Soil profile CO2 gradient monitoring system

NegotiableUpdate on 02/14

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Overview

There are many studies on soil profile CO2 flux, but these monitoring methods are not sufficient to explain the soil CO2 production process. The research on soil profile CO2 gradient monitoring system has become an increasingly hot topic in soil respiration and even ecosystem carbon cycle research. Continuous monitoring of CO2 production at different levels (depths) of soil is crucial for understanding soil CO2 dynamics, as it can elucidate the seasonal and light dependent CO2 flux from soil to atmosphere ..

Product Details

Surface layer of soilCO₂There are many studies on flux, but these monitoring methods are not sufficient to explain soilCO₂Production process, soil profileCO₂Vertical gradient research is increasingly becoming a hot topic in soil respiration and even ecosystem carbon cycling research. Different layers (depths) of soilCO₂Continuous monitoring of production is crucial for understanding soilCO₂Dynamics are extremely important as they can elucidate the transition from soil to atmosphereCO₂The variation characteristics of flux with season, light, temperature, humidity, and soil characteristics.

Vertical gradient of soilCO₂Monitoring can be compared with widely used eddy related monitoring to quantitatively study and analyze carbon exchange in ecosystems.

There are currently two methods for soil gradient:

1. Directly bury the CO2 sensor in the soil Gradient based monitoring of concentration distribution in each layer, simple to use, with two types of precision sensors to choose from,

GMP343 and GMP22X series:

	GMP343	GMP22X
Measurement method:	Diffuse and pump suction	Diffuse and pump suction
Measurement range:	0 . .. 1000 ppm, 0 . ..2 000 ppm 0 . .. 3000 ppm, 0 . .. 4000 ppm 0 . .. 5000 ppm, 0 . .. 2 %	GMP221 probe 0 .. 2 %, 0 . .. 3 %, 0 . .. 5 %, 0 . .. 10%, 0 . .. 20 % CO2 GMP222 probe 0 .. 2000 ppm, 0 ... 3000 ppm, 0 ... 5000 ppm, 0 . ..7 000ppm, 0 . .. 10000 ppm CO2
Accuracy:	0 1000 ppm: ± (3 ppm+1% reading) 0 .. 2000 - 0 . 2%: ± (5 ppm+2% reading)	± (1.5% range+2.0% reading)
Working temperature:	-40~60°C	-20~60 ° C (probe)
Working humidity:	0	0
Shell:	Electroplated aluminum, PC plastic IP66/IP67	PC plastic IP66/IP67

2. Online multi-layer analysis of soil concentration data using infrared analyzer

System advantages:

vUsing an analyzer to analyze multi-layer data,No systematic errors

vOther measuring element analyzers can be replaced,if:N₂O,CH₄Equal gradient measurement content,More flexible experiments

vhigh precision,Easy to use and maintain.The whole machine is simpler and more convenient to use than soil breathing systems

CO₂/H₂O analyzer technical specifications

			CO2 analyzer		H2O analyzer
range			0~20,000 μmol/mol		0~60 mmol/mol
accuracy			1% better than the reading		1.5% better than the reading
Calibration drift		zero drift	<0.15 μmol/mol/℃		<0.003 mmol/mol/℃
		Span drift	<0.03 %/℃		<0.03 %/℃ @ 10 mmol/mol
		Total drift	<0.4 μmol/mol/℃ @ 370 μmol/mol		<0.009 mmol/mol/℃ @ 10 mmol/mol
RMS noise		1 second signal filtering	<1 μmol/ mol@370 μmol/mol		<0.01 mmol/ mol@10 mmol/mol
sensitivity		CO2	——		<0.0001 mmol/mol H2O/ μmol/mol CO2
		H2O	<0.1 μmol/mol CO2/ m mol/mol H2O		——
Measuring principle		Non dispersive infrared analysis	light source lifetime		~18,000 h
standard	CO2	World Meteorological Organization standards		power supply	12~30 V DC
	H2O	LI-610 Portable Generator NIST Standard
Pressure compensation range		15~115 kPa		Working temperature range	-20~45℃
*Atmospheric velocity rate		1 L/min		Relative humidity range	0~95% (non condensing)
output signal		2 analog voltage outputs, 2 current outputs		volume	22.2 L×15.3 W×7.6 H cm
		Digital output: TTL (0-5V) or open circuit		weight	1 kg
Internal cavity volume		14.5mL		Power requirements	12~30 V DC， 14 W during preheating and 3.6 W during stabilization

According to Fick's first law, the flow rate of diffusing material per unit cross-sectional area perpendicular to the diffusion direction per unit time (in the case of steady-state diffusion) is calledDiffusion fluxDiffusion flux，用JAt this section, theconcentration gradientThe concentration grade is directly proportional. Soil profile CO₂Flux（μmol CO2 m⁻²s⁻¹）According to this law, the specific calculation formula is:

J= -D(dC/dx)

among whichDforDiffusion coefficient of CO2 in soil (unit: m)²/s， C is the concentration of CO2 at a depth of x (in meters), which is related to soil temperature, soil volume moisture content, and soil porosity,dC/dxFor concentration gradient,The "-" sign indicates that the diffusion direction is opposite to the concentration gradient, that is, diffusion spreads from the high concentration area to the low concentration area.

Characteristics of the system:

1. Non disturbance in-situ continuous measurement of soil profile CO₂Moisture and temperature (standard configuration is3-8 layers are optional), and soil CO can be calculated using Fick's law₂Flux (soil respiration) is used to achieve continuous and stable in-situ monitoring of soil respiration.

2. Three parameter intelligent sensor for soil, measuring soil moisture, temperature, and salinity.

3. Transparent or non transparent soil respiration chamber method (optional) for measuring surface soil respiration, which can be used to supplement, calibrate, or compare soil profile CO₂Gradient measurement data.

4. Wireless data transmission allows for online browsing and downloading of data at any time.

5. AC battery power supply or solar power supply.

Main technical indicators:

1. Soil moisture measurement:

·measurement range0Volume water content, degree± 1%, repeatability accuracy ±0.2%，；

·Range of soil temperature measurement:-40℃～70℃, measurement accuracy: ±0.2℃

2. Soil CO2 measurement: Non dispersive single beam dual wavelength infrared technology (NDIR), measurement range 0-5000ppm, 0-7000ppm, 0-10000ppm, 0-20000ppm optional, accuracy ± 1.5%, response time 3 seconds;

3. Standard 16 channel data collector (optional 32 channels to monitor CO2 concentration, soil moisture, and soil temperature above 3 layers):

·storable220000Group data with timestamp,16Bit resolution,± 20 mV up to ± 2.5 V 8 range input, degree0.03%；

·Measurement interval3Seconds to4Adjustable hours, average data interval3Seconds to4Hour;

4. Wireless data transmission, browsing and downloading data through software terminals, and conducting statistical analysis on the data.