岷江下游丘陵区3种农业种植模式对铅（Pb）污染土壤的修复效益

为了解间作和轮作组成的农业种植模式对中轻度Pb污染土壤的修复效益,定点调查了岷江下游丘陵区3种农业模式(MI:玉米+红薯-小白菜+菠菜,M2:玉米+生姜-茎用芥菜,M3:水稻)作用下,土壤中Pb含量的变化以及Pb在土壤和作物系统中迁移和分配的特征,采用有时序的灰色关联分析法,比较了 3种模式的综合效益.结果发现,土壤Pb含量变化在模式M1、M2中表现为显著下降后持平的"L"形特点(降幅10.65%、13.91%).M3中为显著下降(降幅14.17%).Pb在作物非食用器官中含量是食用器官的1.10～33.00倍.玉米和稻谷食用器官中Pb的含量安全,生姜受到中度Pb污染,红薯、小白菜、菠菜等食用器官中Pb污染较严重,人体通过模式中作物日摄入Pb总量是WHO/FAO标准的4.23倍,但由于人体对Pb具有的耐性和清除机制、食用前对农产品的加工措施、当地农户将红薯和菠菜等作为猪饲料使用,以及现今社会人类日常饮食种类的丰富性等,有效地降低了农产品中Pb含量超标对人体危害的风险性.分析表明,3种模式的综合效益是显著的,灰色关联分析法的排序结果为M2＞M1＞M3.

Remediation Efficiency of Three Cropping Systems for Lead(Pb)Contaminated Agricultural Soils in Hilly Region of Minjiang River

Lead(Pb) pollutant has been considered as one of the most serious environmental problems worldwide.Including others,monoculture in agriculture may be successful for metal phytoremediation in short-term(two to three years),although significant yield reduction in longer term applications.Intercropping and rotation systems might remedy this flaw by reasonably assigned.However,little information has been available on the remediation efficiency of cropping systems by assigning intercropping and rotation systems ...