720 EXPEEIMENT STATION EECOED. 



It is concluded that as regards the difference between forested and cultivated 

 soils in absorbing power, concentration of soil solution, and content of easily 

 oxidizable organic matter, the forested soil represents a state of continuous 

 chemical and physical evolution and is profoundly modified when it reaches 

 the cultivated condition. 



A list of references to related literature is appended. 



Nitrogen in forest soils, A. Pakeozzani (Ann. R. Staz. Sper. Agrum. e 

 Frutticol. Acireale, 2 (1914), pp. 14-22) .—After presenting the views of others 

 as to the forms of nitrogen occurring in forest soils, the results of mechanical 

 and chemical analyses of soils from two forests growing beech, common and 

 cork oak, and chestnut trees and broom {Genista aetnensis) are reported. 



Nitrates were found in all of the soils, except those growing broom, and 

 showed no relation to lime content. Deep soils contained more nitrates than 

 shallow soils. More nitrates were found in the oak soils than in the soils 

 growing other trees and were more evident in the surface than in the subsoil, 

 especially in soils of medium and loose texture. Five soils were rich in nitrates 

 and two were not. Under identical conditions the nitrite content of the oak 

 soils was superior to that of the chestnut and beech soils. 



A list of references to literature bearing on the subject is appended. 



Correlation between humus and mineral matter in dark colored soils, A. A. 

 Blagonkavov (Abs. in Zhur. Opytn. Agron. {Russ. Jour. Expt. Landiv.), 14 

 (1913), No. 5, pp. 457, 458). — Assuming that degraded dark colored soils have 

 been at one time less degraded and comparing their chemical composition by 

 calculating the percentage composition of the zeolitic portion, the author finds 

 that the changes in the mineral part of these soils correspond with the changes 

 of the humus content. On this basis, and assuming that the lime is carried 

 from the higher horizons downward in the form of calcium crenate, he calculates 

 a series of " simple correlations " between the lime and crenic acid, for which 

 he takes Mulder's formula C24H24O16. 



With the aid of these correlations it is considered possible, from the differ- 

 ence in the humus of any two soils and the amount of lime in one, to calculate 

 the contents of the zeolitic lime in the other. The values so calculated differ 

 from those found by actual analysis only in hundredths of one per cent. Other 

 constituents of the zeolitic portion are also found by means of calculations from 

 a whole series of ratios. On the basis of correlations between different elements 

 so obtained the difference in the composition of two soils is expressed in the 

 form of formulas by the aid of which, having previously determined the lime 

 percentage, the contents of all the other constituents are calculated. Then 

 accepting for humic acid Detmer's formula CooHmOzt, the ratios to humic acid 

 of the various bases soluble in 10 per cent hydrochloric acid are found and 

 from these ratios, guided again by the relation between humus and lime (1:4), 

 a formula is deduced for the composition of the mineral constituents of a given 

 soil. 



In conclusion, the author reduces the soils of different regions to a small 

 number of groups, being guided by the ratio of the amount of carbon in the 

 humus to the sum of mineral substances (from 10 per cent hydrochloric acid 

 solution). 



Bacteria of frozen soil, III, H. J. Conn (Centbl. Bakt. [etc.'], 2. Abt, 42 

 {1914), No. 11-18, pp. 510-519, figs. S).— Further studies on the subject (E. S. R., 

 26, p. 520) confirm the former conclusion that the number of bacteria in frozen 

 soil is generally higher than in unfrozen soil. This was true not only of cropped 

 soil but also of sod and fallow soil. Other results of these studies have been 

 reported by the author in bulletin form (E. S. R., 32, p. 33). 



