Direct effects of litter decomposition on soil dissolved organic carbon and nitrogen in a tropical rainforest

• Soil DOC and DN concentrations decreased significantly after the first month peak.
• PC1 explained 61.3% and 71.2% of soil DOC and DN concentrations variation, respectively.
• Litter carbon mass controlled DOC and hemicellulose mass controlled DN concentrations.
• Litter decomposition was the predominant factor controlling surface-soil DOC and DN dynamics.

To clarify how litter decomposition processes affect soil dissolved organic carbon (DOC) and soil dissolved nitrogen (DN) dynamics, we conducted a field experiment on leaf litter and collected DOC and DN from the underlying soil in a tropical rainforest in Xishuangbanna, southwest China. Principal components analysis (PCA) showed the first PCA axis (corresponding to degraded litter quantity and quality) explained 61.3% and 71.2% of variation in DOC and DN concentrations, respectively. Stepwise linear regression analysis indicated that litter carbon mass controlled DOC and hemicellulose mass controlled DN concentrations. Litter decomposition was the predominant factor controlling surface-soil DOC and DN dynamics in this tropical rainforest.