Li Xin-Yang, Long Jian, Wang Shu-Bing, Chen Qi, Dong Xia, Jiang Kai, Hou Hong-Bo, Peng Pei-Qin, Liao Bo-Han
College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China.
Agricultural Integrated Service Center of Huangxing Town, Changsha 410100, China.
Huan Jing Ke Xue. 2018 Jan 8;39(1):406-414. doi: 10.13227/j.hjkx.201704220.
Pot experiments were used to study the differences of Cd uptake and accumulation in double-cropping rice in typical soil types. To analyze the soil availability of Cd (DTPA-Cd) in soils and the Cd accumulation in double-cropping rice at different growth stages of the rice, we conducted pot experiments that selected the yellow clayey soil (paddy soil developed from plate shaley parent materials) and the granitic sandy soil (paddy soil developed from granitic parent materials). Exogenous Cd was added with gradients of 0, 0.5, 1.0, 2.0, 5.0, and 10.0 mg·kg. Results showed that, during the rice growth period, the available Cd in the yellow clayey soil was higher than that in the granitic sandy soil, and the difference was significant (<0.01). This showed that the content of Cd in rice (roots, shoots, leaves, rice shells, and brown rice) increased along with the treatment level and with the extension of the rice growth period. The accumulation characteristics of Cd in rice grains and other tissues of rice indicated differences between two seasons and two soil types, that is, late rice was higher in Cd than was early rice, and reddish yellow clayey soil was higher in Cd than granitic sandy soil. Significant positive linear correlations were found between the effective contents of Cd in soils and those in rice tissues (roots, shoots, leaves, and brown rice). The prediction model of Cd in rice and the characteristic equation for rice accumulation of Cd were applied to calculate the critical values of Cd:0.98 mg·kg for early rice and 0.83 mg·kg for late rice in reddish yellow clayey soil, and 0.86 mg·kg for early rice and 0.56 mg·kg for late rice in granitic sandy soil. These threshold values are higher than the National Standards given in "farmland environmental quality evaluation standards for edible agricultural products (HJ 332-2006)." The soil security threshold values and the soil environmental capacities of the two different parent materials varied greatly; therefore, different environmental quality standards may be formulated and different measures may be needed to control Cd pollution in different parent materials.
通过盆栽试验研究典型土壤类型中双季稻镉吸收与积累的差异。为分析土壤中镉的有效态含量（DTPA-Cd）以及双季稻不同生育期的镉积累情况，选取了黄黏土（由板页岩母质发育而成的水稻土）和花岗岩砂质土（由花岗岩母质发育而成的水稻土）进行盆栽试验。外源镉添加梯度为0、0.5、1.0、2.0、5.0和10.0 mg·kg。结果表明，在水稻生长期间，黄黏土中有效镉含量高于花岗岩砂质土，差异显著（<0.01）。这表明水稻（根、茎、叶、稻壳和糙米）中镉含量随处理水平的提高以及水稻生育期的延长而增加。水稻籽粒和其他组织中镉的积累特征表明，两季和两种土壤类型存在差异，即晚稻镉含量高于早稻，红黄黏土镉含量高于花岗岩砂质土。土壤中有效镉含量与水稻组织（根、茎、叶和糙米）中镉含量之间存在显著正线性相关。应用水稻镉预测模型和水稻镉积累特征方程计算镉的临界值：红黄黏土中早稻为0.98 mg·kg，晚稻为0.83 mg·kg；花岗岩砂质土中早稻为0.86 mg·kg，晚稻为0.56 mg·kg。这些阈值高于《食用农产品产地环境质量评价标准（HJ 332-2006）》给出的国家标准。两种不同母质的土壤安全阈值和土壤环境容量差异很大；因此，可能需要制定不同的环境质量标准，并采取不同措施控制不同母质中的镉污染。
