KOtES AND ABSTRACTS. 



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represented a variety of types, ranging from heavy clayey (adobe) 

 soils to light sandy soils, from deep subsoils to surface soils, from soils 

 rich in organic matter to poor sands, and from alkali soils to normal 

 soils free from injurious amounts of injurious salts. He found that 

 these soils still contained after thirty years a strong ammonifying 

 power and a fair nitrogen fixation power, showing the remarkable 

 persistence of the bacteria concerned in these processes ; on the other 

 hand, the nitrification bacteria were almost completely desrtoyed. The 

 effects of drying upon the organisms in the soil are of great scientific 

 and practical importance, as establishing the relative resistance and 

 distinguishing features between groups of organisms concerned in the 

 processes of ammonification, nitrification, and nitrogen fixation. It 

 is also of interest that the soil organisms are able to live much longer 

 in the soil itself than in other media — that is to say, the soil performs 

 a protective function involving one or probably more factors. It 

 is known that hygroscopic moisture has a protective function for 

 plants by cooling the soil by evaporation, and it is very likely that the 

 cooling influence produces a more favourable condition for the bacterial 

 flora of soils, especially those exposed to direct rays of the summer sun 

 in arid regions. The thickness of the film of hygroscopic moisture 

 (calculated by A. D. Hall as 0*00001 of an inch) may in itself offer 

 sufficient moisture for the maintenance of a portion of the soil flora, 

 and the very minute size of the organisms may even permit of their 

 complete protection in soils of high hygroscopic power. While 

 hygroscopic moisture is a protective factor, gravitational and capillary 

 water are rejuvenating forces. The results in this paper show that 

 the bacterial activity may be renewed by the addition of sufficient 

 moisture to dry soils. Thus in ammonification and nitrogen fixation 

 though the original number of organisms is reduced, they become 

 physiologically active when placed in solutions. Nitrification in most 

 cases does not proceed, because the extreme drying period to which 

 the soils had been subjected had entirely destroyed the nitrifying 

 bacteria. The author emphasizes the fairly obvious conclusion that 

 irrigation of arid soils must bring about rapid bacterial development 

 in such soils by the striking effects of water on the bacterial flora. — F. C. 



Soils Sterilized and Re-inoculated, Water-soluble Matter in. 

 By T. L. Lyon and J. A. Bizzell {U.S.A. Exp. Stn., Cornell, Bull. 

 326; Jan. 1913 ; figs.). — A general outline of previous experiments 

 is given, and the authors show that when steamed soils are inocu- 

 lated with fresh soil, and with heated soil, there is a gradual decrease 

 of water-soluble matter for several weeks, the decrease being more 

 rapid for a time in that inoculated with fresh soil, and then slowing 

 down, so that at the expiration of six months the sample inoculated 

 with fresh soil contained the greater amount of soluble matter. 



Analysis showed little difference in the amounts of available 

 nutritive substances, and the authors consider the indications point 

 to the production of some substance toxic to the plants. They also 



