农用地土壤可持续安全利用的研究与实践——以浙江省镉污染农田为例

Research and Practice on Sustainable and Safe Utilization of Soil in Agricultural Land-A Case Study of Cadmium Contaminated Farmland in Zhejiang Province

农用地土壤可持续安全利用对有效改善农用地土壤环境质量、保障农产品质量安全及人体健康具有重要意义。以长江三角洲经济最发达地区之一的浙江省为例,分析探讨了农用地土壤环境存在的主要问题和发展趋势,研究思考了农用地土壤可持续安全利用的理论和方法。在“十三五”期间,基于浙江省历年1︰5万大比例尺农用地土壤污染调查成果,在温岭市、桐庐县等地开展了以农用地土壤重金属镉(Cd)污染治理为重点的省级试点示范工作,综合采取以污染源头解析与防控、多维度农业安全利用技术筛选和应用以及超标农作物秸秆安全处置等方法,形成一批具有显著地域特点、高效防治效果、自主知识产权、适用于Cd轻中度和中重度污染的农用地土壤污染综合治理技术模式。主要结果:(1)大气沉降源是农用地生态系统Cd的主要外来输入源之一,约占总输入量的24%~59%。(2)筛选出以甬优538为主的低积累品种53个,比选出以石灰性物质类为主的钝化材料20种以及以硅基和硒基为主的叶面阻控材料10种。(3)以稻/麦轮作等适用于Cd轻中度污染农用地安全利用技术模式可有效降低土壤有效态Cd20%~50%以上,以超积累植物为主的适用于Cd中重度污染农用地的“边生产边修复”技术模式可有效降低土壤全量Cd30%以上、土壤有效态Cd50%以上,均可实现农产品安全生产。本文创新提出农用地土壤重金属污染可持续安全利用总体思路和技术路径,总结了农用地土壤重金属污染可持续安全利用的经验策略,以期为我国大范围开展受污染农用地土壤安全利用提供示范样板与技术参考。

【Objective】The sustainable and safe utilization of agricultural soil is of great significance to effectively improve the quality of the agricultural soil environment,and to ensure the quality and safety of agricultural products and human health.【Method】Taking Zhejiang Province,one of the most developed areas in the Yangtze River Delta,as an example,the main problems and development trends of agricultural land soil environment were analyzed,and the theory and method of sustainable and safe utilization of agricultural land soil were studied.During the 13th Five-year Plan period,based on the survey results of agricultural land soil pollution in Zhejiang Province at a scale of 1︰50000 over the years,provincial pilot demonstrations focusing on the control of heavy metal cadmium pollution in agricultural land were carried out in Wenling City and Tonglu County.The methods of pollution source analysis and prevention,multi-dimensional agricultural safety utilization technology screening and application,and safe disposal of over-standard crop straws were comprehensively adopted to form a batch of agricultural land soil pollution comprehensive treatment technology models with significant regional characteristics,high-efficiency control effects,and independent intellectual property rights,which are suitable for mild to moderate and moderate to severe cadmium pollution.【Result】The main results were as follows:(1)Atmospheric deposition source is one of the main external input sources of Cd in the agricultural land ecosystem,accounting for about 24%–59%of the total input.(2)58 varieties with low accumulation(mainly Yongyou 538)were screened out,20 passivation materials with calcareous substances as the main,and 10 leaf resistance control materials with silicon and selenium as the main were selected.(3)The safe utilization technology mode of rice/wheat rotation,which is suitable for light and moderate Cd polluted agricultural land can effectively reduce the available state of Cd in soil by more than 20%–50%.The production and remediation technology mode which is suitable for moderate and severe Cd polluted agricultural land,mainly with hyperaccumulators,can effectively reduce the total amount of Cd in soil by more than 30%and the available state of Cd in soil by more than 50%.【Conclusion】This paper innovatively puts forward the general idea and technical route of sustainable and safe utilization of heavy metal polluted agricultural land soil.It also summarizes the experience and strategy of sustainable and safe utilization of heavy metal polluted agricultural land soil,to provide a demonstration model and technical reference for the safe utilization of contaminated agricultural land soil in China.