124 EXPERIMENT STATION RECORD. 



rate of nitrification was determined for carbamid, thiocarbamid, uric acid, 

 asparagin, glycin, aectamid, anilin, sulphate, nietliylamin sulphate, ammonium 

 oxalate, and ammonium sulphate in a special form of apparatus permitting por- 

 tions of the nitrifying solution to be withdrawn for examination without danger' 

 of contamination by the air. A mixture of hydrolytic and nitrifying organisms 

 obtained from the secondary contact beds of a sewage works was used and the 

 progress of nitrification was traced by periodic determinations of ammonia, 

 nitrous, and nitric nitrogen. 



Thiocarbamid and anilin sulphate did not nitrify at all, but 90 per cent of the 

 nitrogen of the latter was converted into ammonia, indicating simply hydroly- 

 sis. The rate of nitrification for the other substances was approximately the 

 same, which leads the author to conclude " that nitrogenous substances, typical 

 of the products of albuminoid hydrolysis, when exposed under identical condi- 

 tions to the action of the bacteria contained in a typical filter-bed, nitrify at 

 approximately the same rate." In no case was more than 95 per cent of the 

 total nitrogen recovered in the form of nitrate. 



In the case of ammonium sulphate and oxalate there was a temporary dis- 

 appearance of nirogen as measured by the sum of ammonia, nitrous, and nitric 

 nitrogen. The author concludes " that it is in some stage of oxidation inter- 

 mediate between ammonia and nitrous acid that the nitrogen becomes non- 

 realizable. 



" Oxidation by bacterial agency can not be regarded as being of a violent 

 nature, and it seems hardly conceivable that the nitroso-bacteria should be able 

 to oxidize ammonia straight to nitrous acid, without passing through any inter- 

 mediate stages of oxidation. . . . 



" It appears probable that in the oxidation of the ammonium radicle by bac- 

 terial agency there are formed, in the course of the reaction, certain intermedi- 

 ate substances which must be regarded as more or less hydroxylated ammonium 

 radicles." 



Soil bacteria and soil productiveness, F. Lohnis {Boden-Bakterien und 

 Boden-Fruchtharkeit. Berlin, 1914, PP- VII-\-70). — This pamphlet describes the 

 nature of bacterial life in soils and discusses the activities of soil organisms 

 and ferments with, reference to their relation and importance to soil produc- 

 tion. It discusses particularly the biological transformation of carbon and 

 nitrogen and nitrogen assimilation in soils, but also deals briefly with the 

 activity of soil organisms in unlocking stores of plant food and in decomposing 

 organic manures. 



The productiveness of the soil is considered to depend primarily upon its 

 fertility or plant food content and its activity as determined by the physical, 

 chemical, and biological changes going on in it. The more active the life of 

 the soil the higher is its productiveness. The various direct and indirect means 

 by which these life activities may be controlled with a consequent increase in 

 productiveness of the soil are indicated. 



Improving' sandy soils by the use of green manure crops, R. W. Allen and 

 W. K. Dean (Oregon Sta. Bui. 120 (1914), PP- 3-14, figs. 7).— This bulletin 

 deals with the need of the arid soils for an adequate supply of nitrogen and 

 decaying organic matter, and gives the results of experiments at the Umatilla 

 substation at Hermiston to determine the plants best suited for this purpose 

 under the conditions prevailing at that place. 



These experiments indicated that hairy vetch was the most valuable of the 

 crops tested for green manuring on light soils under irrigation, and the methods 

 of growing and handling this crop for the purpose are described. 



