随着经济社会的快速发展,茶园土壤重金属污染问题日趋严重,不仅影响茶叶的生长和品质,也威胁着人类的健康。以江浙两省优质名茶种植园为例,利用地统计学方法对茶园土壤重金属含量、相关关系及空间异质性等特征进行分析。结果表明:①东山镇土壤Zn超标率最高,达到67.50%;其次是溪龙乡土壤Se,达到50.00%;其他土壤重金属的超标率均比较低。②酸性条件及丰富的有机质有利于土壤Se的贮存,且土壤Se与土壤Cd、As极易共存,但不易与土壤Cu、Zn共存。③土壤重金属含量空间分布受结构性因素和随机性因素共同作用的影响,溪龙乡土壤Cd块金系数为0.890,受随机性因素影响最大;而溪龙乡土壤As块金系数为0.049,受随机性影响因素最小。④各重金属空间分布特征不同,为改善茶园土壤环境,提高茶叶品质,应结合重金属空间分布规律对其进行有效监管并提出有针对性的治理措施。
With the rapid economic and social development, the pollution of heavy metals in soil is becoming more and more serious, which will affect the quality and yield of tea. Study on the spatial pattern of heavy metal contents in the typical tea garden soil can provide theoretical reference for quality control of the high quality-tea gardens. Taking the typical tea gardens in Jiangsu and Zhejiang provinces as the study areas, this paper analyzed the content, the correlation and the spatial heterogeneity characteristics of heavy metals in soil, by using GIS techniques and geostatistics method. The results showed that: (1) The content of Zn in the soil of Dongshan was over the standard (most seriously), and its standard-exceeding rate was 67.50%; the second was the content of Se in the soil of Xilong, the standard-exceeding rate of which was 50.00%; the contents of the others were lower. (2) Correlation analysis proved that, acidic conditions and rich organic matter were beneficial to the storage of Se in soil; Se could promote the enrichment of As and Cd in soil, while it was not conducive to the enrichment of Cu and Zn in soil. (3) The coefficient of nugget indicated that, the spatial distribution of heavy metal contents in the soil of tea plantation was influenced both by the structural factors and by the random factors; the nugget coefficient of Cd in the soil of Xilong was 0.890, which was influenced by random factors mostly, but its spatial autocorrelation was the weakest; while the nugget coefficient of As in the soil of Xilong was 0.049, and it was the least influenced by the random factors, but its spatial autocorrelation was the strongest. (4) Kriging interpolation displayed that, for the difference of spatial distribution of heavy metals in the soil of the study areas, the contents of heavy metals should be supervised and controlled, and the targeted measures should be taken, according to the spatial distribution of heavy metals, to improve the soil environment and the quality of tea.