Figure 2
NMDS plot (left) of Bray–Curtis dissimilarity matrix of enzyme activity data among 24 samples from long-term experiments and a VPA map (right) of the effects of pH, experimental site, fertilization and their interactions on the soil enzymes.
In the NMDS plot, stress values and Shepard R2 values are shown in the upper right and the lower right of the plot, respectively. The bubble size indicated the goodness of fit and poorly fitted sample have larger bubbles. JL, SD, AH and HN indicate the samples collected from the long-term experiments at Jilin Province, Shandong Province, Anhui Province and Hunan Province of China, respectively. CF means the treatment applied with only chemical fertilizer and COF means the treatment applied with both organic and inorganic fertilizer. The treatments labeled in blue are collected from the COF treatment and the treatments labeled in red are collected from the CF treatment. The three bubbles closest to the treatment label stand for the three replicates of each treatment obtained from the same long-term experiment. In the VPA map, circles on the edges of the triangle show the percentage of variation explained by each factor alone. The percentage of variation explained by interactions between two or three of the factors is shown as black circles on the sides and as a square at the center of the triangle. The unexplained variation is depicted in the square at the bottom. **Indicate significance at P < 0.01.
