622 EXPERIMENT STATION RECOED. 



acal nitrogen must be set the loss of nitrogen by volatilization of ammonia or 

 ammonium compounds. 



Laboratory and pot experiments show that when ammonium salts are applied 

 to soils containing considerable amounts of calcium carbonate there is a con- 

 siderable loss of nitrogen in the form of annnonium carbonate, especially if 

 the ammonium salts are applied on the surface of a moist soil and allowed to 

 lie some time before being cultivated in. These facts explain why ammonium 

 salts give better results as a rule upon soils poor in lime than on those contain- 

 ing an abundance of this material, and why they are more efficient when 

 thoroughly mixed with the soil than when applied as a top-dressing. It is not 

 believed that the conversion of a part of the nitrogen of annnonium salts into 

 less readily availal»le forms l)y the action of soil bacteria plays any appreciable 

 part in reducing the efficiency of this material as a fertilizer. 



Field experiments on the fertilizing action of sulphate of ammonia 

 as compared with nitrate of soda, Kretschmer et al. (Afh. iJciit. Landw. 

 Gescll., 1006, No. 121, pp. XXUI-\-23h map 1; abs. in Mitt. Dent. Landw. Gesell., 

 21 (1906), A'o. '/2, pp. 103-105). — Cooperative experiments by the Wagner 

 method at the experiment stations of Bonn, Bernberg. Ilalle, and Kiislin in 

 contituiation of those by Wagner already noted (E. S. R., 15, p. 234) are 

 reported. 



The results, as in other experiments, vary with the character of the soil, 

 weather, and crop, although in general nitrate of soda gave better results than 

 ammonium sulphate, thus confirming Wagner's conclusions. In many cases, 

 however, the ammonium sulphate was more effective than nitrate of soda. The 

 nitrate is apparently better suited to acid soils than the sulphate. On the other 

 hand, ammonium sulphate is more efficient than the nitrate on leachy soils in 

 wet seasons. 



The results show quite 'clearly that ammonium sulphate should not be used 

 as a top-dressing on soils rich in lime. A map is given which shows the loca- 

 tions of sources of supply of fertilizing materials of various kinds. 



Is nitrogen lost from the soil in fertilizing with nitrate of soda? J. 

 Stoklasa (Gcntbl. Bait, [etc.], 2. Abt., 11 {1906), No. 1-2, pp. 21-33; abs. in 

 Chcm. Ztg., 30 {1906), No. 90, Repert. No. 1,3, p. 386; Chcm. CentbL, 1906, II, 

 No. 25, p. 1718). — Recent investigations regarding deuitriflcation are briefly 

 reviewed and culture experiments in which 50 gm. samples of unmanured soil, 

 of soil fertilized with barnyard manure, and of soil fertilized with nitrate of 

 soda, were mixed with 500 cc. of Giltay solution, and the changes which the 

 nitrogen underwent were observed, are I'eported. 



The results confirm iu general those of previous investigations by the author 

 and lead to the conclusion that in the reduction of nitric acid to elementary 

 nitrogen, nitrous acid is always an intermediary product. The reduction of the 

 nitric acid to nitrous acid is brought about by the action of nascent hydrogen, 

 which is set free ahmg with carbon dioxid by the cleavage action of enzyms on 

 carbohydrates or organic acids. 



The Bavarian beet soils used in these investigations were so deficient in a 

 I'eadily assimilable carbon supply for the respiration processes of the denitrifica- 

 tion organisms that nitric acid was not reduced to elementary nitrogen in these 

 soils to a sufficient extent to be detected by ordinary analytical processes. With 

 free access of air such as accompanies ordinary thorough cultivation of soils or 

 in soils of high air capacity loss of elementary nitrogen through denitrificatiou 

 does not occur, although nitrites are always formed from nitrates. 



Can calcareous fertilizers be held responsible for a deficiency of nitrogen 

 in soils? Clausen {IIIks. Laiidir. Zfi/.. 26 {1906). No. IS. pi). 61'i< 675. figs. 

 3). — Pot experiments with clover and oats on sandy soil are reported, which 



