Abstract: The red loam samples are collected from the Zone of Economic and Technological Development in Qujing. Having been polluted by heavy metal Pb/Cd, the soil samples are treated with two kinds of organic fertilizers with different concentrations, and their physical and chemical properties and heavy metal contents in different forms are determined. The effects of the two kinds of organic fertilizers on the physical and chemical properties and morphology changes of Pb and Cd of the red soil polluted by heavy metals are studied. The results show that the nitrogen, phosphorus and potassium content in the red soil increase significantly after the application of soil organic fertilizer (A). The nitrogen, phosphorus and potassium content in the red soil has not improved obviously after applying Dvo (B). At the same time, the two kinds of organic fertilizers can effectively reduce the proportion of exchangeable Pb in the polluted soil, increase the organic binding state and residue state in the soil, but lead to the increase of both exchangeable Cd and residue Cd content in the soil. The results also show that application of an organic fertilizer could significantly improve the nitrogen, phosphorus and potassium content in the red soil, while application of organic fertilizer B could not significantly improve the effect. Both of the two organic fertilizers can be used as remediation agents to weaken the harm of Pb, but the repair effect of Cd is not ideal.

Key words: organic fertilizer, heavy metals, morphological analysis, physical and chemical properties