Spatial heterogeneity of pH and heavy metal Cd in the soils of tea gardens in the plateau mountain regions, PR China

• Published in: Environmental monitoring and assessment 2021-10, Vol.193 (10), p.646-646, Article 646
• Main Authors: Jiachun, Zhang, Zhang, Zhenming, Huang, Xianfei
• Format: Article
• Language: English
• Subjects: Agricultural land; Agricultural pollution; Agriculture; Atmospheric Protection/Air Quality Control/Air Pollution; Cadmium; Cadmium content; Chemical indicators; Coefficient of variation; Contamination; Distribution; Earth and Environmental Science; Ecology; Ecotoxicology; Environment; Environmental factors; Environmental Management; Environmental monitoring; Environmental quality; Environmental science; Gardens; Gardens & gardening; Heavy metal content; Heavy metals; Heterogeneity; Indicators; Land pollution; Monitoring/Environmental Analysis; Mountain regions; Mountains; Patchiness; pH effects; Plateaus; Polygons; Soil; Soil chemistry; Soil contamination; Soil pH; Soil quality; Soils; Spatial distribution; Spatial heterogeneity; Tea; Wind
• ISSN: 0167-6369; 1573-2959
• DOI: 10.1007/s10661-021-09431-1

To explore the spatial heterogeneity of pH and cadmium (Cd) content in the soils of the tea gardens in the plateau mountain regions as well as its driving factors, the pH values, Cd content and other physical and chemical indicators from 423 soil samples were examined. A coefficient of variation method and a semivariance function model was adopted to explore the soils’ spatial heterogeneity, and a random forest approach was applied to evaluate the factors influencing environmental Cd under different pH values. The results show that the pH values of the soils of the tea gardens in the plateau mountain regions were within the appropriate range for the growth of tea plants, and soil samples with pH values falling between 4.5 and 6.0 account for 74% of all samples. A comparison against the criteria of risk screening values for the contamination of agricultural land, a component of quantifying soil environmental quality in China, was preformed; it was determined that the content of heavy metal Cd in the soil of the tea gardens did not exceed the limit. The content of soil pH in the research area gradually declined from southwest to northeast, exhibiting two distinct parallel distribution zones running along the southwest-northeast direction. The spatial distribution of the heavy metal Cd content in the soil showed a gradually decreasing trend from north to south, with low-value polygons dominantly appearing in the southeasternmost area and high-value polygons concentrated in the north. When the soil pH ≤ 5.5, it had the largest effect on the Cd content; when 5.5