• 关键词：磷源  土壤有效态镉  土壤pH  土壤速效磷

• 基金项目：国家"十一五"科技支撑计划重点项目(No.2008BADA7B03)

• 陈青云
• 华中农业大学微量元素中心, 华中农业大学资源与环境学院, 武汉 430070

• 胡承孝
• 华中农业大学微量元素中心, 华中农业大学资源与环境学院, 武汉 430070

• 谭启玲
• 华中农业大学微量元素中心, 华中农业大学资源与环境学院, 武汉 430070

• 孙学成
• 华中农业大学微量元素中心, 华中农业大学资源与环境学院, 武汉 430070

• 摘要：本研究采用湖北省具有代表性的黄棕壤和潮土进行室内培养试验, 研究了5种磷源和5个施磷量(0、0.1、0.2、0.4、0.8 g·kg^-1,以每kg土中有效态P₂O₅含量计)对土壤镉(Cd)有效性的影响. 结果表明, 培养8周后, 随着磷酸氢二铵(DAP)、磷酸二氢铵(MAP)和过磷酸钙(SSP)施入量的增加,两种土壤的pH均显著降低, 速效磷和有效态Cd含量显著增加; 磷酸氢钙(DCP)和磷酸三钙(TCP)对土壤pH影响不大, 随磷施入量及土壤速效磷含量的增加, 土壤有效态Cd含量显著降低. 各种磷源酸化土壤的能力由强到弱排序为: DAP>MAP>SSP> DCP、TCP. 相同施磷水平下, 黄棕壤速效磷含量由高到低依次为: SSP>MAP、DAP>DCP>TCP, 且随施磷水平的升高差异性越显著; 潮土中,各种磷源酸化土壤速效磷含量由高到低依次为: DAP>SSP>MAP>DCP>TCP, 但随施磷水平的升高差异性变小. DAP、MAP、SSP和TCP不同磷水平下土壤pH与有效态Cd含量均呈显著负线性关系, 说明4种磷源主要是通过改变土壤pH来影响土壤Cd有效性; 施用DCP在改变土壤pH的同时可能会发生其他反应而影响土壤Cd有效性.

• Abstract：To investigate the effects of five phosphates with five application rates (0, 0.1, 0.2, 0.4, 0.8g (P₂O₅)·kg^-1 (soil)) on the availability of soil cadmium (Cd), soil incubation experiment was carried out with yellow brown and fluvo-aquic soil, two types of typical soil, collected from Wuhan, Hubei, China. The results showed that, after eight weeks incubation, the pH of two types of soils significantly reduced and the available phosphorus (P) and available Cd concentrations significantly increased, with increasing rate of diammonium phosphate (DAP), monoammonium phosphate (MAP) and superphosphate (SSP). Dicalcium phosphate (DCP) and tricalcium phosphate (TCP) had no significant effect on pH of two types of soils, but available P significantly increased and available Cd significantly decreased with increasing rate of DCP and TCP. The capability of five phosphates in acidifying soil varied in following order: DAP>MAP>SSP> DCP, TCP. At the same rate of phosphate addition, soil available P in yellow brown soil followed the sequence of SSP>MAP, DAP> DCP>TCP, and the difference increased with elevated rate of phosphates. Available P in fluvo-aquic soil was in order of DAP>SSP>MAP> DCP>TCP, and its difference reduced with increasing rate of phosphates. In all phosphate treatments except for DCP treatment, a negative correlation was observed between soil pH and available Cd. This suggested that DAP, MAP, SSP and TCP could influence available Cd by reducing soil pH, while DCP may also introduce other reactions that may affect available Cd.

• Key words：phosphate sources  soil available Cd  soil pH  soil available phosphorus

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