玉米套作蜈蚣草修复砷污染农田土壤的效应研究

Effect of maize(Pteris vittata L.) intercropping on remediation of As-contaminated farmland soil

为探明作物-超富集植物套作模式对修复砷污染土壤的效应,采用盆栽实验,探讨了玉米(Zea mays L.)与蜈蚣草(Pteris vittata L.)开放性套作、限制性套作和单作模式对植物生长及As吸收累积的影响。结果表明:和单作相比,开放性套作和限制性套作模式下蜈蚣草生物量显著提高,其地上部分别提高了55.7%和43.9%,但玉米生物量没有显著差异;三种处理间除根无显著差异外,玉米茎、叶和籽粒中As含量均呈单作>限制性套作≈开放性套作。和单作相比,开放性套作和限制性套作显著降低了玉米茎、叶、籽粒中As含量,茎中分别降低了35.2%和31.9%,叶片中分别降低了21.9%和18.6%,籽粒中分别降低了24.2%和12.1%;和单作相比,限制性套作对蜈蚣草根部砷含量影响不明显,但显著提高了蜈蚣草地上部砷含量,提高幅度达11.3%;开放性套作同时显著提高了蜈蚣草根和地上部砷含量,分别提高了32.4%和17.9%。开放性套作显著降低了玉米和蜈蚣草根际土有效态As含量,分别降低了9.3%和15.4%;限制性套作显著降低了玉米根际土有效态As含量,降低了9.1%,但对蜈蚣草有效态砷含量影响不显著。玉米与蜈蚣草套作抑制了玉米体内As的累积量,同时促进了蜈蚣草的生长及对土壤中砷的吸收累积。这为中轻度砷污染农田的安全利用提供了参考依据。

Arsenic, as a common metalloid element in the earth′s crust, can enter the body by the food chain and does great damages to human health eventually. To explore the effect of crops-hyperaccumulation plants intercropping on remediation of As-contaminated farmland ecosystem, the effect of open intercropping, restrictive intercropping and monocropping on growth, As uptake and accumulation in maize（Zea mays L.）and Pteris vittata L. were investigated in a pot experiment. The results showed that：compared with monocropping, open intercropping and restrictive intercropping significantly increased the shoot biomass of Pteris vittata L. by 55.7% and 43.9%, respectively, but did not exert significant effect on maize biomass. As concentration in stems, leaves and corn kernel of restrictive intercropping as well as open intercropping maize were lower than those of monoculture maize,but no significant differences of As concentration in roots occurred among the three cultures. The decreased extents in As concentration of open intercropping and restrictive intercropping were 35.2% and31.9% in stems, 21.9% and 18.6% in the leaves, and 24.2% and 12.1% in the corn kernel, respectively. Compared with monoculture, restrictive intercropping significantly increased As concentration of Pteris vittata shoots by 11.3%, but had no obvious effect on As concentra-tion in Pteris vittata-roots, while open intercropping significantly increased As concentration of Pteris vittata in both roots by 32.4% and shoots by 17.9%, respectively. Open intercropping significantly reduced available arsenic concentration in maize and Pteris vittata rhizosphere soil, the decrease extents were 9.3% and 15.4%, respectively. Restrictive intercropping significantly reduced available arsenic concentration in maize rhizosphere soil by 9.1%, but had no obvious effect on available arsenic concentration in Pteris vittata rhizosphere soil.The results suggested that Maize（Pteris vittata L.）intercropping inhibited the As accumulation in maize, while promoted the growth, As uptake and accumulation in Pteris vittata L.. The results would provide a guidance for the safe use of low to moderate levels of arsenic contaminated farmland.