SOILS FERTILIZERS. 19 



quantity of soil thus removed is insigiiilieant and tlie danger of loss of fertility 

 from this cause is not serious. 



The kaolinizing' action of roots on the Roman lava rocks, G. de Angelis 

 u'OssAT {Alti li. Accad. Liiicci, Rend. CI. ISci. Fw., Mat. c Nat., 5. ser., 19 {1910), 

 I. Ao. 3, pp. 15Ji-151). — Fresh fragments of lava rock were graded by sieves to 

 grains of approximately 2 mm., 1 mm., and 0.8 mm. in diameter. Equal parts of 

 the three sizes were mixed and thoroughly washed with distilled water. One 

 part of the mixture was put into a glass pot and tlie other into an earthen pot 

 that had been immersed in water acidulated with hydrochloric acid until effer- 

 vescence ceased. In the earthen pot chaff of meadow grass (GraminecB and 

 Leguminos;e) was sown. The two pots were protected from rain, watered twice 

 a week with distilled water, and kept under identical conditions for a solar year. 

 At the end of that time the mixture in the pot without plants contained 5.5 per 

 cent of fine earth and a trace of clay, while iu the pot with plants the pex'centage 

 of fine earth was 9.7 and of clay a trifle over 2. 



Investigations on the soil, E. J. Russell (Jour. Southeast. Agr. Col. ^Vyc, 

 I 'JOS, No. 17, pp. Ji:2S-.'i33). — A brief account is here given of the beginning of 

 investigations on the absorptive power of soils for oxygen and on the effect of 

 partial sterilization of soils, as well as of all other problems relating to soil 

 fertility which have been noted from time to time. A list of the author's publi- 

 cations on these investigations is given. 



A new form of Dr. Russell's oxidation apparatus for soils, P. V. Darbi- 

 SHIRE (Jour. Southeast. Ayr. Col. Wye., 1908, No. 11, pp. 229-232, pis. 2).— A 

 simpler form of apparatus which can be more easily charged and read and yet 

 yields reliable and accurate results is described. See also a previous note 

 (E. S. 11.. 10, p. 1120). 



Nitrification in the soil under different conditions, B. Welbel (Zap. Imp. 

 Obshcli. Selstc. Kho.:;. Yuzli. Ross.. 1908, No. 9, pp. 1-^2; abs. in Zhur. Opuitn. 

 Ayroii. (Russ. Jour. E.tpt. Landtv.), 10 (1909), No. 4, p. 532). — In lysimetric 

 investigations the conditions affecting percolation and aeration differ from those 

 in the field, hence the Ploti_ Experiment Station took up a study of the reliabil- 

 ity of this method of examining the processes of nitrification and of the 

 moisture in the soil of the field and of the lysimeter. The investigations showed 

 that in lysimeters. under fallow culture, the moisture of the soil was consider- 

 ably less than that of fallow soil in the field, especially in summer, but varies 

 with the time of the year. 



The results of all the methods of investigation (vegetation pots, periodical 

 chemical analysis of the soil; data of field experiments and of chemical analy- 

 sis of the crops) concordautly corroborate the data of the lysimetric investiga- 

 tions as to the increase in the soil of assimilable nitrogen under cultivation of 

 leguminous plants. The lysimetric investigations also shovx-ed that the fallow 

 culture and application of manure increased the quantity of nitrate nitrogen in 

 the soil, and thi.s was corroborated l)y the other methods of investigation. 



The nitrogen enriching- of soils, A. Krainskii (Ccnthl. Bakt. [etc.], 2. .\bt., 

 ..'()■ ( HI 10), No. 6-7, pji. 231-23')). — In a series of experiments undertaken to de- 

 termine the ability of nitrogen-fixing orgahisms. like Azotobacter, to enrich the 

 f-oil by the fixation of free nitrogen from the air, the following results were 

 obtained : 



(1) The soil can be enriched with nitrogen by the action of nitrogen-fixing 

 bacteria, accomi)anied by a moderate economic consumption of organic material 

 during the nitrogen assimilation: (2) li(]uid cultures of Azotobacter consumed 

 from 100 to 200 units of sugar to 1 unit of fixed nitrogen pnuluced : (o) in sand 

 cultures the Azotobacter developed luxuriantly. assinfilMting large quantities of 

 nitrogen and consuming in the process from 11 to 30 units of carbon to every 



