Ecosystem respiration, ecosystem autotrophic respiration, ecosystem heterotrophic respiration data (2021)

This data-set contains the field measurements of ecosystem respiration, soil temperature and soil water content along the altitudinal gradient (30°30′-30°32′N, 91°03′E; 4500 m, 4600 m, 4700 m, 4800 m, 4900 m, 5000 m, 5100 m, 5200 m). The period of this data-set is from June to September of 2021. On sunny days during the growing season (June–September) of 2021, diurnal variation (08:00–18:00, local time) of ecosystem respiration were measured using the opaque chamber of Li-8100 103 automatic soil CO2 flux system (LI-COR Biosciences, Lincoln, NE, USA). Soil temperature and soil moisture at each collar were measured simultaneously with Re by a Time Domain Reflectometer.

0 2022-01-20

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

Survey data set of plant and soil carbon and nitrogen cycle in representative sites (2019-2020)

The data set includes three types of data, which are: (1) the data of soil physical and chemical indexes, carbon and nitrogen, plant carbon and nitrogen, and microbial carbon and nitrogen in the collapse area of the Qinghai Tibet Plateau in 2020. These data provide an important reference for the assessment of the carbon and nitrogen cycle in the Tibetan Plateau. This data is mainly obtained through field observation during the investigation in Gangcha, Qinghai Province in 2020. The obtained plant and soil samples were taken back to the laboratory for preliminary classification and impurity removal, and then dried to constant weight in an oven at 65 ° C. Carbon and nitrogen components in soil and plants were measured. A total of 40 quadrats of 4 typical plots were obtained. The data can be used to reveal the spatial variation of soil and plant carbon and nitrogen components, and understand the distribution of carbon and nitrogen components in soil plant microbial system. (2) Data of soil nutrient composition of grassland horizontal transect in Qinghai Tibet Plateau in 2019. This data is mainly obtained from the field drilling during the sample belt investigation in 2019. The soil samples were taken back to the laboratory for preliminary classification, root removal and stone screening. The soil samples were dried naturally, then mixed evenly and divided into two parts (about 100g each). One part was sieved with 2mm soil sieve to obtain sieved samples, and the other part was ground with ball mill to obtain ground samples. The content elements included: the contents of total C, N, P, K, Fe, Mn, Cu, Zn, CA, Na and total Mg; the contents of available P, K, Fe, Mn, Cu, Zn, CA, Na and Mg. Determination of soil total C and N: the grinding samples were packed, and then the contents of total C and N were determined by chnos elemental analyzer (vario El III, GmbH, Hanau, Germany). Determination of total elements in soil: the grinding samples were pressed by a tablet press, and then the contents of total P, K, Fe, Mn, Cu, Zn, CA, Na and total Mg in the samples were determined by X-ray fluorescence spectrometry (XRF, panalytical Axios max, Almelo, the Netherlands). Determination of soil available elements: the sieved samples were extracted, and the contents of available P, K, Fe, Mn, Cu, Zn, CA, Na and Mg were determined by inductively coupled plasma atomic emission spectrometry (ICAP 6300, Thermo Electron Corporation, Waltham, Ma, USA). A total of 13 transects were obtained. Each plot obtained three soil layers (0-10 cm, 10-20 cm, 20-30 cm). Therefore, there are 117 data of each soil nutrient element (C, N, P, Mn, Zn, etc.) in each quadrat. The data are directly obtained from the field soil samples obtained by this scientific research. After air drying, screening and grinding, the data are determined by the relevant analyzer (above) according to the corresponding test specifications, and the quality is reliable, which can be used to analyze the distribution law of soil carbon and nitrogen content or density in different regions and to evaluate soil nutrient In particular, it can be used for the research and modeling of carbon and nitrogen cycle driven by precipitation change, which has a wide range of application value and application prospects. (3) Vegetation productivity data of grassland horizontal transect in Qinghai Tibet Plateau in 2019. This data is mainly obtained from the field observation during the transect survey in 2019. After obtaining the plant samples, they were taken back to the laboratory for preliminary classification, gravel and other impurities were removed, and then dried in the oven at 65 ° C to constant weight. According to the biomass of the sample, it was converted into the key element of ecosystem carbon cycle vegetation productivity (NPP). A total of 13 transect points and 39 quadrats were obtained. The content elements of the data include aboveground biomass, aboveground biomass and NPP. The unit is gram per square meter; this data is the field observation data obtained from this scientific research, with reliable quality, which can be used to analyze the distribution law of vegetation productivity, vegetation cover, carbon storage assessment of ecosystem in different regions, especially for the study of carbon cycle driven by precipitation change and its modeling, and has a wide application value and application prospect.

0 2021-04-19

HiWATER: Dataset of Soil respiration observed by Li-8100 in the lower of Heihe River Basin from Jul to Aug , 2014

Soil respiration observation was carried out for the typical vegetation ground in the lower reaches of the Heihe River Basin during the aviation flight experiment in 2014. The observation started on 23 July, 2014 and finished on 2 August, 2014. 1. Observation time Days from 23 July to 2 August, 2014 (25 July, 2014 excepted) 2. Samples and observation methods Large areas with relatively homogeneous vegetation (greater than 100 m * 100 m) were chosen as the observation samples. And combined the flux tower sites distribution of the lower reaches, five field samples closed to the sites were selected The observation sites sampled including Populus and Tamarix mixed forest, Populus, Tamarix group, bare ground and melon quadrats. 3-5 plots were observed for each samples. The PVC soil rings were installed one day before observation and kept about 5 cm out of the ground (the inner diameter of the PVC is 19.5 cm, the outer diameter is 20.0 cm, and the height is 12.0 cm). Minimal the effects to the surface of vegetation and withered matter when install the rings. In order to avoid fluctuations of the soil respiration value by the PVC rings, soil respiration rate was obtained when it returned to its original state (about 24h after the rings install). The observation time for each day was from 8:00 to 12:00 when soil respiration is relatively stable and can represent the whole day in this time. The Li-8100 Open Path soil carbon flux automatic analyzer was used (Model 8100-103) once for each plot. Cycles of observation for all plots of the five samples were completed for every morning. The soil respiration values of the samples were obtain by averaging the values of plots of the samples. 3. Observation instrument Li 8100 4. Data storage The observation recorded data were stored in excel and the original Soil respiration data were stored in 81x files.

0 2019-09-14

HiWATER: Dataset of the Portable Soil Respiration in the middle reaches of the Heihe River Basin (2012)

During the 2012 aerial remote sensing experiment conducted midstream, Li-Cor8100 was used to measure soil respiration every five days in the EC matrix area. Instrument: LI-Cor8100 Measuring Method: Soil respiration ring was made using PVC pipe with length of 10 cm. Before measuring soil respiration, soil respiration ring was inserted into the soil, 4 cm in soil and 6 cm above soil. Soil respiration measurement should be taken after standing for at least 24 hours science ring was inserted in soil. Sample measurement time is during 9-12 in the morning. Set of three replicates per plot. Marked according to EC site name. Data content: Data content includes header information, and once every five days repeated three times observations value and the average value. Measuring location: EC sites within the matrix core experiment area (No. EC01 to EC17), each plot set three repeat samples. For the superstation (EC15) plot set nine repeat samples. Measuring time: From 6 June to 20 August, 2012, once every five days for site EC01, EC03, EC05, EC10, EC11, EC12, EC13, EC14, and EC17; from 1 July to 20 August, 2012, once every five days for site EC02, EC04, EC06, EC07, EC08, EC09 and EC16. The time used in this dataset is in UTC+8 Time. Part of the observation points during the observation just irrigation, these times are not observable.

0 2019-09-13

HiWATER:Dataset of the chamber soil respiration in the middle of Heihe River Basin (2012)

During the period of middle stream experiment in 2012, closed chamber and gas chromatography method was used to measure soil respiration of different land surface, including farmland, orchard, wetland, sparse grassland (Huazhaizi), Gobi, desert. Instrument: Assimilation Chamber Measuring method: Assimilation chamber consists of two parts: the base and the box. Base made of PVC material, the bottom buried in the soil. The box is made of stainless steel cubes, with one open side. When measuring the box cover on the base, air in the box was sampled using injector. The extracted air was injected into the gas sampling bag, and shipped back to the laboratory analysis of the concentration of CO2 by gas chromatography in Institute of Botany, The Chinese Academy of Sciences. Using the difference of concentration of CO2 at two times to calculate soil respiration. Each measurement points are located three repeat. After five minutes sealed box cover start mining the 1st sample, and then taken once every sample interval of 10 minutes, four times in total mining. Date content: Data content includes header information and once every 10 days three times repeated observations and the average of the three times. Measuring location: Gobi (Bajitan Gobi station), Wetland (Zhangye wetland Station), Sparse grassland (Huazhaizi desert steppe Station), Desert (Shenshawo sandy desert Station), Orchard (site No.17 eddy covariance system), Maize Farmland (Daman Superstation) Measuring time: 16-6-2012, 28-6-2012, 9-7-2012, 18-7-2012, 30-7-2012, 11-8-2012, 21-8-2012, 2-9-2012, 13-9-2012, 22-9-2012 (UTC+8).

0 2019-09-12

HiWATER: Dataset of soil respiration observed in the middle reaches of the Heihe River Basin

Soil respiration rate was measured at the super station of Daman irrigation district in Zhangye city using the open circuit soil carbon flux measurement system LI-8100 (LI-COR, Lincoln, NE, USA) 1) Objective: The aim of soil respiration rate measurement is to explore the diurnal variation characteristics of soil respiration rate and to provide a scientific basis for the assessment of farmland ecosystem carbon cycle and carbon balance. 2) Measurement instruments and ways Measurement instruments: the open type of cold dry soil carbon flux measurement system LI-8100 (LI-COR, Lincoln, NE, USA). Measurement means: soil respiration chamber was placed in PVC ring (10 cm of diameter, 5 cm of height), which was inserted into the soil about 1 to 2 cm 1 d before measurement. The observation is automatic with a power supply of solar panels. 3) Measurement time Soil respiration rate was continuously measured mainly in the corn growing season. The time used in this dataset is in UTC+8 Time. 4) Data processing The data was periodically collected from the data collection instrument and saved as *.81x file, then was converted to text format file using LI-8100 (M) PC Client v2.0.0 software.

0 2019-09-12