Geochemical characteristics and growth suitability assessment of Georgi in the Earth's critical zone of North China.

Geochemical differentiation of soils has a series of consequences on plant and places pressure on the ecological environment. The quantitative evaluation of element migration in the Earth's critical zone is a challenging task. In this study, two demonstration study areas of Georgi were selected, and multiple chemical weathering indexes, chemical loss fraction, mass migration coefficients and biological enrichment coefficient method were used to assess the ecological and geochemical suitability. The results show that for the element of Fe, Zn, Se, Cu, Co, Ni, Mo and Ge, the degree of weathering and soil maturation, were greater in the rhyolitic tuff area than in the Plagioclase gneiss area. In both research sites, the heavy metal level of samples in Georgi did not exceed the standard limits. The plagioclase gneiss region's surface soil environment was more alkaline, and the content of soil organic matter was lower, resulting in a higher bioenrichment intensity of Ge, Co, Cu, and Se elements in Georgi than in the rhyolite-tuff area. The elements of Cd, Nb, Mo, Pb and As are considerably enriched in the soil of the plagioclase gneiss area but lost by leaching in the soil of the rhyolite tuff area, which is connected to the interplay of elemental abundance and human impact in the parent materials. This study provides a good example of how to assess growth suitability of Chinese medicinal materials in the Earth's critical zone.