Microbial biomass plays a significant role in nutrient transformation and ecosystem conservation
under tropical and temperate climates,
as turnover of microbial biomass influences the
amount of N being stored or released, and thus
availability of N for plant uptake Moreover, rates of net mineralization and nitrification
during laboratory or field in situ incubation
provide an effective indicator of N availability
Therefore, there is a strong need
for more field studies on rhizosphere nutrient
cycling under different climates and tree species
for providing more realistic views of rhizosphere
processes
In the river channel of the mainstream of the midlower
Yangtze River, there is a large number of floodplains
which are valuable land resources
Afforestation is recommended as a viable
option for ecological restoration and enhancement
of biological diversity in such less favorable soils that
are often periodically flooded.
The primary objective
of this study was to quantify and compare the effects
of different tree species on soil N transformations
in the rhizosphere under seasonally flooded field
conditions. We hypothesized that (1) rhizosphere
effects would lead to increased N mineralization due
to enhanced microbial activity in the close vicinity
of roots for all three species and (2) the magnitude
of these effects would differ among the species or
gene types due to differences in intrinsic biological
characteristics.