SOILS FERTILIZERS. 621 



The effect of heat was fouiid to be small compared with that of chloroform, 

 and in the double treatment tests the differences between heat then chloroform 

 and chloroform then heat were marked. Toxic extracts were obtained from 

 soils, but it was found that the demonstration of toxins in soils depends upon 

 obtaining a soil in which the toxins exceed the nutrients in amount. Equal 

 parts of soil and water generally yielded the most toxic extract. It was further 

 found that an accumulation of toxic substances does not occur in dry soils and 

 that two kinds of bacteriotoxins exist, viz, those thermolabile in the soil and 

 those thermostable in the subsoil. Soils were found to have a variable bac- 

 teriotoxic content. A soil originally toxic became nontoxic when washed with 

 water and upon incubation again became toxic. 



The ammoniacal fermentation of blood saturated either with paraffin or 

 vaselin was not accelerated by chloroform treatment. While naphthalin in- 

 duced an increase in the number of bacteria in uumanured soils, it is con- 

 cluded that there is no corresponding increase in the formation of ammonia 

 from the organic matter ortginally present or added as dried blood. 



The sterilization or disinfection of the soil, F. Beethault {Jour. Agr. Prat., 

 n. ser., 27 (1914), No. 17, pp. 523, 524)- — Various investigations bearing on this 

 subject are briefly summarized, with the general conclusion that it is well 

 established that sterilization of the soil by heat or antiseptic substances, such 

 as carbon disulphid. tar liquor, toluene, and sulphur, is capable of greatly in- 

 creasing the yield of crops although the mode of action of these substances 

 has not yet been determined with certainty. 



Special reference is made to box and plat experiments by Mi^ge during 

 1912 and 1913 on the effect of partial sterilization of soil by toluene, carbon 

 disulphid, sulphur, formic aldehyde, chloroform, tar water, creosote, acetic 

 ether, naphthol, phenol, copper and barium sulphates, and potassium perman- 

 ganate on mustard and barley. Boxes 0.43 meter square each received from 

 1 to 15 cc. of the liquids and from 0.2 to 2 gm. of the solids. Plats 10 meters 

 square received from 50 to 200 cc. of the liquids and from 5 to 20 gm. of the 

 solids. 



Most of the substances used were beneficial especially in small doses. 

 Barium sulphate, naphthol, and creosote were injurious. Copper sulphate was 

 injurious in the box experiments but beneficial in the plat experiments. 



iRock and soil in relation to plant nutrition, E. Blanck (Laiidw. Vers. 

 St-at., 84 {1914), No. 5-6, pp. 399-425). — Pot exi>eriments were conducted with 

 oats and peas using three kinds of granite, shale quartzite, and porphyry pul- 

 verized as the growth medium to determine the relative crop yields and extent 

 to which the plant food in these rocks is available to plants. The yields of 

 peas and oats were greater with the granites and porphyry than with the shale 

 quartzite, but the plant food contained in the latter was better utilized than 

 that in the granite and porphyry. A further proof of the author's views 

 (E, S. R., 27, p. 520) that mica potash, especially that of biotite, is more easily 

 available for plants than feldspar potash was obtained. 



A comparison of the results with those obtained in sandstone experiments 

 (E. S. R., 27, p. 513) showed that greater yields were obtained with the sand- 

 stone and that the sandstone plant food was better utilized. 



Relation of the mineralogical and chemical composition to the fertilizer 

 requirements of North Carolina soils, J. K. Plummee {North Carolina Sta. 

 Tech. Bui. 9 {1914), PP- 3-29). — Chemical and mineralogical analyses of the 

 mountain. Piedmont, and coastal plain soils of North Carolina are reported, 

 together with a summary of the results of field experiments previously noted 

 (E. S. R., 23, p. 635; 24, p. 336; 25, p. 721 ; see also p. 629). 



