1917] SOILS FERTILIZEES. 725 



carbon dioxid, there was somewhat less ammonia produced than when oxygen 

 was present at the beginning. Ammonia was formed in rather large quantities 

 under such conditions. Nitrate determinations showed that nitrates are pro- 

 duced in ammonification tests even though the organic content is high and the 

 period of incubation is short. 



A list of 27 references to literature bearing on the subject is appended. 



The cause of the disappearance of coumarin, vanillin, pyridin, and quino- 

 lin in the soil, W. J. Robbins (Science, n. ser., 44 (1016), No. 1147, pp. 894, 

 895). — It was found that when soil in pots was treated with coumarin, 

 vanillin, pyridin, and quinolin separately at a concentration of 1,000 parts per 

 million, the numbers of micro-organisms increased enormously after three 

 months and after, in some cases, an initial decrease in numbers. Additions of 

 the substances to sterile soils and to sterile soils inoculated with nonsterile 

 soil showed that after two months' incubation the growth of wheat plants 

 from sterile seed was not affected in the inoculated soils, but the toxic prop- 

 erties of the compounds were still evident in the sterile soil. These results are 

 taken to indicate that the disappearance of the compounds was due chiefly 

 to biological causes. In this connection three species of bacteria were isolated, 

 one of which uses pyridin as a source of nitrogen, and oae vanillin and one 

 coumarin as sources of carbon. 



The formation of soda in the soil, E. V. Bobko (Is ResuVt. Yeget. Opytov 

 Lab. Rabot (Rec. Trav. Lab. Agron.), Moskov. Selsk. Khoz. Inst., 10 (1914), 

 pp. 355-365, pi. 1; Izv. Moskov. Selsk. Khoz. Inst. (Ann. Inst. Agron. Moscou), 

 22 (1916), No. 2, pp. 115-125). — Artificial zeolite washed with a solution of 

 sodium chlorid yielded small but measurable quantities of soda, and the quantity 

 of soda increased with the length of time of the reaction and with an increase 

 of the amount of zeolite. If an excess of sodium salt was added the process of 

 the formation of soda was depressed, but was restored when the washing was 

 repeated. 



Loss of fertilizers by leaching, S. E. Coixison and S. S. Walker (Florida 

 Sta. Bui. 132 (1916), pp. 20, figs. 5). — Five years' experiments on the loss of 

 fertility constituents in the drainage water of fertilized and unfertilized sandy 

 soils in four large steel tanks previously described (E. S. R., 25, p. 117) are 

 reported. 



The authors conclude that under Florida conditions and with soil similar to 

 that used in this experiment " newly cleared land when exposed to heavy rain- 

 fall soon loses much of its fertility through leaching. The fertility of the soil 

 may be maintained by growing legumes and applying fertilizers. Much of the 

 loss may be prevented by growing crops. The gi*eatest loss of fertility from 

 unfertilized soils occurs with the nitrogen, which leaches through in considerable 

 quantities. Nitrification of the soil organic matter, thus changing the nitrogen 

 to a form readily lost by leaching, proceeds rapidly in cultivated soils under 

 Florida conditions. 



" Phosphoric acid and potash are lost in small quantities from the unfertilized 

 soil, since they are present largely in insoluble forms. Lime is lost in con- 

 siderable quantity, thus bringing about an acid condition in the soil. 



" When cultivated soils are fertilized with a complete fertilizer, the element 

 lost in largest amounts by leaching is nitrogen. Nitrate of soda leaches more 

 rapidly and in larger amounts than sulphate of ammonia or dried blood. 

 Nitrate of soda should be used in small amounts at frequent intervals and 

 usually as a top-dressing. 



" Distribution of rainfall influences to a considerable extent the amounts of 

 the fertilizing constituents which leach through. Soils similar to that used in 

 this work have the capacity for fixing large quantities of phosphoric acid ap- 



