Autotrophic component of soil respiration is repressed by drought more than the heterotrophic one in dry grasslands

Balogh, János; Papp, Marianna; Pintér, Krisztina; Fóti, Szilvia; Posta, Katalin; Eugster, Werner; Nagy, Zoltán

doi:10.5194/bg-13-5171-2016

Cited by 50 publications

(26 citation statements)

References 53 publications

(88 reference statements)

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“…During summer in SDS, the Cistus plant community, unable to access deep water, moved to a dormant status in order to maintain turgor. This caused a reduction in photosynthates and substrate availability; however, the observed summer depression of SR was not due to a modification of SR h but to the suppression of autotrophic respiration, as already similarly observed in other ecosystem types under drought [13,58,59], and SR h accounted for almost 100% of SR. Concurrently, a significant increase in WEOC was observed, likely because of the high root mortality occurring in summer in Mediterranean ecosystems [60,61] and the simultaneous photodegradation of surface litter at high irradiance [62,63], which both release high amounts of C into the soil. At the same time, a change in the microbial community assemblage could be detected.…”

Section: Discussionsupporting

confidence: 76%

The Response of Soil CO2 Efflux to Water Limitation Is Not Merely a Climatic Issue: The Role of Substrate Availability

Dato¹,

Lagomarsino²,

Lellei‐Kovács

et al. 2017

Forests

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Abstract:Water availability, together with temperature, represents the most limiting abiotic factor regulating soil CO 2 efflux (SR). Besides the direct effect of water limitation, drought also influences plant activity, determining changes in the quality and quantity of root exudates, thus indirectly affecting soil microbial activity. To determine how the seasonal changes of plant activity and soil microbial metabolism and structure affect SR response to drought, we investigated the correlation between leaf gas exchange, soil carbon pools and soil respiration sources and the role of soil carbon pools on microbial populations and soil respiration, in a summer deciduous Mediterranean (SDS) and a winter deciduous temperate (WDS) shrublands, experiencing a dry summer period. In both sites, drought reduced photosynthesis, but affected SR differently: in SDS, SR decreased, although microbial heterotrophic respiration (SR h ) remained unchanged; in WDS, SR did not vary but SR h was reduced. While in SDS the microbial community was able to respire more complex substrates, in WDS it was strongly dependent on easily decomposable molecules, thus on plant activity. Therefore, the response of soil CO 2 efflux to water limitation is not exclusively influenced by climate as it is modulated by the degree of adaptation of the microbial community to drought.

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Section: Discussionsupporting

confidence: 76%

The Response of Soil CO2 Efflux to Water Limitation Is Not Merely a Climatic Issue: The Role of Substrate Availability

Dato¹,

Lagomarsino²,

Lellei‐Kovács

et al. 2017

Forests

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“…In the present case study, this mowing effect on the soil respiration was more visible in 2016, compared to 2017 and 2018, because of the limited amount of rainfall that occurred in these latter 2 years that might suppress both the microbial activities [42] and the root respiration [40]. Some studies have reported that mowing has an indirect effect on the soil respiration due to herbage removal and exposure of the soil to higher incident solar radiation, which might stimulate the soil microbial activity due to the soil temperature increase [24].…”

Section: The Effects Of Management Practices On Soil Respirationmentioning

confidence: 56%

“…A role for grasslands in climate change mitigation is widely recognized, and the numerous studies that have been carried out recently testify their importance at the global level [5,24,26,32,[39][40][41]. Future climate scenarios in southern Europe suggest that changes in annual temperatures, precipitation patterns, and atmospheric CO 2 concentrations might negatively alter grassland biodiversity and the associated ecosystem services, including regulating services linked to carbon cycling, especially in areas with low summer rainfall [5,41].…”

Section: Relationships Between Soil Respiration Water Content and Tementioning

confidence: 99%

Soil Respiration Dynamics in Bromus erectus-Dominated Grasslands under Different Management Intensities

et al. 2019

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Reduction of soil greenhouse gas emissions is crucial to control increases in atmospheric CO2 concentrations. Permanent grasslands are of considerable importance in climate change mitigation strategies as they cover about 13% of the global agricultural area. However, uncertainties remain for the effects of management practices on soil respiration, especially over the short term. This study investigated the influence of different mowing intensities on soil respiration over the short term for Bromus erectus-dominated grasslands in the central Apennines. From 2016 to 2018, soil respiration, temperature, and moisture were measured under three different management systems: customary management, intensive use, and abandonment. Both soil water content and temperature changed over time, however mowing did not affect soil water content while occasionally altered soil temperature. The intensive use promoted higher seasonal mean soil respiration compared to the abandonment only during the 2016 growing season. Soil temperature was the main driver of soil respiration above a soil water content threshold that varied little among treatments (18.23–22.71%). Below the thresholds, soil moisture was the main driver of soil respiration. These data suggest that different mowing regimes have little influence on soil respiration over the short term in Bromus erectus-dominated grasslands. Thus, more intensive use would not have significative impacts on soil respiration, at least over the short term. Future studies need to clarify the role of root mycorrhizal and microbial respiration in the light of climate change, considering the seasonal redistribution of the rainfall.

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“…However, from the field observations, plots under drought conditions had very sparse vegetation if not completely bare (Figures 2E,F), suggesting a higher contribution of heterotrophic respiration to the measured CO 2 flux than autotrophic respiration. In support, Balogh et al (2016) found that rhizospheric respiration, a component of autotrophic respiration was highly sensitive to drought. Moreover, Hanson et al (2000), asserts that the root contribution to total soil respiration is higher during the growing season and lower during the dormant periods of the year while allude to the stronger relationship between plant growth and root respiration.…”

Section: Effect Of Drought and Grazing On Soil Carbon Storage And Co mentioning

confidence: 94%

Disentangling Drought and Grazing Effects on Soil Carbon Stocks and CO2 Fluxes in a Semi-Arid African Savanna

Munjonji

Ayisi

Mudongo

et al. 2020

Front. Environ. Sci.

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Grasslands cover ca. 30% of the global land surface and provide critical ecosystem services. Among them, carbon storage is one of the most important. However, grasslands are increasingly threatened by drought and overgrazing which might negatively affect soil carbon stocks. Despite this threat, there is a dearth of information on how drought and grazing jointly impact soil carbon stocks and CO 2 fluxes in dryland grasslands. With the aid of a large field experiment, we studied the combined effects of a 5-year extreme drought and moderate grazing on soil carbon stocks, CO 2 fluxes and soil chemical properties. Extreme drought was induced by reducing ambient rainfall by 66% using large rainout shelters. We found CO 2 fluxes to strongly respond to the 5-year experimental drought. Extreme drought reduced CO 2 emission rates by 32% compared to ambient conditions. CO 2 fluxes averaged 5.7 mg m −2 min −1 under drought compared to 8.3 mg m −2 min −1 under ambient conditions. CO 2 fluxes were, however, not influenced by grazing. At the end of the growth period, grazed plots under ambient rainfall had released 16.3 tons of CO 2 ha −1 which was 58% higher than observed on grazed plots subjected to severe drought. Soil carbon stocks were higher under drought conditions due to slower decomposition rates. Drought resulted in increased concentrations of primary macronutrients (N, P, and K), micronutrients (Zn and Mn) and pH in the top 30 cm of the soil relative to ambient conditions. The results also showed that grazing reduced the concentration of N and P in the topsoil compared to the ungrazed plots. This study provided insights on the soil carbon storage, CO 2 emission rates and nutrient dynamics in a semi-arid dryland grassland as influenced by both drought and grazing. Our study also revealed that long-term extreme drought may be favorable in terms of preserving the existing soil carbon stocks through reduced CO 2 release. This finding is critical for understanding future soil carbon dynamics in dryland grasslands in the face of climate change.

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Autotrophic component of soil respiration is repressed by drought more than the heterotrophic one in dry grasslands

Cited by 50 publications

References 53 publications

The Response of Soil CO2 Efflux to Water Limitation Is Not Merely a Climatic Issue: The Role of Substrate Availability

The Response of Soil CO2 Efflux to Water Limitation Is Not Merely a Climatic Issue: The Role of Substrate Availability

Soil Respiration Dynamics in Bromus erectus-Dominated Grasslands under Different Management Intensities

Disentangling Drought and Grazing Effects on Soil Carbon Stocks and CO2 Fluxes in a Semi-Arid African Savanna

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