126 EXPERIMENT STATION RECORD. [Vol. 41 



A bibliography of 51 titles is appended. See also a previous note (E. S. R., 

 40, p. 418). 



The solubility of the soil potash in various salt solutions, D. K. Tressler 

 (Soil Sci., 6 (1918), No. 3, pp. 237-257, figs. ^).— This paper, a thesis submitted 

 to the faculty of the Graduate School of Cornell University, describes inves- 

 tigations in which a study was made of the effect upon the solubility .of the 

 potash contained in several soils of allowing them to remain in contact with 

 various salt solutions of different concentrations xmtil the systems reached 

 equilibrium. Dunkirk silt loam and Genessee humus loam secured near 

 Ithaca, N. T., Whiteland clay subsoil and Yamhill silt loam from the vicinity 

 of Corvallis, Oreg., Porters sandy loam and Durham sandy loam fi-om North 

 Carolina, and Merrimac fine sandy loam from the experimental plats of the 

 Massachusetts Experiment Station comprised the soils examined. The salts 

 employed included the component parts of commercial acid phosphate, viz., 

 calcium sulphate and tri-, di-, and monocalcium phosphate, calcium car- 

 bonate, sodium nitrate, sodium chlorid, and sodium carbonate. About 125 

 gm. of dry soil, or its equivalent in moist soil, was placed in a liter of water, 

 various amounts of the salts added, and the solutions allowed to stand for 

 three weeks. The amount of K2O in parts per million of the solution was then 

 determined. The results secured may be summarized as follows: 



When commercial acid phosphate liberated potash in the soils used in this 

 investigation the effect was found to be due to the gypsum which it contained. 

 Calcium sulphate in solution increased the solubility of the potash compounds 

 in some soils, this effect being much more marked in clay than in silt or sand 

 and offering a possible explanation of the fact that only certain soils are bene- 

 fited by applications of gypsum. Calcium sulphate solutions did not seem 

 to be particularly active in dissolving the potash of silt and sands containing 

 mica. It is deemed probable that on some, if not all fertile clay loam a. id 

 clay soils, some potash isjnade soluble by the application of gypsum. In Dun- 

 kirk clay loam and silt loam, only a small amount of calcium suphate was re- 

 quired in the solution in order to affect materially the solubility of the 

 potash, this possibly indicating why small applications of gypsum are quite 

 beneficial on some soils. 



The soil potash of Dunkirk silt loam was found to be somewhat more soluble 

 in solutions of carbon dioxid and calcium bicarbonate than in a solution of 

 carbonic acid containing the same amount of carbon dioxid. It is stated that 

 soils high in organic matter may derive some soluble potash from the effect of 

 the calcium bicarbonate in the soil water after the addition of a large amount 

 of lime. 



Sodium salts were quite active in dissolving potash from soils. The fact 

 that sodium chlorid solutions were active in dissolving potash and that beets 

 require sodium for proper growth is believed to explain why beets derive bene- 

 fit from applications of salt, since they are very resistant to the tonic action 

 of sodium chlorid. 



A list of 29 titles comprising the literature cited is appended. 



Relation of fluorin in soils, plants, and animals, L. A. SteinkoeniCi (Jour. 

 Indus, and Engin. Chew.. 11 (1919), No. 5. pp. /,63--'f6.5) .—The author briefly 

 reviews the work of other investigators, together with observations made by 

 himself on the amount of fluorin present in both surface and subsoil samples 

 of 9 different types of soil. He concludes that the original source of fluorin 

 in the soil is such minerals as biotite, tourmalin, muscovite, apatite, fluorite, 

 and phlogopite. In the soils examined fluorin occurred in amounts averaging 

 0.03 per cent, but a higher content may be expected in soils carrying larger 



