Divergent responses of soil and microbial stoichiometry to plant detritus reduction across global forests

The stoichiometric balance of carbon (C), nitrogen (N), and phosphorus (P) is fundamental to primary productivity, nutrient cycling, and food web dynamics in terrestrial ecosystems. However, the decline in plant detritus inputs due to human-induced global changes threatens these balances. Although plant detritus serves as a critical source of C, N, and P for forest soils, the consequences of its reduction on the stoichiometry of soil organic matter and microbial biomass (i.e., soil and microbial C:N:P) remain poorly understood. Here we conducted a meta-analysis of 1524 observations from 134 studies to assess the effect of plant detritus removal on soil and microbial C:N:P across global forests. Our results showed that plant detritus removal significantly decreased soil C:N by 2 %, C:P by 5 %, and N:P by 5 %. Conversely, it significantly increased microbial C:P by 52 % and microbial N:P by 60 %. The increase in microbial C:P was more pronounced in broadleaved forests than in coniferous forests, suggesting an aggravating microbial P limitation in response to declining detritus inputs, especially in broadleaved forests. These findings reveal a decoupling of soil and microbial stoichiometry in response to plant detritus removal, likely driven by shifts in microbial P utilization strategies. We provide valuable insights for forest management by highlighting the potential intensification of microbial P limitation following plant detritus removal and its implications for nutrient balance and soil C sequestration.