锶在土壤-作物中迁移富集机制及作物富锶标准探讨:以河南固始史河一带为例

Strontium in Soil-crop Migration and Enrichment Discussion on the Standard of Strontium Enrichment in Crops:A Case Study from the Shihe Area in Gushi,Henan

通过系统采集和分析河南固始史河一带土壤、作物样品,进行土地质量地球化学评价,查明了区域土壤锶地球化学特征、影响因素,以及锶在土壤、作物中迁移富集机制,确定了土壤锶形态含量表现为残渣态>强有机结合态>离子交换态>铁锰氧化态>腐殖酸结合态>碳酸盐结合态>水溶态,其中残渣态和强有机结合态锶累计占98%,Sr主要以难溶态稳定形式赋存在土壤中。在弱酸性环境下,难溶含锶矿物SrSO_(4)、SrCO_(3)通过水化作用和水解作用形成易溶于水的锶岩Sr(HCO_(3))_(2)、SrCl_(2),并被植物吸收利用,形成锶在土壤-作物中的迁移。对比国内外相关作物Sr含量,提出了花生、小麦、玉米、水稻等作物富锶标准,即:水稻中的富锶下限值为0.65 mg/kg,花生、小麦、玉米的富锶下限值为1.08 mg/kg。依据此Sr含量标准,研究区内小麦、花生籽粒富锶,水稻部分富锶。本研究成果为固始史河流域富锶土地资源开发、发展富锶农产品提供了新的参考依据。

By systematically collecting and analyzing soil and crop samples in the Shihe river basin of Gushi(Henan Province),and conducting geochemical evaluation of land quality,we identified regional soil Sr geochemical characteristics,influencing factors,and migration and enrichment mechanisms in soil and crops,i.e.,residue state>strongly organic bound state>ion-exchange state>ferromanganese oxidation state>humic acid bound state>carbonate bound state>water-soluble state account for 98%.Strontium exists primarily in the soil in an insoluble stable form.In a weakly acidic environment,the insoluble Sr-bearing minerals(SrSO_(4) and SrCO_(3))hydrate and hydrolyze to form water-soluble Sr(HCO_(3))_(2) and SrCl_(2),which are absorbed and utilized by plants to facilitate Sr migration in soil and crops.The Sr-rich standard for peanut,wheat,corn,rice,and other crops was proposed by comparing the Sr content of related crops(domestic and international),i.e.,the lower limit is 0.65 mg/kg for Sr-rich rice,and 1.08 mg/kg for Sr-rich peanut,wheat,and corn.According to this Sr content standard,our wheat and peanut(and some rice)samples are Sr-rich.Our results provide a new reference for the development of Sr-rich land resource and Sr-rich agricultural products in the Shihe river basin.