ABSTRACTS OF AMERICAN BACTERIOLOGICAL 

 LITERATURE 



BACTERIOLOGY OF SOILS 



Effect of Grinding Soil on the Number of Microorganisms. E. B. 



Fred. Science, 1916, 44, 282-283. 



The soil was ground in a ball mill for varying periods of time. Very 

 marked reductions were obtained after one hour and an "enormous 

 decrease" followed eight or twenty-four hours grinding. Soil pro- 

 tozoa were also destroyed by grinding. — C. M. H. 



Preliminary Investigations in Comparison of Field with Laboratory 

 Experiments in Soil Biology. G. P. Koch. Soil Science, 1916, 2, 

 87-92. 



Biological experiments (e.g., in ammonification) can be successfully 

 carried out in the field. As a rule, a greater amount of organic mat- 

 ter seems to be ammonified in the laboratory tests than in the field, 

 and field studies of nitrogen fixation and nitrification are greatly inter- 

 fered with by rains. The nitrogen content of the soil varies consider- 

 ably, even over a comparatively small area. — Z. N. 



Sources of Error in Soil Bacteriological Analysis. H. C. Lint and D, 



A. Coleman. Soil Science, 1916, 2, 157-162. 



A comparison is made of the soil shaker with the spatula method of 

 mixing soil for bacteriological analysis, to the great advantage of the 

 former. The experimental error is smaller with the soil shaker. The 

 shaker is easily sterilized; it is also exceptionally well adapted to the 

 incorporation into soil of very small quantities of materials in a finely 

 pulverized condition. — Z. N. 



The Effect of Soil Reaction on Ammonification by Certain Soil Fungi. 



N. KoPELOFF. Soil Science, 1916, 1, 541-573. 



Three soil fungi, Rhizopus nigricans, Zygorhynchus vuilleminii and 

 Penicillium sp. 10, were studied as to their reaction requirements in 

 soil. They possess a comparatively narrow range of reaction toler- 

 ance for maximum ammonification which was found to be between the 

 neutral point and an acidity equivalent to 2000 pounds CaO per acre. 

 This was true whether sandy or clay soils were used with either dried 

 blood or cottonseed meal. 



Where the soil reaction is unfavorable for the activities of the soil 

 bacteria concerned in ammonification, the soil fungi might prove to be 

 an important compensating factor in maintaining fertility.— Z. N. 



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