Respiratory release of CO2 in alfalfa and soybean under field conditions☆

DaCosta, João Batista Neves; Rosenberg, Norman J.; Verma, Shashi B.

doi:10.1016/0168-1923(86)90005-5

Cited by 16 publications

(5 citation statements)

References 14 publications

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“…At this growth stage, essentially all the incoming radiation is intercepted by the canopy and the only difference between their approach and ours is that we included soil fauna and flora respiration in our calculations. However, very low soil respiration rates (0.034 mg m-2 s-1 ) were measured during that experiment ( da Costa et al, 1986). The small difference between 3.1 g C02 Mr 1 PAR reported by Baldocchi et al (1981) and the slope measured for LAI > 1 in our experiment (2.87 to 3.44 g C0 2 MJ-1 IPAR) sug- :j: Based on the sampling of 20 plants and expressed per meter square of ground by multiplying by averaged plant density (42 plants m-2 ).…”

Section: Radiation Use Efficiencymentioning

confidence: 82%

Crop Net Carbon Dioxide Exchange Rate and Radiation Use Efficiency in Soybean

et al. 1995

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Plant growth is directly related to the fraction of the C fixed by photosynthesis that is converted into phytomass. We report here the results of a study aiming at the estimation of the net CO2 exchange rates (CNCER) of a soybean crop over the growing season. Hourly values of CNCER were estimated based on eddy correlation measurements of CO2 fluxes above the canopy, on chamber measurements of CO2 fluxes at the soil surface, and on the assumption that root respiration can be computed as a fraction of plant daily photosynthesis. Mean daytime CNCER varied between 0.70 and 0.83 mg m−2s−1 for a leaf area index (LAI) greater than 1, with a maximum hourly value of 1.48 mg m−2s−1. Absolute mean nighttime CNCER values were usually <20% of daytime values. Hourly CNCER varied nonlinearly with intercepted photosynthetically active radiation (IPAR). The accuracy of the CNCER estimates was evaluated by comparing the radiation use efficiency of the soybean crop calculated using CNCER estimates with radiation use efficiency calculated using phytomass accumulation. Agreement between the two approaches was within 10% for LAI>2, but calculated CNCER overestimated radiation use efficiency based on phytomass accumulation for smaller values of LAI.

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Section: Radiation Use Efficiencymentioning

confidence: 82%

Crop Net Carbon Dioxide Exchange Rate and Radiation Use Efficiency in Soybean

et al. 1995

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“…It is also important to note that at times, particularly in the late afternoon, isotope-partitioned R eco dropped below R soil which is unexpected. Above-ground autotrophic respiration in agricultural systems typically ranges between 37-62% of total R eco (Suleau et al, 2011) and was previously measured to be 35% of total R eco in alfalfa (Da Costa et al, 1986). Therefore, we would expect the ratio of R soil :R eco to vary across ecosystems with a general trend that R soil underestimates R eco (Janssens et al, 2001).…”

Section: Discussionmentioning

confidence: 95%

Revisiting the partitioning of net ecosystem exchange of CO2 into photosynthesis and respiration with simultaneous flux measurements of 13CO2 and CO2, soil respiration and a biophysical model, CANVEG

Oikawa

Sturtevant

Knox

et al. 2017

Agricultural and Forest Meteorology

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The partitioning of net ecosystem exchange of CO 2 (NEE) into photosynthesis and respiration can be challenging and is often associated with assumptions that yield unknown amounts of uncertainty, thereby hindering model development. This occurs because we are inferring two pieces of information from one equation and measurement, NEE. While there are multiple methods for partitioning NEE, each has unique limitations that are difficult to evaluate as these techniques are often not implemented simultaneously. Here we present an analysis of multiple partitioning methods (a non-linear regression model known as the Reichstein method, artificial neural networks (ANN), stable carbon isotopes, and soil respiration (R soil) measurements) under ideal field conditions. We measured ecosystem-scale fluxes of stable C isotopes via a new quantum cascade laser (QCL) spectrometer and paired those measurements with a biophysical model CANVEG in order to close a system of equations and solve for gross primary productivity (GPP) and ecosystem respiration (R eco). Isotope-partitioned GPP and R eco were on average 10-13% lower than Reichstein-and ANN-partitioned GPP and R eco. These results suggest that the Reichstein and ANN approaches, which use nighttime NEE to infer daytime R eco , may be overestimating R eco and GPP during the day. This may be attributed to higher plant respiration rates at night compared to the day, otherwise known as the Kok effect. As isotope measurements and theory become more accessible to diverse ecosystems it will grow to be more than a benchmarking technique and into a valuable means of improving understanding of carbon cycling. Future studies are encouraged to evaluate these techniques in increasingly complex ecosystems to determine when significant differences appear between partitioning methods and how those differences influence modeling of terrestrial carbon budgets.

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“…On the basis of growing season data, soil respiration is the dominant component of ecosystem respiration in the successional field ( Figure 6), and we demonstrate enhancement of ecosystem respiration under warm and wet conditions. It is possible (though not determined by these results) that in addition to contributing directly to NEP through CO 2 assimilation, early successional vegetation may indirectly offset NEP by reducing soil temperature (shading) and soil , 1986, and 1920(J. Wang and H. Epstein, unpublished data, 2005, suggesting interplay between vegetation and controls on ecosystem respiration.…”

Section: Comparing Tower-based and Ground-based Carbon Fluxmentioning

confidence: 91%

Carbon dioxide exchange and early old‐field succession

Emanuel¹,

Albertson²,

Epstein³

et al. 2006

J. Geophys. Res.

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Old‐field succession is a widespread process active in shaping landscapes in the eastern United States, contributing significantly to the terrestrial sink of atmospheric carbon dioxide, particularly at midlatitudes. However, few studies document ecosystem‐scale carbon dioxide exchange during the early years of old‐field succession, particularly during the temporal transition from cultivation to abandonment. Rates of carbon dioxide exchange were measured for 20 months over a field in Virginia during the transition from an actively cultivated crop field to an unmanaged old field, including one season of crop growth and two seasons of successional growth. Ecosystem carbon respiration exceeded carbon assimilation during growing seasons and dormant periods, resulting in a net flux of carbon dioxide from the biosphere to the atmosphere of between 1.27 and 1.85 kg C m−2 for the entire 20‐month period (an average loss to the atmosphere of 2.07 to 3.01 g C m−2 day −1). Crop growth (from 10 January 2001 to 6 June 2001) resulted in a net loss of between 0.22 and 0.32 kg C m−2 to the atmosphere (an average daily loss of 1.5 to 2.2 g C m−2), whereas the two seasons of successional growth combined contributed an additional 1.05 to 1.53 kg C m−2 to the atmosphere (an average daily loss of 2.2 to 3.3 g C m−2). Empirical modeling was used to demonstrate control of ecosystem carbon respiration by soil temperature, soil moisture status, and the status of vegetation growth activity. Tower‐based estimates of carbon loss were compared at both short (half hourly) and long (seasonal) timescales to independent, ground‐based measurements. Using estimates of carbon exchange from previously published studies, these results are placed in the context of a trajectory of old‐field succession.

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Respiratory release of CO2 in alfalfa and soybean under field conditions☆

Cited by 16 publications

References 14 publications

Crop Net Carbon Dioxide Exchange Rate and Radiation Use Efficiency in Soybean

Crop Net Carbon Dioxide Exchange Rate and Radiation Use Efficiency in Soybean

Revisiting the partitioning of net ecosystem exchange of CO2 into photosynthesis and respiration with simultaneous flux measurements of 13CO2 and CO2, soil respiration and a biophysical model, CANVEG

Carbon dioxide exchange and early old‐field succession

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