云南喀斯特地貌区土壤重金属污染风险评估及水稻叶面肥筛选

Soil heavy metal pollution risk assessment and foliar fertilizer screening for rice in Yunnan karst landscape area

为探究云南水稻种植区土壤重金属含量与叶面肥种类对水稻中重金属迁移,以及对糙米质量安全的影响,本研究选取地质高背景区泸西县水稻种植区作为研究区,采用单因子污染指数法、内梅罗综合污染指数法、潜在生态风险指数法对研究区稻田土壤污染情况进行了评估,并以锰锌肥、硅硒肥两种不同成分叶面肥作为试验材料,通过转运系数等指标探究不同成分叶面肥在田间大规模应用中的效果。研究结果表明:研究区稻田土壤中As、Cd、Cr的平均值均超过云南省土壤重金属背景值且变异系数较大,主要以Cd污染最为严重。研究区土壤总体上处于轻度污染状态,As、Pb、Cr均处于轻微潜在生态危害,40%的Cd处于中等潜在生态危害,但综合潜在生态危害指数仍为轻微潜在生态危害。喷施叶面肥的处理较仅喷施清水的处理而言,茎叶-糙米间转运系数降低,糙米及茎叶中重金属含量显著降低,产量无显著差异。供试的锰锌肥的肥效较硅硒肥更为显著,适合在田间大规模种植使用。

To investigate the impact of soil heavy metal content and foliar fertilizer types on heavy metal migration in rice,as well as the quality and safety of brown rice,the study was conducted in the rice planting areas with high geological background in Luxi County,Yunnan Province.The contamination status of paddy soil in the study area was assessed using the single factor pollution index method,Nemerow comprehensive pollution index method,and potential ecological risk index method.Additionally,two different types of foliar fertilizers,manganese-zinc fertilizer and silicon-selenium fertilizer,were used as experimental materials.The effects of various foliar fertilizers in large-scale field application were examined by using transfer coefficients and other indicators.The results showed that the average concentrations of As,Cd,and Cr in the paddy soil exceeded the background values of soil heavy metals in Yunnan Province,and the variation coefficitents were high;Cd pollution was significantly severe.However,the overall soil pollution in the study area was classified as light.As,Pb,and Cr showed slight potential ecological hazards,while 40%of Cd exhibited medium potential ecological hazards.Nonetheless,the comprehensive potential ecological hazard index indicated a slight potential ecological hazard.Compared with control,the application of foliar fertilizers was observed that the transfer coefficient between stem and leaf-brown rice decreased,resulting in a significant reduction in heavy metal content in brown rice and stem and leaf.Importantly,no significant differences were found in yield among the different foliar fertilizer treatments.Manganese-zinc fertilizer demonstrated more significant fertilizer efficiency compared with silicon-selenium fertilizer,making it suitable for large-scale field planting.