SOILS FERTILIZERS. 721 



119-129, figs. 3). — The Investigations here reported have already been noted 

 from another source (E. S. R., 30, p. 22). 



The theory of antagonism of salts and its significance in soil studies, 

 C. B. LiPMAN (Proc. Soc. Prom. Agr. Sci., 34 {1913), pp. 33-^0). — A previous 

 paper setting forth the same views has already been noted (E. S. R., 31, p. 317). 



The deposits in drainpipes in drainage of swamp soil, B. Tacke (Zentbl. 

 Agr. Che 111., Jf3 {1914), A'o. 5, pp. 308-311). — Investigations of the incrustations 

 in drainpipes in swampy soil showed that the trouble was due mainly to fine 

 sand and clay separations which penetrated the drain joints. The reddish- 

 yellow color was due to iron oxid. Most of the incrustation was found at the 

 joints. The trouble was best prevented by covering the joints with peat muclJ. 



Some chemical and bacteriological effects of clearing grass land by burn- 

 ing, F. QuisuMBiNG and G. Ocfemia {Philippine Agr. and Forester, 3 {1914), 

 No. 4, pp. 7G-78). — It is stated that grass lands in the Philippines are com- 

 monly cleared by burning, but experiments are referred to which show that 

 this practice results in a large loss of nitrogen and humus in the surface soil. 

 A study of the bacterial life of the soil showed that burning not only greatly 

 reduced the number of organisms in it, but profoundly modified their character. 

 The work did not go far enough to show whether this was an advantage or 

 disadvantage. 



Mobilization of the soil phosphoric acid under the influence of the life 

 activity of bacteria, S. Sevebin {V{estnik Bakt. Agron. StantsU V. K. Ferrem, 

 No. 18 {1911), pp. 156-246; ahs. in Zhur. Opytn. Agron. {Russ. Jour. Expt. 

 Landw.), 13 {1912), No. 4, pp. 629, 650).— This is a detailed account of investi- 

 gations more briefly reported elsewhere (E. S. R., 20. p. 817). 



Enriching of soils in nitrogen in connection with the life activity of 

 aerobic micro-organisms assimilating free nitrogen, A. V. KuainskiI {Univ. 

 Izv. [Kief], 52 {1012), Nos. 4, pt. 2, Art. 3, pp. 1-58; 8, pt. 2, Art. 3, pp. 59-131, 

 figs. 7; 9, pt. 2, Art. 5, pp. 133-182, figs. 2; ahs. in Zhur. Opytn. Agron. {Russ. 

 Jour. Expt. Landw.), 13 {1912), No. 4, pp. 625-629) .—This, elaborate report first 

 reviews the literature, then describes the methods used by the author, and 

 finally reports in detail the results of his investigations on the subject. 



The biological nature of nitrogen fixation in soils was deduced from re- 

 sults of experiments with antiseptics (chloroform and thymol). The higher 

 the humus content the larger the water content of the soil required for optimum 

 nitrogen fixation. The mutual relations of different groups of organisms were 

 affected by vai-ying conditions of light. No nitrogen was fixetl under strictly 

 anaerobic conditions (in an atmosphere of nitrogen), although it occurred in 

 a chernozem soil with high moisture content. There apijeared to be a certain 

 associative action of anaerobic and aerobic organisms. 



Increasing the organic matter of the soil did not increase nitrogen fixation, 

 but the organic matter was quickly decomposed. Nitrogen fixation was more 

 active in naturally rich or well-fertilized soils than in poor soils. Azotobacter 

 was shown to be capable of using carbohydrates, alcohol, and acids as sources 

 of energy. 



With an increase of aeration the amount of organic matter required to fix a 

 unit of nitrogen diminished and the process of fixation was accelerated. In 

 sand cultures the curve of respiration ran parallel with or lagged behind the 

 curve of fixation. In water cultures it ran ahead. Ammonium sulphate de- 

 pressed fixation of free nitrogen by Azotobacter. Aspergillus niger and 

 PeniciUium glaucum assimilated free nitrogen best in a 5 per cent sugar 

 solution. The ratio of carbon consumed to free nitrogen assimilated was on 

 the average about 10 : 1 in sand cultures. In soils with high contents of water 



