3.3. Variation of soil enzyme activities in different vegetation
types
The type of vegetation significantly affected soil amylase, urease, and
sucrase activities (Fig. 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 0-20 cm soil
layer, the amylase activity in GL vegetation was significantly higher
than that of the other three vegetation types (Fig. 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 (Fig. 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 (Fig. 3D). In the 20-40 cm 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).