| 河套平原腹地土壤硒的赋存形态特征及生物有效性 |
| 摘要点击 2345 全文点击 406 投稿时间：2023-11-20 修订日期：2024-02-18 |
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| 中文关键词 硒（Se） 土壤 赋存形态 生物有效性 影响因素 河套平原 |
| 英文关键词 selenium（Se） soil occurrence form bioavailability influencing factors Hetao Plain |
| DOI 10.13227/j.hjkx.20241150 |
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| 中文摘要 |
| 为查明土壤硒元素（Se）和Se生物有效性的影响因素,在河套平原腹地系统采集了1985件土壤样品和120组农作物及根系土样品,分析了土壤Se、不同赋存形态Se及农作物Se及重金属含量特征．结果表明,约5.59%的土壤样品超出GB 15618-2018风险筛选值,农作物As等重金属含量低,重金属污染风险总体较低.研究区土壤Se有显著的自相关性,呈正态分布,Se的局部富集主要与自然因素有关.根系土中Se的7种形态含量排序为：残渣态>腐植酸态>水溶态≈强有机态>碳酸盐态>离子交换态>铁锰氧化态,较全国大部分地区表现出高可利用态、高潜在可利用态和低不可利用态的特征.按照农作物Se含量和生物富集系数排序,均为：白瓜籽>葵花籽>玉米.通过聚类分析和相关性分析,研究了影响土壤Se富集及Se生物有效性的影响因素,认为土壤质地、有机质和酸碱度等对土壤Se和Se的生物有效性具有双重影响,黏性土壤、高有机质和低碱性等因素能够促进土壤Se的积累,但也限制着有效态Se的活性.基于农作物和根系土样本数据,讨论了土壤富硒阈值,认为采用土壤ω（全量Se）≥0.222 mg·kg-1为阈值,土壤富硒比例与农作物富硒水平更加接近. |
| 英文摘要 |
| In order to find out the influencing factors of soil selenium （Se） and bioavailability of Se, 1985 soil samples and 120 sets of crop and root soil samples were collected in the hinterland of the Hetao Plain, and the characteristics of soil Se, different forms of Se, and crop Se and heavy metal content were analyzed. The results showed that approximately 5.59% of soil samples exceeded the risk screening values for soil contamination of agricultural land of GB15618-2018 standard, but the heavy metal content in crops was much lower than the standard value, suggesting that the overall risk of heavy metal pollution was low. Se had significant autocorrelation in soil and appeared enriched locally, which were mainly related to natural factors. The content of different forms of Se in root soil was ranked as： residue state > humic acid state > water soluble state ≈ strong organic state > carbonate state > ion exchange state > iron and manganese oxidation state, this result showed that the characteristics of Se in root soil were high availability state, high potential availability state, and low unavailability state compared with those of most areas in China. At the same time, the results showed that water-soluble, ion exchange, and carbonate Se of root soil were significantly correlated with Se of crops,indicating that they were effective forms that could be absorbed and utilized by plants. According to the Se content and bioconcentration factor, different crops were ranked as： white melon seeds > sunflowers > corn. By means of cluster analysis and correlation analysis, the factors affecting the total Se and bioavailability of Se in soil were studied. It was concluded that soil texture, organic matter, and pH had opposite effects on Se and bioavailability of Se in soil. Factors such as clay soil, high organic matter, and low pH degree could promote the accumulation of Se in soil but also limited the activity of available Se. Based on crop and root soil sample data, the soil Se enrichment threshold was discussed. The results demonstrated that using “ω（total Se）≥0.222 mg·kg-1” as the threshold, the proportion of soil Se enrichment was closer to the Se enrichment level of crops than others. |
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