422 EXPERIMENT STATION EECOED. 



sible that the conditions limiting the growth of hlghex' plants in one case may 

 be different from those in another. Continuous cropping, especially without 

 fertilization, reduced the nitrifying power of the soils. "Although the possi- 

 bility of the production of toxic material is not eliminated, it seems that in the 

 plats studied the deleterious effects of continuous cropping on higher plants, as 

 well as on the bacteria, are closely connected with the nitrogen relations." 



The results of nitrification studies in solutions, using the Omelianslii solu- 

 tions to which were added portions of greenhouse soils from the station, indi- 

 cate that the organisms producing nitrification in these soils are Micrococcus 

 nitriflcans and Bacillus nitriflcans. The growth of the nitrite formers was 

 much more feeble in solution than was that of the nitrate formers. Aqueous 

 extracts of ignited and nonignited soils used when reinforced by the regular 

 mineral nutrients possessed no superiority over Omelianski's nutrient solution 

 for the growth of the nitrate producer. 



The results of nitrification studies in porous media led to the conclusion 

 that soil, particularly ignited soil, as a medium possesses the property of sup- 

 porting nitrification better than sand. 



A critical consideration of the present methods of studying nitrification 

 led to the conclusion that " the methods in vogue for studying the process of 

 nitrification . . . contain many errors, which must be largely eliminated before 

 the problem of soil bacteriological differences can be satisfactorily attacked." 



Action of oligodynamic elements on the nitrifying bacteria, C. Montanari 

 (Stas. Sper. Agr. Ital., ]ft (19U), No. 6, pp. U1-U8).— The author briefly 

 reviews the work of others bearing on the subject, and reports experiments on 

 the effect of the dioxid, sulphate, and carbonate of manganese on nitrification 

 in different soils treated with ammonium sulphate. 



Nitrification was apparently stimulated in the soils treated with the dioxid 

 and carbonate of manganese, particularly in the case of a sand washed with 

 hydrochloric acid and distilled water. Manganous sulphate stimulated nitrifi- 

 cation much less than the other manganese compounds and was often detri- 

 mental. 



As a result of further experiments, the stimulation of nitrification by the 

 dioxid and carbonate of manganese is attributed to the oxygen introduced 

 directly by the former and indirectly by the latter rather than to any catalytic 

 action of the element manganese. 



Note on nitrification in the peat soil in the vicinity of Laon, CoQuinfi 

 (Conipt. Rend. Acad. Sci. [Parisi, 160 {1915), No. 7, pp. 253-255).— Several plats 

 of uncultivated peat soil in natural condition were fertilized with different 

 combinations of potassium chlorid, kainit, sodium nitrate, and slag to determine 

 the effect of fertilization, particularly with nitrates, on the natural vegetation. 



Each fertilizer when used alone had an effect on the vegetation, but nitrates 

 were especially effective in increasing the growth. Favorable results were 

 obtained with mixtures containing the three fertilizing elements, but where 

 nitrate was excluded the results were unsatisfactoi'y- 



Observations on the formation and layer distribution of nitrates in soils 

 with different nitrogen fertilizers, V. I. Tkachenko {Ehosiaistvo, Nos. 37-40 

 (1912) ; al)s. in Zhur. Opytn. Agron. (Russ. Jour. Expt. Landw.). 14 (1913), No. 

 6, p. 585). — In a study of the amount and distribution of nitrates at different 

 depths in the soil from .Tune 27 to September 9, 1911, and from April S to May 

 10, 1912, it was found that the minimum amount of nitrate was present in the 

 latter part of August and the earlier part of September, but no direct connec- 

 tion between nitrate and temperature and moistui'e was observed. 



Fertilizing with nitrate of soda in general increased the nitrate content of the 

 soil, but not in all cases. Cyanamid and ammonium sulphate increased the ac- 



