治理式休耕对“长株潭”镉污染稻田土壤理化特性及镉含量的影响

Effect of managed fallow on soil physicochemical properties and cadmium content in cadmium-contaminated paddy fields in“Changzhutan”

为探索治理式休耕对镉污染稻田的治理效果,在湖南“长株潭”镉污染稻田区域设置29个监测点,探讨对照(正常耕种)、一般休耕和治理式休耕对土壤理化性质、土壤养分状况、总镉及有效态镉含量的影响。结果表明:治理式休耕较不休耕对照土壤有效镉含量显著降低了20.60%,而不休耕对照和一般休耕处理间差异不显著。治理式休耕较不休耕对照土壤pH值显著提高了0.31个单位,并显著提高土壤交换性钙、镁含量15.34%和14.46%;治理式休耕还分别提高了土壤有机质、有效硫和有效硅含量15.45%、15.28%和10.44%。相关性分析表明,土壤有效态镉含量与土壤有机质含量和土壤pH值存在显著负相关关系。研究表明,治理式休耕可以有效治理酸性稻田镉污染,并能显著改善土壤酸化,调节土壤肥力,达到改土培肥的效果。

This study aimed to explore the effect of control fallow on cadmium-contaminated paddy fields.Therefore,29 monitoring points were set up in a cadmium-contaminated paddy area of“Changzhutan”in Hunan Province to explore the effects of normal cultivation(CD),general fallow(CS),and managed fallow(CV)conditions on the physicochemical properties of soil,its nutrient status,and whole and effective state cadmium content.The results showed that the soil effective cadmium content of CV decreased significantly by 20.60%compared with that of CD,but there was no significant difference between CD and CS.CV significantly increased the soil pH value by 0.31 units compared with CD;while the soil exchangeable calcium and magnesium contents were significantly increased by 15.34%and 14.46%.The managed fallow also increased the soil organic matter,effective sulfur,and effective silicon content by 15.45%,15.28%,and 10.44%,respectively.Correlation analysis showed that there was a significant negative correlation between active state cadmium content in the soil,soil organic matter content,and soil pH.In summary,managed fallow can effectively control cadmium pollution in acidic rice fields and significantly alleviate soil acidification by adjusting soil fertility to achieve the required effect.