SOILS — FERTILIZERS. 133 



On sandy soils poor in lime there was no loss of nitrogen with either am- 

 monium sulphate or lime nitrogen applied as a top-dressing. On soils rich in 

 lime, there was considerable loss of nitrogen when ammonium sulphate was 

 applied as a top-dressing, but almost no loss of nitrogen with lime nitrogen. 

 With a high clay content the loss from ammonium sulphate on soils rich in 

 lime was greatly reduced through the absorbent action of the clay. 



With natural soils neither the natural nor the highly absorbent artificial 

 zeolites were capable of fixhig appreciable quantities of ammoniacal nitrogen 

 in the soil for a long period. Ammonium sulphate and sodium nitrate gave like 

 results on soils containing either high or low contents of clay. 



Green manuring with yellow clover was more effective than with peas, beans, 

 and vetch, espec-ially on imperfectly aerated soils, because of the greater readi- 

 ness with which the clover decomposed. The elTect of the clover was not so 

 pronounced on the sandy as on the clay soil, 40.8 per cent of the nitrogen of 

 the clover being assimilated in the clay soil as compared with 36.5 per cent in 

 the sandy soil. The nitrogen of peas, beans, and vetch was assimilated at the 

 rate of 30.5 per cent in the clay soil as compared with 33.5 per cent in the 

 sandy soil. 



Fertilizer experiments with sodium nitrate, ammonium sulphate, lime 

 nitrogen, and Norwegian nitrate, Hey {Sachs. Landw. Ztschr., 58 (1910), Nos. 

 10, pp. 124-126; 11, pp. I'i2, UiS). — In comparative tests on light loam soil with 

 oats and rye the sodium nitrate gave the best results with rye during the first 

 year and lime nitrogen the best returns with oats. The following year, with 

 spring application, both lime nitrogen and Norwegian nitrate gave better results 

 than sodium nitrate. The nitrogenous fertilizers were especially effective on 

 crops following potatoes which had received liberal applications of manure. 



Sulphate of ammonia, C. G. Atwater {Penn. Dept. Agr. Bill. 193, pp. 106- 

 110). — This is a plea for the introduction of by-products of eolje ovens into the 

 United States with a view to saving the large amount of sulphate of ammonia 

 now going to waste in the coking of coal. 



The nitrogen of the air and its utilization, K. Kaiser {Der Luftfiiclcstoff und 

 seine Verwertung. Leipsic, 1910, pp. 102, figs. 13). — This is a concise summary 

 of the present knowledge T\fith reference to nitrogen in the economy of nature, 

 sources of nitrogen, nitrogen combustion, the formation of ammonia and cyanid 

 compounds from atmospheric nitrogen, and fixation of nitrogen by means of 

 bacteria. The book describes some of the newer processes for manufacturing 

 nitrogen compounds from the air and discusses the industrial aspect of this 

 subject, 



Calcium cyanamid and some of its decomposition products, A. Stutzeb 

 and F. Reis (Jour. Landio., 58 (1910), No. 1, pp. 65-76; abs. in Jour. Chem. 

 Soc. [London], 98 (1910), No. 572, II, p. 537).— This article is based upon in- 

 vestigations which have been in part reported elsewhere (B. S. R., 23, p. 718). 



It is shown that the first stage in the decomposition of calcium cyanamid is 

 brought about by the absoiiition of carbon dioxid, followed by the decomposi- 

 tion of the cyanamid by chemical and not biological processes into urea and 

 similar compounds. Ferric oxid is the most important soil constituent con- 

 cerned in this change. The urea is rapidly converted into ammonia and sub- 

 sequently into nitrates. Dicyandiamid is not available as a source of nitrogen 

 for higher plants, but there is no danger from its formation from lime nitrogen 

 in the soil. It remains in the soil unchanged for a long time, and while it may 

 retard germination it is not injurious to growing plants, bacteria, yeasts, and 

 streptothrix if other available forms of nitrogen are present. 



Comparative tests of the action of 40 per cent potassium chlorid, potas- 

 sium silicate, and feldspar, F. Honcamp et al. (Mitt. Deut. Landw. Oesell., 



