SOILS — FERTILIZEES. 615 



halts. Berlin, 1911, pp. 59; reiK in Wasser u. Ahivasser, 5 {1912), No. 2, pp. 

 79-81). — Studies on the character and composition of the soil of one of the 

 sewage farms near Berlin befare and after several years' application of sewage 

 showed that the humus, nitrogen, and potash content of the surface soil was 

 doubled under sewage irrigation. The phosphoric acid was appreciably in- 

 creased to a depth of 1 meter, but the lime content was decidedly decreased. 

 Further investigations showed that not only did the sandy soil which was 

 used in these experiments have a low absorptive power for lime, but that the 

 application of sewage brought about conditions favorable to the solution and 

 leaching out of the lime of the soil. 



Detailed analytical data are given and work of other investigators on the 

 same subject is reviewed. 



Notes on sewag'e sludge and its disposal, J. Grossman (Jour. Soc. Chem. 

 Indus., 31 (1912), No. 1, pp. 3-1; Surveyor, 1,1 {1912), No. 1050, pp. 352, 358- 

 360). — Discussing the agricultural utilization of sludge, the author refers to 

 the report of the British Royal Commission as showing that sewage sludge 

 does not as a rule produce the fertilizing effect which its content of nitrogen, 

 phosphoric acid, and potash would lead one to expect, and he suggests that this 

 is due to the fact that grease predominates to such an extent in the sludge as 

 to render the manurial constituents practically inoperative. After examination 

 of various methods of disposal, he has reached the conclusion that the best 

 method of utilization is distillation with superheated steam for the production 

 of gas and ammonium sulphate. 



"The hygienic disposal of sewage sludge is the keystone of sewage purifi- 

 cation, and the most rational mode of sludge disposal is that of putting it back 

 on the land. But to use it in the shape of sludge, wet, pressed, or dried, for 

 farming purposes is nearly always impracticable and always open to serious 

 objections on hygienic grounds. There will always be a suspicion that it may 

 disseminate disease amongst cattle and human beings; it should never be used 

 where cattle is grazing, and not where the plant shoots have appeared above 

 ground. . . . Ordinary drying of sludge is no guaranty of sterilization. To 

 make the sludge available for farming puii^oses it must be deprived of its 

 grease, and the residue exposed to such a temperature as will be a guaranty 

 that it is thoroughly sterilized." 



Sewage sickness in land filtration, J, E. Purvis, A. C. N. McHattie, and 

 R. H. J. Fisher {Jonr. Roy. Sanit. Inst., 32 {1911), No. 9, pp. 439-U2 ; al)s. in 

 Wasser u. Ahwasser, 5 {1912), No. 2, p. 83). — Examinations of the Cambridge 

 sewage farm on which 2,250,000 gal. of sewage daily were being disposed of 

 on an area of 102 acres, rotating on 25 acres at a time, showed that certain of 

 the sections were sewage sick. This was found to be a physical condition due 

 to blocking up of the pores of the soil by suspended solids and growths and 

 was easily and cheaply corrected by plowing and harrowing the land. Crop- 

 ping was not considered necessary. 



SOILS— FERTinZERS 



The chemical nature of the organic nitrogen in the soil, S. L. Jodidi and 

 A. A. Wells {Iowa Sta. Research Bui. 3, pp. 113-134). — Investigations in con- 

 tinuation of those already noted (E. S. R., 26, p. 320) are here reported. 



These reports deal more fully than the previous articles with the nature of 

 the oi'ganic nitrogenous compounds in soils treated with various organic ma- 

 terials under different cropping systems. The more important conclusions 

 reached are that "the amount of ammoniacal nitrogen in all of the plats ex- 

 amined is insignificant, ranging from 0.000649 to 0.001508 per cent of the oven- 



