SOILS — FERTILIZERS. 315 



to the International Congress of Applied Chemistry at London and deals with 

 the results of practical experiments to test the fertilizing value of basic lime 

 nitrate, calcium cyaiiaiiiid, and dicyiindianiid. 



The actual status of the new nitrogenous fertilizers, G. L. IIagondet {Jour. 

 Soc. Cent. Ayr. BvJ(j., JO' (IDOU), Xo. 7, i>i). .iO'i-i'-h !'<J^- 2).— This is a report 

 upon the present status of the manufacture and agricultural utilization of basic 

 lime nitrate and lime nitrogen. The results of held experiments with these fer- 

 tilizers on a variety of crops are reported. 



Fertilizer experiments with phosphates, H. Klebahn (Jahrh. Ilamhurg. 

 Wiss'. Anst., 25 {1907), Bciheft 3, pi). 279-291, pis. 2).— Comparative pot and 

 field tests of Thomas slag, superphosphate, and agricultural phosphate (fine 

 ground raw phosphate) with kainit and nitrate of soda on barley, oats, and 

 beans grown in sandy and peaty soil are reported. While the results were not 

 altogether conclusive they show that the agricultural phosphate and Thomas 

 slag were nearly equally effective on moor soils, but less effective on sandy 

 soils. 



The solution of phosphoric acid in water-insoluble compounds under the 

 action of bacteria and yeasts, 10. Kp.uber (Jdiir. Ijntdir., .57 iUXI'.i) Ao. J, pp. 

 5-80). — Previous investigations on this subject, particularly those of Stoklasa, 

 are reviewed, and a series of studies to verify the conclusions from these in- 

 vestigations and to study the influence of various conditions upon the activity 

 of bacteria and yeasts in rendering phosphates soluble is reported. 



The investigations show in general that the activity of acid-forming bacteria 

 and yeasts is of great importance in rendering phosphoric acid soluble in the 

 soil. Of first importance in this respect is carbon dioxid, but other acids, such 

 as acetic acid, butyric acid, and lactic acid produced by bacteria also exert a 

 considerable influence. The presence of basic substances which readily com- 

 bine with these acids interfere with solution as long as the bases are in excess 

 in the soil. 



The amount of active lime and calcium carbonate in the soil, as well as the 

 form of nitrogenous fertilizers used, plays an important role in the action of 

 the phosphatic fertilizers. In compost experiments it is of importance from 

 the standpoint of solubility of the phosphate whether the mixture gives an 

 acid or alkaline reaction, since in the latter case the neutralization of the acids 

 would prevent solution of the phosphoric acid. 



The author concludes from his experiments that the life activities of the 

 bacteria, that is, assimilation of phosphoric acid by the living organism, play 

 little or no direct part in solution of the phosphates, but that the latter is due 

 to the action of the organic acids and of the carbon dioxid produced. 



The action of yeasts in rendering phosphoric acid soluble increased with the 

 increase of neutral phosphate added to the nutrient solution, of carbon dioxid 

 produced, of the sugar content up to an optimum, and in general, with the im- 

 provement of conditions which increased the production of carbon dioxid. 



The acids produced by bacteria acted upon all kinds of phosphates, reducing 

 them to the soluble monophosphate, but the rate of solution varied widely with 

 the different phosphates. Tricalcium phosphate in precipitated form, dical- 

 cium phosphate, and tetracalcium phosphate of Thomas slag were much more 

 rapidly dissolved than the crystalline phosphates or the so-called amorphous 

 phosphates. 



The better action of difficultly soluble phosphates in humus soils is attributed 

 not only to the fact that such soils are rich in humus acids, but that there is 

 au active respiratiiai and fermentation of acid-forming bacteria, molds, and 

 yeasts in such soils. 



