水保所知识产出(1956---)知识库

Subsoil exposure due to factors including erosion and terracing, evidently decreases soil organic carbon storage
and productivity, but the responses of bacterial communities and their carbon dynamics remain unclear. Soils
from0–20cm,20–60 cmand60–100cmwerecollectedfromthree100cmprofilesinbarelandontheLoessPla-
teau, and incubated in buried pots for a year (July 2016 to July 2017) to simulate subsoil exposure, with ongoing
monitoring of the microbial mineralization rate of soil organic carbon (K c ), using Li-Cor 8100. At the end of the
incubation period, the exposed soil and the in situ control soil were sampled to investigate changes in bacterial
community composition, as represented by 16S rRNA, and the activities of enzymes involved in soil carbon cy-
cling. Both copiotrophic (Actinobacteria and Alphaproteobacteria) and oligotrophic (Thermoleophilia) groups
were stimulated in the exposed vs. control soil at 20–60 and 60–100 cm. The exposed vs. control soil from 60
to 100 cm produced the greatest bacterial responses, such as greater diversity and altered keystone groups
(Thermoleophilia vs. unidentified Acidobacteria). Enzyme activities were greater in the exposed vs. control soil
atboth20–60cm(β-D-xylosidaseandcellobiohydrolase)and60–100cm(β-D-xylosidaseandβ-D-glucosidase).
Theexposedsoilfrom20–60cmand60–100cmhadlowerK c andQ 10 valuesthanthoseat0–20cm.Ourfindings
revealed the existence of bacterial depth-specific responses to subsoil exposure, and highlight the effect of an-
thropogenic soil redistribution on soil carbon flux and its potential responses to future climate change.