[Sustained Effects of Remediation Materials on Soil Copper Remediation Under Oil-Rice Rotation]

In this study, a continuous rape-rice rotation plot experiment was conducted over three years. Repair materials were continuously applied in the first two years, and no repair materials were applied in the second year. The repair effects of hydroxyapatite, lime, biochar, bio-organic fertilizer, and nano-materials on copper contaminated soil and the enrichment of copper in different parts of rape and rice were investigated. The results show that hydroxyapatite, lime, and nanomaterials can significantly increase soil pH, and different restoration materials can effectively inhibit the movement of soil copper. The effective copper treatment with lime restoration soil had the largest decrease. The four seasons of continuous application of restoration materials were 38.9%, 34.9%, 27.88%, and 29.04%, respectively, and the subsequent effect of lime passivation of effective copper was better than other restoration materials. The application of the repair material significantly reduced the copper content in edible parts of rape and rice. In the four seasons of application of the repair material, the maximum copper content in edible parts of different crops decreased by 46.03%, 22.2%, 29.44%, and 31.71%, respectively. Due to the application effect of the repair material, the copper content in the edible part of the two season crops, without the repair material, did not exceed the national food safety limit. With the use of different repair materials, the yields of rapeseed and rice were improved. This test can provide some theoretical basis and technical support for soil improvement in copper-contaminated areas.