Limits...
Differences in SOM decomposition and temperature sensitivity among soil aggregate size classes in a temperate grasslands.

Wang Q, Wang D, Wen X, Yu G, He N, Wang R - PLoS ONE (2015)

Bottom Line: The results showed that temperature and aggregate size significantly affected on SOM decomposition, with notable interactive effects (P<0.0001).Cumulative C emission differed significantly among aggregate size classes (P <0.0001), with the largest values occurring in MA (1101 μg g-1), followed by MF (976 μg g-1) and MI (879 μg g-1).These findings suggest that feedback from SOM decomposition in response to changing temperature is closely associated withsoil aggregation and highlights the complex responses of ecosystem C budgets to future warming scenarios.

View Article: PubMed Central - PubMed

Affiliation: Resources and Environment College, Anhui Agricultural University, Hefei, China; Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.

ABSTRACT
The principle of enzyme kinetics suggests that the temperature sensitivity (Q10) of soil organic matter (SOM) decomposition is inversely related to organic carbon (C) quality, i.e., the C quality-temperature (CQT) hypothesis. We tested this hypothesis by performing laboratory incubation experiments with bulk soil, macroaggregates (MA, 250-2000 μm), microaggregates (MI, 53-250 μm), and mineral fractions (MF, <53 μm) collected from an Inner Mongolian temperate grassland. The results showed that temperature and aggregate size significantly affected on SOM decomposition, with notable interactive effects (P<0.0001). For 2 weeks, the decomposition rates of bulk soil and soil aggregates increased with increasing incubation temperature in the following order: MA>MF>bulk soil >MI(P <0.05). The Q10 values were highest for MA, followed (in decreasing order) by bulk soil, MF, and MI. Similarly, the activation energies (Ea) for MA, bulk soil, MF, and MI were 48.47, 33.26, 27.01, and 23.18 KJ mol-1, respectively. The observed significant negative correlations between Q10 and C quality index in bulk soil and soil aggregates (P<0.05) suggested that the CQT hypothesis is applicable to soil aggregates. Cumulative C emission differed significantly among aggregate size classes (P <0.0001), with the largest values occurring in MA (1101 μg g-1), followed by MF (976 μg g-1) and MI (879 μg g-1). These findings suggest that feedback from SOM decomposition in response to changing temperature is closely associated withsoil aggregation and highlights the complex responses of ecosystem C budgets to future warming scenarios.

Show MeSH
Relationship between temperature sensitivity (Q10) and SOC quality.The Q10 values werecalculated using an exponential equation. Values were the means (n = 3); bars indicate the SD.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4334239&req=5

pone.0117033.g003: Relationship between temperature sensitivity (Q10) and SOC quality.The Q10 values werecalculated using an exponential equation. Values were the means (n = 3); bars indicate the SD.

Mentions: Temperature and aggregate size had a significant influence on SOM decomposition rates, with notable interactive effects (P<0.0001). In addition, the Q10 values of SOM decomposition calculated using either the exponential model orthe Arrhenius model differed significantly among aggregate sizes (Fig. 1, S1 Fig., Table 2), ordered as follows: MA > MF > bulk soil > MI. We also found that the differences in Q10 values decreased with increasing temperature (F = 299.98, P<0.0001) (Fig. 2,Table 3). Significant negative correlations were observedbetween Q10 and the C quality index (P = 0.001, Fig. 3, S2 Fig.). Similarly, negative correlations were observed between Q10 values and Ea (F = 374.43, P<0.0001, Table 3), which is consistent with the CQT hypothesis.


Differences in SOM decomposition and temperature sensitivity among soil aggregate size classes in a temperate grasslands.

Wang Q, Wang D, Wen X, Yu G, He N, Wang R - PLoS ONE (2015)

Relationship between temperature sensitivity (Q10) and SOC quality.The Q10 values werecalculated using an exponential equation. Values were the means (n = 3); bars indicate the SD.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4334239&req=5

pone.0117033.g003: Relationship between temperature sensitivity (Q10) and SOC quality.The Q10 values werecalculated using an exponential equation. Values were the means (n = 3); bars indicate the SD.
Mentions: Temperature and aggregate size had a significant influence on SOM decomposition rates, with notable interactive effects (P<0.0001). In addition, the Q10 values of SOM decomposition calculated using either the exponential model orthe Arrhenius model differed significantly among aggregate sizes (Fig. 1, S1 Fig., Table 2), ordered as follows: MA > MF > bulk soil > MI. We also found that the differences in Q10 values decreased with increasing temperature (F = 299.98, P<0.0001) (Fig. 2,Table 3). Significant negative correlations were observedbetween Q10 and the C quality index (P = 0.001, Fig. 3, S2 Fig.). Similarly, negative correlations were observed between Q10 values and Ea (F = 374.43, P<0.0001, Table 3), which is consistent with the CQT hypothesis.

Bottom Line: The results showed that temperature and aggregate size significantly affected on SOM decomposition, with notable interactive effects (P<0.0001).Cumulative C emission differed significantly among aggregate size classes (P <0.0001), with the largest values occurring in MA (1101 μg g-1), followed by MF (976 μg g-1) and MI (879 μg g-1).These findings suggest that feedback from SOM decomposition in response to changing temperature is closely associated withsoil aggregation and highlights the complex responses of ecosystem C budgets to future warming scenarios.

View Article: PubMed Central - PubMed

Affiliation: Resources and Environment College, Anhui Agricultural University, Hefei, China; Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.

ABSTRACT
The principle of enzyme kinetics suggests that the temperature sensitivity (Q10) of soil organic matter (SOM) decomposition is inversely related to organic carbon (C) quality, i.e., the C quality-temperature (CQT) hypothesis. We tested this hypothesis by performing laboratory incubation experiments with bulk soil, macroaggregates (MA, 250-2000 μm), microaggregates (MI, 53-250 μm), and mineral fractions (MF, <53 μm) collected from an Inner Mongolian temperate grassland. The results showed that temperature and aggregate size significantly affected on SOM decomposition, with notable interactive effects (P<0.0001). For 2 weeks, the decomposition rates of bulk soil and soil aggregates increased with increasing incubation temperature in the following order: MA>MF>bulk soil >MI(P <0.05). The Q10 values were highest for MA, followed (in decreasing order) by bulk soil, MF, and MI. Similarly, the activation energies (Ea) for MA, bulk soil, MF, and MI were 48.47, 33.26, 27.01, and 23.18 KJ mol-1, respectively. The observed significant negative correlations between Q10 and C quality index in bulk soil and soil aggregates (P<0.05) suggested that the CQT hypothesis is applicable to soil aggregates. Cumulative C emission differed significantly among aggregate size classes (P <0.0001), with the largest values occurring in MA (1101 μg g-1), followed by MF (976 μg g-1) and MI (879 μg g-1). These findings suggest that feedback from SOM decomposition in response to changing temperature is closely associated withsoil aggregation and highlights the complex responses of ecosystem C budgets to future warming scenarios.

Show MeSH