中文摘要：

选择富含有机质的黄棕壤型水稻土，提取小于2μm的黏粒，将其中1／2黏粒去除有机质，分别制成为不同阳离子（Na^＋、K^＋、NH4^＋、Ca^＋、Cd^2＋和La^3＋）饱和的土样，用Wien效应法研究土壤有机质对阳离子与土壤黏粒相互作用的影响。研究结果表明：原土悬液的起始电导率大于去有机质土者；除含Na^＋悬液外，去有机质土悬液的电导率随场强而增加的速率在50～100kVcm^-1以上，明显大于原土。有机质会使Na^＋以外的阳离子的平均结合自由能增大，Ca^2＋的结合能增加最大（增量为0．57kJmol^-1），而Cd^2＋的结合能增加最小（增量为0．03kJmol^-1）。对于供试土壤悬液，不同阳离子的结合能顺序均为Na^＋〈K^＋≈NH4^＋〈Ca^2＋≈Cd^2＋〈La^3＋。有机质会使除Na^＋外阳离子的平均吸附自由能减小，K^＋和Nn4^＋分别在50和70kVcm。以上时，Ca^2＋和Cd^2＋在50kVcm。以上，La^3＋在70kVcm^-1以上时原土的吸附能小于去有机质土，并随场强增加愈益明显，有机质会使阳离子难以剥离到溶液中。除Na^＋外去有机质土的阳离子剥离度明显大于原土，其差值（AIs）在不同阳离子间的顺序为：K^＋〈NH4＋〈La^3＋〈Ca^2＋〈Cd^2＋，这表明有机质可使土壤黏粒吸着Cd^2＋最难剥离下来。对于饱和阳离子为Na^＋和K^＋的土壤黏粒，有机质会使动电电位正移40mV左右；对于含NH4^＋、Ca^2＋、Cd^2＋和La^3＋的黏粒，有机质则使ζ电位负移17—36mV。

英文摘要：

Paddy soil derived from yellow-brown soil, rich in organic matter, was used to extract clay particles 〈 2 μm, half of which was deprived of organic matter, and then prepared into samples saturated with Na^ ＋ , K^ ＋ , NH4 ^＋ , Ca^2＋ , Cd^2＋ and La^3 ＋ cations, separately. Effects of organic matter （OM） on interactions between cations and soil clay particles were investigated with the aid of the suspension Wien effect. It was found that threshold electrical conductivity was higher in the suspensions of original soil than in the suspensions of OM-removed soils. In all the suspensions, except for Na ^ ＋ -saturated one, the rate increasing electrical conductivity of the OM-removed soil suspensions with field strength in the range 〉 50 - 100 kV cm^-1 was apparently higher than that of the original soil suspensions. OM increased the mean free binding energies of all the cations other than Na ^＋ , with the effect being the most significant on Ca^2＋ , about 0. 57 kJ mol^-1, and being the least on Cd^2＋ , around 0.03 kJ mol^-1. In all the soil suspensions, binding energies of various cations followed the sequence of Na ^ ＋ 〈 K ^ ＋≈ NH4 ^＋ 〈 Ca^2＋≈ Cd^2 ＋ 〈 La^3＋ . OM reduced the mean free adsorption energies of all the cations except Na^＋. The effect was significant for NH4^＋ at field strengths 〉70 kV cm^-1 , for K^＋ , Ca^2＋ and Cd^2 ＋ at field strengths 〉 50 kV cm^-1 and for La^3 ＋ at field strengths 〉 70 kV cm^-1, and the difference got more obvious with increasing field strength. OM made it more difficult for cations adsorbed on clay particles to get released into the solu- tion. Stripping intensities of the cations except Na＋ were distinctly higher in the suspension of OM-removed soil than in the suspension of original soil, with the difference AIs following the order of K ^＋ 〈 NH4 ^＋ 〈 La^3＋ 〈 Ca^2＋ 〈 Cd^2＋ , which indicated that OM made Cd^2＋ adsorbed on clay particles most difficultly strip off. In Na ^＋ and K^ ＋ saturated