. E., ei qIa, Soil Survey of Shawnee County, Kansas; Kans. 

 Agr. Exp. Sta., Bui. 200, 1914. 



*Alway, F. J., and McDole, G-. E., TJis Loess Soils of the Nehraslca 

 Portion of the Transition Begion: I. Hygroscopic^tyf Nitrogen and 

 Organic Carbon; Soil Sei, Vol. I, No. 3, pp. 197-238^ Mar., 1916. 



^ Eosi, 0. 0., and Alway^ P. J., Minnesota Glacial Soil Studies; I. A 

 Comparison of the Soih of the Late Wisconsin and lowan Drifts; 

 Soil Sci., Vol. XI, No. 3, pp. 161-BOO, Mar., 1921. 



^'Soil nitrogen is determined by either the Kjeldalil or the Gunning 

 method. These will be described later. See paragraph 165. 



''Salter, E. M., and Wells, C. F., Analyses of West Virginia Soils; 

 W. Va. Agr. Exp. Sta., BuL 168, Dec, 1918. 



