SOILS — FERTILIZERS. 717 



representative of each of the groups of nitrogeu-trausformiug or assimilating 

 bacteria except Bacteriinn radicicola. A new species of Azotobacter was also 

 found. The species of Xitrosoiuonas found in this soil had spores. 



On the fixation of the free atmospheric nitrogen by micro-organisms, II. R. 

 Christensen {TiiLsskr. Luinlbr. I'hintvavJ, 16 (1900), Xo. 2, pi). 30.i-336, figs. 

 5). — A resume of the more im|M>rtant investigations relating to this subject, 

 covering the period from Ilellriegel and Willfarth to recent times (May. 1909). 

 A bibliograi)h.v of the subject is given at the close of the article. 



Bacillus amylobacter in its morphological, physiological, and systematic 

 relations, G. Brkdemann (Centhl. Bald. [etcA, 2. AM., 23 (1909), A'O. l.',-20, pp. 

 3S5-06S, pis. 6, figs. 13; al)s. in Jour. Chem. Soc. [London], 96 (1909), No. 561, 

 II, p. 601). — The present state of kuowletlge with reference to this organism, 

 especially as regards its nitrogen-fixing powei*, is summarized in this article. 

 A very complete bibliography of the subject is also given. 



The characteristic features of the organism are its power of fixing nitrogen, 

 decomposing carbohydrates with the formation of alcohol and volatile acids, 

 and malving and storing glycogen. As indicated by the amount of volatile acids 

 produced, there was little variation in function in organisms from different 

 sources. 



Manganese in soils and in plants, P. Boname (Sfa. Agron. Mauritius Bui. 20, 

 1909, pp. J0-5-J).— Analyses are reported which show that manganese is widely 

 distributed in considerable amounts (as high as 0.4 per cent) in the soils of 

 Mauritius and consequently is present in considerable amounts in plants (as 

 high as 1.2(; pe* cent in arrowroot) grown on these soils. 



Humus — its importance to soil fertility and its use with lime, J. N. Hoff 

 {Jour. Amer. Peat Soc, 2 (1909), No. 2, pp. Jfl-52). — ^A brief general discussion 

 of the subject is given. 



A contribution to Volger's theory of the formation of soil water, Kruger 

 (Gsndhts. Ingcn., 32 (1909), No. 28, pp. 469-/,73).—X series of laboratory and 

 field experiments is reported, the results indicating in general that the free 

 water of the soil is very slightly increased by capillary condensation of the 

 moisture of the air. 



Soil mulches for checking evaporation, S. Fortier ( U. S. Dcpt. Agr. Year- 

 hook 1908, pp. 465-472, figs. 7). — The extent of the loss of water from the soil 

 under irrigation is pointed out and the use of deep fuiTOws and granular soil 

 mulches to reduce this loss is explained. It is shown as a result of tank experi- 

 ments in different localities that " the deeper the mulch the less the evaporation, 

 but there are practical considerations which limit the depth of soil mulches. A 

 depth of less than 9 in. and more than 3 in. would meet the requirements of the 

 arid region in general." 



Peat and swamp lands, J. H. Pratt (Jour. Amer. Peat Soc., 2 (1909), No. 1, 

 pp. 13-17). — This article briefly discusses the extent and importance of drainage 

 and the agricultural and industrial value of drained peat and swamp lands. 



The drainage and value of peat lands for agriculture, S. M. Woodward 

 (Jour. Amer. Peat Soc., 1 (1908), No. 3, pp. 61-67). — The history, methods, and 

 extent of drainage work are briefly reviewed in this article, the information 

 given being based largely upon the work of the Drainage Investigations of this 

 Office. 



Swamp lands and their reclamation, H. M. Wilson (Jour. Amer. Peat Soc, 1 

 (1908). Nos. 1, pp. 8-10: 2, pp. 3'i, 35). — This article gives information regard- 

 ing the extent of swamp lands in the TTnited States and the reclamation of 

 such lauds by the individual States and by the United States. 



