4种修复剂对镉污染农田土壤及糙米的降镉效果

Effects of 4 Types of Remediation Agents on Reducing Cd Contents in Soil and Rice on Cd-contaminated Farmland

以衡阳市某县镉重度污染稻田为研究对象,以隆两优华占为供试水稻品种,以DG叶面阻控剂、SMA微生物菌剂、XFJ有机肥和LXM钙硅类钝化剂4种修复剂开展大田试验,探究施用不同种类修复剂对土壤有效态镉和水稻糙米镉含量以及水稻产量的影响。结果表明:与CK相比,施用DG叶面阻控剂后土壤有效态镉含量不降反增,糙米镉含量有所降低,但效果不显著;施用SMA微生物菌剂后土壤pH值、土壤有效态镉含量、糙米镉含量随施用量增加表现出先降再增的趋势,3个水平的处理中SMA2处理的土壤有效态镉含量最低,与CK相比降低了8.59%,其余2个水平的处理不降反增;施用XFJ有机肥和LXM钙硅类钝化剂后能够提高土壤pH值,降低土壤有效态镉含量和糙米镉含量,土壤有效态镉含量、糙米镉含量随施用量增加而降低;与CK相比,XFJ3处理土壤有效态镉含量降低了9.40%,糙米镉含量下降了57.28%;LXM3处理土壤有效态镉含量降低了14.57%,糙米镉含量最低,较CK降低了71.57%。总体来讲,LXM钙硅类钝化剂的降镉效果最好,其最佳施用量为6 000 kg/hm^(2)。

A field experiment was carried out in Cd-contaminated rice fields in a county of Hengyang to explore the effects of different types of remediation agents on the contents of soil available Cd and rice Cd,and rice yield by using one rice variety Longliangyouhuazhan,and 4 kinds of remediation agents:DG foliar control agent,SMA microbial inoculant,XFJ organic fertilizer and LXM calcium-and silicon-based passivator as test materials.The results showed that compared with CK,after applying DG foliar control agent,soil available Cd content increased rather than decreased,whereas rice Cd content decreased,not reaching a significant level.When applied with SMA microbial inoculant,soil pH value,soil available Cd and rice Cd contents showed a downward then upward trend with the increase of its application rates.Between 3 levels of SMA treatments,the content of soil available Cd in SMA2 was the lowest,decreased by 8.59%in comparison with CK,contrarily,two other SMA treatments were increasing instead of decreasing in the content of soil available Cd.The application of XFJ organic fertilizer and LXM calcium-and silicon-based passivator increased soil pH value,and reduced soil available Cd and rice Cd contents;the contents of soil available Cd and rice Cd decreased with their application rates increasing.Compared with CK,XFJ3 reduced soil available Cd content by 9.40%,and significantly reduced rice Cd content by 57.28%.In LXM3 treatment,soil available Cd content reduced by 14.57%,rice Cd content was 71.57%lower than CK,reaching the lowest level.In general,LXM calcium-and silicon-based passivator had the best Cd reduction effect,with the optimal application amount of 6000 kg/hm^(2).