Response index (mean ± SE) of soil properties and microbes of Rhus typhina in monoculture (a) and mixture (b) and Ailanthus altissima in monoculture (b) and mixture (d) under three nitrogen addition levels. Differing lowercase letters indicated significant differences according to post-hoc Tukey’s HSD test. P values represented the result of one-way ANOVA of nitrogen deposition on invasive soil legacy index of invasive R. typhina and native A. altissima. SN: soil nitrogen; SP: soil phosphorus; G+: gram-positive bacteria; G-: gram-negative bacteria; and B/F: bacteria to fungi ratio. N0: no nitrogen addition; N8: moderate nitrogen addition (8 N m-2 year-1); and N20: high nitrogen addition (20 N m-2 year-1). The bar colours represent the nitrogen addition treatments of R. typhina and A. altissima.