Co-Authors:
Chengbao, L., Institute of Soil Science, Chinese Academy of Sciences, P.O. Box 821, Nanjing 210008, China
Friedman, S.P., Inst. of Soil, Water,/Environ. Sci., Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel
Anzhen, Z., Institute of Soil Science, Chinese Academy of Sciences, P.O. Box 821, Nanjing 210008, China
Abstract:
The electrical conductivities (ECs) of suspensions containing 25 and 30 g kg-1 solids prepared from the electrodialyzed clay fraction (< 2 μm in diameter) of latosol, yellow-brown soil, and black soil, dispersed in various nitrate solutions having concentrations of 1 × 10-4/z mol L-1, where z is the valence, and in distilled water, were measured at field strengths ranging from 14 kV cm-1 to 210 kV cm -1. On the basis of analyses of the charge density and exchangeable ion composition on the surfaces of soil particles in the suspensions, and of the characters of the EC-field strength curves of the various suspensions, it was inferred that the increment of EC (ΔEC) and/or relative electrical conductivity (REC) can indicate the bonding strength between cations and soil particles. The bonding strengths of various cations with the soils diminished in the order: K+ > Zn2+ > Mg2+ = Ca 2+ > Na+ for latosol, Ca2+ > Zn 2+ > Mg2+ = K+ > Na+ for yellow-brown soil, and Zn2+ ≥ Ca2+ ≥ Mg 2+ > K+ > Na+ for black soil.