722 EXPERIMENT STATION EECORD. 



tion and nitrification to a marked extent. lioss of nitrogen by volatilization of 

 ammonia increased with the amonnt of sand in the soil. 



A comparison of the results of pot experiments with those obtained by Ilemy's 

 water-culture method showed that the bacterial characteristic of a soil was 

 brought out more clearly and naturally in experiments with soils than with 

 culture solutions, but even with soils the results were reliable only when fre- 

 quent determinations were made of the different forms of nitrogen. 



A bibliography of the literature on the subject is added. 



Why do some soils nitrify organic nitrogenous substances and the am- 

 monium salts of organic acids faster than they do ammonium sulphate or 

 ammonium chlorid? J. C. Temple (/16s. in Science, n. sci\, 35 (1912), No. 

 893, pp. 227, 228).— "Of 26 Georgia soils tested for nitrification, 24 were found 

 to nitrify tankage more readily than ammonium sulphate. In some cases the 

 amount of nitrate recovered from tankage was 10 times that recovered when 

 ammonium sulphate was the source of nitrogen. Tankage, cotton-seed meal, 

 cowpea vines, gelatin, peptone, asparagin, urea, ammonium citrate, ammonium 

 oxalate, ammonium tartrate, ammonium bicarbonate, and ammonium hydrate 

 were nitrified faster than ammonium sulphate or chlorid. This condition was 

 not due to the nature of the nitrifying organism in the soil, as the same thing 

 held true when the nitrifying organisms were supplied as pure cultures, obtained 

 from a number of sources. When calcium carbonate was added to the soil, 

 ammonium sulphate was nitrified as well as any of the other substances. 



"The explanation offered for this condition was that these soils (all of the 

 Cecil group) were acid, and that the soil organisms decomposed the substances 

 of organic origin in a way that more ammonia than acid was produced, thus 

 correcting the acidity and bringing about a condition favorable for the growth 

 of the nitrifying organisms. When ammonium sulphate or ammonium chlorid 

 was added to the soil there was no chance for a similar decomposition and the 

 soils remained acid." 



The awakening of the soil, A. Muntz and H. Gaudechon {Conipt. Rend. 

 Acad. Sci. [Paris], 154 (1912), No. J,, pp. 163-168, fig. 1; ahs. in Rev. Sci. [Paris], 

 50 (.1912), I, No. 5, p. 156). — From a study of nitrification, which is considered 

 the most pronounced and characteristic bacterial action of soils, the authors 

 trace a relation of cause and effect which they designate as the awakening 

 of the soil. That is, there is a maximum action and activity in the multipli- 

 cation and function of micro-organisms in the soil at the time of the spring 

 awakening between March 28 and April 25 in the climate of Paris. After a 

 period of maximum intensity of nitrification there succeetls a pronounced slack- 

 ening of activity which continues for a certain length of time, and if there is a 

 further increase in nitrification it is never as great as at the period of maximum 

 activity. 



The gain in nitrogen during a five-year pot experiment with different 

 legumes, B. L. Habtwell and F. R. Pember (Rhode Island Sta. Bui. Up', pp. 

 3-l.'f, pis. 2). — "This bulletin contains the details of a 5-year experiment in 

 pots 12 in. in diameter, to ascertain the amount of nitrogen secured from the 

 air, whether through the influence of nodule bacteria or of other micro- 

 organisms, during the growth of legumes in a light gravelly soil, without the 

 addition of nitrogenous manure but with optimum amounts of other manures. 



"Vetch was grown in all the pots each winter in the greenhouse and was 

 mixed with the soil at blossoming time. This was followed separately each 

 summer by cowpea, soy bean, white-podded adzuki bean, and crimson clover. 

 The summer legumes, exclusive of the roots, were usually removed from the 

 soil and the nitrogen content determined. Preparatory to growing the vetch, 

 the pots were usually transferred to the winter greenhouse." 



