白及不同种植年限下土壤-植株系统重金属含量及富集特征研究

Study on Content and Enrichment Characteristics of Heavy Metals in Soil-Bletilla striata System under Different Planting Years

为了解白及种植土壤及其块茎中重金属含量随种植年限的变化规律,以为白及生产种植过程中的重金属污染防治提供理论依据。本研究对白及不同种植年限土壤及其块茎中的重金属含量进行分析检测,探究土壤-植株系统重金属及其与种植年限间的关系。结果表明,除重金属Cr,Cd、Pb、As及Cu含量的最大值均出现在种植3年的土壤中;As和Cu以种植1年的块茎中含量最高,2年的块茎中Cd含量最高,Cr和Pb随年限的增加逐渐增加。参照《绿色食品——产地环境质量》和《土壤环境质量——农用地土壤污染风险管控标准(试行)》,种植3年的土壤中Cd含量超标;单因子污染指数和地积累系数分析结果表明,种植3年的土壤受Cd污染;综合污染指数表明,种植3年的土壤属于警戒线或轻度污染;参照《药用植物及制剂进出口绿色行业标准》,影响块茎品质的为Cd;种植2年的块茎对Cd、种植2年和3年的块茎对Cr及种植1年的块茎对As的富集系数均大于1。相关性分析表明,贵州土壤-白及系统主要受重金属Cd影响,种植年限与Cd呈正相关但不显著。

In order to understand the change rule of heavy metals in soil and tuber of Bletilla striata with the planting years, and provide theoretical bases for prevention and control of heavy metal pollution in the process of B. striata production, the content of heavy metals in soil and tuber under different planting years were analyzed and detected, and the relationship between heavy metal content in soil-plant system and planting years was explored. The results showed that the maximum values of the content of Cd, Pb, As and Cu was in the 3-year soil except for Cr. The content of As and Cu was the highest in the one-year tuber, and the content of Cd was the highest in the two-year tuber. The content of Cr and Pb increased gradually with the increase of planting years. Referring to Green Food-Environmental Quality of Producing Area and Soil Environmental Quality-Soil Pollution Risk Control Standard of Agricultural Land(Trial), the content of Cd in the three-year soil exceeded the standard. The analysis results of single factor pollution index and the land accumulation coefficient showed that the soil with three planting years was polluted by Cd. The comprehensive pollution index showed that the 3-year planting soil belonged to the warning line or light pollution. Referring to The Green Industry Standard for Import and Export of Medicinal Plants and Preparations, the quality of tubers was affected by Cd. The enrichment indexes of Cd in 2-year tuber, Cr in 2-and 3-year tuber and As in one-year tuber were more than 1. The correlation analysis showed that the soil and Bletillastriata system in Guizhou was mainly affected by Cd, and the planting year was positively correlated with Cd content but not significantly.