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Register for Soil Gas Flux Online Training

Soil gas flux rates depend on many environmental and biological factors, including the effects of the instrument itself. Register for free online training about the basics of soil gas flux measurements and how to get the best possible data.

The Soil Flux Training Course Will Cover

  • Theory and Measurement of Soil CO2 Flux with a Closed System
  • Operational Overview of the LI-8100A Soil Gas Flux System
  • Software and Data Processing
  • Applications

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accurate-fluxAccurate Soil CO2 Flux Measurement at High Spatial and Temporal Resolution
Using an automated 16-chamber system to satisfy spatial and temporal sampling requirements.
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spatial-varSpatial Variability of Soil CO2 Flux in a Cornfield
In and between row comparison of soil CO2 flux.
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eq-pressureEqualizing Pressures Between A Soil CO2 Flux Chamber and the Ambient Air Under Windy Conditions
LI-COR's vent design, based on the Bernoulli equation that reduces the speed of wind as it passes over the vent opening.
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Application Notes

Capturing and Processing Soil GHG Fluxes Using the LI-8100A

Describes how to interface third party gas analyzers with the LI-8100Ato measure trace gases, and use SoilFluxPro™ to compute fluxes for these additional gases.

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8100-401 Chamber
Control Kit

Using LI-COR automated soil gas flux chambers with a custom interface.

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Measurement of CO2 Evolution in a Multiplexed Flask System

Uses the LI-8100/
8150 System to rapidly measure CO2 fluxes from multiple samples and has the ability to track fluxes over long time courses.

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Addressing Spatial Variability: Determining the Number of Readings Required

Accounting for the variability of soils and determining the number of readings necessary for accurate measurements.

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Powering the LI-8100/8150 in a Remote Location: Power Requirements and Solar Panel Solution

Powering the LI-8100/8150 "off grid" in remote locations with a solar panel

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Using the LI-8100 System to Collect Air Samples for Estimating Soil Trace Gas Flux

Use LI-8100 to Sample Soil Trace Gas FluxAir samples can be collected from the same air stream used to measure soil CO2 flux.
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Atmospheric CO2 Profile Measurements Using the LI-8100/ 8150 System

In a multiplexed system, atmospheric CO2 profile measurements can be performed, in addition to soil CO2 flux measurements, with minimal added cost.

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Comparisons Between the LI-COR LI-6400 and LI-8100

The theory underlying the two systems is outlined with a comparison of results obtained using each system.

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The experienced application scientists and analysts at LI-COR are committed to providing the highest level of customer service and support.

Contact Us

US Toll-Free: 1-800-447-3576

International: 1-402-467-3576


Frequently Asked Questions

Q What cable/hose assembly do I need?

A If you are performing long-term measurements with a single chamber, the 8100-704 Cable/Hose Assembly (2m) is used to connect the 8100-104 Long-Term Chamber to the LI‑8100A Analyzer Control Unit. The 8150-705 Cable/Hose Extension Assembly (15m) is used to connect to the LI‑8150 Port Multiplexer and is required to multiplex with multiple long-term chambers. Both the 8100-102 and 8100-103 survey chambers include an attached cable/hose assembly.

Q What is the importance of measuring spatial and temporal variability?

A Soils physical properties associated with CO2 flux are highly variable. In addition to spatial heterogeneity, the processes that produce CO2 in the soil are coupled to changes in soil water content, temperature, soil organic carbon resources, etc. and therefore exhibit both diurnal and seasonal patterns of variation in CO2 evolution. To accurately obtain site CO2 fluxes, it is often necessary to take readings with adequate spatial as well as temporal resolution. For more information, refer to the application note.

Q Can you measure CO2 diffusion from an isolated source of biomass?

A The LI‑8100A Automated Soil CO2 Flux System is designed to measure CO2 diffusion out of the soil; however, it does have the ability to measure CO2 evolution in flasks on fruits, insects, nuts etc. The LI‑8100A could be used to measure CO2 diffusion from an isolated source of biomass. The biomass could be placed in a flask or the LI‑8100A could measure the biomass naturally in the outside environment by separating the soil from the biomass. In the outside application, one could simply place the biomass inside a sealed collar and perform a simple measurement to measure the CO2 diffusion out of the biomass over time.

Q If I have an LI‑8100 Analyzer Control Unit (ACU), can I upgrade to an LI‑8100A ACU?

A The LI‑8100 cannot be upgraded to the LI‑8100A; however, current owners of the LI‑8100 can upgrade to the latest software for the LI‑8100A. This software supports the use of Windows, iOS, Ethernet and high CO2 capabilities. Contact LI‑COR for more information.

Q Do I need an Analyzer Control Unit to do flask measurements?

A Yes, you do need an Analyzer Control Unit and the LI‑8150 Multiplexer to perform flask measurements because together they operate as a closed system, determining CO2 flux from the change in the CO2 mole fraction over time in a fixed volume. The ACU is the gas analysis, data storage and communication center for your measurements. For more information, refer to the application note.

Q Can I use a survey chamber with the LI‑8150 Multiplexer?

A No, survey chambers are not configured to work with the LI‑8150 Multiplexer.

Q How long will the 6400-03 battery last when used for survey measurements?

A One 6400-03 Rechargeable Battery lasts approximately 2-3 hours.

Q Can I purchase the LI‑8100A wireless components somewhere else?

A You cannot purchase the 8100-552 Wireless Card elsewhere; however, the iOS device can be purchased from a third-party source.

Q How long does it take to take a measurement?

A A typical soil CO2 flux measurement takes approximately 1-2 minutes.

Q Can I upgrade my 8100-104 Long-term Chamber to the 8100-104C Long-term Clear Chamber?

A Yes, you can upgrade your 8100-104 Long-term Chamber to the 8100-104C Long-term Clear Chamber. The Upgrade Kit to convert an 8100-104 to an 8100-104C is the 8100-910 Clear Chamber Bowl Assembly

Q How often should I send my LI‑8100A Analyzer Control Unit in for calibration?

A The LI‑8100A Analyzer Control Unit should never require factory recalibration unless it is returned for repair. If you perform a zero and span of your analyzer periodically and everything appears to be working correctly, no factory calibration is necessary.

Q You offer two part numbers for your soil moisture and temperature probes. What are differences between those?

A The soil moisture and temperature probes that begin with the part number 8100-XXX, must be used with the LI‑8100A Analyzer Control Unit for either survey or single long-term measurements. The sensors that begin with the part number 8150-XXX are used with long-term chambers.

Q What do I need to make survey measurements?

A The LI‑8100A Analyzer Control Unit, either the 8100-102 10cm Survey Chamber or the 8100-103 20cm Survey Chamber, the 6400-03 Rechargeable Batteries, the LI‑6020 Battery Charger. LI‑COR recommends the 8100-565 Wireless Communication Package.

Q Can I mix and match chambers when using the LI‑8150 Multiplexer?

A The following chambers can be used together in any number adding up to a total of sixteen: 8100-101, 8100-104, and 8100-104C. Survey chambers cannot be used with the LI‑8150 Multiplexer.

Q Can you collect trace gas samples from the LI‑8100A?

A Yes, we offer the 8100-664 Trace Gas Sampling Kit. For more details, refer to the application note.

Q What are the power requirements when in Multiplex mode?

A The exact power requirements are dependent on the number of chambers and sampling frequency. Generally, the instrument will have a continuous draw of 2-3 amperes at 12 Volts. For more details, refer to the application note.

Q What is the difference between the 6400-09 Soil CO2 Flux Chamber and the 8100-102 10cm Survey Chamber?

A The physical design of both chambers is very similar. However, the 6400-09 in conjunction with LI‑6400XT uses a draw-down technique to measure soil CO2 flux at the ambient CO2 concentration. The 8100-102 in conjunction with the LI‑8100A ACU uses a combination of automated chamber closure and a mathematical algorithm to measure soil CO2 flux at the ambient concentration. For more details, refer to the application note.

Q Can I measure Soil CO2 Flux and atmospheric profile measurements with the same system?

A Yes, the LI‑8150-16 has up to 16 ports where any combination of chambers and profile ports can be used for both flux and atmospheric profile measurements. For more details, refer to the application note.


Thomazini, A., et al. (2014). Spatial Variability of CO2 Emissions from Newly Exposed Paraglacial Soils at a Glacier Retreat Zone on King George Island, Maritime Antarctica. Permafrost and Periglacial Processes 25(4): 233–242.

Troxler, T. J., et al. (2015). Component-specific dynamics of riverine mangrove CO2 efflux in the Florida coastal Everglades. Agricultural and Forest Meteorology.

W. Babel, T. Biermann, H. Coners, E. Falge, E. Seeber, J. Ingrisch, P.-M. Schleuß, T. Gerken, J. Leonbacher, T. Leipold, S. Willinghöfer, K. Schützenmeister, O. Shibistova, L. Becker, S. Hafner, S. Spielvogel, X. Li, X. Xu, Y. Sun, L. Zhang, Y. Yang, Y. Ma, K. Wesche, H.-F. Graf, C. Leuschner, G. Guggenberger, Y. Kuzyakov, G. Miehe, and T. Foken (2014). Pasture degradation modifies the water and carbon cycles of the Tibetan highlands. Biogeosciences, 11, 6633–6656.

On Maintaining Pressure Equilibrium Between a Soil CO2 Flux Chamber and the Ambient Air
A version of this paper was published by AGU (see reference below). Copyright (2006) American Geophysical Union.

Liukang Xu*, Michael D. Furtaw, Rodney A. Madsen, Richard L. Garcia, Daniel J. Anderson, Dayle K. McDermitt, (2006), On Maintaining Pressure Equilibrium Between a Soil CO2 Flux Chamber and the Ambient Air, Journal of Geophysical Research, VOL. 111, D08S10, doi:10.1029/2005JD006435. To view the published open abstract, click here.

Hanson, P.J, Childs, K.W., Wullschleger, S.D., Riggs, J. S., Thomas, W. K., Todd, D. E., and Warren, J. M. (2011), A method for experimental heating of intact soil profiles for application to climate change experiments. Global Change Biology, 17: 1083—1096. doi: 10.1111/j.1365-2486.2010.02221.x

Heinemeyer, A., Di Bene, C., Lloyd, A. R., Tortorella, D., Baxter, R., Huntley, B., Gelsomino, A. and Ineson, P. (2011), Soil respiration: implications of the plant-soil continuum and respiration chamber collar-insertion depth on measurement and modelling of soil CO2 efflux rates in three ecosystems. European Journal of Soil Science, 62: 82—94. doi: 10.1111/j.1365-2389.2010.01331.x

Herbst, Mathias, Friborg, Thomas, Ringgaard, Rasmus, Soegaard, Henrik Catchment-Wide Atmospheric Greenhouse Gas Exchange as Influenced by Land Use Diversity Vadose Zone Journal 2011 10: 67-77

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