SOILS — FERTILIZERS. 325 



in Individual layers. The organic nitrogen in tlie soil derived from the humus 

 varied from almost nothing in the lower depths of the soil to as much as 0.13 

 per cent in the upper 3 ft. The average of the first foot of the soil columns was 

 0.07 per cent, and for each of the 3 upper feet 0.05 per cent. 



Phosphoric acid was present in the humus of these soils to the extent of from 

 0.01 to 0.08 per cent throughout the entire depth to which humus reaches, 

 though usually more so in the upper few feet. The humus content was some- 

 times less in the first foot than in the second on account of being gradually 

 destroyed by cultivation and summer fallowing. Arid soils are considered to 

 have an immense advantage over those of the humid region on account of this 

 distribution of humus and its nitrogen, as well as of mineral plant food, through 

 a depth of many feet. It is thought that the practical value of California soils 

 can not be based alone upon the nature of the surface and subsoils, but chiefly 

 upon the texture and depth of the soil. 



The presence of proteoses and peptones in soils, E. H. Walters {Jour. 

 Indtis. and Engin. Chem., 7 (1915), No. 10, pp. 860-863) .—The general charac- 

 teristic properties of proteoses and peptones are described, and laboratory experi- 

 ments with a sandy loam soil are reported. The results are taken to indicate 

 that proteins undergo hydrolytic decompositions in the soil in much the same 

 way as in digestion by enzyms, acids, or alkalis, and that a mixture of the 

 various proteoses and peptones resulting from such decompositions exists and 

 persists in the soil as such for a considerable period. 



The effect of certain organic compounds on wheat pla,nts in the soil. — 

 Preliminary paper, F. W. Upson and A. R. Powell {Jour. Indus, and Engin. 

 Chem., 7 {1915), No. 5, pp. ^20-^22, fig. 1; abs. in Chem. Abs., 9 (1915), No. 13, 

 p. 1817). — Experiments at the Nebraska Experiment Station on the behavior 

 of vanillin in concentrations varying from 2.50 to 1,000 parts per million toward 

 wheat plants in black silt loam, silt loam, and in water cultures showed that 

 vanillin was not appreciably toxic to wheat plants when present in the soil 

 in the highest concentrations used, and was much less toxic in the soil than in 

 water cultures. 



Salicylic aldehyde used in concentrations varying from 10 to 500 parts per 

 million was much less toxic to wheat and corn plants in the soil than in water 

 cultures, the toxic effect on wheat at the highest concentration being practically 

 negligible. Further experiments showed, however, that the effect of salicylic 

 aldehyde on wheat and corn is different for different soils. 



" Preliminary experiments on the behavior of cumarin, quinone, and dihy- 

 droxystearic acid toward wheat plants in the soil indicate that the effect is 

 entirely different from the effect of these substances in water solutions. Quinone 

 in concentrations below 500 parts per million in soil is beneficial to the growth 

 of wheat. The other two substances are somewhat more toxic in the soil than 

 is vanillin." 



A bacterial test for plant food accessories (auxim.ones), W. B. Bottomley 

 {Proc. Roy. Soc. [London], Ser. B, 89 {1915), No. B 610, pp. 102-108).— In ex- 

 periments to discover a bacterial test for plant-food accessories in soils 

 (a\iximones) it was found that when the phosphotungstic acid extract from 

 1 gm. of bacterized peat is added to a normal nitrifying culture solution in- 

 oculated with nitrifying organisms and the whole is incubated at 26" C. a 

 thick scum is formed on the surface of the liquid. Further tests showed that 

 the scum is due to the presence aind specific action of the auximone from the 

 bacterized peat. 



An examination of the scum showed that it consists of two predominant 

 kinds of organisms, namely, a thin bead rod form and a spindle-shaped form. 



