Statistics
Soil N-hydrolyzing enzyme activities in soil were normalized to SON
concentration (enzyme: SON) to analyze the specific enzyme activities.
Multiple-way Analysis of Variance
(ANOVA) was used to test the statistical significance of land use types,
seasons, depths and their interactive effects on soil
variables (two N-hydrolyzing
enzyme activities). One-way ANOVA
with Tukey’s HSD test was used to further test the statistical
significance of land use types, seasons, depths on soil enzyme
activities, respectively. Analysis for all of the data was carried out
using IBM SPSS Statistics 21.0 software (Armonk, NY, USA). The Pearson
correlation coefficients using IBM SPSS Statistics 21.0 and redundancy
analysis (RDA) using Canoco5.0 were performed to quantify the
correlations between soil enzyme activities and soil variables. The
significance level was established at p < 0.05. Soil C-, N-
and P-hydrolyzing enzyme activities were loge-transformed prior to
stoichiometric analyses following the conventions of stoichiometric
studies and to better achieve normality (Sterner and Elser 2002;
Sinsabaugh et al., 2009)