Magnetic properties of agricultural soils and their relationships with environmental factors in Jinghong, Yunnan, China

Abstract Environmental magnetism, with its advantages of speed, sensitivity, cost-effectiveness, and harmlessness, has extensive applications in various fields such as environmental science, climate research, and soil science. However, studies on the magnetism of agricultural are limited. This study conducted magnetic investigations on 21 agricultural soil profiles (including farmland and tea plantations) and 6 adjacent natural soil profiles (forestland) in the southwestern subtropical region of China. By analyzing and comparing the soil magnetic characteristics of natural soil and agricultural soil profiles and using the structural equation model, the influencing factors of soil magnetism in different soil layers (0-70cm and 70-140 cm) were determined. This study revealed that soil magnetic susceptibility is influenced by soil organic carbon (SOC), drainage conditions, and weathering intensity. In the 0–70 cm soil layer, SOC and drainage conditions were the primary factors affecting soil magnetism. The differences in soil drainage conditions result in variations in dry–wet cycling patterns, which, along with the influence of SOC on the formation and transformation of magnetic minerals in redox alternations, affects soil magnetic susceptibility. In the 70–140 cm soil layer, weathering intensity was the primary factor influencing soil magnetism.