CONCENTRATION OF SODIUM-CHLORIDE SOLUTIONS IN PORES OF VARIOUS SIZE

A coarse mantle loam was moistened with 0.02, 0.05, 0.17, and 0.34 N N aCl solutions. Fractions of the soil solution (SS) were extracted by a Richards' press at nitrogen pressure varying from 1 to 150 kPa. The e xtracted soil solution differed significantly from the initial one, wi th the sharpest distinctions being observed in the fractions extracted at 10-100 kPa. The concentration of Na+ was higher in large pores (0- 10 kPa) than in fine pores and increased with a rise in concentration of the initial solution, The concentration of Ca2+ and Mg2+ was somewh at lower in large pores than in fine pores, and that of Cl- changed in significantly. The cation concentration in SS fractions was directly r elated to the Na+ concentration in the initial NaCl solution. The rela tive concentrations of ions [Na+]/[Na+](0) and [Na+]/[Ca2+] + [Mg2+] a re directly related to the logarithm of [Na+] concentration in the ini tial solution ([Na+](0)) for all SS fractions.