2种轮作模式对镉污染土壤修复潜力的比较

Comparison of remediation potential for two crop rotation patterns on Cd contaminated soils

选取重金属Cd污染较严重的郴州矿区废弃农田土壤进行盆栽实验,以红叶甜菜-菊苣和菊苣-油葵作为研究对象,研究2种轮作模式对土壤重金属Cd的修复潜力。实验结果表明:3种作物在轮作期间生长状态良好且对重金属都表现出较强的耐性及吸收积累能力。在红叶甜菜-菊苣轮作模式中,甜菜和菊苣的地上部分对Cd的富集系数(BCF)分别为11.34和8.22;在菊苣-油葵轮作模式中,菊苣地下和地上部分对Cd的富集系数分别为14.14和16.32,成熟油葵各个部位的富集系数都大于1,其中,叶和果肉的富集系数分别为2.57和2.19。因此,对于重金属Cd轻、中度污染的土壤来说,甜菜-菊苣轮作模式对于Cd的富集效果要优于菊苣-油葵。总的来说,利用这3种作物两两轮作的轮作模式,能充分利用四季的气候特点,并能在不影响作物产量的前提下大大提高作物对重金属的提取总量。

In this study, soil collected from farmland in Chenzhou polluted with the heavy metal Cd was used to conduct pot experiments.These were used to study the repair potential of planting patterns featuring pairing of two crop species, edible-leaf-beet with endive, and endive with oil sunflower, for extracting heavy metals from polluted soil.The experimental results showed that three kinds of crops grew in good condition during the planting period, and showed good tolerance and capacity for absorption of heavy metals.In the planting pattern edible-leaf-beet-endive pairing, the concentration coefficient （BCF） of the above-ground part of the beet and endive reached 11.34 and 8.22, respectively;while in the endive-oil sunflower pairing, the concentration coefficient of the underground and above-ground parts of the endive reached 14.14 and 16.32 respectively.The concentration coefficients of each part of mature oil-sunflowers were greater than ‘1’;among which parts the concentration coefficient of the leaf and flesh reached 2.57 and 2.19, respectively, and the flesh oil-yield was high.For soil slightly and heavily polluted with the heavy metal Cd, the concentration effect from planting the beet-endive pair for Cd, was better than that from the endive-oil sunflower pair.In general, crop rotation of these three crops could make full use of the climate characteristics of the four seasons, and greatly improve the amount of heavy metals extracted by these crops, while not affecting the crop yield.