12 SOIL FERTILITY. 



The lowest nitrogen content reported was 0.001 per 

 cent, in a neutral very sandy loam, and the highest nitrogen 

 content 0.786 per cent, in a slightly acid clay loam. 



The amounts of humus, nitrogen, and " loss-on-ignition " 

 (volatile and organic matter), as reported in some analyses 

 of soils of other countries are given below. 



The following are the extreme figures taken from a 

 number of analyses bj- Hall and Russell*. 



Loss-on-ignition .. 1% per cent., and 17.16 per cent. 

 Nitrogen .. .. 0.03.3 per cent., and 0.033 per cent. 



In connection with soils of the United States of America, 

 Cameronf gives the average content of organic matter of 

 1,340 samples as 2.06 per cent. In a paper by Cameron 

 and BreazealeJ the percentages of humus and carbon 

 in humus of typical soils of the United States are given, 

 and the lowest humus content recorded is 0.23 ]5er cent., 

 and the highest 12.18 per cent. The following figures are 

 taken from tables by Hilgard||, in which are stated the 

 percentages of the humus, nitrogen in humus, and nitrogen 

 in soils, of the arid and humid regions of California. In 

 soils from the arid region the average content of humus is 

 stated as 0.91 per cent., the lowest percentage of humus 

 recorded being 0.2 and the highest 3.06 ; the average per- 

 centage of nitrogen in these soils being 0.135 — the extreme 

 percentages bemg 0.035 and 0.670. In humid soils from 

 arid and humid regions, the average content of humus is 

 2.45 per cent., the lowest percentage recorded being 0.94 

 and the highest 7.83 ; the average percentage of nitrogen 

 in these soils is given as 0.135, and the extreme percentages 

 are 0.049 and 0.514. 



♦Agriculture and Soils of Kent, Surrey and Sussex. A. D. Hall and 

 E. J. Russell. 



tA comparison of The Organic Matter in Different Soil Types. F. K. 

 Cameron. Jour. Amer. Chem. Society, 1905. 



IThe Organic Matter in Soils and Subsoils. F. K. Cameron and 

 J. F. Breazeale. Jour. Amer., Chem. Society, 1904. 



IlSoils. E. W. Hilgard. 



