324 EXPERIMENT STATION RECORD. 



in small amounts varying from 0.001 to 0.01 per cent in the soil and from 0.002 

 to 0.007 per cent in the subsoil, was present in all soils examined. The content 

 of lithium did not seem to follow that of any other element in the soil, and 

 nearly the same amounts were found in the soil and subsoil. 



Absorption of cations and anions by cultivated soil, A. De Dominicxts 

 (Staz. Sper. Agr. Ital., l^t (19U), No. 7, pp. U9-4'i3; abs. in Chern. Zentbl, 1915, 

 I, No. 8, pp. S91, 392). — In this article a series of experiments on the absorp- 

 tion of the cations and anions of solutions of different salts by five different soils 

 are reported. The cations tested were those of the chlorids of ammonium, 

 potassium, sodium, calcium, magnesium, aluminum, and iron, and the anions 

 were those of the chlorid, nitrate, sulphate, carbonate, silicate, phosphate, and 

 aluminate of sodium. 



It was found that the cations of the salts tested were absorbed without excep- 

 tion by soils, and the anions also in most cases. The degree of absorption 

 increased with the valence of the absorbed ions. The relations of the cation 

 and anion absorption were the same in all soils, but the total absorption varied. 

 Absorption is, therefore, thought to depend on the nature of the soil colloids 

 and of the soil solution. 



Behavior of humic acid toward anions, G. I. Ritman {Iz RezuVt, Vcget. 

 Opytov Lab. Rabat, 9 {1913}, pp. m-Jf.'tl). — In studies of the action of so- 

 called humlc acid solutions on salts and acids it was found that the bases of 

 salts were absorbed. No effect was observed on hydrochloric or sulphuric 

 acids. With pota.ssium nitrate a marked decrease in nitrate in the solution was 

 attributed to reduction processes. 



Humus and humus-nitrogen in California soil columns, R. H. Loughbidge 

 {Univ. Cat. Pubs., Agr. Set., 1 {IBlIf), No. 8, pp. 175-274).— A. brief review of 

 several years' analyses of California surface soils is given and investigations 

 are reported, the main purpo.«!e of which was to ascertain the extent to which 

 humus is present in the lower depths of California soils. For this purpose 110 

 soil columns were taken from 37 counties in regions whose soils are many feet 

 in depth, each column representing a characteristic type of land in its particular 

 region. 



The soils of California were found to be richer in humus than has been gener- 

 ally supposed, containing In their depth o*' 3 ft. more than in the soils of humid 

 regions and in the entire columns of 12 ft. or more double that of humid soils. 

 The humus content was usually dlstributetl through depths of 12 or more feet, 

 the highest percentage being in the upper 3 ft. and diminishing downward. 

 The surface soils were found to have an average of 1.2-8 per cent of humus 

 and the upper 3 ft. of soil proper an average of 1.06 per cent per foot, or a sum 

 of 3.17 per cent. 



The tule swamps showetl the highest percentage of humus on account of the 

 mass of decaying roots and other vegetable matter, while the desert plains 

 showed the least. Humification was retarded in close, compact adobe clays and 

 the humus content was less than in lighter loam and .sandy soils. The soils of 

 the valleys of the coast range in the western part of the State showed higher 

 percentages of humus than any of the other agricultural regions. It was found 

 that the humus of the soils of the State is very generally derived from plant 

 roots instead of from accumulations of vegetable material at various depths 

 during soil formation. 



The black color of the soil was not always due to a high humus content, many 

 black soils showing a smaller percentage of humus than .soils of a gray color. 

 The average percentage of nitrogen in combination in the humus of the first 

 foot of the soil columns was 5.92, while that of ench of the upper 3 ft. was 5.6 

 per cent and a little less for the entire 12 ft, varying from 1 to 20 per cent 



