SOILS FERTILIZERS. 521 



(1907), Nos. 534, II, p. 295; 535, II, p. 388; 536, II, p. 502; 537, II, p. 572; Chem. 

 Zentbl., 1907, II, No. 3, p. 270; Chem. Abs., 2 (1908), No. 1, p. i60).— The lit- 

 erature of investigations on this subject is reviewed and experiments with 

 treated and untreated soils extending over two years are reported. 



The methods used in detecting and determining carbon bisulphid in the 

 treated soils at different stages as well as in studying the effect of the treat- 

 ment on the biological and chemical processes in the soil are described. It was 

 found that treatment with carbon bisulphid increased the yield of rye grain 40 

 to 50 per cent and straw 30 to 40 per cent and that the beneficial effect of the 

 treatment extended into the second season. The yield of oats, potatoes, sugar 

 beets, and grapes was also increased by the treatment. This increase in pro- 

 ductiveness occurred notwithstanding the fact that nitrification was retarded to 

 a marked extent in the sandy soils by treatment with carbon bisulphid. How- 

 ever, this retarding effect preventetl excessive nitrification and waste in the 

 earlier stages and disappeared after a time, being followed by an accelerated 

 nitrification. Tlie increased jn'oductiveness of the treated soil is, however, 

 ascribed mainly to the action of the carbon bisulphid in promoting the activity 

 of Azotobacter and other nitrogen-fixing organisms through preservation of the 

 organic matter of the soil, as well as of oi'ganisms, molds, etc., which produce 

 carbon dioxid and other acids in the soil, and thus increase the amount of avail- 

 able mineral constituents of plant food. The carbon bisulphid treatment also 

 destroys plant parasites of an animal nature as well as weeds and is an effective 

 means of overcoming soil sickness in case of grapes and leguminous plants. It 

 was observed that the total nitrogen was considerably larger in soils treated 

 withf carbon bisulphid than in untreated soil. 



The treatment of air-dry soils with carbon bisulphid increased to a marked 

 extent the soluble potash, magnesia, and lime, while such treatment of fresh 

 soils resulted in a large increase of sulphuric acid. 



Pot experiments in which the soil was treated with bisulphid just befox'e 

 planting are reported which indicate that such treatment by retarding nitrifica- 

 tion will serve as a means of judging the extent of dependence of a given plant 

 upon nitrogen in the foi'm of nitrates. It was found that other sulphur com- 

 pounds, as well as mustard oil, and the green substance of mustard plants, 

 acted like carbon bisulphid in retarding nitrification. This suggests an explana- 

 tion of the unusually good results which have frequently been observed to fol- 

 low the use of mustard as a green manure. 



Contributions to natural pure cultures, F. Stockhausen (Wchnschr. Braii., 

 21, (1907), Nofi. 22, pp. 285-289; 23, pp. 301-30J,; 2-',. pp. 313-316; 25, pp. 325- 

 331). — This is a series of short reviews of the principal recent contributions to 

 the subject of the natural conditions of development of pui*e cultures of organ- 

 isms decomposing cellulose, reducing nitrates, producing vinegar and enzyms of 

 different kinds, and various other reactions with special reference to the recent 

 contributions to this subject of Beijerinck and his pupils. 



The eflB.ciency of soil inoculation in the production of root tubercles, F. L. 

 Stevens (Science, n. sen, 26 (1907), No. 662, p. 311). — This is an abstract of a 

 l>aper read before the North Carolina Academy of Science in which '* data were 

 given concerning the inoculation of soils with liquid cultures obtained from 

 [this Department]. From many tests conducted in various ways there was no 

 evidence whatever that inoculation with these cultures was efficient in the 

 production of tubercles upon legumes. The cultures employed were issued in 

 liquid condition in hermetically sealed test-tubes, and were obtained directly 

 from the Bureau of Plant Industry." 



Soil bacteriology and the fertilizer question with, especial reference to the 

 fertilizing of clover, F. Lohnis (Mitt. Okonom. Gesell. Sachsen, 1906-7, pp. 



