钝化剂对农田土壤Cd有效性及不同水稻品种吸收Cd的研究

为从源头保障农产品质量安全，做好农田土壤镉污染修复，在镉污染农田上研究施加TX土壤调理剂、NL土壤调理剂、生物炭、石灰、硅肥5种钝化剂对土壤pH、有机质、Cd有效态含量、Cd不同形态的影响，并探讨钝化剂对4个不同水稻品种的产量以及水稻各器官吸收Cd的影响，筛选降解Cd效果较优的钝化剂和籽粒吸收Cd较少的水稻品种。结果表明:与对照处理相比，施加TX、NL土壤调理剂、生物炭、石灰、硅肥处理土壤中Cd有效态含量分别降低了59.4%、29.9%、22.8%、22.4%、54.4%。施加钝化剂降低了土壤中弱酸提取态和可还原态含量，增加了可氧化态和残渣态含量。其中，TX土壤调理剂处理的弱酸提取态占比降幅最大为11.9%，残渣态占比增幅最大为15.4%。施加钝化剂可提高水稻产量和抑制水稻各器官（根、茎、籽粒）对Cd的积累，其中施加TX土壤调理剂的效果最优，淮稻5号、扬粳805、扬粳103、南粳9108的产量分别提高了14.2%、18.6%、9.2%、29.2%，籽粒中Cd含量分别显著降低了80.5%、82.8%、65.4%、55.6%。对照处理中，淮稻5号、扬粳805、扬粳103、南粳9108籽粒Cd含量分别为0.836，0.853，1.047，1.22 mg/kg。只有种植淮稻5号和扬粳805同时配施TX土壤调理剂处理，籽粒Cd含量分别为0.163，0.147 mg/kg，符合GB 2762—2017《食品安全国家标准食品中污染物限量》。推荐淮稻5号和扬粳805品种为适应于苏中地区的重金属低积累水稻品种，再结合施用合适钝化剂可在重金属Cd中轻度污染土壤上推广应用以保障农产品安全。

EFFECT OF PASSIVATORS ON Cd AVAILABILITY IN FARMLAND SOIL AND Cd UPTAKE BY DIFFERENT RICE VARIETIES

In order to ensure the quality and safety of agricultural products from the source and repair cadmium pollution in farmland soil, field experiments were carried out on cadmium contaminated farmland soil. The effects of applying five different passivators such as TX,NL soil conditioner, biochar, lime and silicon fertilizer on soil pH, organic matter, available state content of Cd and different forms of Cd were studied, and the effects of the passivators on the yield of four different rice varieties and Cd accumulation in rice organs were discussed. The results showed that compared with the control, after the application of TX, NL soil conditioner, biochar, lime and silicon fertilizer, the available Cd content in soil was decreased by 59.4%, 29.9%, 22.8%, 22.4% and 54.4% respectively. Applying passivator could improve rice yield and inhibit accumulation of Cd in rice organs. When rice variaties of Huaidao 5 or Yangjing 805 treated together with TX soil conditioner, the grain Cd content was 0.163 mg/kg or 0.147 mg/kg, respectively, which achieved the safety and quality standard of agricultural products (China's national standard, GB 2762-2017). The results indicated that two rice varieties of Huaidao 5 and Yangjing 805 were more preferable for low accumulation of Cd in the middle area of Jiangsu, and for planting in moderately Cd polluted soil, in combination with application of appropriate passivators.