Comprehensive observation for carbon dioxide isotopes during soil biochemistry process: synergetic profile observation system of the CO2 and δ13C gradients in the soil and atmosphere (2019-2020)

Soil respiration is the second most important carbon flux, which is only lower than that of photosynthesis in terrestrial ecosystems. The production and transport of CO2 and its δ13C by soil biochemical processes are the limiting factors for the magnitude and process evaluation of soil respiration. According to the characteristics of CO2 gas generation and transportation in soil biochemical process, based on stable isotope infrared spectroscopy technology, the nonlinear on-line calibration technology, multi-channel double-cycle efficient gas circulation path, efficient gas circulation path with pre-reduced gas concentration, and variable temperature technology that can simulate the freezing and thawing process were independently developed. On account of the gas exchange process in soil and air interface, vertical migration process of CO2 in soil profile and the process of soil organic matter decomposition, we develop a comprehensive observation system for measuring the isotope composition of carbon dioxide during soil biochemistry processes. The observation systems were placed in the ecologically fragile areas and measured the concentration and flux of soil CO2 and its δ13C, which effectively solved the comprehensive monitoring problem in generation, migration and release of CO2 during soil biochemical process. A synergetic profile observation system of the CO2 and δ13C gradients in the soil and atmosphere: We develop key gas circuit components for the prereduction of CO2 and δ13C concentrations that are suitable for field and laboratory experiments. For the problems of large variations in greenhouse gas concentrations between the atmosphere and soil and the high greenhouse gas concentration in soil, we use a typical CO2 absorbent or the zero gas in the bypass system to decrease the CO2 concentration in the gas circuit. Meanwhile, the instrument can eliminate the disturbance of “dead gas” on the observation results and improve the accuracy of the observations. From the technical innovation, the on-line calibration system of both low concentration and high concentration was realized for the first time, which solved the nonlinear response and time drift of the instrument, the gas path design of multi-channel double circulation and the gas path design of CO2 concentration pre-reduction, and effectively solved the problem of low gas path switching efficiency caused by pipeline length. The average domestication rate of the equipments is more than 80%, which has been used in the automatic monitoring of forest, grassland and farmland ecosystems, realizing the independent innovation and upgrading of ecological monitoring technology in China, and can be extended to CERN, CFERN, CNERN and similar field stations in other related departments. It is helpful to greatly improve China's R&D capability, level and international influence on ecological monitoring and assessment, effectively support China's terrestrial ecosystem carbon sequestration rate and potential assessment and certification, and provide technical support for national ecological civilization construction, carbon peak, carbon neutrality and ecological security regulation.

0 2021-11-29

Data set of comprehensive observation system for carbon dioxide isotopes during soil biochemistry process: multichannel measurement system for soil microbial CO2 and δ13C fluxes that can automatically control and change the temperature (2019-2020)

Soil respiration is the second most important carbon flux, which is only lower than that of photosynthesis in terrestrial ecosystems. The production and transport of CO2 and its δ13C by soil biochemical processes are the limiting factors for the magnitude and process evaluation of soil respiration. According to the characteristics of CO2 gas generation and transportation in soil biochemical process, based on stable isotope infrared spectroscopy technology, the nonlinear on-line calibration technology, multi-channel double-cycle efficient gas circulation path, efficient gas circulation path with pre-reduced gas concentration, and variable temperature technology that can simulate the freezing and thawing process were independently developed. On account of the gas exchange process in soil and air interface, vertical migration process of CO2 in soil profile and the process of soil organic matter decomposition, we develop a comprehensive observation system for measuring the isotope composition of carbon dioxide during soil biochemistry processes. The observation systems were placed in the ecologically fragile areas and measured the concentration and flux of soil CO2 and its δ13C, which effectively solved the comprehensive monitoring problem in generation, migration and release of CO2 during soil biochemical process. This research developed a multichannel measurement system for soil microbial CO2 and δ13C fluxes that can automatically control and change the temperature. We develop a fully automatic temperature control and measurement system that can simulate the freeze-thaw process. The instrument can adjust the temperature in a culture flask under established procedures and meet the experimental requirements of simulating complex processes during the decomposition of soil organic matter. The temperature control range of the system is -5~35 oC, the temperature control accuracy is better than 0.23 oC, the temperature change rate is 1.06 oC /2 min (0~35 oC) and 0.70 oC /2 min (-5~0 oC), at least 16 channels of culture flask and 3 channels of gas can be controlled simultaneously, which achieve (or better) than the core technical indicators of the project requirements. Soil samples collected in the field were placed in 16 sample bottles, respectively. Based on the multichannel measurement system for soil microbial CO2 and δ13C fluxes, the soil respired CO2 and δ13C data were obtained during the warming and cooling processes from -5℃ to 35℃. Data processing usually begins from the instrument performance parameters for judging data quality first, then the measured CO2 concentration and δ13C were corrected with standard gas. The slope of air humidity, temperature, atmospheric pressure and flux calculation was quality-controlled to eliminate abnormal data. Then the high quality data was obtained and the flux is used to calculate the formula to calculate the CO2 and δ13C flux. The average domestication rate of the equipments is more than 80%, which has been used in the automatic monitoring of forest, grassland and farmland ecosystems, realizing the independent innovation and upgrading of ecological monitoring technology in China, and can be extended to CERN, CFERN, CNERN and similar field stations in other related departments. It is helpful to greatly improve China's R&D capability, level and international influence on ecological monitoring and assessment, effectively support China's terrestrial ecosystem carbon sequestration rate and potential assessment and certification, and provide technical support for national ecological civilization construction, carbon peak, carbon neutrality and ecological security regulation.

0 2021-11-17

Comprehensive observation system for carbon dioxide isotopes during soil biochemistry process: multichannel and dual-cycle observation system for soil CO2 and δ13C fluxes (2019-2020)

Soil respiration is the second most important carbon flux, which is only lower than that of photosynthesis in terrestrial ecosystems. The production and transport of CO2 and its δ13C by soil biochemical processes are the limiting factors for the magnitude and process evaluation of soil respiration. According to the characteristics of CO2 gas generation and transportation in soil biochemical process, based on stable isotope infrared spectroscopy technology, the nonlinear on-line calibration technology, multi-channel double-cycle efficient gas circulation path, efficient gas circulation path with pre-reduced gas concentration, and variable temperature technology that can simulate the freezing and thawing process were independently developed. On account of the gas exchange process in soil and air interface, vertical migration process of CO2 in soil profile and the process of soil organic matter decomposition, we develop a comprehensive observation system for measuring the isotope composition of carbon dioxide during soil biochemistry processes. The observation systems were placed in the ecologically fragile areas and measured the concentration and flux of soil CO2 and its δ13C, which effectively solved the comprehensive monitoring problem in generation, migration and release of CO2 during soil biochemical process. (1) a multichannel and dual-cycle observation system for soil CO2 and δ13C fluxes at the soil-atmosphere interface: We developed an online calibration system for the nonlinear response of CO2 and its δ13C analyzer at multiple concentrations to ensure the accuracy and accuracy of the instrument. By controlling the circuit switch, the instrument can automatically switch and collect circular observations between multiple channels. By controlling the premixing of gas in the channel while waiting to collect an observation, the instrument can decrease the observation time required for every channel and increase the efficiency and frequency of observation collection. By premixing the gas in the channel to be monitored, the instrument can eliminate the “dead gas” disturbances in the observation results and improve the accuracy of the observations. Based on the simulation flux verification system test, the simulated flux of CO2 and δ13C is better than 0.32 μmol m-2 s-1 @ 10 μmol m-2 s-1 (CO2) and 0.52‰ @ 10 μmol m-2 s-1 (CO2), which is better than the core technical index requirements of the project. The average domestication rate of the equipments is more than 80%, which has been used in the automatic monitoring of forest, grassland and farmland ecosystems, realizing the independent innovation and upgrading of ecological monitoring technology in China, and can be extended to CERN, CFERN, CNERN and similar field stations in other related departments. It is helpful to greatly improve China's R&D capability, level and international influence on ecological monitoring and assessment, effectively support China's terrestrial ecosystem carbon sequestration rate and potential assessment and certification, and provide technical support for national ecological civilization construction, carbon peak, carbon neutrality and ecological security regulation.

0 2021-11-17

Soil organic carbon concentrations of representative samples in the Heihe River Basin

The data set includes soil organic carbon concentrations data of representative soil samples collected from July 2012 to August 2013 in the Heihe River Basin. The first soil survey was conducted in 2012. After the representativeness evaluation of collected samples, we conducted an additional sampling in 2013. These samples are representative enough to represent the soil variation in the Heihe River Basin, of which the soil variation in each landscape could be accounted for. The sampling depths in field refer to the sampling specification of Chinese Soil Taxonomy, in which soil samples were taken from genetic soil horizons.

0 2020-05-25

Experimental observation data of water consumption and law of water consumption of different life type desert plants in Heihe River basin (2014)

The evapotranspiration and soil evapotranspiration of lycium rubra and red sand of small shrubs in typical desert weather were observed by using infrared gas analyzer to measure water vapor flux. The measurement system consists of li-8100 closed-circuit automatic measurement of soil carbon flux (li-cor, USA) and an assimilation box designed and manufactured by Beijing ligotai technology co., LTD. Li-8100 is an instrument produced by li-cor for soil carbon flux measurement. It USES an infrared gas analyzer to measure the concentration of CO2 and H2O.The length, width and height of the assimilation box are all 50cm.The assimilation box is controlled by li-8100. After setting up the measurement parameters, the instrument can run automatically.

0 2020-03-10

The data of canopy photosynthesis measurements of desert plants in Heihe River basin (2012)

In the middle of July and August 2012, mass photosynthesis was determined and the plant species was caragana korshinskii. The mass photosynthesis measurement system is composed of li-8100 closed-circuit automatic soil carbon flux measurement system (li-cor, USA) and an assimilation box designed and manufactured by Beijing liaotai technology co., LTD. Li-8100 is an instrument for soil carbon flux measurement produced by li-cor, USA, which USES an infrared gas analyzer to measure CO2 and H2O concentrations.The length, width and height of the assimilation box are all 50cm.The assimilation box is controlled by li-8100, and the instrument can operate automatically after the measurement parameters are set. The photosynthetic rate of population was calculated according to the following formula: CAP (Canopy growth Rate) is the Photosynthetic Rate of the population (mol CO2•m -- 2•s -- 1).A is the total leaf area (m2) of the plant canopy;VA is the total volume (m3) of the population photosynthesis measurement system, which is the product of the height of the assimilation box from the ground (the distance between the upper edge and the inner ground after the special base is placed), the soil area (0.25 m2) and the sum of the volume of the assimilation box (0.125 m3).Is the change rate of CO2 measured by assimilation chamber (mol CO2•mol -- 1•s -- 1) in the process of population photosynthesis measurement;Is the CO2 change rate (mol CO2•mol -- 1•s -- 1) measured in a 20 cm measuring chamber during the soil respiration measurement process;P is atmospheric pressure (Pa), T is the air temperature in the assimilation chamber (℃), and R is the gas constant (8.314 Pa•m3•mol-1• k-1).N is the conversion coefficient, which means the change rate of CO2 caused by soil respiration in the soil area (SA) covered by the assimilation box and in the total volume (VA) of the population photosynthesis measurement system is converted from the measurement in the 20cm measurement chamber, and calculated according to the following formula: SA is assimilation box cover soil area, 0.25 m2, SC is 20 cm soil area of the measuring chamber cover (0.03 m2), VC is plant roots and soil respiration measurement system of the total volume (m3), to 20 cm measurement chamber high from the ground (after ring on measuring the soil in place along with the internal distance) on the ground and soil area is the product of the (SC) and 20 cm measurement chamber volume (4.82 x 10-3 m3) combined.

0 2020-03-04