Huang Jing, Li Xin-Yang, Wen Sha, Jiang Kai, Long Jian, Peng Pei-Qin, Hou Hong-Bo
College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China.
Huan Jing Ke Xue. 2020 Jul 8;41(7):3418-3425. doi: 10.13227/j.hjkx.201911258.
To explore the effects of water management mode on Cd environmental behavior in different parent-material-developed paddy soils, two parent-material-developed paddy soils (yellow clayey soil and granitic sandy soil) under three exogenous Cd levels (0.5, 2.0, and 5.0 mg·kg) with different water management modes (long-term flooding, moistening irrigation, and wet-dry rotation) were cultured in this study. The soil redox potential (Eh value), pH value, Cd concentration in soil solution, and Cd fractionation were also determined. The results showed that water management mode had different effects on the pH and Eh values of soils developed from different parent materials. The change rates of soil pH value were as follows:long-term flooding:-2.61% (yellow clayey soil), 2.25% (granitic sandy soil); alternation of dry and wet:-1.96% (yellow clayey soil); 0.52% (granitic sandy soil); wet irrigation:-4.08% (yellow clayey soil) and -0.52% (granitic sandy soil). The Eh value of the soils was negatively correlated with the pH value. The influence pattern of water management model on Cd mass concentration of soil solutions in two parent-material soils was consistent. The Cd mass concentration of soil solutions in granitic sandy soil was higher than that in yellow clayey soil. The mean values of Cd concentration were 1.03 μg·L for yellow clayey soil and 1.07 μg·L for granitic sandy soil. Water management mode had no significant effect on the proportions of organic bound Cd or Fe-Mn bound Cd in two different parent-material-developed soils. The long-term flooding mode promoted the transformation of exogenous Cd to residual Cd, and this promotion in yellow clayey soil was higher than that in granitic sandy soil. In conclusion, during the process of regulating soil Cd bioavailability through water management, the role of soil parent materials needs to be considered.
为探究水分管理模式对不同母质发育水稻土中镉环境行为的影响，本研究对两种母质发育的水稻土（黄黏土和花岗岩砂质土）在三种外源镉水平（0.5、2.0和5.0 mg·kg）下采用不同水分管理模式（长期淹水、湿润灌溉和干湿交替）进行培养。同时测定了土壤氧化还原电位（Eh值）、pH值、土壤溶液中镉浓度以及镉的形态分布。结果表明，水分管理模式对不同母质发育土壤的pH值和Eh值有不同影响。土壤pH值变化率如下：长期淹水：-2.61%（黄黏土），2.25%（花岗岩砂质土）；干湿交替：-1.96%（黄黏土），0.52%（花岗岩砂质土）；湿润灌溉：-4.08%（黄黏土），-0.52%（花岗岩砂质土）。土壤Eh值与pH值呈负相关。水分管理模式对两种母质土壤中土壤溶液镉质量浓度的影响规律一致。花岗岩砂质土中土壤溶液镉质量浓度高于黄黏土。黄黏土镉浓度平均值为1.03 μg·L，花岗岩砂质土为1.07 μg·L。水分管理模式对两种不同母质发育土壤中有机结合态镉和铁锰结合态镉的比例无显著影响。长期淹水模式促进外源镉向残留态镉转化，且在黄黏土中的促进作用高于花岗岩砂质土。总之，在通过水分管理调控土壤镉生物有效性过程中，需考虑土壤母质的作用。
