3.3. Variation of soil enzyme activities in different vegetation
types
The type of vegetation significantly affected soil amylase, urease, and
sucrase activities (Figure 3).
There were no significant differences in soil catalase activity among
the four vegetation types. However, a two-way ANOVA test revealed a
significant association between soil depth and vegetation type on
catalase activity (Table 3). For the 0-20cm soil layer, the amylase
activity in GL vegetation was significantly higher than that of the
other three vegetation types (Figure 3A); the urease activity of XS
vegetation was significantly higher than that of HR, CK, and GL by
58.75, 69.04, and 48.49 mg/g, respectively (Figure 3C); soil sucrase
activity in GL vegetation was
significantly higher than HR and CK by 110.23 and 423.35 mg/g,
respectively, but no significant difference was observed in XS
vegetation (Figure 3D). In the 20-40cm soil layer, HR amylase activity
displayed significant differences with CK, and displayed no significant
differences with XS and GL. The CK amylase activity was significantly
lower than the other three vegetation types. The soil urease activity in
the 20-40 cm layer of XS vegetation was significantly higher than that
of the other three types of vegetation. As soil depth increased,
vegetation soil catalase and sucrase activities increased (except for
CK). Soil enzyme activity under other vegetation types was greater in
the upper layers than in the lower layers. A two-way ANOVA test
demonstrated extremely significant relationships between soil depth and
vegetation type on enzyme activity (amylase, urease, sucrase) in all
samples studied (Table 3).