3.2 Effects of deforestation and land restoration on SOC, TN storage and soil bulk density
The mean response ratio (lnRR ) was weighted by the mean value and standard deviation of each sample. Before meta-analysis, we tested the data normality using the Shapiro-Wilk test (Shapiro and Wilk, 1965). Overall, the lnRR of SOC, TN storages and soil mass were normally distributed (Table 2), regardless of deforestation or land restoration. The data showed that LUCC had remarkable influence on SOC, TN storage and soil mass (P < 0.05). On the one hand, deforestation had negative effects on SOC and TN storages (lnRR< 0; P < 0.5), indicating that deforestation caused huge SOC and TN losses. Specifically, the lnRR of SOC and TN storage were -0.66 and -0.62, respectively, which means that deforestation caused a loss of 48.3% for SOC and 46.2% for TN respectively. On the other hand, after land restoration, the lnRRof SOC and TN storage were 0.27 and 0.19, which indicates that land restoration increased SOC and TN storage by 31% and 20.9% in the Karst areas. In addition, the lnRR of soil mass after deforestation was 0.09, and the lnRR after land restoration was -0.04, demonstrating that both deforestation and land restoration had great impacts on soil bulk density (Table 2).