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南方水稻镉(Cd)污染是我国当前面临的主要环境问题之一。以中稻丰两优1号为材料,采用大田小区实验,研究了根区施加钙镁磷肥(P1:1 800 kg·hm~(-2)、P2:3 000 kg·hm~(-2))、叶面喷施硅/硒(LS:2.0 mmol·L-1Na_2SiO_3、LX:25μmol·L~(-1)Na_2SeO_3、LSX:1.0 mmol·L~(-1)Na_2SiO_3+12.5μmol·L~(-1)Na_2SeO_3)以及根区与叶面联合处理(P_1LS、P_1LX、P_1LSX、P_2LS、P_2LX、P_2LSX)下水稻对Cd的吸收。结果表明:1)根施钙镁磷肥显著降低了土壤有效态Cd含量(p<0.05),P1、P2较对照分别降低16.1%和29.5%;单独的根施钙镁磷肥或叶喷硅/硒处理后,稻米Cd含量较对照均显著降低(p<0.05),各处理降幅分别为P140.8%、P257.2%、LS 42.3%、LX 35.0%、LSX 39.2%;根施钙镁磷肥与叶喷硅/硒联合调控对降低稻米Cd含量表现出显著的协同效应(p值显著性),其中P_1LS、P_1LX和P_1LSX较单独的P1分别降低了61.2%、59.5%和68.2%,P_2LS、P_2LX和P_2LSX较单独的P2分别降低了75.0%、54.2%和75.7%。2)Cd从秸秆向籽粒转运系数(SS)大于从根向秸秆转运系数(RS),根区与叶面联合处理明显降低RS和SS,并有显著的协同效应(p<0.05),其中P1与Si/Se联合,RS和SS平均降低了7.4%和22.0%,P2与Si/Se联合,RS和SS平均降低了16.0%和19.6%。3)从食品安全来说,单独的根施钙镁磷肥或叶喷硅/硒,大米Cd含量多数超标(国标0.2 mg·kg~(-1)),而根区与叶面联合处理几乎都能实现Cd含量不超标,其中降幅最大的为P2LS和P2LSX,稻米Cd含量不到0.09 mg·kg~(-1)。因此,根施钙镁磷肥与叶喷硅/硒联合处理可显著降低水稻Cd吸收、保障稻米质量安全。
Cadmium (Cd) pollution in southern rice is one of the major environmental problems currently facing China. Taking Fengliangyou 1 of Zhongdao as experimental material, field experiment was conducted to study the effects of Ca, Mg and P fertilizer (P1: 1800 kg · hm -2, P2: 3000 kg · hm -2) (LS: 2.0 mmol·L-1Na_2SiO_3, LX: 25μmol·L -1 Na_2SeO_3, LSX: 1.0 mmol·L -1 Na_2SiO_3 + 12.5μmol·L -1) 1) Na_2SeO_3) and the combination of root zone and foliar treatment (P_1LS, P_1LX, P_1LSX, P_2LS, P_2LX and P_2LSX). The results showed that: (1) Root-applied calcium-magnesium phosphate significantly decreased soil available Cd content (p <0.05), while P1 and P2 decreased by 16.1% and 29.5% After treatment, the content of Cd in rice was significantly lower than that in the control (p <0.05), and the decreasing rates were P140.8%, P257.2%, LS 42.3%, LX 35.0% and LSX 39.2% The combined application of leaf spraying Si / Se showed a significant synergistic effect (p-value significance) on the reduction of Cd in rice. P_1LS, P_1LX and P_1LSX decreased by 61.2%, 59.5% and 68.2%, P_2LS and P_2LX And P 2LSX decreased by 75.0%, 54.2% and 75.7% respectively compared with P2 alone. 2) The Cd transport coefficient (SS) from straw to grain was greater than that from straw to root (RS). The combined treatment of root zone and foliar decreased significantly RS and SS, and had significant synergistic effect (p <0.05) In combination with Si / Se, RS and SS decreased by an average of 7.4% and 22.0%, respectively. The combination of P2 and Si / Se reduced average RS and SS by 16.0% and 19.6% respectively. 3) In terms of food safety, most of the cadmium-magnesium phosphate or leaf-spraying silicon / selenium and rice had excessive cadmium content (GB 0.2 mg · kg -1), while the root zone and foliar treatment almost all The results showed that the content of Cd did not exceed the limit, and the most significant decrease was P2LS and P2LSX. The content of Cd in rice was less than 0.09 mg · kg -1. Therefore, the combination of root-applied calcium-magnesium phosphate and leaf-sprayed silicon / selenium could significantly reduce the Cd uptake by rice and ensure the quality and safety of rice.