腐殖酸对红壤中铅镉赋存形态及活性的影响

Effect of humic acids on species and activity of cadmium and lead in red soil

深入探讨了腐殖酸不同组分对红壤中铅镉形态分级与活性的影响 .结果表明 ,腐殖酸的添加使红壤中Cd和Pb的残渣态向有机态转化 .用量越大、温度越低 ,转化效应越明显 .对植物最有效的可给态Cd和Pb的剧烈变化主要发生在加入腐殖酸 1h之内 ,随着时间的推移趋于稳定 .富里酸 (FA)促进了可给态Cd的增加 ,而胡敏酸 (HA)对可给态Cd和Pb的有一定的抑制和钝化作用 ,其作用以灰色胡敏酸 (GHA) >棕色胡敏酸 (BHA) .因此 ,在农业生产中 ,于红壤中添加HA特别是GHA成分高的有机物料 ,可部分减少Cd和Pb对作物的危害 .

Effect of various fractions of humic acids on form speciation and activity of Cd and Pb in red soil was discussed intensively in this paper. Results showed that the addition of humic acids promoted residual Cd and Pb transfer to organic form. The higher amount and the lower temperature, the more remarkable this transformation efficacy. The acute change of the most bioavailable Cd and Pb dominantly occurred within 1 hour after the addition of humic acids and the contents tended to become stable as time went by. Fulvic acid (FA) enhanced available metals, while humic acid (HA) exhibited certain inhibition and inactivation. The effect strength of the two fractions of HA was in the sequence of GHA>BHA. Thus, to add red soil with the organic materials with the high proportion of HA especially GHA could decrease the harm of Cd and Pb to crops.