118 EXPERIMENT STATION RECORD. . 



No. l.i, })i>- lll-i. Ill'/)- — Tests of Keiiiy's iiietliod, using extracts of a sandy 

 soil and of a clay soil and making reciprocal inoculations with the two soils, 

 gave variable results under aj)i)arently similar conditions. These differences are 

 attributed not to the inoculation but to the character of the soil extract used. 



Bacteriological-chemical invest"' Rations, O. Lemmermann, II. Fischer, et 

 AL. (LdiKlir. ./(ilirb., 38 [l!)()<l), Xo. ,i. pp. Sl'J-36.',; ab.s. in Chem. Zcntbl., 1009, 

 I, JVn. I'l, PI). 1187, 1188; Jour. Soc. Chem. Indus., 28 (1909), No. 9, p. J,85).~ 

 Studies of the putrefactive and nitrogen-fixing power, nitrification, and denitri- 

 flcatiou in moor and cultivated soils handled in different ways, as shown by 

 number, distribution, and kind of bacteria and molds, are reported. 



The authors conclude that changes which go on in the soil should be studied 

 under as natural conditions as possible. Sand culture methods were not found 

 to be a reliable means of studying changes in the decomposition of the nitrog- 

 enous organic matter of the soil nor of the action of various methods of fer- 

 tilizing. In the study of denitrification the sand culture method .showed that 

 the denitrifying organisms were more active in mineral soils than in moor soils. 

 The addition of lime promoted denitrification both in the moor soils and in sandy 

 soil. Denitrification was much greater in sand cultures than in ordinary soil 

 cultures. Sulphate of ammonia was more rapidly transformed in moor soils 

 fertilized with Thomas slag and kainit than in loam soils. The greater part of 

 the nitrogen of the sulphate was converted into nitric acid and this was the 

 more completely brought about in the case of the moor soils. 



Sterilization had little effect upon the nitrogen compounds in sand and loam 

 soils, but in case of humus soils it increased the amount of nitrogen driven off 

 in distillation with magnesia. The nitrogen of sterilized mineral soils was, how- 

 ever, more easily decomposed by bacteria than that of humus soils similarly 

 treated. In ordinary soil cultures nitrification went on less rapidly in sandy- 

 soils than in loam soils. Sterilization with subsequent inoculation lengthened 

 the period of nitrification, but did not affect the original nitrifying power. Dry- 

 ing reduced the nitrifying power but not the denitrifying power. Sterilized soils 

 which were subsequently inoculated did not completely recover their character- 

 istic power of decomposing nitrogenous oi-gauic matter. Lime nitrogen under- 

 went very slight decomposition during 22 days in unsterilized soil. Ammonia 

 formation and nitrification can go on simultaneously in natural soils. The effect 

 of different kinds of soil on the decomposition of bone meal can be studied in 

 soil cultures, but not in sand and water cultures. 



Studies of changes which go on in soils must be made with fresh soils and 

 the progress of decomposition must be determined analytically throughout the 

 period of the experiment. 



Investigations on bacterial growth, in sterilized soils, H. Fischer {Centhl. 

 Bakt. [etc.], 2. Aht., 22 (1909), No. 2J,-25, pp. 67i-675).— Soils sterilized by 

 steam and then inoculated showed greater bacterial activity than those not so 

 treated. The increased activity is attributed less to purely chemical effects of 

 the sterilization than to nutritive matter furnished by the remains of the organ- 

 isms killed l»y the sterilization. 



Studies in soil bacteriology, I. Nitrification in soils and in solutions, 

 F. L. Stevens, W. A. Withers, et al. {CentbJ. Bakt. [etc.], 2. AM., 23 (1909), 

 No. 10-13, pp. 355-373). — A series of comparative studies of nitrification in 

 soils and in solutions is reported from which the following conclusions are 

 drawn : 



"(1) Many soils which can nitrify ammonium sulphate and cotton-seed meal 

 mixed with them, fail to nitrify ammonium sulphate and cotton-seed meal when 

 used as the inoculum for solutions, such as those of Omelianski, Wiley, and 

 Ashby. 



