Soil <scp>pH</scp> and Organic Carbon Content Governing the Active Iron in Tea Plantation and Maize Field

ABSTRACT Active iron (Fe o ) plays a vital role in soil health and sustainable agriculture. However, the impacts of various land‐use practices on Fe o remain obscure. This study thoroughly investigated these effects, providing a scientific foundation for soil management and agricultural strategies. This study compared soil Fe o content between a tea plantation and a maize field in Yunnan, China. Additionally, the physicochemical properties, elemental content, and microbial community characteristics were analyzed. Structural equation modeling (SEM) was employed to assess factors influencing Fe o . Soil acidification in the tea plantation extended to a depth of 140 cm. Fe o content in the maize field surface layer (0–30 cm) was significantly higher than that in the tea plantation. Primary factors influencing Fe o content in both soils included soil organic carbon (SOC), soil water content (SWC), pH, and redox potential (Eh), with microbial activity playing a lesser role. In the tea plantation, the contribution of SOC to Fe o decreased by 3.86%, while the negative effect of soil pH on Fe o increased by 9.52%, indicating that soil acidification and reduced SOC content are the major reasons for the lower Fe o content in the tea plantation compared to the maize field. This study demonstrates that, at a localized scale, variations in soil Fe o are more strongly influenced by SOC and soil pH than by microbial activity. These findings underscore the importance of mitigating soil acidification and maintaining SOC levels to sustain agricultural soil health and promote Fe o accumulation.