1916] SOILS — FERTILIZERS. 17 



properties produced in soils on tlie addition and sulisequent leaching out of salts. 

 An attempt is made to explain this change on the basis of colloid clieraistry, 

 especially " on tlie contention that the behavior of soils under the influence of 

 salts agrees in some measure with the laws wliich are thought to govern the 

 behavior of dispersed systems to which salts have been added." 



The adsorption of potassium and phosphate ions by typical soils of the 

 Connecticut Valley, R. H. Bogue {Jour. Phys. Chem., 19 {1915), No. 8, pp. 

 665-695, figs. 13). — Experiments conducted at the Massachusetts Agricultural 

 College with sand, fine sandy loam, silt loam, and clay soils to determine their 

 adsorptive powers for potassium and phosphate ions from percolating solutions 

 of monocalcium phosphate and potassium chlorid of concentrations equivalent 

 to 200 parts per million of potassium and phosphoric acid, respectively, are 

 reported. The results are presented in tabular and graphic form. 



It was found that " when soils are subjected to the leaching action of water, 

 the concentration of potassium and phosphate ions in the soil extract ap- 

 proaches a constant which appears to be fixed and definite for any given soil. 

 When soils are subjected to the action of soluble potassium and phosphate 

 salts, the concentration of these salts in the soil extract is at first not materially 

 increased owing to the power of the soils to adsorb these salts, but as adsorption 

 proceeds it becomes weaker and a point is finally reached where the amount 

 of soluble salts in the soil extract is nearly equivalent to the amount applied. 

 The concentration of the potassium and phosphate ions in the soil extract 

 approaches a low constant, which appears to be fixed and definite for each soil, 

 when only a part of the adsorbed ions has been removed by the leaching action 

 of water. 



"The constants attained by the four soils by the leaching action of water 

 are very nearly alike, which would seem to indicate that the concentration of 

 the potassium and phosphate ions in the soil solutions of the various soils were 

 practically the same, and not at all dependent on the amount of adsorbed 

 potassium or phosphate they originally contained. These results substantiate 

 the theory that the concentration of salts in the soil solution is very largely 

 dependent on the specific adsorptive capacity of the individual soil . . . [They] 

 tend to disprove the theory that the composition of the soil moisture, hence 

 the adsorptive capacity of the soil, is determined primarily by the chemical 

 composition of the soil, but tend rather to prove this quality to be dependent 

 on the mechanical texture of the individual soil." 



The results are also taken to indicate that the soils were able to take up 

 the potassium and phosphoric acid by both physical and chemical processes. 



Soil survey of Mississippi County, Arkansas, E. C. Hall, T. M. Bushnell, 

 L. V. Davis, W. T. Cakter, Jr., and A. L. Patrick {U. S. Dcpt. Agr., Advance 

 Sheets Field Operations Bur. Soils, 1914, pp. 42, pi- 1, fig. 1, map 1). — ^Thig 

 survey, issued April 4, 1916, deals with the soils of an area of 575,360 acres 

 in northeastern Arkansas which lies within the River Flood Plains soil province 

 and comprises first and second bottom lands. In general the topography varies 

 little from a nearly flat and level plain. The natural drainage of the county 

 is generally poor owing to the low-lying position of the soils and to the annual 

 overflows of the Mississippi River. Tlie soils range from loose, incoherent 

 sands to heavy, plastic clays and are of alluvial origin. Including meadow 

 and overwash, 22 soil types of 6 series are mapped, of which the Sharkey clay 

 covers 64.7 per cent of the area. 



Soil survey of Webster Parish, Louisiana, A. H. Meyer, E. S. Vanatta, 

 B. W. Tillman, and R. F. Rogers {U. S. Dept. Agr., Advance Sheets Field 

 Operations Bur. Soils, 1914, pp. 40, fig. 1, map 1). — This survey, made in 

 cooperation with the Louisiana Experiment Station and issued ]\Iarch 11, 1916, 



