SOILS FERTILIZERS. 19 



tofore beeu largely luaintaiued by extension of the cultivated area, but empha- 

 sizes the fact that a period has now been reached when more attention must be 

 fijiven to improvements of methods and better utilization of soil resources. 



A possible method of reclamation for the arid West, W. O. Mieir ( Wcst- 

 iiiinslcr, Colo., I'JOD, pp. 21). — In this pamphlet it is argued that the formation 

 of a series of lakes in Salton Basin, Death Valley, and Carson Sink would 

 greatly increase the humidity of this now arid region. " The first improve- 

 ment that should be undertaken in this plan of reclamation is the filling of 

 Salton Sea Basin." 



Contribution to the study of the absorbent power and of the solutions 

 of soils, E. I{oxsseat:x and C. Brioux {Ann. 8ci. Agron., 3. set'., 3 (1908), 11, 

 Xo. 3, pp. 310-396; Bui. Mens. Off. Renseig. Agr. [Paris], S (1909), No. 1, pp. 

 0-26; ahs. in. Chem. Alis., 3 {1909), No. 9, p. 1052). — The investigations reported 

 were made with a sandy soil, the basis of which is green sand, and with a clay 

 soil or gait. Chemical and physical examinations of these soils, as well as de- 

 terminations of the constituents removed by extraction with water, are reported. 

 The distribution of the phosphoric acid in soil particles of different grades and 

 in the soil humus was also studied. 



The results of these experiments agree with those reported by other investi- 

 gators in showing that certain fertilizing constituents, such as nitrates, sulphates, 

 chlorids, and lime, are freely removed in the drainage w^ater, and that potash is 

 more strongly held. The amount of the latter constituent which passes into 

 solution in the soil depends upon the original fertility of the soil and the 

 amount of potash fertilizer added. All of the evidence obtained goes* to show 

 that the water which surrounds the soil particles contains much more nitrate 

 and lime in a soil liberally manured than in a poor or exhausted soil. 



I'hosphoric acid is much less soluble than the other constituents mentioned 

 and the amount of this constituent in soil solutions is generally very small. 

 Nevertheless, it varies widely in different soils, ranging in the experiments re- 

 ported from 0.5 to 18 mg. per liter. The amount yielded to solution, however, is 

 constant for a given soil and furnishes a fixed characteristic of the soil. In a 

 soil poor in lime and containing little clay, with a moderate amount of phos- 

 phoric acid, this constituent was found to be in large part in combination with 

 the humus of the soil. A deficiency of lime is accompanied by low soluI)ility of 

 luimates and a consequent I'eduction of the solubility of the phosphoric acid. It 

 was found that application of free lime either in the form of slag or of burnt 

 lime reduced the solubility of humus and phosphoric acid without decreasing 

 the percentage of phosphoric acid indicated as assimilable by Dyer's method. 

 The application of chemical fertilizers resulted in the solution of a considerable 

 quantity of silica, this effect being most marked in siliceous and ferruginous 

 soils. 



In later experiments on the absorption of phosphoric acid and jiotash by soils 

 of different kinds, the authors observed that potash was as a rule much more 

 rapidly absorbed but was ultimately less firmly fixed than phosi)horic acid. 

 Soluble phosphoric acid applied in the form of superphosphate must be thor- 

 oughly diffused in the soil before it is completely fixed. The acidity due to the 

 superphosphate persists for a long time in soils deficient in lime, undergoing an 

 intermediate fixation with iron oxid, alumina, and humus. Care must there- 

 fore b§ exercised not to use superphosi)hates on soils wiiich are naturally of 

 acid reaction. 



On the suspension of solids in fluids and the nature of colloids and solu- 

 tions, F. II. King {Separate fmnt, Trans. Wis. Aead. Sci., .-iris, and Letters 

 16 [1908], pt. 1, pp. 275-2SS). — This paper develops the theory, based upon 

 " studies of soil solutions and of the influence of soils and sands upon solutions 



