SOILS FERTILIZERS. 123 



especially the former, as the exclusive sources of nitrogen supply for soils may 

 result in actual impoverishment of the soil in nitrogen. He therefore considers 

 exclusive use of such fertilizers a questionable practice. 



On the decomposition of lime nitrogen and nitrogen lime, II, F. Lohnis 

 and A. Sabaschnikoff (CentM. Bakt. [etc.], 2. AM., 20 (1908), No. 11, pp. 

 322-332, fig. 1). — In previous experiments (E. S. R., 17, p. 345) Lohnis shovs^ed 

 that calcium cyanamid was decomposed and dicyandiamid was produced by the 

 action of water without the intervention of micro-organisms. He also showed 

 that under favorable conditions the nitrogen of the cyanamid was completely 

 transformetl into ammonia by the action of vai'ious ammonifying bacteria, ex- 

 periments with pure cultures indicating that urea was an intermediary product 

 in the process of formation of ammonia. This activity of the bacteria was 

 greatly increased by the addition of small amounts of asparagin and grape 

 sugar (about 0.1 per cent). Experiments of similar character showed that in 

 solutions of calcium cyanamid which had been repeatedly heated and in which 

 ilie formation of ammonia had been started by the action of steam the decom- 

 position resulting fi-om the inoculation of the solution with 10 per cent of soil 

 was as rapid as in case of freshly prepared unheated solutions. 



The investigations reported in the present article were undertaken to explain 

 if possible the contradictory results obtained by von Seelhorst, Immendorff, 

 Kappen, and others on the one hand, and by Ulpiani and Perotti on the other, 

 with special reference to the formation and decomposition of dicyandiamid. 



Further experiments showed a decided advantage as regards the ammonifica- 

 tion of the nitrogen of lime nitrogen and nitrogen lime from the addition of 

 isparagin and grape sugar to the culture solutions in Remy's process. The 

 authors never succeeded in producing ammonia in solutions of dicyandiamid 

 inoculated with soil. When, however, the solutions of lime nitrogen and 

 nitrogen lime were repeatedly heated the nitrogen was rapidly anunonified by 

 a number of soil organisms. In this case it is believed that not dicyandiamid 

 l)ut dicarbimid is produced, which is more easily converted into ammonia. 



Of various soil organisms experimented with Bacterium crytlirogenes, B. 

 kirchneri, and B. lipsiense were especially active in producing ammonia. A 

 less active organism in this respect was B. vulgare var. zopflL 



Observations during two years on the influence of season and weather upon 

 the decomposition of lime nitrogen and nitrogen lime in the soil showed that the 

 most active decomposition occurred in May, the least in August, and that there 

 was another period of activity in September, the curves being practically iden- 

 tical for the two seasons, although the first was dry and the second wet. 



Nothing was observed in these experiments to indicate that the lime nitrogen 

 or nitrogen lime in any way interfered with the process of nitrification. 



Recent investigations on the decomposition and the action of lime nitrogen 

 and nitrogen lime, F. Lohnis and A. Sabaschnikoff (FilhHng's Landw. Ztg., 

 57 ( 1008), A'o. 1. pp. 15-29). — In this article the authors discuss their own inves- 

 tigations on this subject (see above) as well as the bearing of recent work by 

 Perotti and Kappen (E. S. R., 18, pp. 537, 1028) on their conclusions with refer- 

 ence to the decomposition of calcium cyanamid in the soil and the fertilizing 

 value of the commercial forms of this compound. They maintain that recent 

 investigations have confirmed the conclusion that calcium cyanamid is not con- 

 verted to any appreciable extent into ammonia in sterile soils and that this 

 transformation is due to the activity of micro-organisms; that under suitable 

 conditions the transformation of the cyanamid as well as the dicyanamid into 

 auunonia by bacterial action is almost complete ; and that the transformation 

 into ammonia and ultimately into nitrates which are readily available to crops is 



57401— No. 2—08 3 



