Results
Soil
enzyme activities
Generally, the mean NAG and LAP enzyme activities increased from the
uncultivated land to cropland to afforested lands (shrubland and
woodland) with higher levels in the top soil than deep soil (Fig. 1).
The seasonal patterns of NAG and LAP enzyme activities showed higher
levels in summer compared to other seasons in all land use types except
the cropland with lower level of NAG enzyme activity in summer at the
top soil (Fig. 2). The mean specific enzyme activities for two
N-hydrolyzing enzymes were significantly lower in the uncultivated soils
than other land use types at both soil layers except in the shrubland of
deep soil (Fig. 3). Notably, two specific enzyme activities were higher
in the top soil than deep soil, but there were no significant
differences in two specific enzyme activities between top soil and deep
soil in the woodland (Fig. 3).