310 University of California Publications in Agricultural Sciences [Vol. 1 



Chemical Studies of the Calcium and Magnesium Content of the 

 Percolate and the Absorption op Sodium 



Onr attention was first directed to the possibility of the ex- 

 istence of a relationship between the two factors mentioned in 

 the heading above, by the following experiment, the outline and 

 results of which appear in Table V, page 309. 



A review of these data discloses the fact that the application 

 of NaCl to a soil increases the calcium and magnesium found in 

 the percolate as compared with the quantities found in the 

 percolate of the normal soil when leached with distilled water. 

 This is in accord with the results of Kullenberg,^ Van Bem- 

 melen" and the work of others, a good list of which is given by 

 Sullivan." To exemplify the above remarks concerning calcium, 

 let us examine the table with respect to that element. The addi- 

 tion of NaCl to the Anaheim sandy loam and Oakley sandy soil 

 has practically tripled and doubled, respectively, the amount of 

 calcium found in the percolates over that of the percolate from 

 the salt-free soil. In the Berkeley adobe and Davis clay-loam soils 

 the NaCl brings about a much more marked increase of calcium 

 in the leachings. It may be remarked also that the results secured 

 with magnesium are quite parallel to those concerning calcium. 



In addition to altering the calcium and magnesium contents 

 of the percolate, the salt treatments materially affected the physi- 

 cal condition of the soil, as shown by a marked retardation of the 

 rate of percolation. All of the soils responded alike to the NaCl 

 treatments, in that they became more impervious and their col- 

 loidal matter exhibited a higher degree of diffusion when sus- 

 pended in water, as shown in the second part of Table V. The 

 degree of imperviousness and diff'usion varied, however, with 

 the different soils, and also appeared to be roughly proportional 

 to the increase of calcium and magnesium in the leachings from 

 the soils receiving NaCl. Thus the salt-treated Berkeley and 

 Davis soils, showing notably greater increases in calcium and 

 magnesium in the percolates, were also more highly diffused than 



9 Jahrb. Fortsch. Agri. Chem., vol. 8, p. 15, 1865. 

 loLandw. Vers. Stat., vol. 21, p. 135, 1878. 

 11 U. S. Geol. Surv., Bull. 312, 1907. 



