In a new research published in Catena, a team led by Prof. LI Dejun from the Institute of Subtropical Agriculture, Chinese Academy of Sciences, revealed that lithology, rather than climate, governs microbial resource limitation through soil geochemistry and microbial traits.

As a fundamental driver of biogeochemical cycles and ecosystem functioning, soil microbial resource limitation is critical for nutrient cycling. Lithology, a key soil-forming factor shaping geochemistry persist substantial uncertainties. Specifically, it remains unclear how lithology regulates microbial resource limitation patterns, how lithology influences microbial metabolism and carbon sequestration in subtropical forests.

To fill these gaps, 42 forest sites on limestone and clastic rock in southwest China were sampled, and soil microbial resource limitation in subtropical forests on limestone and clastic rock across southwest China were investigated.

It showed that clastic rock soils experienced greater microbial carbon (C) and phosphorus (P) limitation, whereas limestone soils exhibited nitrogen (N) limitation or N-P co-limitation. Random forest and structural equation models identified lithology, rather than climate, as the dominant regulator of microbial resource limitation, primarily through its effects on soil geochemistry (e.g., Ca, pH), microbial community composition (e.g., fungi:bacteria ratio), and substrate availability (e.g., dissolved organic carbon).

By focusing on lithological controls in subtropical forests, this research advances the understanding of microbial resource limitation. It posits that lithology, rather than climate, dictates contrasting C/N/P limitation patterns through soil geochemistry and microbial traits. Associate Pro. XIAO Kongcao, the first author, emphasied that these insights underscore the need to integrate lithological effects into Earth system models, improving predictions of nutrient cycling and carbon sequestration under global change.

Contacted: LI Dejun

E-Mail: dejunli@isa.ac.cn

Conceptual framework diagram illustrating the lithological controls on microbial resource limitation and SOC sequestration in subtropical forests (Imaged by XIAO Kongcao)