中文关键词成土母质水分管理镉水稻根表铁膜 英文关键词parent materialwater managementcadmiumriceiron plaque

作者	单位	E-mail
张雨婷	长江大学农学院, 荆州 434025 中国科学院亚热带农业生态研究所, 亚热带农业生态过程重点实验室, 长沙 410125	1873468161@qq.com
田应兵	长江大学农学院, 荆州 434025
黄道友	中国科学院亚热带农业生态研究所, 亚热带农业生态过程重点实验室, 长沙 410125
张泉	中国科学院亚热带农业生态研究所, 亚热带农业生态过程重点实验室, 长沙 410125	quanzhang@isa.ac.cn
许超	中国科学院亚热带农业生态研究所, 亚热带农业生态过程重点实验室, 长沙 410125
朱捍华	中国科学院亚热带农业生态研究所, 亚热带农业生态过程重点实验室, 长沙 410125
朱奇宏	中国科学院亚热带农业生态研究所, 亚热带农业生态过程重点实验室, 长沙 410125

中文摘要 为探讨不同成土母质镉污染稻田土壤进行水分管理对水稻镉吸收累积的影响，以南方典型成土母质花岗岩、板页岩和紫色砂页岩发育的3种水稻土为对象，通过盆栽试验对比分析了淹水和干湿交替2种水分管理模式下，土壤pH值、DTPA提取态重金属、水稻根表铁膜以及不同部位重金属含量等的差异.结果表明，长期淹水处理使花岗岩、板页岩和紫色砂页岩发育水稻土pH升高了0.17~1.33个单位.在水稻灌浆和成熟期，淹水处理的3种水稻土DTPA提取态镉（DTPA-Cd）含量较干湿交替降低了14.39%~36.56%（P<0.05）.但淹水处理土壤DTPA提取态铁（DTPA-Fe）含量较干湿交替上升了35.35%~347.25%（P<0.05）.3个生育时期水稻根表铁膜镉、锰（除铁膜铁外）元素含量在2种水分处理下变化趋势均为分蘖期 < 灌浆期 < 成熟期.淹水处理使3种稻田土中糙米镉含量较干湿交替降低了57.84%~93.79%，且花岗岩、板页岩发育水稻土淹水处理降镉效果显著（P<0.05）.将3种水稻土土壤pH、DTPA-Cd、DTPA-Fe、根表铁膜以及糙米镉含量进行相关性及结构方程模型（SEM）分析，发现淹水降低稻米镉累积主要是通过提高土壤pH及增加土壤Fe的有效性，从而降低了土壤Cd的有效性，并且改变水稻根表铁膜对镉的吸附固定量.因此，水分管理模式调控稻米镉累积效应在不同土壤母质类型间存在明显差异，受土壤理化性质及根表铁膜等多重因素影响，且在不同母质发育水稻土上的作用机制并不完全一致.在镉污染的花岗岩、板页岩发育水稻土上进行水分管理可有效降低土壤镉的有效性，达到削减水稻对镉吸收累积的目标.综上，对于水分管理调控水稻镉吸收累积应根据成土母质类型区别进行. 英文摘要 In order to explore the effects of water management on the Cd accumulation of rice in paddy soils with different parent materials, a pot experiment with three paddy soils with different parent materials from Hunan Province (granite sandy soil, plate shale soil, and purple sandy shale soil) with different water management treatments ［flooding and alternate wetting and drying (AWD)］ was performed. The soil pH, DTPA-Cd, Fe plaque in the rice roots, and heavy metal concentration in the rice were determined. The results showed that the soil pH of the three paddy soils under the flooding treatment was increased by 0.17-1.33 units. During the filling and maturity periods, compared with that under AWD, the DTPA-Cd concentration in the three paddy soils was reduced by 14.39%-36.56% under the flooding treatment, but the DTPA-Fe concentration was increased by 35.35%-347.25%. In the three growth stages, the Cd and Mn concentrations in the Fe plaque (except for DCB-Fe) were in the order of tillering stage < filling stage < mature stage. Compared with that under AWD, the brown rice Cd concentration in the three soils was reduced by 57.84%-93.79% under flooding treatment. The Cd accumulation in rice was reduced under flooding treatment by reducing the DTPA-Cd via increasing the soil pH and DTPA-Fe and by decreasing the formation of Fe plaque. According to the results of the correlation and SEM analysis, the soil pH and DCB-Cd were the main factors affecting the Cd accumulation in rice grains, although the changes in the DTPA-Cd and DTPA-Fe also impacted the Cd in rice grains. In summary, our study demonstrated that water management had a significant impact on the Cd content in rice, and there were significant differences among the three paddy soils with different parent materials. In conclusion, the Cd content in rice grains was affected by the soil parent material, soil physicochemical properties, and Fe plaque on the surface of the rice roots. The granite sandy soil and plate shale soil with different water management treatments had significant impacts on the contents of heavy metals in rice. Continuous flooding is a valuable strategy for improving soil acidity and alkalinity and minimizing soil available Cd, but the soil parent materials must be considered.

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