江苏省土壤锌元素地球化学特征及其利用前景

    Geochemical characteristics and utilization prospects of Zn in farmland soils, Jiangsu Province

    • 摘要: 基于江苏省区域生态地球化学调查及土地质量地球化学评估等获取的农田土壤地球化学数据资料,在深入分析、系统研究土壤Zn地球化学特征的基础上,探讨利用富锌土壤生产天然富锌食品的前景。研究结果显示:①江苏省农田土壤Zn空间分布不均衡,平均含量约为70 mg/kg,土壤有效Zn占土壤Zn的20%左右,土壤Zn控制土壤有效Zn的分布,二者具有显著正相关性;②土壤质地、成因类型、TOC和Fe等均对土壤Zn富集分布有重要影响,石灰岩土是江苏省最富Zn的土壤类型,全新统海积粉砂土是最富Zn的成土母质,土壤Zn同Se、Cu、Fe、Al、Mo、TOC等之间具有(较)显著正相关性;③研究区稻米Zn均量为18 mg/kg,生物富集系数均值为0.2,稻米Zn同土壤Zn、Se、TOC具有显著正相关性,同土壤pH具有显著负相关性;麦籽Zn均量为28 mg/kg,生物富集系数均值为0.36,麦籽Zn同土壤Zn、Se、B、TOC具有显著正相关性,稻麦籽粒Zn与Se也有显著正相关性;④参照行业标准,确定江苏省富锌土壤、富锌稻米、富锌麦籽占比依次为11.39%、29%、13.69%,指示其富锌土壤资源开发利用前景广阔。将天然富锌食品与富硒土壤资源开发、农田土壤改良(改善其TOC、pH)等有机结合起来,会极大提高开发利用效率。研究成果为科学利用江苏省Zn等有益微量土壤资源提供了依据。

       

      Abstract: Based on the geochemical data of farmland soils in Jiangsu Province, obtained from regional eco-geochemical surveys and the geochemical assessment of land quality in past years, this study delved into the geochemical characteristics of Zn in soils, aiming to explore the prospects of producing natural zinc-rich food in Zn-rich soils. The results indicate that Zn in farmland soils in Jiangsu Province exhibited an uneven distribution, with an average Zn content of approximately 70 mg/kg. The available Zn accounted for about 20% of the total Zn in soils. The total Zn in soils dictated the distribution of available Zn, with a significant positive correlation between both. Significant factors influencing the enrichment and distribution of Zn in soils included soil texture, genetic type, total organic carbon (TOC) content, and Fe content. Among various soils, limestone soils were the most enriched in Zn in Jiangsu Province, while the Holocene marine silty soils served as soil parent materials most enriched in Zn. Zn in soils manifested (relatively) significant positive correlations with Se, Cu, Fe, Al, Mo, and TOC contents. Rice seeds showed an average Zn content of 18 mg/kg, with an average bio-concentration factor (BCF) value of 0.2. Zn in rice seeds was significantly positively correlated with Zn, Se, and TOC content in soils but significantly negatively correlated with soil pH. In contrast, wheat seeds showed an average Zn content of 28 mg/kg, with an average BCF value of 0.36. Zn in wheat seeds was significantly positively correlated with Zn, Se, B, and TOC content in soils. Additionally, a significant positive correlation between Zn and Se was observed in both rice and wheat seeds. According to the industrial standards, the proportions of zinc-rich soils, zinc-rich rice seeds, and zinc-rich wheat seeds in Jiangsu Province were 11.39%, 29%, and 13.69% respectively, suggesting promising prospects for the development and utilization of zinc-rich soil resources in Jiangsu Province. The development and utilization efficiency of zinc-rich soil resources can be significantly enhanced by combining the production of natural zinc-rich food and the amelioration of farmland soils (e.g., improving TOC content and pH in soils). Overall, the results of this study provide a basis for scientifically utilizing beneficial trace elements such as Zn in soils in Jiangsu Province.

       

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