过磷酸钙与石灰混施对污染农田低累积玉米生长和重金属含量的影响

通过田间实验,研究了过磷酸钙和石灰混施对重金属污染农田上低累积玉米产量以及籽粒、茎叶重金属含量的影响,并分析了施用过磷酸钙和石灰后土壤pH和有效重金属含量的变化。结果表明,与单施过磷酸钙和单施石灰相比,过磷酸钙和石灰混施更能显著提高玉米生物产量,且过磷酸钙和石灰均有一定的后效。单施石灰处理、石灰与过磷酸钙混施处理都均显著降低玉米籽粒Cd、Zn和Cu含量,其中以中量(0.4 kg/m2)、高量石灰(0.6 kg/m2)+中量过磷酸钙(0.2kg/m2)处理效果最佳,其玉米籽粒Cd、Zn和Cu含量降低到了国家食品卫生标准允许的含量水平。石灰处理均不同程度地提高了玉米籽粒Pb含量,配施过磷酸钙也不能明显降低玉米籽粒Pb含量,但仍低于饲料卫生标准允许的含量水平。另外,单施石灰处理和石灰与过磷酸钙混施处理均显著降低了玉米茎叶Cd、Pb、Zn和Cu含量,可以安全用作有机肥。

Effect of lime and superphosphate on maize production and heavy metals uptake by low-accumulating maize

A field experiment was carried out to study effects of the combined application of lime and superphosphate on growth and heavy metals(Cd,Pb,Zn,Cu) concentration of a low-accumulating cultivar of Zea mays in a soil contaminated by wastewater from a lead/zinc mining.Changes in soil pH and available heavy metal contents after application of lime and superphosphate were also assessed.Results showed that the combined application of lime and superphosphate significantly increased the yields of Z.mays compared to the single additions.The favorable influence still exhibited in the second crop without further applications.The concentrations of Cd,Zn and Cu in grain of Z.mays were decreased by the single application of lime and the mixed application of lime and superphosphate.Furthermore,the best results was found in the treatments of the lime in the middle level(0.4 kg/m2) and the combined application of lime in high level(0.6 kg/m2) and the superphosphate in middle level(0.2 kg/m2).They were both below the limits of Chinese food standards.While the concentration of Pb in grain of Z.mays increased with lime addition,and exceeded the limit of Chinese food standard,and the combined application with superphasphate could not significantly decrease Pb content in corn grain.However they were still conformed to the Chinese feed standard.The concentrations of Cd,Pb,Zn and Cu in stem and leaf of Z.mays were all decreased by the single lime application and the lime and superphosphate mixed application and it was safe to be served as organic fertilizer.