Ecosystem carbon storage research method and observation system

The carbon storage of ecosystems is one of the basic contents of carbon cycle research. The observation and estimation of carbon storage is the basic data for evaluating the carbon sink function of ecosystem carbon sources and global climate change research. Vegetation and soil are the largest carbon pools in the ecosystem, and the observation of vegetation and soil carbon storage is the key to improving the accuracy of ecosystem carbon storage estimation.

2 observation system design

2.1 Purpose

The observations of ecosystem vegetation and soil carbon storage involve many observations, various observation techniques and methods, and large changes in observation time and spatial scale. The observation system is not only convenient for collecting, rapid analysis, processing of observation data, but also for users. The selected model is used to calculate the carbon storage of ecosystems at different scales.

The measurement of carbon content in vegetation and soil samples is an important part of carbon storage observation and a relatively time consuming task. The traditional method uses chemical methods, requires sample preparation, chemical reagents, and also produces toxic waste liquid during the measurement process, polluting the environment.

The AZ-C701 Ecosystem Carbon Storage Observing System is based on the requirements of China's Integrated Earth Observation System. It is integrated with the international advanced carbon measurement technology and database platform, and integrated vegetation and soil carbon storage observation system. Laser spectroscopy is used to measure the carbon content of vegetation and soil samples without the need for sample preparation, chemical reagents, fast measurement, and measurement of N, P, K, Ca, Mg, S and other macroelements and Fe, Cu, Mn, Trace elements such as Zn, B., Mo, Ni, Cl.

2.2 Observations

    According to the ten-year plan of China's integrated Earth observation system, combined with the requirements of the International Earth Observation System, the observations are as follows:

2.2 Observation point layout

In the observation plot, the leaf area index, tree height, DBH, and soil moisture observation points were determined.

Biomass sample collection points: Determine the aboveground biomass and underground biomass collection points with reference to forest, farmland, grassland, and wetland biomass measurement specifications.

Soil sample collection points: According to soil fertility, whether the soil moisture content is uniform, etc., diagonal, checkerboard or serpentine sampling methods can be used.

2.3 sampling frequency and sample processing, analysis

After the observation points are determined, the vegetation basic information of the observation points is recorded in the format of the farmland/forest/grassland/wetland sample plot information of Ecograph-C software, and the soil basic information of the observation points is recorded according to the soil sample surface.

The leaf area index and soil moisture can be measured multiple times in the growing season and stored in the Ecograph-C software.

Vegetation biomass, tree height, and DBH: 1 time/year or 1/5 years according to the research scale. For the forest plots, the sampling and measurement results of the felled wood and its side branches were recorded according to the Ecograph-C felled wood and the felled wood side branch biomass table.

Soil carbon storage: The initial (2a ~ 4a) sampling frequency is 1 time / year; the interval time can be longer, the sampling frequency is 3a ~ 5a a special case to increase the observation frequency. Soil sample information was entered according to the soil sampling location table and the soil sample record form in Ecograph-C.

    Measurement of carbon content of collected soil and plant samples such as leaves: directly into the measurement chamber of the AZ-C701 Ecosystem Carbon Storage Observing System, and the results are obtained in a few seconds. The system software provides a variety of data analysis tools, such as: PCA, PLS, multi-parameter linear regression, chemical statistical analysis, etc., to obtain quantitative analysis results of complex, multi-component samples.

    The Ecosystem Carbon Storage Observing System provides both raw data on soil and vegetation carbon storage observations and a comprehensive system of carbon storage calculations at different scales.

  Technical indicators:

Measurement principle: laser spectrum 190nm-1000nm, shutter delay range: 50ns-1ms; resolution: 25ns; automatic XYZ process

Measurement parameters:

Trace elements: Fe, Cu, Mn, Zn, B., Mo, Ni, Cl

Trace elements: detect almost all elements of the chemical periodic table

Leaf area index (LAI), leaf allocation angle (LAD), average leaf angle (MLA)

Breast diameter measurement range: 40cm ~ 127cm

Soil moisture: TDR principle, measuring range: 0-100%

Tree height: laser method, measuring height: 0-999m

3 data processing

The Ecograph-C software in the AZ-C701 ecosystem carbon storage observation system manages the basic information data of the observation points. The built-in model and calculation formula calculate the biomass and forest biomass of individual plants based on the original data; The amount of carbon, the carbon density is calculated, and the carbon storage of soil and vegetation is calculated.

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