Global Change Reshapes Microbial Residues and Plant Lignin Components in Soils

Microbial- and plant-derived carbons are critical sources of soil organic carbon (SOC), but the specific responses of soil amino sugars and lignin phenols to global change remain unclear. In this study, we conducted 3193 observations across 553 experiments aimed at investigating the potential role of amino sugars and lignin phenols in maintaining SOC accumulation in response to land-use change, nutrient additions, elevated C dioxide (eCO2), warming, and drought. The results showed that land restoration increased amino sugars (35.1%), glucosamine (53.8%), galactosamine (68.6%), muramic acid (33%), lignin phenols (79.3%), and vanillyl phenols (68%), whereas land degradation reduced these compounds, including syringyl. Nitrogen (N) and phosphorus (P) additions enhanced amino sugar, glucosamine, and muramic acid contents, whereas P addition selectively increased glucosamine content. N, P, and potassium additions increased glucosamine (16.8%), galactosamine (17.3%), muramic acid (21.6%), and lignin phenol (4.8%) contents, while eCO2 only increased amino sugar content by 14.6%. Warming increased glucosamine and muramic acid contents, whereas drought had no effect on amino sugar and lignin phenol contents. Soil amino sugars played a more critical role than lignin phenols in SOC accumulation, and their dynamics were influenced by soil nutrient availability and microbial communities under global change. These findings advanced our understanding of the dominant role of microbial residues in SOC accumulation mediated by the nutrient stoichiometry and microbial communities.