1918) SOILS FERTILIZERS. 421 



was somewhat effective at 0.1 per cent strength ; and sulphuric acid was fairly 

 effective, a one-day exposure accounting for from 91.3 to 96.7 per cent of the 

 organisms, two-day exposures for from 68.3 to 86.9 per cent. P'ormaldehyde 

 proved to be most effective, having killed more than 99 per cent of the organ- 

 isms in four of six trials and 97.2 per cent in a fifth trial. " The gas seems 

 to combine with, or in some way to affect, the albuminous contents of the 

 bacterial cell, thus inhibiting reproduction." 



Steam is considered more effective than any chemical, but proved to be 

 cuniber.some to use and of limited range. Formaldehyde was estimated to 

 have cost about 1.5 cts. per square yard of application. 



Samples of soil taken from plats which had^ received air-slaked lime, quick- 

 lime, and eWorld of lime at the rate of 150 bu. per acre, and representing 

 depths near the surface, from 3 to 6 in., and from 6 to 9 in., showed from 36 

 to 60 per cent less organisms for the surface of the limed plats than for 

 untreated check plats, but increases in the bacterial population for the other 

 depths ranging from 51 to 498 per cent. 



Researches on the equilibrium between the nitrogen and carbon in the 

 soil, P. Felbeb {Mitt. Landw. Lehrkanz. K. K. HocJisch. Bodenkul. Wien, 3 

 (1916), No. 1, pp. 23-54; «&«■ in Internat. Inst. Agr. [Rome'\, Intemat. Rev. Set. 

 and Pract. Agr., 8 {1911), No. 1, pp. 22-25; Abs. Bad., 1 {1917), No. 4, p. 308).— 

 Analysis of a variety of soils indicated that the carbon-nitrogen relations are 

 fairly constant. 



The influence of bacterial activity as indicated by the carbon-nitrogen ratio 

 upon these soils with and without the addition of various substances was 

 determined. In the control test the bacterial activity caused a loss in both 

 organic matter and nitrogen. A similar loss occurred with soy-bean meal. 

 With straw the loss in nitrogen was less. The addition of lime intensified the 

 decomposition of organic matter but did not influence the loss in ammonia. 

 Nitrification, denitrification, and nitrogen fixation were not affected by the 

 lime. The digestion of earth with water at 30° C. for three days showed that 

 the ratio between carbon and nitrogen was altered, there being an increased 

 proportion of nitrogen. Denitrification of saltpeter occurred when it was 

 added in combination with straw meal or dextrose. Without these sources 

 of carbon there was an elimination of carbon but the saltpeter was not de- 

 stroyed. 



The humus content of the soil, H. J. Wheeler {Proc. Amer. Assoc. Farmers' 

 Inst. Workers, 21 {1916), pp. 19-90, figs. 2). — This is a lecture dealing with 

 humus, its origin, production, and activity in soil witli special reference to its 

 relation to the fertility of different soil types. 



Soil survey of the Riverside area, Cal., J. W. Nelson, R. L. Pendleton, J. E. 

 Dunn, A. T. Strahorn, and E. B. Watson {TJ. S. Dept. Agr., Adv. Sheets Field 

 Oper. Bur. Soils, 1915, pp. 5-88, pis. 4, fig- 1, f^ap i).— This survey, made in 

 cooperation with the California Experiment Station, deals with the soils of an 

 area of 387,840 acres situated in the western part of Riverside County and 

 the southwestern corner of San Bernardino County. Topographically, it con- 

 sists mainly of a series of large alluvial fans extending from the surrounding 

 mountains and merging into an extensive, gently sloping plain, while several 

 low mountains occur within the area. As a whole the region is well drained, 

 although local low-lying spots having a high-water table are affected with 

 alkali. 



The soils of the area are largely derived from granite, gneiss, and schists, 

 and have been spread over the region as extensive alluvial-fan deposits. 

 Thirty-five soil types representing 13 series are mapped, in addition to river- 



