NOTES AND ABSTRACTS. 



* 



889 



less prevalent, was absolutely unaffected by the above treatment. The 

 only remedy so far is not to use seed from infected districts, and to be 

 careful not to use smut-infected machinery. — D. M. C. 



Soil Bacteria. By E. Heine {Garten flora, vol. Hx. pt. viii. 

 pp. 165-176; 3 figs.). — 'Bacillus radicicola and Azotohacter enable the 

 plants to take up nitrogen from the atmosphere; other bacteria bring 

 about the decay of dead animal or vegetable matter and convert the 

 nitrogenous constituents into a form which is available for assimilation 

 by plants — e.g. Micrococcus ureae sets free ammonia from urea. 

 Nitrosomonas and Nitrohacter oxidize ammonia to nitrite and nitrate 

 respectively. This action is encouraged by the presence of chalk in 

 the soil. Unfortunately, the soil also contains noxious bacteria, such 

 as B. pyocyaneus , which destroy the nitrates. They may be kept in 

 check by good drainage and tillage. 



Soil fatigue may be due to the fact that the roots of the plants in 

 cultivation exude some substance which favours the growth of noxious 

 bacteria. The remedy is to inoculate the ground or treat the seeds with 

 culture of beneficial bacteria. — S. E. W . 



Soil Formed, How is. By W. Sanders (Gartenflora, vol. hx. 

 pt. X. pp. 216-220). — There is nothing new in this article. — S. E. W. 



Soil, Injurious Substances in. By F. B. Guthrie (Agr. Gaz. 



N.S.W. vol. xxi. pt. V. pp. 434-441). — Infertihty may be due to 

 shallowness of surface soil, sourness, alkalinity, or to the presence of 

 pyrites, manganese, excess of magnesia, toxic substances secreted by 

 plants, or to organisms which destroy nitrogen-forming bacteria. Want 

 of lime, deficiency of humus, absence of bacteria, and want of plant 

 food also render soil infertile. — S. E. W. 



Soils, Heat Transference in. By H. E. Patten {U.S.A. Dep. 



Agr., Bur. of Soils, Bull. 59, September 1909; figs.). — Experiments 

 were conducted to ascertain the rate of transference of heat in various 

 soils under varying controlled conditions. It is shown that heat is more 

 readily transferred in a damp than in an air-dry soil, since heat passes 

 from water to soil more readily than from air to soil ; but under normal 

 conditions " air-eddies " in the air-dry soil would be likely to cause 

 more rapid heat- transference. The rate of transference also depends 

 upon the quantity of water as compared with the area of the soil par- 

 ticles, but small soil particles may assist in making contact between 

 the larger ones in the soil, and so assist in the transference of heat. 

 The method of experiment and the results are fully set out.— F. J. C. 



Soils of Nebraska, Chang-es in Composition of. Caused by 

 Cultivation. By F. J. Alway {U.S.A. Exp. Sfn., Nebraska, Bull. Ill, 

 Dec. 1909). — Analyses are given of the virgin soils of the prairies and 

 of similar soils which have been long under cultivation. It is found 

 that*while phosphoric acid, potash, and lime have been little diminished 

 (since they are as abundant in the subsoil as in the surface soil), organic 

 matter and humus have been greatly diminished, especially through 



