Li Yong-Chun, Liu Jiu-Fen, Li Xue-Zhen, Zhang Dong, Chen Guo-Dong, Du Yu-Chun-Zi, Zhou Wen-Hui
Hohhot General Survey of Natural Resources Center, China Geological Survey, Hohhot 010010, China.
School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China.
Huan Jing Ke Xue. 2024 Nov 8;45(11):6734-6744. doi: 10.13227/j.hjkx.202311175.
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 "（total Se）≥0.222 mg·kg" as the threshold, the proportion of soil Se enrichment was closer to the Se enrichment level of crops than others.
为了探明土壤硒（Se）的影响因素及硒的生物有效性，在河套平原腹地采集了1985份土壤样品以及120组作物与根际土壤样品，分析了土壤硒特征、不同形态硒以及作物硒和重金属含量。结果表明，约5.59%的土壤样品超过了GB15618—2018标准农用地土壤污染风险筛选值，但作物中的重金属含量远低于标准值，表明重金属污染总体风险较低。硒在土壤中具有显著的自相关性且局部出现富集，这主要与自然因素有关。根际土壤中不同形态硒的含量排序为：残渣态＞腐殖酸态＞水溶态≈强有机态＞碳酸盐态＞离子交换态＞铁锰氧化态，该结果表明与中国多数地区相比，根际土壤中硒的特征为高有效性态、高潜在有效性态以及低无效性态。同时，结果表明根际土壤中的水溶态、离子交换态和碳酸盐态硒与作物中的硒显著相关，表明它们是可被植物吸收利用的有效形态。根据硒含量和生物富集系数，不同作物的排序为：白瓜子＞向日葵＞玉米。通过聚类分析和相关分析，研究了影响土壤总硒及硒生物有效性的因素。得出结论：土壤质地、有机质和pH对土壤中硒及硒的生物有效性具有相反的影响。黏质土、高有机质和低pH等因素可促进土壤中硒的积累，但也限制了有效硒的活性。基于作物和根际土壤样品数据，探讨了土壤硒富集阈值。结果表明，以“（总硒）≥0.222 mg·kg”为阈值时，土壤硒富集比例比其他阈值更接近作物的硒富集水平。
