四川成都市唐昌镇土壤硒分布特征及影响因素

龚仓; 王亮; 王顺祥; 王德伟; 陆海川; 张志翔; 江凌云; 严步青; 熊韬; 刘玖芬

doi:10.15898/j.cnki.11-2131/td.202111180179

四川成都市唐昌镇土壤硒分布特征及影响因素

Distribution Characteristics of Soil Selenium and Its Influencing Factors in Tangchang Town of Chengdu City, Sichuan Province

摘要

摘要: 硒是人体必须的微量元素之一，食用含硒农产品是人体获取硒元素的重要途径。调查土壤硒的含量特征、划定富硒区、查明硒空间分布和迁移富集的影响因素，对富硒土地资源利用和富硒农产品开发具有重要意义。本文选择成都市唐昌镇采集土壤样品，采用原子荧光光谱法(AAS)和电感耦合等离子体发射光谱/质谱法(ICP-OES/MS)等方法测定土壤中的Se、As、总有机碳(TOC)等组分含量和pH值，运用方差分析、相关性分析、地理探测器等方法对土壤硒含量、分布特征及影响因素进行探讨。结果表明：①研究区土壤硒含量范围为0.082~1.10mg/kg，平均含量为0.337mg/kg，分别是成都市、四川省和全国土壤硒平均含量的1.47、4.02和1.16倍；②全镇99.2%的土壤硒呈足硒及富硒状态，且土壤硒含量随着深度增加总体呈降低趋势，空间分布上，高硒区整体呈北西向带状分布于战旗、柏木、大云和竹林等村落；③相关性分析表明土壤Pb、Cr、Ni、Cd、Hg、As、总钾(TK)、总氮(TN)、pH、TOC和海拔高度对土壤硒的富集迁移均有极为显著(P < 0.01)的影响，但影响程度不一；④地理探测器的因子探测发现，TOC对表层土壤硒的空间变异独立解释能力最大(0.29)，Zn次之(0.18)，第三是Cd(0.16)；交互探测发现，土壤TOC与其他17种影响因子交互作用的解释程度均在0.30以上，是表层土壤硒空间分异的主导因素。

Abstract:
BACKGROUND Selenium is one of the essential trace elements for humans. Eating agricultural products containing selenium is an important way for humans to obtain selenium. It is of great significance for the utilization of selenium-enriched soil resources and the development of selenium-enriched agricultural products to investigate the content characteristics of soil selenium, delimit selenium-enriched soil areas, and determine the influencing factors of soil selenium spatial distribution, migration and enrichment.
OBJECTIVES To discuss the content, distribution characteristics and influencing factors of soil selenium in the study area.
METHODS Tangchang Town in the Pidu District of Chengdu City was chosen as the study area. 788 surface soil samples (0-20cm) and 46 profile soil samples (100-150cm) were collected. The pH values and contents of Se, As, Hg, Cu, Pb, Zn, Ni, Cr, CD, TP, TK, TN and TOC in soil were determined by AFS, XRF and ICP-MS/OES. Geostatistical analysis, variance analysis, correlation analysis and geographic detectors were applied to systematically determine the content, distribution characteristics and influencing factors of soil selenium.
RESULTS (1) Results showed that surface soil selenium content of Tangchang Town ranged from 0.082 to 1.10mg/kg, with an arithmetic mean value of 0.337mg/kg, which was 1.47, 4.02 and 1.16 times the average Se content of soil in Chengdu, Sichuan and China, respectively. (2) The Se-sufficient and Se-enriched topsoil reached 99.2% of Tangchang Town. In the profile soil samples, the soil selenium content decreased with increasing depth. In the spatial distribution, high selenium concentrate areas generally showed a northwest zonal distribution trend in Zhanqi Village, Baimu Village, Dayun Village, and Zhulin Village. (3) Correlation analysis showed that lead, chromium, nickel, cadmium, mercury, arsenic, total potassium, total nitrogen, pH, TOC and altitude were factors affecting spatial distribution variability of the soil selenium but varied in extent (P < 0.01). (4) The factor detection showed that TOC was the highest in the effect, explaining 0.29 of the variability, followed by Zn, which was 0.18, and the third was Cd, which was 0.16. Interaction detection showed the interpretation degree of the interaction between soil TOC and 17 influencing factors was more than 0.30, which was the dominant factor of spatial differentiation of selenium in topsoil.
CONCLUSIONS The town is characterized by selenium-enriched soil resources; it is suggested to organically combine the selenium-enriched area with the characteristic industries of chives in Tangyuan to build an ecological chain of selenium-enriched industry, and further carry out collaborative analysis on the influencing factors of selenium migration and enrichment in soil crops.

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