620 EXPERIMENT STATION EECOED. 



neither the absolute nor the relative ammonifying power of the soil organisms 

 experimented with {Bacillus suhtilis, B. mycoides, and various soil complexes) 

 can be ascertained by testing them in solutions. Even the rehitive ammonifying 

 power of two soils or two organisms can not be determined with certainty by 

 this method. Some bacterial soil complexes ammonify faster in solutions and 

 some ammonify faster in soils. " Some pure cultures of organisms ammonify 

 faster in soils, others faster in solutions. The rank of soils, bacterial soil com- 

 plexes, or of piu-e cultures is different as measured in soils or in solutions." 



The assimilation of ammoniacal, nitrate, and amid nitrogen by micro- 

 org-anisms, S. Bierema (Ccnthl. Bakt. [etc.]. 2. AM., 23 (1909), No. 21-25, pp. 

 672-726; abs. in Jour. Chem. Soc. [Londonl, 96 {1909), No. .562, II, pp. 692, 

 693). — Experiments with a great variety of sources of nitrogen and of carbon, 

 and of manure and soil organisms, in pure and mixed cultures, are reported and 

 the results discussed in detail. 



Sodium nitrate was readily assimilated in the presence of sucrose, glycerol, 

 and calcium lactate, less readily in presence of levulose, starch, maltose, and 

 calcium succinate. Ammonium nitrate was less readily assimilated in all cases 

 than sodium nitrate, and magnesium-ammonium phosphate appeared to be the 

 best source of nitrogen tested in these experiments. Formamid and acetamid 

 were not readily assimilated, but the latter was capable of supplying both 

 nitrogen and carbon. Guanidin carbonate alone was not actively assimilated, 

 but was somewhat more readily taken up in the presence of calcium lactate, 

 sucrose, and glycerol. Uric acid was completely converted into ammonium car- 

 bonate, but less readily into urea. Leucin and tyrosin, especially the first, were 

 readily assimilated. Ammonium formate was slightly assimilated, anunoniuni 

 acetate more readily, especially in presence of dextrose, and ammonium 

 butyrate still more readily assimilated. 



Comparative studies of the bacteria content of cultivated soils in relation 

 to external influences, D. Engberding {Ccnthl. Bakt. [etc.], 2. Abt., 23 (1909), 

 No. 21-25, pp. 5(J9-6-'i2). — Studies of the influence of the methods of making the 

 counts, the culture medium, the strength of the original seeding, moisture, tem- 

 perature, cultivation, and organic matter of the soil, and mineral fertilizers are 

 reported. 



The moisture content seemed to have more influence on the bacteria content 

 of the soil than temperature. The addition of readily assimihable carbohy- 

 drates increased the bacteria content to a marked extent. The influence of 

 mineral fertilizers was variable. Anunouium sulphate, sodium nitrate, potas- 

 sium sulphate, and caustic lime in liberal amounts increased the bacteria con- 

 tent slightly. Magnesium sulphate caused a moderate increase. The influence 

 of the mineral fertilizers on the bacteria content was in general the reverse 

 of their effect on nitrogen fixation. 



Soil disinfection in agriculture, O. Loew {Porto Rico 8ta. Circ. 11, pp. 8- 

 12).— This circular deals with the effect of chemical disinfectants, more par- 

 ticularly carbon bisulphid. upon the fertility of soils. Attention is called to the 

 fact that there are in Porto Rico certain cases of sick or tired soils which are 

 not benefited by the application of ordinary fertilizers. A series of experiments 

 with carbon bisulphid and creolin has been started on certain of these soils. 



All agricultural wealth from the soil, T. Cherry (Rpt. Austral. Assoc. Adv. 

 Sci., It {1907), pp. 227-232).— This" is part of an address before the Australasian 

 Association for the Advancement of Science in The Outlook for Agriculture, dis- 

 cussing briefly the productiveness and potential fertility of soils in general, de- 

 scribing the peculiarity of Australian soils on the basis of the average results of 

 analyses of 186 samples of Victorian soils, and explaining the importance of 

 live stock in the maintenance of soil fertility. 



