THE ORGANIC MATTER OF THE SOIL 117 



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

 ures on the Russian Tschernozen x 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 OF ORGANIC MATTER (C X 1.724) IN CERTAIN 

 REPRESENTATIVE SOILS OP THE UNITED STATES. 



Description 



2 



6 



30 



Residual soils — Robinson 2 



Glacial and loessial soils — Robin- 

 son 2 



Kansas till soils — Call 3 



Nebraska loess soils — Alway 4 . . . . 



Minnesota till, soils — Rost and 

 Alway 5 



Surface 



1.76 



4.59 

 2.86 

 3.83 



7.46 



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 6 of soils 

 varies with the organic matter and may range in surface 

 mineral soils from .01 to .60 per cent. West Virginia 7 soils, 



1 Kossowitsch, P., Die Schwarzerde ; Internat. Mitt. f. Bodenkunde, 

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



2 Robinson, W. O., The Inorganic Composition of Some Important 

 American Soils; U. & Dept. Agr., Bui. 122, 1914. 



3 Call, L. E., et al*, Soil Survey of Shawnee County, Kansas; Kans. 

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



4 Alway, F. J., and McDole, Gr. R., The Loess Soils of the Nebraska 

 Portion of the Transition Begion: I. Hygroscopicity, Nitrogen and 

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



5 Rost., C. O., and Alway, F. J., Minnesota Glacial Soil Studies; I. A 

 Comparison of the Soils of the Late Wisconsin and Iowan Drifts; 

 Soil Sci., Vol. XI, No. 3, pp. 161-200, Mar., 1921. 



6 Soil nitrogen is determined by either the Kjeldahl or the Gunning 

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



7 Salter, R. M., and Wells, C. F., Analyses of West Virginia Soils; 

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



