Partitioning of ecosystem respiration in winter wheat and silage maize—modeling seasonal temperature effects

Demyan, Michael Scott; Ingwersen, Joachim; Funkuin, Yvonne Nkwain; Ali, Rana Shahbaz; Mirzaeitalarposhti, Reza; Rasche, Frank; Poll, Christian; Müller, Torsten; Streck, Thilo; Kandeler, Ellen; Cadisch, Georg

doi:10.1016/j.agee.2016.03.039

Cited by 23 publications

(24 citation statements)

References 63 publications

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“…. With an average flux of 1.54 g C m −2 d −1 , 1.55 g C m −2 d −1 , and 3.19 g C m −2 d −1 , measured average daily R h , R a and R eco were within the range of values reported for winter wheat by Demyan et al (), Prolingheuer et al (), and Zhang et al ().…”

Section: Resultssupporting

confidence: 81%

“…Different in situ and in vitro approaches as well as combinations of measurement techniques in order to separate R eco into R a and R h , including root exclusion, physical separation of components, isotopic techniques, and modelling based approaches were compared and evaluated in a number of studies (Hanson et al, 2000;Kuzyakov and Larionova, 2005;Subke et al, 2006). Out of these, especially root exclusion techniques, such as tree-girdling in forest ecosystems (Bhupinderpal-Singh et al, 2003) and root removal and trenching in grassland and cropland ecosystems (Suleau et al, 2011) were used in recent field studies (Suleau et al, 2011;Zhang et al, 2013;Prolingheuer et al, 2014;Demyan et al, 2016). Compared to forest or perennial ecosystems, root exclusion methods are easy to implement in croplands by not sowing or regularly weeding the fallow plot (e.g., Suleau et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

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Combining a root exclusion technique with continuous chamber and porous tube measurements for a pin‐point separation of ecosystem respiration in croplands

Hoffmann

Wirth

Beßler

et al. 2017

J. Plant Nutr. Soil Sci.

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To better assess ecosystem C budgets of croplands and understand their potential response to climate and management changes, detailed information on the mechanisms and environmental controls driving the individual C flux components are needed. This accounts in particular for the ecosystem respiration (Reco) and its components, the autotrophic (Ra) and heterotrophic respiration (Rh) which vary tremendously in time and space. This study presents a method to separate Reco into Ra [as the sum of Ra (shoot) and Ra (root)] and Rh in order to detect temporal and small‐scale spatial dynamics within their relative contribution to overall Reco. Thus, predominant environmental drivers and underlying mechanisms can be revealed. Reco was derived during nighttime by automatic chamber CO2 flux measurements on plant covered plots. Rh was derived from CO2 efflux measurements, which were performed in parallel to Reco measurements on a fallow plot using CO2 sampling tubes in 10 cm soil depth. Ra (root) was calculated as the difference between sampling tube CO2 efflux measurements on a plant covered plot and Rh. Ra (shoot) was calculated as Reco – Ra (root) – Rh. Measurements were carried out for winter wheat (Triticum aestivum L.) during the crop season 2015 at an experimental plot located in the hummocky ground moraine landscape of NE Germany. Reco varied seasonally from < 1 to 9.5 g C m−2 d−1, and was higher in adult (a) and reproductive (r) than juvenile (j) stands (g C m−2 d−1: j = 1.2, a = 4.6, r = 5.3). Observed Ra and Rh were in general smaller compared to the independently measured Reco, contributing in average 58% and 42% to Reco. However, both varied strongly regarding their environmental drivers and particular contribution throughout the study period, following the seasonal development of soil temperature and moisture (Rh) as well as crop development (Ra). Thus, our results consistently revealed temporal dynamics regarding the relative contribution of Ra (root) and Ra (shoot) to Ra, as well as of Ra and Rh to Reco. Based on the observed results, implications for partitioning of Reco in croplands are given.

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Section: Resultssupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Combining a root exclusion technique with continuous chamber and porous tube measurements for a pin‐point separation of ecosystem respiration in croplands

Hoffmann

Wirth

Beßler

et al. 2017

J. Plant Nutr. Soil Sci.

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show abstract

“…Wilson et al (2002) reported no clear differences in EBC between flat and sloped terrain sites across 22 research sites. A comparison of two different agroecosystems in China, a degraded grassland and a maize cropland, showed similar EBC of about 80 % (Du et al, 2014). The comparison of a mature boreal jack pine forest and a jack pine clear-cut site by Kidston et al (2010) revealed that depending on the surface characteristics, the loss of low frequencies can contribute significantly to the energy imbalance.…”

Section: Introductionmentioning

confidence: 95%

Evaluating multi-year, multi-site data on the energy balance closure of eddy-covariance flux measurements at cropland sites in southwestern Germany

et al. 2019

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Abstract. The energy balance of eddy-covariance (EC) measurements is typically not closed, resulting in one of the main challenges in evaluating and interpreting EC flux data. Energy balance closure (EBC) is crucial for validating and improving regional and global climate models. To investigate the nature of the gap in EBC for agroecosystems, we analyzed EC measurements from two climatically contrasting regions (Kraichgau – KR – and Swabian Jura – SJ) in southwestern Germany. Data were taken at six fully equipped EC sites from 2010 to 2017. The gap in EBC was quantified by ordinary linear regression, relating the energy balance ratio (EBR), calculated as the quotient of turbulent fluxes and available energy, to the residual energy term. In order to examine potential reasons for differences in EBC, we compared the EBC under varying environmental conditions and investigated a wide range of possible controls. Overall, the variation in EBC was found to be higher during winter than summer. Moreover, we determined that the site had a statistically significant effect on EBC but no significant effect on either crop or region (KR vs SJ). The time-variable footprints of all EC stations were estimated based on data measured in 2015, complimented by micro-topographic analyses along the prevailing wind direction. The smallest mean annual energy balance gap was 17 % in KR and 13 % in SJ. Highest EBRs were mostly found for winds from the prevailing wind direction. The spread of EBRs distinctly narrowed under unstable atmospheric conditions, strong buoyancy, and high friction velocities. Smaller footprint areas led to better EBC due to increasing homogeneity. Flow distortions caused by the back head of the anemometer negatively affected EBC during corresponding wind conditions.

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“…This is slightly lower than yearly TER measured on a winter wheat study site in Belgium with 23.18 t C-CO 2 ha −1 a −1 (Suleau et al, 2011). Demyan et al (2016) reported lower values, with an average total of 11.43 t C-CO 2 ha −1 a −1 , derived from observations spanning six growing seasons in southwestern Germany. However, all studies are possibly prone to overestimations of the emissions from September to November, as daily emissions are generated with a multiple linear regression model, and in our case, are based on our hourly measurements of air temperature and soil moisture.…”

Section: Measured Co 2 Fluxesmentioning

confidence: 61%

Constraining a complex biogeochemical model for CO<sub>2</sub> and N<sub>2</sub>O emission simulations from various land uses by model–data fusion

2017

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Abstract. This study presents the results of a combined measurement and modelling strategy to analyse N 2 O and CO 2 emissions from adjacent arable land, forest and grassland sites in Hesse, Germany. The measured emissions reveal seasonal patterns and management effects, including fertilizer application, tillage, harvest and grazing. The measured annual N 2 O fluxes are 4.5, 0.4 and 0.1 kg N ha −1 a −1 , and the CO 2 fluxes are 20.0, 12.2 and 3.0 t C ha −1 a −1 for the arable land, grassland and forest sites, respectively. An innovative model-data fusion concept based on a multicriteria evaluation (soil moisture at different depths, yield, CO 2 and N 2 O emissions) is used to rigorously test the LandscapeDNDC biogeochemical model. The model is run in a Latin-hypercube-based uncertainty analysis framework to constrain model parameter uncertainty and derive behavioural model runs. The results indicate that the model is generally capable of predicting trace gas emissions, as evaluated with RMSE as the objective function. The model shows a reasonable performance in simulating the ecosystem C and N balances. The model-data fusion concept helps to detect remaining model errors, such as missing (e.g. freeze-thaw cycling) or incomplete model processes (e.g. respiration rates after harvest). This concept further elucidates the identification of missing model input sources (e.g. the uptake of N through shallow groundwater on grassland during the vegetation period) and uncertainty in the measured validation data (e.g. forest N 2 O emissions in winter months). Guidance is provided to improve the model structure and field measurements to further advance landscape-scale model predictions.

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Partitioning of ecosystem respiration in winter wheat and silage maize—modeling seasonal temperature effects

Cited by 23 publications

References 63 publications

Combining a root exclusion technique with continuous chamber and porous tube measurements for a pin‐point separation of ecosystem respiration in croplands

Combining a root exclusion technique with continuous chamber and porous tube measurements for a pin‐point separation of ecosystem respiration in croplands

Evaluating multi-year, multi-site data on the energy balance closure of eddy-covariance flux measurements at cropland sites in southwestern Germany

Constraining a complex biogeochemical model for CO<sub>2</sub> and N<sub>2</sub>O emission simulations from various land uses by model–data fusion

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Partitioning of ecosystem respiration in winter wheat and silage maize—modeling seasonal temperature effects

Cited by 23 publications

References 63 publications

Combining a root exclusion technique with continuous chamber and porous tube measurements for a pin‐point separation of ecosystem respiration in croplands

Combining a root exclusion technique with continuous chamber and porous tube measurements for a pin‐point separation of ecosystem respiration in croplands

Evaluating multi-year, multi-site data on the energy balance closure of eddy-covariance flux measurements at cropland sites in southwestern Germany

Constraining a complex biogeochemical model for CO&lt;sub&gt;2&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O emission simulations from various land uses by model–data fusion

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Constraining a complex biogeochemical model for CO<sub>2</sub> and N<sub>2</sub>O emission simulations from various land uses by model–data fusion