Changes in Soil Enzyme Activities and Microbial Biomass after Revegetation in the Three Gorges Reservoir, China

134-146

Artikel aus einer Zeitschrift

200206095

Abstract: Soil enzymes and microbes are central to the decomposition of plant and microbial detritus,
and play important roles in carbon, nitrogen, and phosphorus biogeochemistry cycling at the
ecosystem level. In the present study, we characterized the soil enzyme activity and microbial biomass
in revegetated (with Taxodium distichum (L.) Rich. and Cynodon dactylon (L.) Pers.) versus unplanted
soil in the riparian zone of the Three Gorges Dam Reservoir (TGDR), in order to quantify the effect
of revegetation on the edaphic microenvironment after water flooding in situ. After revegetation,
the soil physical and chemical properties in revegetated soil showed significant differences to those
in unplanted soil. The microbial biomass carbon and phosphorus in soils of T. distichum were
significantly higher than those in C. dactylon and unplanted soils, respectively. The microbial biomass
nitrogen in revegetated T. distichum and C. dactylon soils was significantly increased by 273% and
203%, respectively. The enzyme activities of T. distichum and C. dactylon soils displayed no significant
difference between each other, but exhibited a great increase compared to those of the unplanted soil.
Elements ratio (except C/N (S)) did not vary significantly between T. distichum and C. dactylon soils;
meanwhile, a strong community-level elemental homeostasis in the revegetated soils was found.
The correlation analyses demonstrated that only microbial biomass carbon and phosphorus had
a significantly positive relationship with soil enzyme activities. After revegetation, both soil enzyme
activities and microbial biomasses were relatively stable in the T. distichum and C. dactylon soils,
with the wooded soil being more superior. The higher enzyme activities and microbial biomasses
demonstrate the C, N, and P cycling and the maintenance of soil quality in the riparian zone of
the TGDR.

Keywords: revegetation; microbial biomass; chloroform fumigation extraction; enzyme activities; stoichiometric homeostasis; the Three Gorges Reservoir