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| Titel |
Responses of microbial respiration in grazed and ungrazed grasslands to
glucose addition |
| VerfasserIn |
Xingliang Xu, Qianyuan Liu, Rui Pang |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250151083
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| Publikation (Nr.) |
 EGU/EGU2017-15627.pdf |
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| Zusammenfassung |
| Grazing can change species composition, alter soil properties, and thus modify microbial
activities, affecting biogeochemical processes in grasslands. However, it remains unclear how
microbial respiration in grazed and ungrazed grasslands responds to glucose addition. Here
we hypothesize that microbial respiration in grazed grasslands will respond more strongly to
glucose addition than in ungrazed grasslands because moderate grazing can enhance
microbial activity. To examine the hypothesis above, we collected the upper 10 cm soil from
grazed and ungrazed grasslands at five sites of China. Three sites (Hulunbuir 1, Hulunbuir 2
and Xielingele) were located in Inner Mongolia and two in the Tibet Plateau) Soils
were incubated with low glucose input (50% MBC), high glucose input (150%
MBC), and water for 60 days in 21oC. CO2 released from soil was trapped with 1 M
NaOH. The results showed that the effect of grazing on microbial respiration has
two distinct patterns, depending on soil types and addition amount. After glucose
addition, cumulative CO2 efflux from grazed soils was significantly higher than from
ungrazed soils in two temperate grasslands (Hulunbuir 1 and Xielingele). This may be
ascribed to that moderate grazing promoted microbial activity. On the contrary,
microbial respirations from grazed soils were lower than ungrazed soils in two
alpine meadows of Haibei and Dangxiong and in Hulunbuir 2. This effect of grazing
was not obvious in Hulunbeier 2 soils at low carbon addition level. Grazing may
decrease soil organic carbon, nitrogen availability and thus microbial activity in
alpine grasslands. These findings indicate that soil microorganisms could have
different adaptation mechanisms to grazing in temperate and alpine grasslands. |
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