耕作方式对成都平原稻麦轮作系统吸收累积镉的影响

为研究不同耕作方式（翻耕、旋耕、免耕与秸秆还田）对成都平原水稻-小麦轮作系统吸收累积重金属Cd的影响,探讨Cd污染耕地最优的耕作方式,在轻度污染农田开展了2年定位试验,研究翻耕秸秆还田、翻耕无秸秆、旋耕秸秆还田、旋耕无秸秆、免耕秸秆还田和免耕无秸秆处理对作物产量以及收获物、秸秆和土壤中重金属Cd含量的影响。试验结果表明,与旋耕和免耕相比,翻耕处理能够显著降低小麦籽粒和水稻稻谷中的重金属Cd含量。相同耕作方式下,是否秸秆还田对小麦籽粒和水稻稻谷中的Cd含量影响不显著。在翻耕条件下,表层土壤有效Cd和总Cd含量、小麦和水稻秸秆中Cd含量均显著低于旋耕和免耕处理。因此,从保证作物产量和降低农产品Cd含量的角度出发,翻耕可作为成都平原轻中度Cd污染耕地水稻-小麦安全生产的一项有效技术措施。

Effects of Tillage Methods on Heavy Metal Cadmium Accumulation in Rice-Wheat Rotation System in Chengdu Plain

To study the effects of tillage methods (plow tillage, rotary tillage, no-tillage and straw retention) on heavy metal cadmium accumulation in rice-wheat rotation system in Chengdu Plain, and to explore the optimal agricultural production pattern in Cd contaminated fields, a two-year field experiment was performed on the Cd contaminated fields. The experiment was carried out with different tillage methods, including plow tillage with straw retention, plow tillage with straw removed, rotary tillage with straw retention, rotary tillage with straw removed, no-tillage with straw retention and no-tillage with straw removed, to analyze their effects on crop yield and Cd content in straw and soil. The results showed that plow tillage treatment could significantly reduce the heavy metal Cd concentration in wheat and rice grain compared with the rotary tillage and no-tillage. Under the same tillage method, straw retention had no great impact on the wheat and rice grain Cd concentration. Compared with the rotary tillage and no-tillage, the total and available Cd content of topsoil and the Cd content in straw under plow tillage were significantly lower. Therefore, to ensure the crop yield and reduce the Cd content in agricultural products, plow tillage is one of the effective technical patterns for the safe production of the wheat-rice rotation system in Cd contaminated fields in Chengdu Plain.