不同污染程度耕地下稻米镉综合治理效果研究

    Study on the Effect of Comprehensive Treatment Technology on Rice Cadmium Content Under Different Cd Polluted Cultivated Land

    • 摘要: 为探究不同"VIP+n"综合治理技术(V为种植低镉积累品种,I为优化水分管理,P为施用石灰,n为喷施叶面阻控剂)在不同程度重金属污染酸性稻田土壤中对双季稻稻米镉含量的应用效果,于2017年分别采用"VIP+n"技术在湖南省湘潭县轻、中、重度镉污染稻田开展"VIP+n"技术模式区域化研究与示范,研究结果表明:"VIP+n"技术对双季稻糙米镉含量、土壤pH值效应显著或极显著(P < 0.05或0.01),稻田污染程度对双季稻糙米镉含量、土壤全镉和有效态镉含量效应显著或极显著(P < 0.05或0.01),两者交互作用对晚稻糙米镉含量效应显著(P < 0.05)。未采用"VIP"技术处理早稻糙米镉含量在耕地土壤轻度、中度和重度重金属污染条件下分别为0.29、0.88和3.85 mg·kg-1,晚稻分别为0.22、0.55和2.64 mg·kg-1;采用"VIP+n"技术处理早稻糙米镉含量分别为0.09、0.34和1.17 mg·kg-1,较对照分别降低70.00%、61.19%和69.66%,差异达显著水平(P < 0.05);晚稻分别为0.03、0.32和1.01 mg·kg-1,较对照分别降低87.16%、41.49%和61.71%,差异达显著或极显著水平(P < 0.05或0.01)。其中,晚稻运用"VIP"技术的效果较早稻好。相关分析表明,双季稻田成熟期糙米镉含量与土壤pH值呈负相关(r=-0.002,r=-0.181),而与土壤有效镉含量呈极显著正相关(r=0.658,P < 0.01;r=0.772,P < 0.01)。总体而言,应用"VIP+n"技术在不同程度重金属镉污染稻田中均能有效改善土壤pH值,降低土壤镉生物有效性及双季稻糙米镉含量,使轻度污染条件下糙米镉含量达到GB 2762-2017《国家食品安全限量标准》。

       

      Abstract: To explore the application effect of different "VIP+n" technology (V, planting of low-cadmium accumulation varieties; I, optimized irrigation management; P, applying lime; n, spraying foliar inhibitor) on Cd content of double-cropping rice from acidic paddy field with different degrees of heavy metal pollution, the "VIP+n" technology were carried out in the lightly, mediumly and heavily cadmium-polluted rice fields in Xiangtan City of Hunan in 2017. The "VIP+n" technology had significant or extreme significant effects on the content of Cd in brown rice of double-cropping paddy field and soil pH (P < 0.05 or 0.01). The pollution degree of Cd in paddy field had significant or extremely significant effects on the content of Cd in brown rice of double-cropping paddy field and the contents of total Cd and extractable Cd in soil (P < 0.05 or 0.01). And their interaction effects on the content of Cd in brown rice of late-rice were significant (P < 0.05). The Cd contents of brown rice for early-rice were 0.29, 0.88 and 3.85 mg·kg-1, respectively, under lightly, moderately and heavily Cd polluted soil, and those for late rice were 0.22, 0.55 and 2.64 mg·kg-1, respectively. However, the Cd contents of early-rice with "VIP+n" technology were 0.09, 0.34 and 1.17 mg·kg-1 with a reduction of 70.00%, 61.19% and 69.66%, respectively, significantly different from the control (P < 0.05), and those for late-rice were 0.03, 0.32 and 1.01 mg·kg-1 with a reduction of 87.16%, 41.49% and 61.71%, respectively, significantly or extremely significantly different from the control (P < 0.05 or 0.01). Hence, the application effect of "VIP" technology was better for late-rice than that for early-rice. The correlation analysis show that the Cd contents of brown rice at the mature stage of double-cropping rice were negatively correlated with soil pH (rearly=-0.002;rlate=-0.181), but positively correlated with the extractable Cd content of soil (rearly=0.658, P < 0.01;rlate= 0.772, P < 0.01). The "VIP+n" technology can effectively improve the soil pH, reduce the Cd content of brown rice from double-cropping paddy fields with different degrees of Cd pollution, and under light Cd pollution make it meet the National Food Safety Standards (GB 2762-2017).

       

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