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Changes in Temperature Sensitivity and Activation Energy of Soil Organic Matter Decomposition in Different Qinghai-Tibet Plateau Grasslands.

Li J, He N, Wei X, Gao Y, Zuo Y - PLoS ONE (2015)

Bottom Line: The Q10 values differed significantly among different grasslands, and the overall trends were as follows: alpine meadow (1.56 ± 0.09) < alpine steppe (1.88 ± 0.23) < alpine desert (2.39 ± 0.32).The exponential negative correlations between Ea and R at 20°C across all grassland types (all Ps < 0.001) indicated that the substrate-quality temperature hypothesis is applicable to the alpine grasslands.Our findings provide new insights for understanding the responses of SOM decomposition and storage to warming scenarios in this Plateau.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China; Institute of Grassland Science, Northeast Normal University, Changchun, 130024, China; Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun, 130024, China.

ABSTRACT
Qinghai-Tibet Plateau grasslands are unique geographical regions and store substantial soil organic matter (SOM) in the soil surface, which make them very sensitive to global climate change. Here, we focused on three main grassland types (alpine meadow, steppe, and desert) and conducted a soil incubation experiment at five different temperatures (5, 10, 15, 20, and 25°C) to investigate SOM decomposition rates (R), temperature sensitivity (Q10), and activation energy (Ea). The results showed that grassland type and incubation temperature had significant impact on R (P < 0.001), and the values of R were exponential correlated with incubation temperature in three alpine grasslands. At the same temperature, R was in the following order: alpine meadow > alpinesteppe > alpine desert. The Q10 values differed significantly among different grasslands, and the overall trends were as follows: alpine meadow (1.56 ± 0.09) < alpine steppe (1.88 ± 0.23) < alpine desert (2.39 ± 0.32). Moreover, the Ea values differed significantly across different grassland types (P < 0.001) and increased with increasing incubation time. The exponential negative correlations between Ea and R at 20°C across all grassland types (all Ps < 0.001) indicated that the substrate-quality temperature hypothesis is applicable to the alpine grasslands. Our findings provide new insights for understanding the responses of SOM decomposition and storage to warming scenarios in this Plateau.

No MeSH data available.


The relationships between activation energy and soil organic matter (SOM) decomposition rate at 20°C in the grasslands of the Qinghai-Tibet Plateau.A: Alpine meadow; B: Alpine steppe; C Alpine desert.
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pone.0132795.g005: The relationships between activation energy and soil organic matter (SOM) decomposition rate at 20°C in the grasslands of the Qinghai-Tibet Plateau.A: Alpine meadow; B: Alpine steppe; C Alpine desert.

Mentions: Grassland type (F = 105.043, P < 0.001) and incubation time (F = 11.525, P < 0.001) had a significant influence on Ea. At the same incubation time, Ea increased in the following order: alpine meadow < alpine steppe < alpine desert (Fig 4). At 56 days of incubation, Ea was the lowest in alpine meadow (36.61 KJ mol–1), followed by that in the alpine steppe (53.44 KJ mol–1) and alpine desert (69.73 KJ mol–1). With an increase in incubation time, Ea increased across all grassland types (R2 = 0.92, P = 0.005 for alpine meadow; R2 = 0.98, P = 0.018 for alpine steppe; R2 = 0.97, P = 0.001 for alpine desert; Fig 4). Moreover, across all grassland types, Ea was exponential negatively correlated with R at 20°C (Fig 5).


Changes in Temperature Sensitivity and Activation Energy of Soil Organic Matter Decomposition in Different Qinghai-Tibet Plateau Grasslands.

Li J, He N, Wei X, Gao Y, Zuo Y - PLoS ONE (2015)

The relationships between activation energy and soil organic matter (SOM) decomposition rate at 20°C in the grasslands of the Qinghai-Tibet Plateau.A: Alpine meadow; B: Alpine steppe; C Alpine desert.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4503348&req=5

pone.0132795.g005: The relationships between activation energy and soil organic matter (SOM) decomposition rate at 20°C in the grasslands of the Qinghai-Tibet Plateau.A: Alpine meadow; B: Alpine steppe; C Alpine desert.
Mentions: Grassland type (F = 105.043, P < 0.001) and incubation time (F = 11.525, P < 0.001) had a significant influence on Ea. At the same incubation time, Ea increased in the following order: alpine meadow < alpine steppe < alpine desert (Fig 4). At 56 days of incubation, Ea was the lowest in alpine meadow (36.61 KJ mol–1), followed by that in the alpine steppe (53.44 KJ mol–1) and alpine desert (69.73 KJ mol–1). With an increase in incubation time, Ea increased across all grassland types (R2 = 0.92, P = 0.005 for alpine meadow; R2 = 0.98, P = 0.018 for alpine steppe; R2 = 0.97, P = 0.001 for alpine desert; Fig 4). Moreover, across all grassland types, Ea was exponential negatively correlated with R at 20°C (Fig 5).

Bottom Line: The Q10 values differed significantly among different grasslands, and the overall trends were as follows: alpine meadow (1.56 ± 0.09) < alpine steppe (1.88 ± 0.23) < alpine desert (2.39 ± 0.32).The exponential negative correlations between Ea and R at 20°C across all grassland types (all Ps < 0.001) indicated that the substrate-quality temperature hypothesis is applicable to the alpine grasslands.Our findings provide new insights for understanding the responses of SOM decomposition and storage to warming scenarios in this Plateau.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China; Institute of Grassland Science, Northeast Normal University, Changchun, 130024, China; Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun, 130024, China.

ABSTRACT
Qinghai-Tibet Plateau grasslands are unique geographical regions and store substantial soil organic matter (SOM) in the soil surface, which make them very sensitive to global climate change. Here, we focused on three main grassland types (alpine meadow, steppe, and desert) and conducted a soil incubation experiment at five different temperatures (5, 10, 15, 20, and 25°C) to investigate SOM decomposition rates (R), temperature sensitivity (Q10), and activation energy (Ea). The results showed that grassland type and incubation temperature had significant impact on R (P < 0.001), and the values of R were exponential correlated with incubation temperature in three alpine grasslands. At the same temperature, R was in the following order: alpine meadow > alpinesteppe > alpine desert. The Q10 values differed significantly among different grasslands, and the overall trends were as follows: alpine meadow (1.56 ± 0.09) < alpine steppe (1.88 ± 0.23) < alpine desert (2.39 ± 0.32). Moreover, the Ea values differed significantly across different grassland types (P < 0.001) and increased with increasing incubation time. The exponential negative correlations between Ea and R at 20°C across all grassland types (all Ps < 0.001) indicated that the substrate-quality temperature hypothesis is applicable to the alpine grasslands. Our findings provide new insights for understanding the responses of SOM decomposition and storage to warming scenarios in this Plateau.

No MeSH data available.