以下辽河平原11年长期定位试验为平台, 采用原状土柱淋溶实验, 通过比较不同用量有机肥处理土壤重金属积累情况及其淋溶特征, 探讨了雨养农业条件下有机培肥措施对土壤表层重金属（Cu, Zn, Cd和Cr）积累的影响, 阐述了重金属在土壤表层(0～20 cm)中的积累特征明确了重金属元素的淋溶特点和垂直迁移规律(0～60 cm)。 研究表明, 随着有机肥用量增加, 表层土壤中Cu, Zn, Cd和Cr的含量都随之升高, 积累速度为Cd＞Cu＞Zn＞Cr。 根据中国土壤环境质量标准(GB15618－1995), 即使施入50 t·ha-1有机肥料, 也未造成表层土壤Cr, Cu和Zn的污染, 其中Cr仍符合Ⅰ类土壤质量标准, 而Cu和Zn符合国家Ⅱ类土壤质量标准, 但对Cd而言, 此时表层土壤含量已接近国家Ⅲ类土壤质量标准阈值, 存在较大风险, 应引起足够重视。 土柱淋溶实验表明, 只有个别淋溶液Cu和Cd浓度属于国家Ⅲ类水质量标准（GB/T14848—93）, 其余均符合国家Ⅱ类及以上水质标准, 且所有淋溶液Cr的含量都符合国家Ⅰ类水质标准, 表明在下辽河平原, 即使有机肥使用量达到50 t·ha-1时, 仍未对地下水构成任何风险。 另外, 淋溶液中的重金属含量均随土层深度增加呈现下降趋势(Cr除外), 表现出重金属不易下移的特点, 但相对而言, Zn和Cr向深层土壤淋溶能力较强, Cu和Cd则更易积累在表层土壤。

Based on an 11-year fertilizer field trial (located at the lower liaohe river plain), the effects of different organic manure application rates on the accumulations of heavy metals (Cu, Zn, Cd and Cr) in surface soil (0～20 cm), and the leaching characteristic and vertical migration pattern of heavy metal have been investigated in this rainfed agro-ecosystem using undisturbed soil columns. The result showed that the content of heavy metal in surface soil was elevated with the increase of manure application. The increasing magnitude was in the order of Cd>Cu>Zn>Cr. According to the Chinese soil quality standard (GB15618—1995), the application of manure (not exceeding 50 t·ha-1) did not result in serious heavy metal pollution in the surface soil. Chromium met the Grade Ⅰ, and Cu and Zn met the Grade Ⅱ; whereas, Cd was almost exceeded the threshold of Grade Ⅲ. The potential risk of Cd in soil should be paid more attentions in future research. According to the National water quality standard (GB/T14848—93), the Cu and Cd concentrations in leachate samples were up to the Grade Ⅱ except only a few samples that fell in Grade Ⅲ. Furthermore, Cr in the leachate all matched Grade Ⅰ water quality standard. These results indicated long-term application of manure (not exceeding 50 t·ha-1) in our site had not induced contaminant risks of heavy metals in underground water. In addition, the Cu, Zn and Cd (except Cr) in leachate all declined with the increase of soil depth, indicating the low capacity of vertical migration of heavy metal. Among the four heavy metals, Zn and Cr tended to be leached into deep soil, whereas Cu and Cd were more prone to be accumulated in surface soil.