Responses of soil heterotrophic respiration to changes in soil temperature and moisture in a Stipa krylovii grassland in Nei Mongol

2014 ◽  
Vol 38 (3) ◽  
pp. 238-248
Author(s):  
LI Yue ◽  
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◽  
◽  
◽  
...  
Keyword(s):  
Soil Temperature ◽  
Heterotrophic Respiration ◽  
Stipa Krylovii ◽  
Soil Heterotrophic Respiration ◽  
Soil Temperature And Moisture

scholarly journals Investigating the sensitivity of soil respiration to recent snow cover changes in Alaska using a satellite-based permafrost carbon model

2020 ◽  
Author(s):  
Yonghong Yi ◽  
John S. Kimball ◽  
Jennifer D. Watts ◽  
Susan M. Natali ◽  
Donatella Zona ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Soil Temperature ◽  
Soil Carbon ◽  
Snow Cover ◽  
Carbon Fluxes ◽  
Cold Season ◽  
Heterotrophic Respiration ◽  
Surface Model ◽  
Total Soil ◽  
Soil Heterotrophic Respiration

Abstract. The contribution of soil heterotrophic respiration to the boreal-Arctic carbon (CO2) cycle and its potential feedback to climate change remain poorly quantified. We developed a remote sensing driven permafrost carbon model at intermediate scale (~ 1 km) to investigate how environmental factors affect the magnitude and seasonality of soil heterotrophic respiration in Alaska. The permafrost carbon model simulates snow and soil thermal dynamics, and accounts for vertical soil carbon transport and decomposition at depths up to 3 m below surface. Model outputs include soil temperature profiles and carbon fluxes at 1-km resolution spanning the recent satellite era (2001–2017) across Alaska. Comparisons with eddy covariance tower measurements show that the model captures the seasonality of carbon fluxes, with favorable accuracy in predicting net ecosystem CO2 exchange (NEE) in both tundra (R > 0.8, RMSE = 0.34 g C m−2 d−1) and boreal forest (R > 0.73, RMSE = 0.51 g C m−2 d−1). Benchmark assessments using two regional in-situ datasets indicate that the model captures the complex influence of snow insulation on soil temperature, and the temperature sensitivity of cold-season soil respiration. Across Alaska, we find that seasonal snow cover imposes strong controls on the contribution from different soil depths to total soil carbon emissions. Earlier snow melt in spring promotes deeper soil warming and enhances the contribution of deeper soils to total soil respiration during the later growing season, thereby reducing net ecosystem carbon uptake. Early cold-season soil respiration is closely linked to the number of snow-free days after land surface freezes (R = −0.48, p 

scholarly journals Investigating the sensitivity of soil heterotrophic respiration to recent snow cover changes in Alaska using a satellite-based permafrost carbon model

2020 ◽  
Vol 17 (22) ◽  
pp. 5861-5882
Author(s):  
Yonghong Yi ◽  
John S. Kimball ◽  
Jennifer D. Watts ◽  
Susan M. Natali ◽  
Donatella Zona ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Snow Cover ◽  
Land Surface ◽  
Carbon Fluxes ◽  
Cold Season ◽  
Heterotrophic Respiration ◽  
Surface Model ◽  
Thermal Dynamics ◽  
Total Soil ◽  
Soil Heterotrophic Respiration

Abstract. The contribution of soil heterotrophic respiration to the boreal–Arctic carbon (CO2) cycle and its potential feedback to climate change remains poorly quantified. We developed a remote-sensing-driven permafrost carbon model at intermediate scale (∼1 km) to investigate how environmental factors affect the magnitude and seasonality of soil heterotrophic respiration in Alaska. The permafrost carbon model simulates snow and soil thermal dynamics and accounts for vertical soil carbon transport and decomposition at depths up to 3 m below the surface. Model outputs include soil temperature profiles and carbon fluxes at 1 km resolution spanning the recent satellite era (2001–2017) across Alaska. Comparisons with eddy covariance tower measurements show that the model captures the seasonality of carbon fluxes, with favorable accuracy in simulating net ecosystem CO2 exchange (NEE) for both tundra (R>0.8, root mean square error (RMSE – 0.34 g C m−2 d−1), and boreal forest (R>0.73; RMSE – 0.51 g C m−2 d−1). Benchmark assessments using two regional in situ data sets indicate that the model captures the complex influence of snow insulation on soil temperature and the temperature sensitivity of cold-season soil heterotrophic respiration. Across Alaska, we find that seasonal snow cover imposes strong controls on the contribution from different soil depths to total soil heterotrophic respiration. Earlier snowmelt in spring promotes deeper soil warming and enhances the contribution of deeper soils to total soil heterotrophic respiration during the later growing season, thereby reducing net ecosystem carbon uptake. Early cold-season soil heterotrophic respiration is closely linked to the number of snow-free days after the land surface freezes (R=-0.48, p<0.1), i.e., the delay in snow onset relative to surface freeze onset. Recent trends toward earlier autumn snow onset in northern Alaska promote a longer zero-curtain period and enhanced cold-season respiration. In contrast, southwestern Alaska shows a strong reduction in the number of snow-free days after land surface freeze onset, leading to earlier soil freezing and a large reduction in cold-season soil heterotrophic respiration. Our results also show nonnegligible influences of subgrid variability in surface conditions on the model-simulated CO2 seasonal cycle, especially during the early cold season at 10 km scale. Our results demonstrate the critical role of snow cover affecting the seasonality of soil temperature and respiration and highlight the challenges of incorporating these complex processes into future projections of the boreal–Arctic carbon cycle.

scholarly journals Insights Into Fire-based Soil Temperature and Moisture Changes From a Long-term Data Set in Alaska

2021 ◽  
Author(s):  
Kristen Manies ◽  
Jennifer Harden ◽  
William Cable ◽  
Jamie Hollingsworth
Keyword(s):  
Soil Temperature ◽  
Data Set ◽  
Term Data ◽  
Soil Temperature And Moisture

ROOT-SURFACE MYCOFLORA OF SOYBEAN IN RELATION TO SOIL TEMPERATURE AND MOISTURE IN A FIELD ENVIRONMENT

1972 ◽  
Vol 52 (2) ◽  
pp. 199-208 ◽  
Author(s):  
K. C. IVARSON ◽  
A. R. MACK
Keyword(s):  
Soil Temperature ◽  
Relative Frequency ◽  
Incubation Temperature ◽  
Growing Season ◽  
Root Surface ◽  
Growing Seasons ◽  
Field Environment ◽  
Abundant Genus ◽  
Field Plots ◽  
Soil Temperature And Moisture

Studies were made on the root-surface fungi of soybean grown in field plots where various soil temperature and moisture environments had been maintained for five previous growing seasons. Washed-root segments were incubated on agar plates at temperatures corresponding to those of the field plots. Fusarium was the most abundant genus appearing on the plates. Species of Mucor, Trichoderma, Alternaria, Mortierella, Aspergillus, Corynespora, Rhizoctonia, Penicillium, Gliocladium, and sterile forms appeared fairly frequently. Statistical analysis of the data revealed that changes in soil and incubation temperature markedly affected the relative frequency of 12 genera, and age of plant significantly affected nine genera. Soil moisture influenced the frequency of only one genus. High soil and incubation temperature (28 C) encouraged greater root populations of Rhizoctonia early in the season, Trichoderma and Aspergillus throughout the growing season, and Fusarium late in the season. Low soil temperature conditions (12 C) favored growth of Pythium, Mortierella, Mucor, Alternaria, Cladosporium, throughout the growing season, and Corynespora and Cylindrocarpon, primarily during mid-season. Late in the season Gliocladium preferred the intermediate temperature of 20 C.

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