机构地区:[1]农业部环境保护科研监测所,天津300191 [2]农业部产地环境质量重点实验室/天津市产地环境与农产品安全重点实验室,天津300191
出 处:《环境工程学报》2016年第11期6383-6391,共9页Chinese Journal of Environmental Engineering
基 金:国家自然科学基金资助项目(41371463;41471274;41101306);中国农科院科技创新工程项目;农业生态环境保护项目
摘 要: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。Contamination of rice with cadmium( Cd) in Southern China is a major environmental problem.A field experiment was conducted to investigate how Cd uptake by paddy rice( Fengliangyou 1) was influenced by the soil application of calcium magnesium phosphate( CMP),leaf spraying with Si / Se,or a combination of the two. The CMP treatments were P_1( 1 800 kg·hm^(-2)) and P_2( 3 000 kg·hm^(-2)). The leaf spraying treatments were LS( 2. 0 mmol · L^(-1)Na_2SiO_3),LX( 25 μmol·L^(-1)Na_2SeO_3),and LSX( 1. 0 mmol · L^(-1)Na_2SiO_3 mixed with 12. 5 μmol·L^(-1)Na_2SeO_3). The results indicated that CMP led to a soil exchangeable Cd that was lower by 16. 1% and 29. 5% under the P_1 and P_2treatments,respectively,than that of the control( CK). Soil application of CMP or leaf spraying with Si/Se treatments alone led to Cd concentration in paddy ricethat were lower by 40. 8%,57. 2%,42. 3%,35. 0%,and 39. 2% than that of the CK under treatments P_1,P_2,LS,LX,or LSX,respectively. The combined CMP/leaf spraying treatment had a significant synergistic effect. The Cd concentrations after the P_1 LS,P_1LX,and P_1 LSX treatments were 61. 2%,59. 5%,and 68. 2%,respectively,higher than those after P_1 treatment alone. In contrast,the Cd concentrations after the P_2LS,P_2LX,and P_2LSX treatments were 75. 0%,54. 2%,and 75. 7% lower,respectively,than those after treatment with P_1 alone. The Cd root-to-straw transport coefficient( RS) was larger than the straw-to-seed ratio( SS). The combined treatments exerted significant synergistic effects on the decrease in RS and SS( p 0. 05). When P_1 and the leaf spraying( Si / Se) treatment was combined,RS and SS were reduced by 7. 4% and 22. 0% on average,while the P_2and leaf spraying( Si / Se) combination led to average declines in RS and SS of 16. 0% and19. 6%,respectively. From a food safety viewpoint,the soil application of CMP or leaf spraying with Si / Se single treatments resulted in Cd concentrations in padd
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