A method for obtaining the contribution of soil respiration to carbon dioxide emissions

Abstract

The present invention belongs to the field of crop information detection technology and ecological environment governance technology, and specifically relates to a method for obtaining the contribution of soil respiration to carbon dioxide emissions. Based on a two-terminal mixed model, the present invention obtains the contribution of soil respiration to carbon dioxide emissions under the same conditions. 13 C was cultured in soil labeled with exogenous carbon of different abundances, and an additional isotope was introduced 13 The processing step of C labeling can distinguish the contribution of three end members (organic carbon, inorganic carbon and exogenous carbon) to soil respiration, and solve the dilemma that the two end member mixing model in the prior art cannot calculate the contribution of the three end members.

Description

Technical Field

[0001] The invention belongs to the field of crop information detection technology and ecological environment governance technology, and specifically relates to a method for obtaining the contribution share of carbon dioxide emissions from soil respiration. Background Art

[0002] Exploring the share of carbon dioxide provided by different carbon sources in soil respiration is the basis for accurately estimating the carbon fixation and carbon sink potential of the soil system. Currently, the two-pool mixing model is mainly used to calculate the contribution of carbon sources in the soil to carbon dioxide emitted by soil respiration. However, the two-pool mixing model can only distinguish the relative contribution of exogenous carbon and organic carbon or organic carbon and inorganic carbon in the soil to carbon dioxide emissions from soil respiration, and quantitatively identify the contribution of the two-pool in carbon dioxide emissions from soil respiration.

[0003] However, soils in karst areas usually develop from carbonate parent materials, and the sources of carbon dioxide emitted by their respiration include soil organic carbon mineralization and inorganic carbon decomposition, as well as degradation of exogenous carbon. Therefore, continuing to use the two-terminal mixed model will not be able to distinguish the contribution of each component in the karst soil to carbon dioxide release, let alone deeply understand the stimulating effect of exogenous carbon on soil organic and inorganic carbon pools. Summary of the invention

[0004] In view of this, the present invention provides a method for obtaining the contribution share of carbon dioxide emissions from soil respiration. The method provided by the present invention can obtain the contribution share of exogenous carbon, organic carbon and inorganic carbon to the release of carbon dioxide from soil respiration.

[0005] In order to solve the above technical problems, the present invention provides a method for obtaining the contribution share of carbon dioxide emissions from soil respiration, comprising the following steps:

[0006] Detection of organic carbon and inorganic carbon in the original soil 13 The abundance of C;

[0007] The original soil and the high-abundance marker are first mixed to obtain a soil with high-labeled exogenous carbon;

[0008] The original soil and the low-abundance marker are mixed for the second time to obtain a soil with low-labeled exogenous carbon; 13 The difference in C abundance is 10 to 100‰;

[0009] The soil with high labeled exogenous carbon and the soil with low labeled exogenous carbon are cultured in microcosms under the same conditions respectively;

[0010] Detection of carbon dioxide emissions from soil microcosms with high labeled exogenous carbon and soil microcosms with low labeled exogenous carbon 13 C abundance;

[0011] According to the original soil organic carbon and inorganic carbon 13 The abundance of C, high abundance markers, and low abundance markers 13 C abundance, carbon dioxide emissions from soil microcosms with high labeled exogenous carbon and soil microcosms with low labeled exogenous carbon 13 C abundance, and calculate the contribution of organic carbon, inorganic carbon and exogenous carbon to carbon dioxide emissions from soil respiration.

[0012] Preferably, the high abundance markers 13 The abundance of C is 100~500‰.

[0013] Preferably, the environmental temperature for culturing the microcosm is 10-30° C.; the relative humidity for culturing the microcosm is 10-50%.

[0014] Preferably, the microcosm is cultured for 1 to 110 days.

[0015] Preferably, the contribution of the exogenous carbon to the carbon dioxide emission from soil respiration is calculated by Formula 1:

[0016]

[0017] Among them, δ 13 C1 is a high abundance marker 13 The abundance of C, δ 13 C2 is a low abundance marker 13 The abundance of C, δ 13 CO 2Total-1 Carbon dioxide emission from soil microcosm cultivation with high exogenous carbon labeling 13 C abundance, δ 13 CO 2Total-2 Carbon dioxide emission from soil microcosm cultivation with low labeled exogenous carbon 13 C abundance, f C It is the contribution of exogenous carbon to carbon dioxide emissions from soil respiration.

[0018] Preferably, the contribution of organic carbon to carbon dioxide emissions from soil respiration is calculated by Formula 2:

[0019]

[0020] Among them, δ 13 C SOC Organic carbon in the original soil 13 The abundance of C, δ 13 CSIC Inorganic carbon in the original soil 13 The abundance of C, f SOC The contribution of organic carbon to carbon dioxide emissions from soil respiration.

[0021] Preferably, the contribution of the inorganic carbon to the carbon dioxide emission from soil respiration is calculated by Formula 3:

[0022] f SIC =1-f SOC -f C Formula 3;

[0023] Among them, f SIC It is the contribution of inorganic carbon to carbon dioxide emissions from soil respiration.

[0024] Preferably, the organic carbon and inorganic carbon in the original soil are detected. 13 The method also includes: removing impurities from the original soil, wherein the impurities removed include fine roots, weeds and insects.

[0025] Preferably, the original soil includes gray-calcium soil, brown-calcium soil, volcanic ash soil, purple soil, rocky soil or lime soil.

[0026] Preferably, the lime soil is karst lime soil.

[0027] The present invention provides a method for obtaining the contribution of soil respiration to carbon dioxide emissions, comprising the following steps: respectively detecting the organic carbon and inorganic carbon in the original soil; 13 C abundance; first mixing the original soil and the high abundance marker to obtain a soil with high labeled exogenous carbon; second mixing the original soil and the low abundance marker to obtain a soil with low labeled exogenous carbon; 13 The difference in C abundance is 10-100‰; the soil with high labeled exogenous carbon and the soil with low labeled exogenous carbon are cultured in microcosms under the same conditions; the carbon dioxide emitted by the microcosms cultured in the soil with high labeled exogenous carbon and the soil with low labeled exogenous carbon is detected respectively. 13 C abundance; calculate the contribution of organic carbon, inorganic carbon and exogenous carbon to carbon dioxide emitted by soil respiration. 13 C soil labeled with exogenous carbon of different abundances was used to cultivate microcosms, and an additional isotope was introduced 13 The C-labeled processing steps are used to distinguish the contribution of the three end members (organic carbon, inorganic carbon and exogenous carbon) to soil respiration, solving the dilemma that the two-end member mixing model in the existing technology cannot calculate the contribution of the three end members; thereby deeply understanding the stimulating effect of exogenous carbon on soil organic and inorganic carbon pools. DETAILED DESCRIPTION

[0028] The present invention provides a method for obtaining the contribution share of carbon dioxide emission from soil respiration, comprising the following steps:

[0029] Detection of organic carbon and inorganic carbon in the original soil 13 The abundance of C;

[0030] The original soil and the high-abundance marker are first mixed to obtain a soil with high-labeled exogenous carbon;

[0031] The original soil and the low-abundance marker are mixed for the second time to obtain a soil with low-labeled exogenous carbon; 13 The difference in C abundance is 10 to 100‰;

[0032] The soil with high labeled exogenous carbon and the soil with low labeled exogenous carbon are cultured in microcosms under the same conditions respectively;

[0033] Detection of carbon dioxide emissions from soil microcosms with high labeled exogenous carbon and soil microcosms with low labeled exogenous carbon 13 C abundance;

[0034] According to the original soil organic carbon and inorganic carbon 13 The abundance of C, high abundance markers, and low abundance markers 13 C abundance, carbon dioxide emissions from soil microcosms with high labeled exogenous carbon and soil microcosms with low labeled exogenous carbon 13 C abundance, and calculate the contribution of organic carbon, inorganic carbon and exogenous carbon to carbon dioxide emissions from soil respiration.

[0035] The present invention detects organic carbon and inorganic carbon in the original soil respectively. 13 The method provided by the present invention is preferably applicable to gray calcium soil, brown calcium soil, volcanic ash soil, purple soil, stone soil or lime soil, and more preferably applicable to lime soil. In an embodiment of the present invention, the original soil is karst lime soil. In the present invention, the method for detecting the abundance of organic carbon and inorganic carbon in the original soil is preferably applicable to gray calcium soil, brown calcium soil, volcanic ash soil, purple soil, stone soil or lime soil, and more preferably applicable to lime soil. 13 Before determining the abundance of C, it is also preferred to include: removing impurities from the original soil. In the present invention, the impurity removal can remove impurities such as fine roots, weeds and insects in the original soil. The present invention has no special requirements for the impurity removal method, as long as the impurities in the original soil can be removed.

[0036] In the present invention, the detection device is preferably a gas isotope mass spectrometer, and the gas isotope mass spectrometer is preferably MAT252.

[0037] The present invention first mixes the original soil and the high-abundance marker to obtain soil with high-labeled exogenous carbon. 13The abundance of C is preferably 100-500‰, more preferably 140-200‰. In the present invention, the high-abundance marker preferably includes a high-abundance tobacco biomass marker or a high-abundance corn biomass marker, more preferably a high-abundance tobacco biomass marker. The present invention has no special requirements for the source of the high-abundance marker, as long as it can meet the required abundance. In the present invention, the high-abundance tobacco biomass marker is preferably prepared according to the following method:

[0038] The tobacco seedlings were transplanted into Hoagland's nutrient solution, and then placed in a transparent glass sealed box with a length of 50 cm, a width of 30 cm, and a height of 40 cm. The air in the transparent sealed box was extracted from the exhaust port by a vacuum pump to make the vacuum degree in the transparent sealed box -0.02 Mpa to form a vacuum condition; the tobacco seedlings were starved for photosynthesis for 30 minutes under the vacuum condition; after the starvation photosynthesis, 500 mL of nutrient solution was introduced into the transparent sealed box from the air inlet. 13 CO2 gas was used for 2 days of labeled photosynthesis; the plants after labeled photosynthesis were taken out of the transparent sealed box and placed in the air for 2.5 days of natural photosynthesis; the steps of starvation photosynthesis, labeled photosynthesis and natural photosynthesis were repeated 5 times to obtain 13 The carbon isotope marker with a C abundance of 10526.35‰; 13 The carbon isotope marker with a C abundance of 10526.35‰ was dried at 50°C for 40h to obtain a dry 13 C-labeled tobacco ( 13 C abundance is 10526.35‰); the unlabeled tobacco was dried at 50°C for 40h to obtain dried unlabeled tobacco ( 13 C abundance is -23.78‰); dry 13 C-labeled tobacco and dried unlabeled tobacco are mixed, ground, and then passed through a 60-mesh sieve to obtain the high-abundance tobacco biomass marker. 13 The mass ratio of C-labeled tobacco to dried unlabeled tobacco is preferably 1:40 to 80.

[0039] In the present invention, the exogenous carbon in the soil with high labeled exogenous carbon 13 The abundance of C and high abundance markers 13 In the present invention, the mass ratio of the high-abundance marker to the original soil is preferably 1:20 to 100, more preferably 1:30 to 60, and even more preferably 1:40 to 50. The present invention has no particular limitation on the first mixing, as long as it can be mixed evenly.

[0040] The present invention further mixes the original soil and the low-abundance marker to obtain soil with low-labeled exogenous carbon. 13The difference in C abundance is 10-100‰, preferably 30-80‰. In the present invention, the low-abundance marker preferably includes a low-abundance tobacco biomass marker or a low-abundance corn biomass marker, and more preferably a low-abundance tobacco biomass marker. The present invention has no special requirements on the source of the low-abundance marker, as long as the required abundance can be met. In the present invention, the low-abundance tobacco biomass marker is preferably prepared according to the method for preparing a high-abundance tobacco biomass marker, except that the drying 13 C labeled tobacco and dried unlabeled tobacco have different mass ratios; the dried 13 The mass ratio of C-labeled tobacco to dried unlabeled tobacco is preferably 1:100-140.

[0041] In the present invention, the exogenous carbon in the soil with low labeled exogenous carbon is 13 The abundance of C and low abundance markers 13 In the present invention, the mass ratio of the low-abundance marker to the original soil is preferably consistent with the mass ratio of the high-abundance marker to the original soil.

[0042] The present invention has no special requirements for the second mixing, as long as the mixing can be uniform.

[0043] After obtaining the soil with high labeled exogenous carbon and the soil with low labeled exogenous carbon, the present invention cultured the soil with high labeled exogenous carbon and the soil with low labeled exogenous carbon in microcosms under the same conditions.

[0044] In the present invention, the environmental temperature of the microcosm is preferably 10-30°C, more preferably 15-25°C; the relative humidity of the microcosm is preferably 10-50%, more preferably 20-40%. In the present invention, the microcosm is preferably cultured for 1-110 days, more preferably 6-85 days, further preferably 12-78 days, and most preferably 20-58 days.

[0045] After the microcosm is cultivated, the present invention detects the carbon dioxide emitted by the microcosm cultivation of soil with high labeled exogenous carbon and soil with low labeled exogenous carbon respectively. 13 C abundance. The present invention preferably further comprises, before detection: separating and purifying the gas produced after the microcosm is cultured. In the present invention, the separation and purification method is preferably a cold trap. The present invention separates carbon dioxide from the gas produced after the microcosm is cultured by separation and purification. In the present invention, the detection device is preferably a gas isotope mass spectrometer, and the gas isotope mass spectrometer is preferably MAT252.

[0046] The present invention is based on the organic carbon and inorganic carbon in the original soil 13 The abundance of C, high abundance markers, and low abundance markers 13C abundance, carbon dioxide emissions from soil microcosms with high labeled exogenous carbon and soil microcosms with low labeled exogenous carbon 13 C abundance, calculate the contribution of organic carbon, inorganic carbon and exogenous carbon to carbon dioxide emitted by soil respiration. In the present invention, the contribution of exogenous carbon to carbon dioxide emitted by soil respiration is preferably calculated by formula 1:

[0047]

[0048] Among them, δ 13 C1 is a high abundance marker 13 The abundance of C, δ 13 C2 is a low abundance marker 13 The abundance of C, δ 13 CO 2Total-1 Carbon dioxide emission from soil microcosm cultivation with high exogenous carbon labeling 13 C abundance, δ 13 CO 2Total-2 Carbon dioxide emission from soil microcosm cultivation with low labeled exogenous carbon 13 C abundance, f C It is the contribution of exogenous carbon to carbon dioxide emissions from soil respiration.

[0049] In the present invention, the contribution of organic carbon to carbon dioxide emissions from soil respiration is preferably calculated by Formula 2:

[0050]

[0051] Among them, δ 13 C SOC Organic carbon in the original soil 13 The abundance of C, δ 13 C SIC Inorganic carbon in the original soil 13 The abundance of C, f SOC The contribution of organic carbon to carbon dioxide emissions from soil respiration.

[0052] In the present invention, the contribution of the inorganic carbon to the carbon dioxide emission from soil respiration is preferably calculated by Formula 3:

[0053] f SIC =1-f SOC -f C Formula 3;

[0054] Among them, f SIC It is the contribution of inorganic carbon to carbon dioxide emissions from soil respiration.

[0055] In the present invention, dual isotope labeling overcomes the dilemma that the two terminal mixing model in the prior art cannot solve the contribution of three parameters. The dual isotope labeling method provided by the present invention can be flexibly designed and processed according to actual research needs, is not limited by the research object, and has the characteristics of simplicity, easy operation and high accuracy.

[0056] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0057] Example 1

[0058] The tobacco biomass marker was prepared according to the following method:

[0059] The tobacco seedlings were transplanted into Hoagland's nutrient solution, and then placed in a transparent glass sealed box with a length of 50 cm, a width of 30 cm, and a height of 40 cm. The air in the transparent sealed box was extracted from the exhaust port by a vacuum pump to make the vacuum degree in the transparent sealed box -0.02 Mpa to form a vacuum condition; the tobacco seedlings were starved for photosynthesis for 30 minutes under the vacuum condition; after the starvation photosynthesis, 500 mL of nutrient solution was introduced into the transparent sealed box from the air inlet. 13 CO2 gas was used for 2 days of labeled photosynthesis; the plants after labeled photosynthesis were taken out of the transparent sealed box and placed in the air for 2.5 days of natural photosynthesis; the steps of starvation photosynthesis, labeled photosynthesis and natural photosynthesis were repeated 5 times to obtain 13 The carbon isotope marker with a C abundance of 10526.35‰; 13 The carbon isotope marker with a C abundance of 10526.35‰ was dried at 50°C for 40h to obtain a dry 13 C-labeled tobacco ( 13 C abundance is 10526.35‰); the unlabeled tobacco was dried at 50°C for 40h to obtain dried unlabeled tobacco ( 13 C abundance is -23.78‰); dry 13 C-labeled tobacco and dried unlabeled tobacco were mixed in a ratio of 1:60, ground and passed through a 60-mesh sieve to obtain 13 C abundance of 144.26‰ tobacco biomass marker; 13 C-labeled tobacco and dried unlabeled tobacco were mixed in a ratio of 1:120, ground and passed through a 60-mesh sieve to obtain 13 C abundance of tobacco biomass markers at 67.01‰;

[0060] Karst lime soil was selected as the research object, and the organic carbon (SOC) and inorganic carbon (SIC) in karst lime soil were detected by gas isotope mass spectrometer MAT252. 13The abundance values ​​of C are: -23.15‰ and -0.07‰;

[0061] The karst lime soil was divided into two soil samples with a mass of 50.00 g each; 1.00 g was added to one soil sample. 13 The tobacco biomass marker with a C abundance of 144.26‰ was mixed evenly to obtain soil with high labeled exogenous carbon;

[0062] To another soil sample, add 1.00 g 13 The tobacco biomass marker with a C abundance of 67.01‰ was mixed evenly to obtain soil with low labeled exogenous carbon;

[0063] The soil with high labeled exogenous carbon and the soil with low labeled exogenous carbon were cultured in microcosms at a temperature of 25°C and a relative humidity of 40% respectively; after 6 days of culture, the gas produced after the culture was separated by cold trap to obtain carbon dioxide gas, and the gas isotope mass spectrometer MAT252 was used to detect the carbon dioxide gas separated. 13 The abundance of C is shown in Table 1.

[0064] Repeat the above detection process, the difference is that the detection of the gas in the microcosm after cultivation 13 The abundance of C was observed at 26, 32, 52, 58, 78, 84 and 104 days of microcosm cultivation, respectively. The results are listed in Table 1.

[0065] The contribution of organic carbon, inorganic carbon and exogenous carbon (tobacco biomass marker) to the production of carbon dioxide in soil respiration was calculated according to formulas 1 to 3, and the results are listed in Table 1.

[0066] Table 1 Detection results of microcosm cultivation at different times according to the method of Example 1

[0067]

[0068] From the results in Table 1, it can be seen that the CO2 emission from soil respiration after 6 days of microcosm cultivation mainly comes from soil organic carbon and exogenous carbon (tobacco biomass marker), of which the contribution of organic carbon is 62.47% and the contribution of exogenous carbon is 38.53%. With the increase of cultivation time, the proportion of CO2 in the soil from exogenous carbon gradually increases, and the proportion from organic carbon gradually decreases. At the same time, there is also a small amount of CO2 emission from inorganic carbon. After 104 days of microcosm cultivation, the contribution of organic carbon, inorganic carbon and exogenous carbon to soil respiration CO2 emission are 35.82%, 8.09% and 56.06% respectively, indicating that inorganic carbon is also an important source of soil respiration CO2 emission. At the same time, when tobacco biomass is used as exogenous carbon, it shows a positive excitation effect on the organic carbon of the soil body, prompting the decomposition of the organic carbon of the soil body to produce CO2, which is not conducive to carbon fixation and emission reduction. This is consistent with the conclusion that tobacco biomass prompts the CO2 emission of soil body organic carbon in the two-terminal mixed model, indicating that the method for obtaining the contribution share of soil respiration carbon dioxide emission provided by the present invention is reliable.

[0069] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for obtaining the contribution of soil respiration to carbon dioxide emissions, comprising the following steps: Detection of organic carbon and inorganic carbon in the original soil 13 The abundance of C; the original soil includes gray calcium soil, brown calcium soil, volcanic ash soil, purple soil, rocky soil or lime soil; The original soil and the high-abundance marker are first mixed to obtain a soil with high-labeled exogenous carbon; The original soil and the low-abundance marker are mixed for the second time to obtain a soil with low-labeled exogenous carbon; 13 The difference in C abundance is 10 to 100‰; The soil with high labeled exogenous carbon and the soil with low labeled exogenous carbon are cultured in microcosms under the same conditions respectively; Detection of carbon dioxide emissions from soil microcosms with high labeled exogenous carbon and soil microcosms with low labeled exogenous carbon 13 C abundance; According to the original soil organic carbon and inorganic carbon 13 The abundance of C, high abundance markers, and low abundance markers 13 C abundance, carbon dioxide emissions from soil microcosms with high labeled exogenous carbon and soil microcosms with low labeled exogenous carbon 13 C abundance, calculate the contribution of organic carbon, inorganic carbon and exogenous carbon to carbon dioxide emitted by soil respiration; The contribution of the exogenous carbon to the carbon dioxide emission from soil respiration is calculated by formula 1: Among them, δ 13 C1 is a high abundance marker 13 The abundance of C, δ 13 C2 is a low abundance marker 13 The abundance of C, δ 13 CO 2Total-1 Carbon dioxide emission from soil microcosm cultivation with high exogenous carbon labeling 13 C abundance, δ 13 CO 2Total-2 Carbon dioxide emission from soil microcosm cultivation with low labeled exogenous carbon 13 C abundance, f C is the contribution of exogenous carbon to carbon dioxide emissions from soil respiration; The contribution of organic carbon to carbon dioxide emissions from soil respiration is calculated by formula 2: Among them, δ 13 C SOC Organic carbon in the original soil 13 The abundance of C, δ 13 C SIC Inorganic carbon in the original soil 13 The abundance of C, f SOC is the contribution of organic carbon to carbon dioxide emissions from soil respiration; The contribution of inorganic carbon to carbon dioxide emissions from soil respiration is calculated by formula 3: f SIC =1-f SOC -f C Formula 3; Among them, f SIC It is the contribution of inorganic carbon to carbon dioxide emissions from soil respiration.

2. The method according to claim 1, characterized in that The high abundance markers 13 The abundance of C is 100~500‰.

3. The method according to claim 1, characterized in that The environmental temperature of the micro-universe culture is 10-30° C.; the relative humidity of the micro-universe culture environment is 10-50%.

4. The method according to claim 1 or 3, characterized in that: The microcosm culture time is 1 to 110 days.

5. The method according to claim 1, characterized in that Detection of organic carbon and inorganic carbon in original soil 13 The method also includes: removing impurities from the original soil, wherein the impurities removed include fine roots, weeds and insects.

6. The method according to claim 1, characterized in that The lime soil is karst lime soil.

Images