| 干湿交替灌溉制度下纳米修复材料对杂交籼稻籽粒Cd累积及产量的影响 |
| 摘要点击 1948 全文点击 783 投稿时间：2020-05-18 修订日期：2020-07-24 |
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| 中文关键词 杂交籼稻 干湿交替灌溉 混合钝化 纳米材料 镉(Cd) |
| 英文关键词 indica hybrid rice wetting-drying alternation irrigation multiple passivation combination nano material cadmium (Cd) |
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| 中文摘要 |
| 干湿交替灌溉具有节水高产特性，但在重金属Cd污染稻田，干湿交替灌溉常导致稻米Cd含量>0.20 mg·kg-1，通过添加钝化剂可能对水分高效利用及优质稻米生产具有显著的调控效应.为此，本研究以吸收能力较强的籼型亚种为试材，在前期筛选出的高积累品种（深两优1813）和低积累品种（两优6206）基础上，于Cd轻度污染稻田设置灌溉制度和钝化剂双因素多水平处理开展大田小区试验.结果表明，干湿交替灌溉下，成熟期土壤有效态Cd含量较移栽前降低17.13%~61.01%，而传统淹灌水稻的降低幅度为-43.45%~21.07%，干湿交替灌溉较传统淹灌表现出显著降低土壤有效态Cd含量（P<0.05）.水稻植株地上部各器官Cd含量则表现为干湿交替灌溉处理明显高于传统淹水灌溉处理.不同钝化剂处理相比较，多孔纳米陶瓷+石灰处理对于降低土壤有效态Cd含量和籽粒Cd含量效果最好，显著优于多孔纳米陶瓷、石灰+有机肥、石灰+生物炭、石灰及不施任何钝化剂处理（P<0.05）.深两优1813和两优6206在多孔纳米陶瓷+石灰组合修复模式下的籽粒Cd含量分别为0.23~0.24 mg·kg-1和0.16~0.21 mg·kg-1.产量在灌溉制度、品种、钝化剂处理间差异不显著（P>0.05）.干湿交替灌溉的籽粒Cd含量在多孔纳米陶瓷+石灰组合模式下存在超标风险（深两优1813品种为0.24 mg·kg-1；两优6206品种为0.21 mg·kg-1），但通过选用低积累品种，籽粒Cd含量具有可预见性的达标（<0.20 mg·kg-1）潜力.因此，干湿交替灌溉+多孔纳米陶瓷和石灰组合修复模式+低积累品种可视为Cd轻度污染稻田节水高产优质稻米的调优生产模式. |
| 英文摘要 |
| Wetting-drying alternation irrigation (WDI) can harvest high grain yield under effective irrigation water saving conditions. However, the kernel cadmium (Cd) content usually exceeds the national standard of 0.20 mg Cd per kg kernel in WDI. Applying a passivating agent with high-efficient repairing capabilities could be a feasible approach to reduce Cd content lower than 0.20 mg·kg-1 in WDI. Therefore, a field experiment was conducted with different irrigation regimes and passivating agents in a mildly Cd-polluted paddy field, of which the irrigation regimes were WDI and traditional flooded irrigation (FI) and the six passivating agents treatments were CK (no passivating agent; T1), slaked lime with 1125 kg·hm-2(T2), 1125 kg slaked lime and 3000 kg biochar per hectare (T3), 1125 kg slaked lime and 3000 kg organic fertilizer per hectare (T4), 1500 kg porous Nano stupalith per hectare (T5), and 1125 kg slaked lime combined with 1500 kg porous Nano stupalith per hectare (T6). Two typical Indica hybrid rice varieties with a high accumulated capacity named cultivar Shenliangyou 1813 and a low accumulated trait named cultivar Liangyou 6206 were utilized. The main reason that Indica hybrid rice cultivars were selected was their higher absorbed and accumulated characteristics than that of Japonica rice. The results indicated that available Cd content of the soil significantly declined with 17.13%-61.01% decreasing amplitude at maturity when compared with pre-transplanting in WDI; however, the reduction was in the range of -43.45%-21.07% for the FI treatment across cultivars and passivating agents treatments. The available Cd content at maturity was significantly greater in FI than in WDI (P<0.05). In contrast, WDI had higher Cd content on stem, leaf, and kernel organs at maturity than with FI treatment of both cultivars and all of the passivating agents (P<0.05). Generally, the T1 treatment had the maximum available Cd content in the soil layer and highest accumulated Cd content on different aboveground organs, followed by the T2, T3, T4, T5, and T6 treatments considering both cultivars and irrigation regimes. The Cd kernel contents were 0.23-0.24 mg·kg-1 and 0.16-0.21 mg·kg-1 for cultivars Shenliangyou 1813 and Liangyou 6206, respectively, in the T6 treatment. The higher Cd kernel content was generally related to a larger Cd content in the stem organ. For the grain yield, no significant differences were observed among cultivars, irrigation regimes, or passivating agents treatments (P>0.05). Under WDI, the kernel Cd content was still slightly higher than 0.20 mg·kg-1 in the T6 treatment (0.24 mg·kg-1 for cultivar Shenliangyou 1813 and 0.21 mg·kg-1 for cultivar Liangyou 6206); however, there is a predictability potential to produce lower than 0.20 mg·kg-1 kernel content in the T6 treatment if a cultivar with low accumulated capacity is used. Thus, the combined mode of the WDI+T6+cultivar with accumulated low Cd content could be considered an optimized cultivation scheme to obtain no Cd contaminated kernels with high grain yield and water-use efficiency in mildly polluted paddy fields. |
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