DISTRIBUTION CHARACTERISTICS AND INFLUENCING FACTORS OF GERMANIUM-RICH SOIL IN TYPICAL AGRICULTURAL AREA OF CHONGQING MUNICIPALITY

By collecting 8 496 topsoil samples from Nanchuan district, a typical agricultural area in Chongqing Municipality, the study tests the contents of germanium (Ge) and other elements in soil and discusses their characteristics and influencing factors. The results show that the soil Ge content is 0.13×10^-6-13.59×10^-6, averagely 1.54×10^-6, higher than the average Ge content in the "one-hour economic circle" and purple soil in Chongqing. The Ge-rich (>1.4×10^-6) soil area is up to 1 559.8 km², mainly distributed in the south of the study area. The high-Ge soil in Nanchuan district is mainly distributed in the Upper Permian Wujiaping Formation and Changxing Formation, as well as the Lower Triassic Daye and Jialingjiang formations. The soil Ge content is mainly controlled by parent materials, which is positively correlated with soil organic matter and associated with 8 heavy metals. The high-value area in the middle is greatly affected by concentrated coal mines and human activities.