SOILS FERTILIZERS. 219 



Nitrate of soda as compared with a mixture of nitrate of soda and sul- 

 phate of ammonia, I). FEiadLio (Ann. 11. Shi:. S/x-i: Afjr. I'dinc, S {l!)Oli). 

 [ip. 7.c?-7'6'). — The results of ]il;it experiments with wiieat here reported indieate 

 that the nitrate ahjne in - applications was more effective than a mixture 

 of nitrate of soda and sulphate of annnonia. 



The influence of soil bacteria on the solubility of the phosphoric acid of 

 different phosphates, A. Koch and E. KmiuER {Fiihliii(/'s Landw. Ztg., 55 

 (J906), Xo. 7, in). 225-2.i5; aU. in Clirni. Ztg., SO (JDOG), .\o. S',, Repot. No. 12. 

 j). l-'i'i). — Bacteriological and chemical studies with a large numher of insoluhle 

 l)hosphates showed that bacteria i)r()duce acids which render such phosphates 

 soluble. These acids must, however, first neutralize ammonia, lime, or calcium 

 and magnesiiun carbonate, and similar suhstances which may he present. The 

 hacteria work on all phosphates, hut at varying rates, depending upon the com- 

 position. They woi'k with particular rapidity on Thomas slag once the basic 

 constituents are neutralized. A larger amount of acid is required, as a rule, than 

 the chemical reaction would indicate. The better action of bone meal on hunms 

 soils is due not only to the solvent action of the humus and carbon dioxid but 

 also to the greater activity of acid-forming bacteria in such soils. The applica- 

 tion of lime nentralizes these acids and thus interferes with their solvent action 

 on the i)hosphates. 



Aluminum phosphate as compared with mineral superphosphate and 

 Thomas slag, /. P.o.no.mi (Aidi. K. St(i.z\ Spcr. Agr. Id inc. S (1906), pp. 

 26-32). — Pot experiments on spring wheat and clover with these phosphates 

 combined with other fertilizing materials are reported. 



The aluminum phosphate used contained 20.48 per cent of phosphoric acid 

 soluble in neutral citrate, 14.72 per cent soluble in Wagner's solution, 42.37 

 per cent soluble in alkaline citrate, and 45.5G per cent total phopshorie acid. 

 The superphosphate contained 13.25 per cent of phosphoric acid soluble in 

 neutral citrate, the Thomas slag 10.18 per cent soluble in neutral citrate and 

 13.89 per cent soluble in Wagner's citric-acid solution. 



The results show that the aluminum phosphate itroduced a substantial increase 

 of yield in case both of clover and wheat. l)ut was always inferior to the super- 

 phosphate. In case of spring wheat the aluminum phosphate was inferior to 

 the Thomas slag. l)ut superior to it in casc^ of the clovtn'. 



Calcium superphosphate as compared with Thomas slag, Z. Bonomi {Ann. 

 R. mas. Sper. Agr. Udinc, S {1906), pp. 38-65. pi. i ) .—Comparative field tests 

 are reported of Thomas slag containing 14.5 per cent of phosphoric acid soluble 

 in citric acid and 10 per cent of free lime, and mineral superphosphate contain- 

 ing 9.38 per cent of phosphoric acid soluble in water and 13.18 per cent soluble 

 in neutral citrate solution. The results show in general that the Thomas slag 

 was the more economical fertilizer, but in many cases the superphosphate sup- 

 plemented by applications of lime gave larger increase in yield. 



The economical use of potash fertilizers, Z. Bonomi {A)in. R. Staz. Sper. 

 Agr. I'll inc. S (19(1(1). fip. 11-Sl). — The results of field experiments on red clover 

 were somewhat inconclusive. Although the use of i)otash fertilizers in all cases 

 increased the yield, in many cases this was not sufficient to return the cost of 

 the fertilizer. The author thePi'fore concludes that potash fertilizers should 

 be used with caution. 



Sulphate of potash, L. Bargeron {Jour. Agr. Prat., n. ser., 11 {1906), No. 

 21-22, pp. 667, 66S). — This article discusses briefly the sources, manufacture, 

 and consumption of this salt, as well as the relative economy of sulphate and 

 chlorid of potash. 



Salt, F. E. Enoelhardt (Sgraciise, N. Y.: Aiitlmr \ 1906]. pp. 15). — An ac- 

 count is given of the formation of salt deposits in general and of the discovery 



