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Assessing the distribution and risks associated with the soil lead content in the Tieguanyin tea plantations of Anxi County is critical, given the county's significance as the primary Tieguanyin tea production area in Fujian Province. This study examined the distribution characteristics of soil lead in Anxi County's tea plantations according to the Kriging spatial interpolation of the parameters of the semivariance function of the exponential model. Moreover, the sources of lead content were analyzed, considering geological backgrounds and anthropogenic influences. Ecological risks and the issuance of early warnings were also assessed. The soil lead content in the rocks of the Tieguanyin tea plantations in Anxi County followed the order: andesite > dacite > rhyolite > granite. The soil lead content gradually decreased from the center toward the east and west, forming four distinct north–south parallel zones. High-lead-content areas were identified at the border of Jiandou, Bailai, and Hushang; in the central part of Lutian; and in the southern part of Huqiu. The high levels of soil lead in the tea plantations possibly originated from industrial and mining activities, automobile exhaust, and agricultural activities. The distribution of single-factor pollution indices and potential risk evaluation based on the Soil Environmental Quality Standard, Environmental Technical Conditions for Tea Production Area, and Environmental Technical Conditions for Organic Tea Production Area indicated that the soil in Tieguanyin tea plantations in Anxi County was clean and safe for tea cultivation. [ABSTRACT FROM AUTHOR]

Purpose: Collapsing gully erosion is a specific form of soil erosion that is widely distributed in the hilly granitic region of tropical and subtropical southern China and resulted in extremely rapid water and soil loss. The aim of this study was to investigate the correlations between soil physicochemical and shear properties and the clay mineralogical of different profiles of the non-eroded soils (without soil erosion) and collapsing gully soils in Changting County, Fujian Province, southeastern China. Materials and methods: A total of 32 sampling soils collected from four pedons of non-eroded and collapsing gully soils were subjected to conventional soil analyses for physicochemical properties. The soil shear strength of collected soils was measured using a triaxial shear apparatus according to the unconsolidated-undrained (UU) method. The clay mineralogical of different profiles soils was examined with an X-ray diffraction (XRD) analysis. Results and discussion: The results showed that non-eroded soils had superior physicochemical characteristics. The cohesive force of the non-eroded soils was generally greater than that of collapsing gully soils. The XRD patterns of the clay fraction indicated that kaolinite, illite, hydroxy-interlayered vermiculite (HIV), and gibbsite were the dominant clay minerals in the studied soils. Pearson's correlation analysis showed that the cohesive force of the studied soils had significant and positive correlations with CEC, exchangeable Al3+ + H+, Fed, Ald, and Fet; the correlation coefficients (R value) for cohesive force were greater than those of internal friction angle. The stepwise multiple linear regression analyses indicated that exchangeable Al3+ + H+ and Ald were the dominant factors affecting cohesive force. Conclusions: Compared with collapsing gully soils, non-eroded soils had superior physicochemical and shear properties, indicating that non-eroded soils were better able to resist soil erosion. The findings obtained in the present study were of fundamental significance in understanding the correlation between shear strength and the soil physicochemical properties in the non-eroded soils and collapsing gully soils of tropical and subtropical China. [ABSTRACT FROM AUTHOR]