42 SOIL SCIENCE [Bot. Absts., Vol. VI, 



tilizer by intimate contact of mineral superphosphates with ammoniacal waters in flat pans, 

 followed by evaporation. On mixing the two substances elimination of C0 2 occurs, interac- 

 tion of ammonium carbonate and acid phosphate. The acidity of the perphosphate eliminates 

 hydrocyanic acid and cyanides, which are generally contained in the ammoniacal waters. 

 The resulting compound may have, according to the author, the following formula: 

 Ca(NH 4 HP0 4 )2 + Ca((NH4)2P0 4 )2. After drying the material is crushed and finally has the 

 following characters: odorless, non hygroscopic and unalterable, containing 12.58 per cent 

 P2O5 soluble in citrated water, 3 per cent nitrogen and 12.48 per cent moisture. — A. Bonazzi. 



291. Dustman, R. B. Solubility and availability. Amer. Fertilizer 52 13 : 70-72. 1920. 



292. Jenkins, E. H., and E. Monroe Bailey. Fertilizer report for 1919. Connecticut 

 [New Haven] Agric. Exp. Sta. Bull. 217: 53-106. 1919.— Analyses of 339 brands of fertilizers 

 offered for sale in the state are given. — Henry Dorsey. 



293. Proulx, E. G. Interpretation of guarantees and analysis. Amer. Fertilizer 52 13 : 

 72d-72g. 1920. 



294. Waguet, P. A few notes upon chemical fertilizers. Rev. Prod. Chim. 23 : 207-210. 

 1920. — The world's production of phosphates is shown with a detailed account of the French 

 phosphate resources and methods of preparing ammonium and tetra phosphate. Sources 

 and composition of the world's potash deposits are also given. — R. B. Deemer. 



INFLUENCE OF SALTS ON SOLUBILITY 



295. McCool, M. M., and Millar, C. E. Effect of calcium sulphate on the solubility of 

 soils. Jour. Agric. Res. 19: 47-54. 1920. — Six different soils were treated with a saturated 

 solution of calcium sulfate. The rate of formation of soluble substances was determined by 

 means of the freezing-point method. Whether the soil was used as it occurred in nature or 

 whether soluble substances were first reduced to a minimum by washing with distilled water, 

 the calcium sulfate treatment resulted in an increase in the rate of formation of soluble sub- 

 stances. "It seems that it is possible to alter the composition of the soil solution and that 

 whether such changes will have any effect on plant growth or not or whether the effect will be 

 favorable or unfavorable will depend upon the nature of the soil and of the substances added." 

 — Tenth-normal calcium phosphate used in the same way decreased the rate of formation of 

 soluble substances. When the two are used together the effects of calcium sulfate are counter- 

 acted to some extent. — From carbon dioxide determinations, it is concluded that the increase 

 in the rate of formation of soluble substances brought about by treatment with calcium sulfate 

 is due to something other than increased biological activity. — D. Reddick. 



296. Kearney, Thomas H. The relative absorption by the soil of sodium carbonate and 

 sodium chloride. Soil Sci. 9: 267-273. 1 fig. 1920. — When equal volumes of equal concen- 

 trations of sodium carbonate and sodium chloride have been allowed to remain in contact 

 with sand for several hours, the electrical resistance of the same indicates that more sodium 

 carbonate than sodium chloride has been removed from solution. Conclusions that sodium 

 carbonate is less toxic to plants than sodium chloride are due to failure to consider this fact. — 

 W. J. Robbins. 



297. Sfttrway, C. H. The effect of fertilizer salts treatments on the composition of soil 

 extracts. Michigan Agric. Exp. Sta. Tech. Bull. 45. 18 p. 1919. 



MISCELLANEOUS 



298. Bauer, F. C. The effect of leaching on the availability of rock phosphate to corn. 

 Soil Sci. 9: 235-251. 2 pi., 2 fig. 1920. — Corn was grown in quartz sand in pots to which rock 

 phosphate or acid phosphate and a nutrient solution lacking phosphate were added. Some 

 of the pots were frequently leached with the nutrient solution. Leaching increased the yield 



