SOILS — FERTILIZERS. 1 L39 



Into a bard, comparatively dry cake, while the free alkali had been partially removed. 

 The alkaline liquor in the cathode chamber was then poured out into a beaker and 

 titrated with tenth-normal acid. After resliming the materia] in the anode chamber 

 with the proper quantity <>t water, the apparatus was started again. Willi the con- 

 ditions under which we were working it was found that about one hour sufficed for 

 each run." 



The absorption of potassium by soils, < >. S< iii.timi; and <>. II. Failyer lAbs. 

 in Science, n. %er., .'■>' \ t906) t No. 583, />. 324). — This is an abstract of a paper pre- 

 sented at the New Orleans meeting of the American Association for the Advancement 



of Science. 



The absorption of potash by soils was studied by the same methods used in case 

 of phosphates and an equation representing the absorption i< worked out, which is 



as follows: ' !, = K'{A -y), in which A" is a constant, A the maximum amount of 



<lr 



potassium the soil can absorb under the conditions of the experiment, and y the 

 amount it has absorbed when a volume v of potassium solution has passed through 



the soil. "The removal by water of the absorbed potassium is rapid at first, hut 



the concentration of the percolates soon reaches a constanl value, although only a 



fractional amount of the absorbed potassium has been removed. As far as the obser- 

 vations have been made the solutions obtained by percolating a solution of potassium 

 chlorid through the soil have always been acid." 



The absorption of phosphate by soils, 0. Schbeiner and G. H. Failyer I Abs. in 

 Science, n. %er., 23 (190<;), No. 583, i>i>. 324, 325). — This is an abstract of a paper pre- 

 sented at the New Orleans meeting of the American Association for the Advancement 

 of Science. The subject was studied by percolating different phosphate solutions 

 through soils of several types in an apparatus especially designed for the purpose 

 and analyzing separate fractions of the solution which passed through. The absorp- 

 tion phenomena are represented graphically, and a differential equation, which is 

 said to quite accurately describe them, is given. It was found that the absorptive 

 capacity for phosphates varied greatly in different soils, being as a rule most pro- 

 nounced in the clays and loams and less so in the sandy soils. 



"The solubility of the phosphate originally present in the soils was also deter- 

 mined by percolating water through the untreated soils in the above-mentioned 

 apparatus. It was found that the concentration of the separate fractions >f percolate 

 was practically a constant for each of the soils studied. If this concentration is 

 reduced through any cause, such as the absorption by plants or influx of rain water, 

 the original concentration will he again restored by more of the phosphate of the 

 soil entering into solution. If, on the other hand, the solution is somewhat stronger 

 than the natural concentration for that soil through any cause whatever, such as the 

 application of a soluble phosphate, the concentration is reduced by absorption to the 

 original strength. . . . 



" This constancy in the strength of the soil solution, so far as phosphate is con- 

 cerned, is further shown by the removal by water of the absorbed phosphate, which 

 has been similarly investigated. It was found that the concentration of the separate 

 percolates decreases rapidly until the concentration is reduced approximately to that 

 of the original soil solution. This concentration of phosphate is then maintained 

 with much persistence, although only a fractional amount of the absorbed phosphate 

 has been removed, thus indicating that while the absorbed phosphate is apparently 

 rendered insoluble, it is, nevertheless, slowly but constantly going into the soil 

 moisture and is, therefore, available to plants." 



The absorption of phosphates and potassium by soils, ( >. Schbeiner and 

 G. H. Failyer (U. 8. l>>/>t. Agr., />'"/■. Soils />'«/. 32, pp. 39, figs. 6).— A briefer 

 account of the investigations reported in detail in this bulletin has already been 

 noted (see above). 



