scholarly journals Modeling carbon dynamics in two adjacent spruce forests with different soil conditions in Russia

2008 ◽  
Vol 5 (4) ◽  
pp. 969-980 ◽  
Author(s):  
J. Kurbatova ◽  
C. Li ◽  
A. Varlagin ◽  
X. Xiao ◽  
N. Vygodskaya
Keyword(s):  
Water Table ◽  
Carbon Balance ◽  
Atmospheric Co2 ◽  
Soil Conditions ◽  
Organic Layer ◽  
General Effect ◽  
Spruce Forest ◽  
Spruce Forests ◽  
Net Ecosystem Carbon Exchange ◽  
Wide Range

Abstract. Net ecosystem carbon exchange (NEE) was measured with eddy covariance method for two adjacent forests located at the southern boundary of European taiga in Russia in 1999–2004. The two spruce forests shared similar vegetation composition but differed in soil conditions. The wet spruce forest (WSF) possessed a thick peat layer (60 cm) with a high water table seasonally close to or above the soil surface. The dry spruce forest (DSF) had a relatively thin organic layer (5 cm) with a deep water table (>60 cm). The measured multi-year average NEE fluxes (2000 and –1440 kg C ha−1yr−1 for WSF and DSF, respectively) indicated that WSF was a source while DSF a sink of atmospheric carbon dioxide (CO2) during the experimental years. A process-based model, Forest-DNDC, was employed in the study to interpret the observations. The modeled multi-year average NEE fluxes were 1800 and –2200 kg C ha−1yr−1 for WSF and DSF, respectively, which were comparable with observations. The modeled data also showed high soil heterotrophic respiration rates at WSF that suggested that the water table fluctuation at WSF could have played a key role in determining the negative carbon balance in the wetland ecosystem. A sensitivity test was conducted by running Forest-DNDC with varied water table scenarios for WSF. The results indicated that the NEE fluxes from WSF were highly sensitive to the water table depth. When the water table was high, the WSF ecosystem maintained as a sink of atmospheric CO2; while along with the drop of the water table the length of the flooded period reduced and more organic matter in the soil profile suffered from rapid decomposition that gradually converted the ecosystem into a source of atmospheric CO2. The general effect of water table variation on wetland carbon balance observed from this modeling study could be applicable for a wide range of wetland ecosystems that have accumulated soil organic carbon while face hydrological changes under certain climatic or land-use change scenarios.

scholarly journals Modeling carbon dynamics in two adjacent spruce forests with different soil conditions in Russia

2008 ◽  
Vol 5 (1) ◽  
pp. 271-296
Author(s):  
J. Kurbatova ◽  
C. Li ◽  
A. Varlagin ◽  
X. Xiao ◽  
N. Vygodskaya
Keyword(s):  
Water Table ◽  
Soil Conditions ◽  
Organic Layer ◽  
Spruce Forest ◽  
Eddy Covariance Method ◽  
Southern Boundary ◽  
Organic C ◽  
Spruce Forests ◽  
Net Ecosystem Carbon Exchange ◽  
Wide Range

Abstract. Net ecosystem carbon exchange (NEE) were measured with eddy covariance method for two adjacent forests located at the southern boundary of European taiga in Russia in 1999–2004. The two spruce forests shared similar vegetation composition but differed in soil conditions. The wet spruce forest (WSF) possessed a thick peat layer (60 cm) with a high water table seasonally close to or above the soil surface. The dry spruce forest (DSF) had a relatively thin organic layer (5 cm) with a deep water table (>60 cm). The measured NEE fluxes (2000 and −1440 kg C ha−1 yr−1 for WSF and DSF, respectively) indicated that WSF was a source while DSF a sink of atmospheric carbon dioxide during the experimental years. A process-based model, Forest-DNDC, was employed in the study to interpret the observations. The modeled NEE fluxes were 1800 and −2200 kg C ha−1 yr−1 for WSF and DSF, respectively, which were comparable with the observations. The modeled data indicated that WSF and DSF had similar rates of photosynthesis and plant autotrophic respiration but differed in soil heterotrophic respiration. The simulations resulted in a hypothesis that the water table fluctuation at WSF could play a key role in determining the negative C balance in the ecosystem. A sensitivity test was conducted by running Forest-DNDC with varied water table scenarios for WSF. The results proved that the NEE fluxes from WSF were highly sensitive to the water table depth. When the water table dropped, the length of flooding season became shorter and more organic matter in the soil profile suffered from rapid decomposition that converted the ecosystem into a source atmospheric C. The conclusion from this modeling study could be applicable for a wide range of wetland and forest ecosystems that have accumulated soil organic C while face hydrological changes under certain climatic or land-use change scenarios.

scholarly journals CO<sub>2</sub> fluxes and ecosystem dynamics at five European treeless peatlands – merging data and process oriented modelling

2014 ◽  
Vol 11 (6) ◽  
pp. 9249-9297
Author(s):  
C. Metzger ◽  
P.-E. Jansson ◽  
A. Lohila ◽  
M. Aurela ◽  
T. Eickenscheidt ◽  
...  
Keyword(s):  
Water Table ◽  
Photosynthetic Efficiency ◽  
Heterotrophic Respiration ◽  
Soil Conditions ◽  
Model Parameters ◽  
Co2 Fluxes ◽  
Area Index ◽  
Wide Range ◽  
Process Oriented ◽  
Organic Decomposition

Abstract. The carbon dioxide (CO2) exchange of five different peatland systems across Europe with a wide gradient in landuse intensity, water table depth, soil fertility and climate was simulated with the process oriented CoupModel. The aim of the study was to find out to what extent CO2 fluxes measured at different sites, can be explained by common processes and parameters implemented in the model. The CoupModel was calibrated to fit measured CO2 fluxes, soil temperature, snow depth and leaf area index (LAI) and resulting differences in model parameters were analysed. Finding site independent model parameters would mean that differences in the measured fluxes could be explained solely by model input data: water table, meteorological data, management and soil inventory data. The model, utilizing a site independent configuration for most of the parameters, captured seasonal variability in the major fluxes well. Parameters that differed between sites included the rate of soil organic decomposition, photosynthetic efficiency, and regulation of the mobile carbon (C) pool from senescence to shooting in the next year. The largest difference between sites was the rate coefficient for heterotrophic respiration. Setting it to a common value would lead to underestimation of mean total respiration by a factor of 2.8 up to an overestimation by a factor of 4. Despite testing a wide range of different responses to soil water and temperature, heterotrophic respiration rates were consistently lowest on formerly drained sites and highest on the managed sites. Substrate decomposability, pH and vegetation characteristics are possible explanations for the differences in decomposition rates. Applying common parameter values for the timing of plant shooting and senescence, and a minimum temperature for photosynthesis, had only a minor effect on model performance, even though the gradient in site latitude ranged from 48° N (South-Germany) to 68° N (northern Finland). This was also true for common parameters defining the moisture and temperature response for decomposition. CoupModel is able to describe measured fluxes at different sites or under different conditions, providing that the rate of soil organic decomposition, photosynthetic efficiency, and the regulation of the mobile carbon (C) pool are estimated from available information on specific soil conditions, vegetation and management of the ecosystems.

scholarly journals Coupled stochastic dynamics of water table and soil moisture in bare soil conditions

2008 ◽  
Vol 44 (1) ◽  
Author(s):  
L. Ridolfi ◽  
P. D'Odorico ◽  
F. Laio ◽  
S. Tamea ◽  
I. Rodriguez-Iturbe
Keyword(s):  
Soil Moisture ◽  
Water Table ◽  
Stochastic Dynamics ◽  
Bare Soil ◽  
Soil Conditions

scholarly journals Modelling soil temperature and moisture and corresponding seasonality of photosynthesis and transpiration in a boreal spruce ecosystem

2012 ◽  
Vol 9 (5) ◽  
pp. 6419-6455
Author(s):  
S. H. Wu ◽  
P.-E. Jansson
Keyword(s):  
Soil Temperature ◽  
Transition Period ◽  
Temperature Response ◽  
Net Ecosystem Exchange ◽  
Ecosystem Model ◽  
Heat Fluxes ◽  
Soil Conditions ◽  
Eddy Flux ◽  
Flux Tower ◽  
Wide Range

Abstract. Recovery of photosynthesis and transpiration is strongly restricted by low temperatures in air and/or soil during the transition period from winter to spring in boreal zones. The extent to which air temperature (Ta) and soil temperature (Ts) influence the seasonality of photosynthesis and transpiration of a boreal spruce ecosystem was investigated using a process-based ecosystem model (CoupModel) together with eddy covariance (EC) data from one eddy flux tower and nearby soil measurements at Knottåsen, Sweden. A Monte Carlo based uncertainty method (GLUE) provided prior and posterior distributions of simulations representing a wide range of soil conditions and performance indicators. The simulated results showed sufficient flexibility to predict the measured cold and warm Ts in the moist and dry plots around the eddy flux tower. Moreover, the model presented a general ability to describe both biotic and abiotic processes for the Norway spruce stand. The dynamics of sensible heat fluxes were well described the corresponding latent heat fluxes and net ecosystem exchange of CO2. The parameter ranges obtained are probably valid to represent regional characteristics of boreal conifer forests, but were not easy to constrain to a smaller range than that produced by the assumed prior distributions. Finally, neglecting the soil temperature response function resulted in fewer behavioural models and probably more compensatory errors in other response functions for regulating the seasonality of ecosystem fluxes.

scholarly journals Tree Change in Nemoral Spruce Forests of the Central Forest Reserve

2021 ◽  
pp. 459-476
Author(s):  
M. Yu. Pukinskaya
Keyword(s):  
Deciduous Forest ◽  
Climatic Conditions ◽  
Spruce Forest ◽  
Forest Reserve ◽  
Spruce Forests ◽  
The Past ◽  
Broad Leaved Forest ◽  
The Russian Federation ◽  
Leaved Forest

The paper discusses changes in forest-forming species in the nemoral spruce forests of the Central Forest Reserve (Tver Region, the Russian Federation). A comparison is made of the characterization of vegetation in the reserve spruce forests, carried out during the first survey of the reserve by Ya. Ya. Alekseev in 1931 (Alekseev, 1935) with the descriptions of vegetation made by the author from 2011 to 2019. It is shown that the coverage of nemoral herbs in the spruce forests of the reserve has increased over the past 90 years. In addition, three types of broadleaf trees (Tilia cordata Mill., Acer platanoides L. and Ulmus scabra Mill.) have greatly increased their abundance in the stand, most notably the linden. In recent decades, the decay of nemoral spruce forests has been taking place in the Central Forest Reserve. The birch-aspenspruce stand is not replenished with spruce renewal but is replaced by linden-maple forests. The vitality of spruce undergrowth is deteriorating. After the decay of a spruce forest, a change of the tree dominants occurs on 74% of the trial plots and the stand continues with a spruce forest on 26%. The largest part of the reserve's nemoral spruce forests arose after major disturbances 100–150 years ago (on the site of burned-out areas, hurricane windblows and cuttings). Old nemoral spruce forests were formed during the period when severe frosts prevented linden and maple from entering the stand. Currently, the coincidence of climate warming with the aging of the spruce stand and the removal of anthropogenic influence contributed to the release of maple and linden from the undergrowth into the stand and change to a spruce-deciduous forest. Under the prevailing climatic conditions, a return to the spruce forest is possible in the event of a burning out or when the climate becomes cold. The nemoral spruce forest is an ecotone type and, depending on conditions, becomes a spruce or broad-leaved forest.

Links between hydrological patterns and lateral carbon fluxes: a comparison between a wet and a drained site on a Siberian permafrost floodplain tundra

2021 ◽  
Author(s):  
Sandra Raab ◽  
Mathias Goeckede ◽  
Jorien Vonk ◽  
Anke Hildebrandt ◽  
Martin Heimann
Keyword(s):  
Organic Carbon ◽  
Water Table ◽  
Surface Waters ◽  
Carbon Fluxes ◽  
Flow Patterns ◽  
Control Site ◽  
Water Levels ◽  
Soil Conditions ◽  
Transport Patterns ◽  
Carbon Transport

&lt;p&gt;As a major reservoir for organic carbon, permafrost areas play a pivotal role in global climate change. Vertical carbon fluxes as well as lateral transport from land to groundwaters and surface waters towards the ocean are highly dependent on various abiotic and biotic factors. These include for example temperature, groundwater depth, or vegetation community. During summer months, when soils thaw and lateral carbon transport within suprapermafrost groundwater bodies and surface waters occurs, flow patterns and therefore carbon redistribution may differ significantly between dry and wet conditions. Since dry soil conditions are expected to become more frequent in the future, associated shifts in carbon transport patterns play an important role in quantifying the carbon input into the water body linked to permafrost degradation.&lt;/p&gt;&lt;p&gt;This study focuses on hydrological and carbon transport patterns within a floodplain tundra site near Chersky, Northeast Siberia. We compared a wet control site with a site affected by a drainage ring built in 2004 to study the effect of water availability on carbon production and transport. Water table depths at both sites were continuously monitored with a distributed sensor network over the summer seasons 2016-2020. At several locations, water samples were collected in 2016 and 2017 to determine organic carbon concentrations (DOC) as well as carbon isotopes (e.g. &amp;#8710;&lt;sup&gt;14&lt;/sup&gt;C-DOC). Suprapermafrost groundwater and surface water from the drainage ditch and the nearby Ambolikha river were included in the analysis.&lt;/p&gt;&lt;p&gt;Our results focus on the physical hydrological conditions as well as on DOC and &amp;#8710;&lt;sup&gt;14&lt;/sup&gt;C-DOC observations. The spatio-temporal dynamics of water table depth revealed systematic differences between control and drained sites. The drained area showed a stronger decrease in water tables towards peak summer season in July and stronger reactions to precipitation events. The control area responded less pronounced to short-term changes. At the drained site, the main groundwater flow direction was stable throughout the measurement period. The control site was characterized by a shift in water flow confluence depending on increasing and decreasing water levels. DOC and &amp;#8710;&lt;sup&gt;14&lt;/sup&gt;C-DOC data showed that the highest concentrations of organic carbon and oldest DOC can be found in late summer. DOC concentrations were higher at the drained site compared to the wet site. We will show that the distribution of dissolved carbon can be directly related to hydrological flow patterns, and that understanding of these redistribution processes is essential for interpreting the carbon budget in disturbed permafrost.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

scholarly journals 15N natural abundances in two podsol soils of two spruce forests differing in their atmospheric N deposition conditions

2011 ◽  
Vol 51 (No. 9) ◽  
pp. 416-422 ◽  
Author(s):  
S.P. Sah
Keyword(s):  
Mineral Soil ◽  
Vertical Gradient ◽  
N Deposition ◽  
Climatic Conditions ◽  
Organic Layer ◽  
Atmospheric N Deposition ◽  
Spruce Forests ◽  
Humus Layer ◽  
N Enrichment ◽  
Deposition Conditions

This study aims to investigate the changes in isotope ratios in foliage and soils of the two spruce forests [Picea abies (L.) Karst.] differing greatly in their atmospheric N deposition and climatic conditions. As expected, both N concentrations and <sup>15</sup>N values in both needles and litter were found to be significantly higher in the Solling stand (N-saturated) compared to the Hyytial&auml; stand (N-poor). For the N-limited site (Hyytial&auml; plot), a typical vertical gradient of the soil <sup>15</sup>N-enrichment (both in organic and mineral soil) was observed. The N-saturated site (Solling) differs from the N-limited site (Hyytial&auml;) with respect to the <sup>15</sup>N abundance trend in organic layer. In the upper organic layer up to O-f horizon, i.e. mor layer (0&ndash;3.5 cm depth) of Solling plot, there is almost a trend of slight soil <sup>15</sup>N-depletion with increasing depth, and then there is a <sup>15</sup>N-enrichment from O-h horizon (humus layer) of organic layer to mineral soil horizons. This is explained by the presence of prominent NO<sub>3</sub><sup>&ndash;</sup> leaching at this plot

Simulation of the Responses of Dry Beans (Phaseolus vulgaris L.) to Irrigation

2017 ◽  
Vol 60 (6) ◽  
pp. 1983-1994 ◽  
Author(s):  
Mónica Espadafor ◽  
Lairson Couto ◽  
Morethson Resende ◽  
Delbert W. Henderson ◽  
Margarita García-Vila ◽  
...  
Keyword(s):  
Phaseolus Vulgaris ◽  
Simulation Model ◽  
Soil Water ◽  
Yield Response ◽  
Soil Conditions ◽  
Dry Beans ◽  
Phaseolus Vulgaris L ◽  
Management Options ◽  
Crop Simulation ◽  
Wide Range

Abstract. AquaCrop is a crop simulation model developed by the FAO aimed at assessing the yield response to water supply. Once the model is calibrated and validated, it is a useful tool to simulate crop yields under different management options or climatic and soil conditions. Until now, AquaCrop has not been parameterized for dry beans ( L.), and thus our objective was to calibrate and validate the model for this crop using experiments performed 40 years ago at Davis, California. A set of parameters derived from the calibration with one irrigation experiment was used to validate the model using five experiments carried out in 1977 and 1978 that had treatments vastly differing in irrigation depth and frequency. Yield predictions over a wide range of values (&lt;1 to 3.5 t ha-1) were very good, with RMSE of 0.16 t ha-1 and Willmott’s d of 0.978. Seasonal ET was also accurately predicted by the model (RMSE = 40 mm, d = 0.930), as also evidenced by comparing the lysimeter measured ET of 489 mm against the lysimeter simulated ET of 501 mm. Canopy cover and the time course of biomass were adequately simulated as well. Even though total soil water extraction was well simulated, the simulated soil water distribution with depth differed from measured values in the dryland treatment. We conclude that AquaCrop can now be used for the simulation of dry beans in different environments, and we emphasize the value of carefully conducted field experiments for the validation of crop simulation models. Keywords: AquaCrop, Calibration and validation, Dry beans (Phaseolus vulgaris L.), Irrigation, Simulation model, Water stress.

Modeling soil hydraulic properties for a wide range of soil conditions

2008 ◽  
Vol 219 (3-4) ◽  
pp. 300-316 ◽  
Author(s):  
Vincent Balland ◽  
Joseph A.P. Pollacco ◽  
Paul A. Arp
Keyword(s):  
Hydraulic Properties ◽  
Soil Conditions ◽  
Soil Hydraulic Properties ◽  
Wide Range ◽  
Soil Hydraulic

scholarly journals Climate mediates the biodiversity–ecosystem stability relationship globally

2018 ◽  
Vol 115 (33) ◽  
pp. 8400-8405 ◽  
Author(s):  
Pablo García-Palacios ◽  
Nicolas Gross ◽  
Juan Gaitán ◽  
Fernando T. Maestre
Keyword(s):  
Plant Diversity ◽  
Plant Biomass ◽  
Leaf Traits ◽  
Climatic Conditions ◽  
Soil Conditions ◽  
Ecosystem Stability ◽  
Positive Role ◽  
Insurance Hypothesis ◽  
Wide Range ◽  
Dryland Ecosystems

The insurance hypothesis, stating that biodiversity can increase ecosystem stability, has received wide research and political attention. Recent experiments suggest that climate change can impact how plant diversity influences ecosystem stability, but most evidence of the biodiversity–stability relationship obtained to date comes from local studies performed under a limited set of climatic conditions. Here, we investigate how climate mediates the relationships between plant (taxonomical and functional) diversity and ecosystem stability across the globe. To do so, we coupled 14 years of temporal remote sensing measurements of plant biomass with field surveys of diversity in 123 dryland ecosystems from all continents except Antarctica. Across a wide range of climatic and soil conditions, plant species pools, and locations, we were able to explain 73% of variation in ecosystem stability, measured as the ratio of the temporal mean biomass to the SD. The positive role of plant diversity on ecosystem stability was as important as that of climatic and soil factors. However, we also found a strong climate dependency of the biodiversity–ecosystem stability relationship across our global aridity gradient. Our findings suggest that the diversity of leaf traits may drive ecosystem stability at low aridity levels, whereas species richness may have a greater stabilizing role under the most arid conditions evaluated. Our study highlights that to minimize variations in the temporal delivery of ecosystem services related to plant biomass, functional and taxonomic plant diversity should be particularly promoted under low and high aridity conditions, respectively.

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