土壤-玉米重金属富集迁移特征及秸秆还田

针对重金属的富集与迁移特征的研究多集中在受污染的土壤区域,对未被污染区域重金属富集与迁移特征的研究相对较少.为了研究未被污染区域重金属富集与迁移特征,选取青州市南张楼村为研究区域,研究区是典型的平原村落,区域内无地表水系,以种植玉米、小麦、胡萝卜等农产品为主,远离城区与工业园区,是较为理想的研究场所.通过采集南张楼村根系土-玉米系统(根、下茎、中茎、上茎、叶、籽实)配套样品32套,应用电感耦合等离子体质谱法、X射线荧光光谱法、原子荧光光谱法等测定配套样品各部分中的重金属元素As、Cd、Cr、Hg、Pb、Zn、Cu、Ni的含量,结合统计学方法与生物系数法,研究了重金属元素在土壤-玉米中的富集与迁移特征.分析研究发现,重金属在玉米植株各部位中的含量存在差异,从大到小依次为根、茎、叶、籽实;Cu、Zn、Cd在玉米茎中的富集表现出了明显的顶端聚集,而Pb、Cr、Ni、As的富集则表现出了明显的底端聚集;玉米植株根中Pb、Cr、Ni、As聚集明显,茎中Cu、Cd聚集明显,叶中Hg的聚集明显,籽实中Zn聚集明显,说明不同重金属元素在玉米成长过程中的迁移存在差异;由于重金属元素在玉米植株各部位的富集程度不同,因此在秸秆还田过程中可以考虑部分还田方案.

Enrichment and Migration Characteristics of Heavy Metal in Soil-Maize System and Discussion on Straw Returning

The research on the enrichment and migration characteristics of heavy metals is mostly concentrated in the contaminated soil area, and there are relatively few studies on uncontaminated areas. In order to study the characteristics of heavy metal enrichment and migration in uncontaminated areas, Nanzhanglou Village was selected as the research area. Nanzhanglou Village in Qingzhou City is a typical plain village, with no surface water systems, grow maize, wheat, carrots and other agricultural products, stay away from urban areas and industrial parks.Thus Nanzhanglou Village is an ideal research site. Based on 32 sets of supporting samples of the root soil-maize system (root, lower stem, middle stem, upper stem, leaf, seed) were collected, inductively coupled plasma mass spectrometry, X-ray fluorescence spectrometry, atomic fluorescence spectrometry were used to investigate the content of heavy metal elements including As, Cd, Cr, Hg, Pb, Zn, Cu, Ni in specified parts of the supporting sample, by means of statistical methods and biological coefficient methods to analyze the enrichment and migration of heavy metal elements in soil-maize. Results show that the content of heavy metals in different parts of maize plants is different, from small to large is roots, stems, leaves, and seeds. The content of Cu, Zn, Cd in maize stem shows obvious top aggregation, while Pb, Cr, Ni, As show obvious bottom aggregation. Pb, Cr, Ni, As preferred to gather in maize roots, Cu, Cd prefer to gather in maize stalk, Hg prefer to gather in maize leaf, Zn prefer to gather in maize seeds, which indicates that the migration of different heavy metal elements in maize growth is different. According to the different enrichment law of heavy metal elements in various parts of maize plants,, the idea of selective planting of maize and partly returning straw to field is put forward.