scholarly journals Automation of soil flux chamber measurements: potentials and pitfalls

2016 ◽  
Vol 13 (6) ◽  
pp. 1949-1966 ◽  
Author(s):  
Carolyn-Monika Görres ◽  
Claudia Kammann ◽  
Reinhart Ceulemans
Keyword(s):  
Greenhouse Gas ◽  
Phase 1 ◽  
Temporal Frequency ◽  
Soil Co2 ◽  
Soil Co2 Flux ◽  
Technical Problems ◽  
Field Situation ◽  
Two Systems ◽  
Closed Canopy ◽  
Chamber Measurements

Abstract. Recent technological advances have enabled the wider application of automated chambers for soil greenhouse gas (GHG) flux measurements, several of them commercially available. However, few studies addressed the challenges associated with operating these systems. In this contribution we compared two commercial soil GHG chamber systems – the LI-8100A Automated Soil CO2 Flux System and the greenhouse gas monitoring system AGPS. From April until August 2014, the two systems monitored in parallel soil respiration (SR) fluxes at a recently harvested poplar (Populus) plantation, which provided a bare field situation directly after the harvest as well as a closed canopy later on. For the bare field situation (15 April–30 June 2014), the cumulated average SR obtained from the unfiltered data sets of the LI-8100A and the AGPS were 520 and 433 g CO2 m−2 respectively. For the closed canopy phase (1 July–31 August 2014), which was characterized by a higher soil moisture content, the cumulated average SR estimates were not significantly different with 507 and 501 g CO2 m−2 for the AGPS and the LI-8100A respectively. Flux quality control and filtering did not significantly alter the results obtained by the LI-8100A, whereas the AGPS SR estimates were reduced by at least 20 %. The main reasons for the observed differences in the performance of the two systems were (i) a lower data coverage provided by the AGPS due to technical problems; (ii) incomplete headspace mixing in the AGPS chambers; (iii) lateral soil CO2 diffusion below the collars during AGPS chamber measurements; and (iv) a possible overestimation of nighttime SR fluxes by the LI-8100A. Additionally, increased root growth was observed within the LI-8100A collars but not within the AGPS collars, which might have also contributed to the observed differences. In contrast to the LI-8100A, the AGPS had the gas sample inlets installed inside the collars and not the chambers. This unique design feature enabled for the first time the detection of disturbed chamber measurements during nights with a stratified atmosphere, resulting in unbiased nighttime SR estimates. Thus besides providing high temporal frequency flux data, automated chamber systems offer another possibility to greatly improve our understanding of SR fluxes.

scholarly journals Automation of soil flux chamber measurements: potentials and pitfalls

2015 ◽  
Vol 12 (17) ◽  
pp. 14693-14738 ◽  
Author(s):  
C.-M. Görres ◽  
C. Kammann ◽  
R. Ceulemans
Keyword(s):  
Greenhouse Gas ◽  
Temporal Frequency ◽  
Soil Co2 ◽  
Flux Chamber ◽  
Soil Co2 Flux ◽  
Technical Problems ◽  
Field Situation ◽  
Two Systems ◽  
Closed Canopy ◽  
Chamber Measurements

Abstract. Recent technological advances have enabled the wider application of automated chambers for soil greenhouse gas (GHG) flux measurements, several of them commercially available. However, only few studies addressed the difficulties and challenges associated with operating these systems. In this contribution we compared two commercial soil GHG chamber systems–the LI-8100A Automated Soil CO2 Flux System and the Greenhouse Gas Monitoring System AGPS. From April 2014 until August 2014, the two systems monitored in parallel soil respiration (SR) fluxes at a recently harvested poplar plantation, which provided a bare field situation directly after the harvest as well as a closed canopy later on. For the bare field situation (15 April–30 June 2014), the cumulated average SR obtained from the unfiltered datasets of the LI-8100A and the AGPS were 520 and 433 g CO2 m−2, respectively. For the closed canopy phase (01 July–31 August 2014), which was characterized by a higher soil moisture content, the cumulated average SR estimates were not significantly different with 507 and 501 g CO2 m−2 for the AGPS and the LI-8100A, respectively. Flux quality control and filtering did not significantly alter the results obtained by the LI-8100A, whereas the AGPS SR estimates were reduced by at least 20 %. The main reasons for the observed differences in the performance of the two systems were (i) a lower data coverage provided by the AGPS due to technical problems; (ii) incomplete headspace mixing in the AGPS chambers; (iii) lateral soil CO2 diffusion below the collars during AGPS chamber measurements; (iv) increased root growth within the LI-8100A collars; and (v) a possible overestimation of nighttime SR fluxes by the LI-8100A. In contrast to the LI-8100A, the AGPS had the gas sample inlets installed inside the collars and not the chambers. This unique design feature enabled for the first time the detection of disturbed chamber measurements during nights with a stratified atmosphere, resulting in unbiased nighttime SR estimates. Thus besides providing high temporal frequency flux data, automated chamber systems offer another possibility to greatly improve our understanding of SR fluxes.

scholarly journals Comparison of continuous in-situ CO<sub>2</sub> observations at Jungfraujoch using two different measurement techniques

2014 ◽  
Vol 7 (7) ◽  
pp. 7053-7084
Author(s):  
M. F. Schibig ◽  
M. Steinbacher ◽  
B. Buchmann ◽  
I. T. van der Laan-Luijkx ◽  
S. van der Laan ◽  
...  
Keyword(s):  
Materials Science ◽  
Measurement Techniques ◽  
Ambient Air ◽  
Pollution Monitoring ◽  
Smooth Transition ◽  
Research Station ◽  
Short Term ◽  
Technical Problems ◽  
Two Systems ◽  
Data Coverage

Abstract. Since 2004, atmospheric carbon dioxide (CO2) is measured at the High Altitude Research Station Jungfraujoch by the division of Climate and Environmental Physics at the University of Bern (KUP) using a nondispersive infrared gas analyzer (NDIR) in combination with a paramagnetic O2 analyzer. In January 2010, CO2 measurements based on cavity ring down spectroscopy (CRDS) as part of the Swiss National Air Pollution Monitoring Network have been added by the Swiss Federal Laboratories for Materials Science and Technology (Empa). To ensure a smooth transition – a prerequisite when merging two datasets e.g. for trend determinations – the two measurement systems run in parallel for several years. Such a long-term intercomparison also allows identifying potential offsets between the two datasets and getting information about the compatibility of the two systems on different time scales. A good agreement of the seasonality as well as for the short-term variations was observed and to a lesser extent for trend calculations mainly due to the short common period. However, the comparison revealed some issues related to the stability of the calibration gases of the KUP system and their assigned CO2 mole fraction. It was possible to adapt an improved calibration strategy based on standard gas determinations, which lead to better agreement between the two data sets. By excluding periods with technical problems and bad calibration gas cylinders, the average hourly difference (CRDS − NDIR) of the two systems is −0.03 ppm ± 0.25 ppm. Although the difference of the two datasets is in line with the compatibility goal of ±0.1 ppm of the World Meteorological Organization (WMO), the standard deviation is still too high. A significant part of this uncertainty originates from the necessity to switch the KUP system frequently (every 12 min) for 6 min from ambient air to a working gas in order to correct short-term variations of the O2 measurement system. Allowing additionally for signal stabilization after switching the sample, an effective data coverage of only 1/6 for the KUP system is achieved while the Empa system has a nearly complete data coverage. Additionally, different internal volumes and flow rates between the two systems may affect observed differences.

scholarly journals Synthesizing greenhouse gas fluxes across nine European peatlands and shrublands – responses to climatic and environmental changes

2012 ◽  
Vol 9 (3) ◽  
pp. 3693-3738 ◽  
Author(s):  
M. S. Carter ◽  
K. S. Larsen ◽  
B. Emmett ◽  
M. Estiarte ◽  
C. Field ◽  
...  
Keyword(s):  
Global Warming ◽  
Greenhouse Gas ◽  
Air Temperature ◽  
Environmental Changes ◽  
Negative Relationship ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Prolonged Drought ◽  
Mean Annual Air Temperature

Abstract. In this study, we compare annual fluxes of methane (CH4), nitrous oxide (N2O) and soil respiratory carbon dioxide (CO2) measured at nine European peatlands (n = 4) and shrublands (n = 5). The sites range from northern Sweden to Spain, covering a span in mean annual air temperature from 0 to 16 °C, and in annual precipitation from 300 to 1300 mm yr−1. The effects of climate change, including temperature increase and prolonged drought, were tested at five shrubland sites. At one peatland site, the long-term (>30 yr) effect of drainage was assessed, while increased nitrogen deposition was investigated at three peatland sites. The shrublands were generally sinks for atmospheric CH4 whereas the peatlands were CH4 sources, with fluxes ranging from −519 to +6890 mg CH4-C m−2 yr−1 across the studied ecosystems. At the peatland sites, annual CH4 emission increased with mean annual air temperature, while a negative relationship was found between net CH4 uptake and the soil carbon stock at the shrubland sites. Annual N2O fluxes were generally small ranging from –14 to 42 mg N2O-N m−2 yr−1. Highest N2O emission occurred at the sites that had highest concentration of nitrate (NO3−) in soil water. Furthermore, experimentally increased NO3− deposition led to increased N2O efflux, whereas prolonged drought and long-term drainage reduced the N2O efflux. Soil CO2 emissions in control plots ranged from 310 to 732 g CO2-C m−2 yr−1. Drought and long-term drainage generally reduced the soil CO2 efflux, except at a~hydric shrubland where drought tended to increase soil respiration. When comparing the fractional importance of each greenhouse gas to the total numerical global warming response, the change in CO2 efflux dominated the response in all treatments (ranging 71–96%), except for NO3− addition where 89% was due to change in CH4 emissions. Thus, in European peatlands and shrublands the feedback to global warming induced by the investigated anthropogenic disturbances will be dominated by variations in soil CO2 fluxes.

scholarly journals Spatial and Temporal Variability of Soil CO2 Flux in Sugarcane Green Harvest Systems

2016 ◽  
Vol 40 (0) ◽  
Author(s):  
Rose Luiza Moraes Tavares ◽  
Zigomar Menezes de Souza ◽  
Newton La Scala Jr ◽  
Guilherme Adalberto Ferreira Castioni ◽  
Gustavo Soares de Souza ◽  
...  
Keyword(s):  
Temporal Variability ◽  
Co2 Flux ◽  
Spatial And Temporal Variability ◽  
Soil Co2 ◽  
Soil Co2 Flux

scholarly journals Comparative soil CO2 flux measurements and geostatistical estimation methods on Masaya volcano, Nicaragua

2005 ◽  
Vol 68 (1) ◽  
pp. 76-90 ◽  
Author(s):  
Jennifer L. Lewicki ◽  
Deborah Bergfeld ◽  
Carlo Cardellini ◽  
Giovanni Chiodini ◽  
Domenico Granieri ◽  
...  
Keyword(s):  
Co2 Flux ◽  
Estimation Methods ◽  
Soil Co2 ◽  
Soil Co2 Flux ◽  
Masaya Volcano ◽  
Geostatistical Estimation ◽  
Flux Measurements

Biocrust contribution to soil CO2 flux in desert shrubland ecosystem of northwest Mexico

2021 ◽  
pp. 1-17
Author(s):  
Fernando Ayala-Niño ◽  
Yolanda Maya-Delgado ◽  
Enrique Troyo-Diéguez ◽  
Pedro P. Garcillán
Keyword(s):  
Co2 Flux ◽  
Soil Co2 ◽  
Soil Co2 Flux ◽  
Northwest Mexico ◽  
Desert Shrubland

scholarly journals VARIABILIDADE ESPACIAL DO FLUXO DE CO2 DO SOLO EM POVOAMENTO DE EUCALIPTO

FLORESTA ◽  
2011 ◽  
Vol 41 (2) ◽  
Author(s):  
Alexandre Fonseca D’Andréa ◽  
Marx Leandro Naves Silva ◽  
Diego Antonio França de Freitas ◽  
Nilton Curi ◽  
Carlos Alberto Silva
Keyword(s):  
Organic Matter ◽  
Environmental Factors ◽  
Organic Carbon ◽  
Spatial Variability ◽  
Linear Correlation ◽  
Microbial Biomass Carbon ◽  
Co2 Flux ◽  
Water Evaporation ◽  
Soil Co2 ◽  
Soil Co2 Flux

A matéria orgânica do solo armazena a maior parte do carbono contido nos sistemas terrestres do planeta, sendo a maioria encontrada nos solos com floresta. O objetivo deste trabalho foi quantificar o fluxo de CO2 do solo e a sua variabilidade espacial em povoamento de Eucalyptus sp. Foram avaliados o fluxo de CO2 do solo, fatores ambientais (evaporação de água, temperatura e umidade do solo), atributos relacionados à fertilidade (pH, soma de bases e alumínio trocável), estrutura (densidade do solo e porosidade total) e matéria orgânica do solo (carbono orgânico total e carbono da biomassa microbiana). Análises de correlação linear simples indicaram que parte da variabilidade espacial do fluxo de CO2 do solo pode ser explicada pelo efeito conjunto do teor de carbono orgânico do solo, da biomassa da serapilheira e da presença de árvores no terreno, indicativas da participação de fatores bióticos no processo. No entanto, o fluxo de CO2 do solo é um fenômeno de natureza complexa, não sendo possível identificar um único atributo do solo ou do ambiente que, isoladamente, explique sua variação no espaço.Palavras-chave: Matéria orgânica; fatores ambientais; fertilidade; carbono; respiração do solo.AbstractSoil CO2 flux spatial variability on eucalyptus manmade forest.  The organic matter on soil retains most of carbon contained in the planet terrestrial systems, specially in forest soils. The aim of this work was to quantify soil CO2 flux and its spatial variability on Eucalyptus sp. manmade forest. In order to that, soil CO2 flux, environmental factors (water evaporation, soil temperature and moisture), fertility attributes (pH, bases sum and exchangeable aluminum), structure (bulk density and total porosity), and soil organic matter (total organic carbon and microbial biomass carbon) were evaluated. Simple linear correlation analyses indicated that part of the spatial variability of soil CO2 flux can be explained by the associated effect of soil organic carbon amount, litter biomass and presence of trees, indicatives of participation of biotic factors in the process. However, the soil CO2 flux is a complex phenomenon, been impossible to identify a single soil or environmental attribute, which, individually, could explain its spatial variability. Keywords: Organic matter; environmental factors; fertility; carbon; linear correlation. 

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