Abstract: Invasive plants alter soil microbial communities and physicochemical properties through chemical inputs from litter, root exudates and leachate, impacting a range of soil processes, but precise effects are poorly understood. We investigated the little effects of Solidago canadensis, a common invasive species in China, on soil microbial communities under natural conditions. Experimental treatments included S. canadensis seedling density (1 and 2 plants/pot) and litter quantity (10 and 20 g/pot), with control groups containing no plants or litter. After 120 days, soil samples were analyzed for physico-chemical properties, GC–MS chemical composition, and bacterial community composition using high-throughput sequencing. Results showed that S. canadensis seedlings and litter inputs significantly increased soil pH, soil organic matter (SOM), and total nitrogen (TN), while phosphorus and potassium remained unchanged. We identified 66 chemical compounds, predominantly ketones, alcohol, aldehyde, hydrocarbon, ester, acid, terpenoids and alkaloids, associated with the presence of S. canadensis, alongside shifts in dominant bacterial genera including Sphingomonas, Acidobacteriales and Gemmatimonas. Rarer genera under the invasive treatment species, such as Candidatus, Rhodoplanes and Novosphingobium, were positively correlated with soil TN, pH, and SOM. Collectively, these findings demonstrate that allelochemical inputs from S. canadensis litter and root exudates significantly reshape soil properties and microbial communities, with potential implications for ecosystem dynamics and invasion success.

Key words: allelopathy, invasive plant, litter effects, root exudates, soil microbial communities, high-throughput sequencing