1120 EXPERIMENT STATION RECORD. 



eeutmtiou of alkali most effective iu preveutiiig flofculutioii varies widelj- with 

 different clays and is characteristic for each. The differences in this respect iu 

 case of natural clays are ascribed in part at least to variations in humus acid 

 content. The injurious effect of heavy liming of moor soils is asci'lbed to pre- 

 ciititation of humus acid, thus preventing it from rendering plant food in the 

 soil available. 



On the radioactivity of certain soils, J. H. IIowkll (Truiis. and Proc. yriv 

 Zeal. IiiHt.. 3!i (inod), PI). .Ii3-2.il}, fiff-s. 2).— The fact that the therapeutic 

 properties of the water of certain mineral springs has been ascribed to the 

 germicidal proi)erties of their radioactive products led the author to undertake 

 a study of the radioactivity of the deposits from a number of mineral springs 

 as well as of a light volcanic soil (surface and subsoil) and of a clay soil. A 

 special form of electroscope used iu these investigations is described. The re- 

 sults indicated the presence of radioactive substances in small quantities in the 

 mineral springs deposits and in larger quantities in both surface soils, while the 

 hard volcanic subsoil was about six times as active as the surface soil. 



Oxidation in soils and its relation to productiveness. The influence of 

 partial sterilization, F. Y. Darbishire and E. J. Russell (Jour. Agr. Sci., 2 

 (1907), Xo. 3, PI). 305-326, figs. 3). — In the experiments here reported samples 

 of soil which had been treated with volatile antiseptics (carbon bisulphid, 

 toluene, and chloroform), nonvolatile antiseptics (copper sulphate and mercuric 

 chlorid), and sterilized by steam, were tested by means of the oxidation method 

 described in a previous article ( E. S. 11.. 17. p. 530) and in pot experiments. 



The results are summarized as follows: "(1) Partial sterilization of soil 

 either by heating to 100° or by treatment with volatile antiseptics which are 

 subsequently removed leads to a marked increase in the amount of oxygen ab- 

 sorbed by the micro-organisms of the soil. (2) The yield of nonleguminous 

 crops is distinctly larger on partially sterilized than on unsterilizod soils. 

 Leguminous crops, however, show no increase. (3) Analysis shows that partial 

 sterilization causes an increase in the amount of nitrogen, phosphoric acid, and 

 potash taken ui) by the croi), and in the percentage of nitrogen and phosphoric; 

 acid in the dry matter. In other words it increases the ' availability ' of these 

 plant foods. (4) The increased availability of the plant food appears to be 

 connected with the modification of the bacterial flora brought al)Out by partial 

 sterilization. When the soil is heated, however, chemical decomposition also 

 takes place." 



The increase of nitrogen in certain soils due to nitroculture, A. M. Wright 

 (Trans, and Proc. Xcir Zeal. Inst.. 39 (1906), pp. 121-123; ahs. in Chein. Ahs., 

 2 (1908), Xo. -J. />. 570). — Pot experiments are reported in whicli garden peas 

 were grown on inoculated and uninoculated soils with and without tlie addition 

 of sulphate of potash and superphosphate. The nitroculture used was that pre- 

 pared by this Department, and seed and soil inoculation were compared on 3 

 different soils, one being of a peaty character. There was aiiparently a decided 

 increase of nitrogen when the seed was inoculated, and this increase was greater 

 when sulphate of potash and sui)erphosphate were added to the soil. Except 

 in case of the peaty soil and of a soil to which starch had been added there 

 was apparently no particular increase of nitrogen due to inoculating the soil. 



Inoculation of soils and seeds, A. Df:MOLON (Jour. Agr. Prat., n. scr., l.'f 

 (1907), Xo. 51. j>p. 7s'i-7Si;). — This is a brief account of recent progress in this 

 line, calling attention espe<-ially to the work of Bottomley (E. S. R., 10, p. 832). 



The fixation of atmospheric nitrogen by plants, W. J. V. Woolcock (Pharm. 

 Jour. [London^, .',. scr., 26 (1908), Xo. 1959, pp. 28, 29).— This is also a brief 

 account of the experiments by Bottomley. 



