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研究报告

邹佳玲,辜娇峰,杨文弢,周航,张平,彭佩钦,廖柏寒.不同pH值灌溉水对土壤Cd生物有效性及稻米Cd含量的影响[J].环境科学学报,2017,37(4):1508-1514

Effects of different pH values of irrigation water on soil Cd bioavailability and Cd content in rice

基金项目：农业部财政部科研专项（No.NBCH2016-6）；国家自然科学基金（No.41501344）；湖南省重点学科建设项目（No.2006180）

摘要：通过盆栽种植实验研究了pH值为3.5~6.5的灌溉水对稻田土壤pH值、土壤Cd生物有效性以及2种水稻品种各部位Cd含量的影响.结果表明：1不同pH值灌溉水对土壤pH值影响显著.灌溉水pH为3.5~6.5的处理下，湘晚籼土壤pH值下降了0.6~0.3个单位，威优46号土壤pH值下降了0.7~0.4个单位.2随着灌溉水pH值的升高，土壤交换态和TCLP提取态Cd含量（生物有效性）均有降低的趋势，但TCLP提取态Cd含量不显著.3随着灌溉水pH值从3.5上升到6.5，湘晚籼12号水稻植株各部位Cd含量均逐渐下降，而威优46号水稻植株各部位的Cd含量逐渐上升.与pH=3.5处理相比，浇灌pH值为4.5~6.5的灌溉水，湘晚籼12号根系、茎叶、谷壳和糙米中Cd含量分别下降32.3%~48.0%、16.5%~48.0%、40.0%~56.2%和45.6%~73.9%；相反，威优46号根系、茎叶、谷壳和糙米中Cd含量分别上升30.5%~446.3%、5.3%~201.1%、70.3%~316.7%和71.0%~177.2%.显然，升高灌溉水的pH值有利于降低湘晚籼12号（常规稻）糙米中的Cd含量，但不利于降低威优46号（杂交稻）糙米中的Cd含量.

Abstract：The effects of different pH values of irrigation water (pH=3.5, 4.5, 5.5 and 6.5) on soil pH values, soil Cd bioavailability and Cd contents in different tissues of two rice varieties (XWX12, Xiangwanxian 12, a conventional rice, and WY46, Weiyou 46, a hybrid rice) were studied through a pot experiment. The results showed that pH values of irrigation water had significant effects on soil pH values, and the soil pH values decreased by 0.6~0.3 units for XWX12 and by 0.7~0.4 units for WY46 with pH values of irrigation water increasing from 3.5 to 6.5. Soil exchangeable Cd contents and TCLP extractable Cd contents, namely bioavailability of soil Cd, showed a decrease trend with increasing pH values of irrigation water, but trend of TCLP extractable Cd contents was not significant. Cd contents in four rice tissues (root, straw, husk, and brown rice) significantly decreased for XWX12, and significantly increased for WY46 with pH values of irrigation water increased from 3.5 to 6.5. Compared with pH=3.5 treatment, Cd contents in root, straw, husk, and brown rice were reduced by 32.3%~48.0%, 16.5%~48.0%, 40.0%~56.2%, and 45.6%~73.9% for XWX12 and by 30.5%~446.3%, 5.3%~201.1%, 70.3%~316.7%, and 71.0%~177.2% for WY46, respectively. It was obviously that increasing pH values of irrigation water was beneficial to reducing Cd contents in brown rice of XWX12 (conventional rice), but was unfavorable for reducing Cd contents in brown rice of WY46 (hybrid rice).