EFFECT OF SALT SOLUTION COMPOSITION ON MOISTURE RELEASE CURVES OF SOIL

A pore size index was used to express quantitatively the relative decrease in size of common pore of confined columns of krasnozem, red-brown and alluvial soils, with reduction in electrolyte concentration of percolating solutions of a given sodium absorption ratio (sar). The pore size index of red-brown and alluvial soils decreased markedly with reduction in electrolyte concentration, especially in solutions of high sar. In the krasnozem soil the pore size index remained fairly constant for a wide range of salt solutions. Moisture release curves of red-brown soil for solutions of decreasing electrolyte concentration and constant sar and for solutions of increasing sar and constant electrolyte concentration can be used in combination to obtain moisture release curves of this soil for solutions at any intermediate values of sar and electrolyte concentration. They also reveal the pattern of volume change of different sized pores. © 1979, CSIRO. All rights reserved.