SOILS FERTILIZERS. 323 



are, however, prevented by the growing of cover crops. Ohservations on the 

 .same subject l).v Hall at lioth.-mistetl are also reviewed. 



The study of nitrification in soils by means of drainage water investiga- 

 tions (2Jilt. Dent. Lundu: GescIL, 21 (lOOG), No. IS, pp. 195-203. flys. 2).— This 

 article is based upon reviews of the llothauisted work by Miller and Hall and 

 Bieler (E. S. R., 8, p. 63G ; 17, p. 542), and of Sjollema's investigations in 

 Holland by Ilndig (see p. 322). 



The role of organic matter in nitrification, A. Muntz and E. Laine (Compt. 

 h'ciid. Acad. Sci. \l'ari.s\. I.',2 (I'.KiC), \o. S, pp. .'iJO-J/S.j ; abs. in .Jour. Chcm. 

 -S'oc. [Londuii], 90 (1906). Xo. rj2J,'l/, p. 2.9S).— In view of the fact that Wino- 

 gradsky has shown that organic matter is not necessary to the growth of 

 nitrifying micro-organisms and that there is a general opinion that the pres- 

 ence of organic matter is a disadvantage rather than advantage in the growth 

 of such organisms, the authors undertook to determine the true relation of 

 organic matter to nitrification. Witii this purpose in view they studied the 

 rate of nitrification in neutral anuiioiiiuui huinate prepared from garden soil 

 and in a solution of sulphate of ammonia containing an equal amount of nitro- 

 gen. They also studied the rate of nitriticati<m in natural soils of different 

 kinds, including garden soil, compost, silico-calcareous soil, clay soil, and cal- 

 careous clay soil in unsterilized condition, and in two of the soils, one rich 

 and the other poor in humus, after sterilization and subsequent inoculation 

 both with a soil. poor in humus and with one rich in humus. 



The general conclusions reached in these investigations were that humus even 

 in large quantity does not interfere with nitrification, but, on the other hand, 

 is favorable to it. An abundance of humus is not a necessary condition to 

 nitrification, since soils poor in this constituent gradually develop intensive 

 nitrification. The humus, however, appears to favor the multiplication of the 

 nitrifying organisms, and a soil which contains a large amount of humus is 

 more abundantly supplied with these organisms and more apt to enter into 

 rapid nitrification. The idea that organic matter in the soil interferes with 

 nitrification must therefore be abandoned. 



Investigations on intensive nitrification, A. MtJNTZ and E. Lain^ {Compt. 

 Rend. Acad. .S'c/. [Paris]. U/l {1905), Xo. 22, pp. S61-867; abs. in Jour. 

 Chem. Soc. [London], 90 {1900), No. 520, II. p. ii//).— The possibilitj^ of so 

 intensifying nitrification that it may be made a means of supplying nitrates 

 in time of war when outside supplies might be cut off was studied and experi- 

 ments are reported which indicate that by using solutions containing 7.5 gm. 

 per liter of ammonium sulpliate and coarse-grained animal black in layers 

 2 m. thick, it would be possible at a temperature of 30° C. to produce nitrate 

 at the rate of 5.000.000 to G.000,000 kg. per hectare per year. With a com- 

 post of well-rotted leaves, manure, and soil in a layer 50 cm. deep moistened 

 with a solution of 1 part of ammonium sulphate per 1,000 of water nitrates 

 were produced at a rate of 1.200,000 kg. per hectare annually. A practical 

 difficulty in connection with the method is the very dilute solution of nitrate 

 o])tained, requiring a large amount of evaporation, and the dilute solution 

 of annnonium sulphate which must be used. By following methods similar 

 to those employed in the old niter beds the nitrates were concentrated to 

 27 to 33 gm. per kilogram of soil (2.7 to 3.3 per cent) or over 150 gm. i»er liter 

 of soil solution. The possil)ility of further concentration of solutions obtained 

 from ox'idation by means of animal black by replacing the animoninm sulphate 

 nitrified and passing the mixture of nitrates and annnonium salts through the 

 beds again is being studied. 



Niter and the national defense, A. Mlntz {Ann. Inst. Xat. Agron., 2. ser., 



13987— Xo. 4— 0(5 .\i 3 



