*2.4. Statistical Analyses*

Two-way ANOVAs were used to determine the effects of restoration age, soil depth, and their interaction on SOC, soil TN, and soil TP stocks and C:N, C:P, and N:P ratios. An independent samples *t*-test was used to compare the SOC, soil TN, and soil TP stocks and the C:N, C:P, and N:P ratios from sites grassland30, natural grassland, shrubland47, forestland56, and natural forest (*p* < 0.05). Before ANOVA analyses, we performed tests for normality and homogeneity of variance. In order to compare the effects of vegetation type, we selected SOC, soil TN, and soil TP contents and stoichiometry for the same or similar years from the four restoration types: orchardland (5 years, 10 years, 20 years), grassland (5 years, 11 years as 10 years, 18 as 20 years), shrubland (5 years, 10 years), and forestland (5 years, 10 years). In addition, we selected the SOC, soil TN, and soil TP contents from different soil depths as the rate of change with recovery years and compared the SOC, soil TN, and soil TP sequestration rates between different restoration types. All statistical analyses were conducted using SPSS 21.0 (SPSS Inc., Chicago, IL, USA). Figures were drawn using Origin 9.0.
