CN115656467A - A Method for Obtaining the Contribution Share of Carbon Dioxide Emissions from Soil Respiration - Google Patents

Abstract

The invention belongs to the technical field of crop information detection and ecological environment management, and particularly relates to a method for obtaining contribution of carbon dioxide discharged under the action of soil respiration. The invention is based on the two-end element mixed model and is matched under the same condition ¹³ Culturing the soil with different abundances of C and marked with exogenous carbon, and additionally introducing an isotope ¹³ And C, marking, so that the contribution shares of the three end members (organic carbon, inorganic carbon and exogenous carbon) on the soil respiration are distinguished, and the dilemma that the contribution shares of the three end members cannot be calculated by a two-end member mixed model in the prior art is solved.

Description

A Method for Obtaining the Contribution Share of Carbon Dioxide Emissions from Soil Respiration

technical field

The invention belongs to the field of crop information detection technology and ecological environment management technology, and specifically relates to a method for obtaining the contribution share of carbon dioxide emitted by soil respiration.

Background technique

Discussing the share of carbon dioxide provided by different carbon sources in soil respiration is the basis for accurately estimating the carbon sequestration and carbon sink potential of soil systems. At present, the Two-Pool Mixing Model is mainly used to calculate the contribution of carbon sources in the soil to the carbon dioxide emitted by soil respiration. However, the two-terminal mixed model can only distinguish the relative contribution of exogenous carbon and organic carbon or organic carbon and inorganic carbon to soil respiration carbon dioxide emissions, and quantitatively identify the contribution share of two-terminal carbon dioxide emissions from soil respiration.

However, soils in karst areas are usually developed from carbonate rock parent materials, and the sources of carbon dioxide emitted by respiration include the mineralization of soil organic carbon and the decomposition of inorganic carbon, as well as the 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 soil in the karst area to the release of carbon dioxide, let alone deeply understand the stimulation effect of exogenous carbon on soil organic and inorganic carbon pools.

Contents of the invention

In view of this, the present invention provides a method for obtaining the contribution of carbon dioxide emitted by soil respiration, by using the method provided by the present invention, the contribution of exogenous carbon, organic carbon and inorganic carbon to the release of carbon dioxide by soil respiration can be obtained.

In order to solve the above-mentioned technical problems, the present invention provides a method for obtaining the contribution share of carbon dioxide emitted by soil respiration, comprising the following steps:

Detect the abundance of ¹³ C in the organic carbon and inorganic carbon in the original soil respectively;

The original soil and high-abundance markers are first mixed to obtain soil with high-marked exogenous carbon;

The original soil and the low-abundance marker are mixed for the second time to obtain the soil with low-mark exogenous carbon; the difference in ¹³ C abundance between the high-abundance marker and the low-abundance marker is 10-100‰;

The soil with high labeled exogenous carbon and the soil with low labeled exogenous carbon were respectively cultured in microcosms under the same conditions;

Detect the abundance of ¹³ C in carbon dioxide emitted from microcosm culture in the soil with high-labeled exogenous carbon and the soil with low-labeled exogenous carbon, respectively;

According to the abundance of ¹³ C in organic carbon and inorganic carbon in the original soil, the abundance of ¹³ C in high-abundance markers and low-abundance markers, soils with high-labeled exogenous carbon and soil microcosms with low-labeled exogenous carbon The ¹³ C abundance in the carbon dioxide emitted was cultivated, and the contribution of organic carbon, inorganic carbon and exogenous carbon to the carbon dioxide emitted by soil respiration was calculated.

Preferably, the abundance of ¹³ C in the high-abundance marker is 100-500‰.

Preferably, the ambient temperature of the microcosm cultivation is 10-30°C; the relative humidity of the microcosm cultivation environment is 10-50%.

Preferably, the time for culturing the microcosms is 1-110 days.

Preferably, the contribution of the exogenous carbon to the emission of carbon dioxide by soil respiration is calculated by formula 1:

Among them, δ ¹³ C ₁ is the abundance of ¹³ C in high-abundance markers, δ ¹³ C ₂ is the abundance of ¹³ C in low-abundance markers, and δ ¹³ CO _2Total-1 is the soil with high marker exogenous carbon ¹³ C abundance in carbon dioxide emitted by microcosm culture, δ ¹³ CO _2Total-2 is ^{the 13} C abundance in carbon dioxide emitted by soil microcosm culture with low label exogenous carbon, f _C is the contribution of exogenous carbon to carbon dioxide emitted by soil respiration share.

Preferably, the contribution of the organic carbon to the emission of carbon dioxide by soil respiration is calculated by formula 2:

Among them, δ ¹³ C _SOC is the abundance of ¹³ C in the organic carbon in the original soil, δ ¹³ C _SIC is the abundance of ¹³ C in the inorganic carbon in the original soil, and f _SOC is the contribution of organic carbon to the emission of carbon dioxide by soil respiration .

Preferably, the contribution of the inorganic carbon to the emission of carbon dioxide by soil respiration is calculated by formula 3:

f _SIC = 1-f _SOC -f _C formula 3;

Among them, f _SIC is the contribution of inorganic carbon to carbon dioxide emission from soil respiration.

Preferably, before detecting the abundance of ¹³ C in the organic carbon and the inorganic carbon in the original soil, it also includes: performing impurity removal treatment on the original soil, and the impurities in the impurity removal treatment include fine roots, weeds and insects.

Preferably, the original soil includes lime-calcium soil, brown-calcium soil, volcanic ash soil, purple soil, stony soil or lime soil.

Preferably, the lime soil is karst lime soil.

The invention provides a method for obtaining the contribution of carbon dioxide emitted by soil respiration, comprising the following steps: separately detecting the abundance of ¹³ C in the organic carbon and inorganic carbon in the original soil; first mixing the original soil and the high-abundance marker , to obtain high-labeled exogenous carbon soil; the second mixture of the original soil and low-abundance markers to obtain low-labeled exogenous carbon soil; ^{the 13} C abundance in the high-abundance marker and low-abundance marker The difference is 10 to 100‰; the soil with high-marked exogenous carbon and the soil with low-marked exogenous carbon were respectively cultured in microcosms under the same conditions; the soil with high-marked exogenous carbon and the soil with low-marked exogenous The ¹³ C abundance in carbon dioxide emitted by soil microcosm cultivation of source carbon; calculation of the contribution of organic carbon, inorganic carbon and exogenous carbon to carbon dioxide emitted by soil respiration. Based on the two-terminal mixing model, the present invention conducts microcosm cultivation on soils marked with exogenous carbon with different abundances of ¹³ C under exactly the same conditions, and additionally introduces a treatment step of isotope ¹³ C labeling, thereby distinguishing the three The contribution of endmembers (organic carbon, inorganic carbon and exogenous carbon) to soil respiration solves the dilemma that the mixed model of endmembers in the prior art cannot calculate the contribution of the three endmembers; thus in-depth understanding of the contribution of exogenous carbon to soil Exciting effects of organic and inorganic carbon pools.

Detailed ways

The invention provides a method for obtaining the contribution share of carbon dioxide emitted by soil respiration, comprising the following steps:

Detect the abundance of ¹³ C in the organic carbon and inorganic carbon in the original soil respectively;

The original soil and high-abundance markers are first mixed to obtain soil with high-marked exogenous carbon;

The original soil and the low-abundance marker are mixed for the second time to obtain the soil with low-mark exogenous carbon; the difference in ¹³ C abundance between the high-abundance marker and the low-abundance marker is 10-100‰;

The soil with high labeled exogenous carbon and the soil with low labeled exogenous carbon were respectively cultured in microcosms under the same conditions;

Detect the abundance of ¹³ C in carbon dioxide emitted from microcosm culture in the soil with high-labeled exogenous carbon and the soil with low-labeled exogenous carbon, respectively;

According to the abundance of ¹³ C in organic carbon and inorganic carbon in the original soil, the abundance of ¹³ C in high-abundance markers and low-abundance markers, soils with high-labeled exogenous carbon and soil microcosms with low-labeled exogenous carbon The ¹³ C abundance in the carbon dioxide emitted was cultivated, and the contribution of organic carbon, inorganic carbon and exogenous carbon to the carbon dioxide emitted by soil respiration was calculated.

The invention detects respectively the abundance of ¹³ C in the organic carbon and the inorganic carbon in the original soil. The method provided by the present invention is preferably applicable to lime soil, brown calcic soil, volcanic ash soil, purple soil, stony soil or lime soil, more preferably to lime soil. In an embodiment of the present invention, the original soil is karst lime soil. In the present invention, before the detection of the abundance of ¹³ C in organic carbon and inorganic carbon in the original soil, it preferably further includes: performing impurity removal treatment on the original soil. In the present invention, the impurity removal treatment can remove impurities such as fine roots, weeds and insects in the original soil. The present invention has no special requirements on the method of removing impurities, as long as the impurities in the original soil can be removed.

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

In the invention, the original soil and the high-abundance marker are first mixed to obtain the soil with high-mark exogenous carbon. In the present invention, the abundance of ¹³ C in the high-abundance marker 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 maize biomass marker, more preferably a high-abundance tobacco biomass marker. The present invention has no special requirements on 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:

Transplant the tobacco seedlings in Hoagland's nutrient solution, then place it in a transparent glass airtight box with a length of 50 cm, a width of 30 cm, and a height of 40 cm, and use a vacuum pump to draw the air into the transparent airtight box from the exhaust port. The air makes the vacuum degree in the transparent sealed box to be -0.02Mpa to _form a vacuum condition; the tobacco seedlings are subjected to starvation photosynthesis for 30 minutes under ^vacuum conditions; 2 days of marked photosynthesis; the marked photosynthetic plants were taken out of the transparent airtight box and placed in the air for 2.5 days of natural photosynthesis; the steps of starvation photosynthesis, marked photosynthesis and natural photosynthesis were repeated 5 times to obtain ¹³ C Carbon isotope markers with an abundance of 10526.35‰; carbon isotope markers with an abundance of ¹³ C of 10526.35‰ were dried at 50°C for 40 hours to obtain dry ¹³ C-labeled tobacco (abundance of ¹³ C was 10526.35‰); unlabeled tobacco 50 Dry at ℃ for 40 hours to obtain dry unlabeled tobacco ( ¹³ C abundance is -23.78‰); dry ¹³ C labeled tobacco and dried unlabeled tobacco are mixed, ground and passed through a 60-mesh sieve to obtain the high-abundance tobacco biomass marker thing. In the present invention, the mass ratio of the dried ¹³ C labeled tobacco to the dried unlabeled tobacco is preferably 1:40-80.

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

In the present invention, the original soil and the low-abundance marker are mixed for the second time to obtain the soil with low-mark exogenous carbon. In the present invention, the difference in ¹³ C abundance between the high-abundance marker and the low-abundance marker 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 maize biomass marker, 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 it can meet the required abundance. In the present invention, the low-abundance tobacco biomass markers are preferably prepared according to the method for preparing high-abundance tobacco biomass markers, the difference is that the mass ratios of dried ¹³ C labeled tobacco and dried unlabeled tobacco are different ; The mass ratio of the dried ¹³ C labeled tobacco to the dried unlabeled tobacco is preferably 1:100-140.

In the present invention, the abundance of ¹³ C in the exogenous carbon in the low-marked exogenous carbon soil is consistent with the abundance of ¹³ C in the low-abundance marker. 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.

The present invention has no special requirements on the second mixing, as long as it can be mixed uniformly.

After obtaining the soil with high-labeled exogenous carbon and the soil with low-labeled exogenous carbon, the present invention cultures the soil with high-labeled exogenous carbon and the soil with low-labeled exogenous carbon respectively under the same conditions.

In the present invention, the ambient temperature of the microcosm cultivation is preferably 10-30°C, more preferably 15-25°C; the relative humidity of the microcosm cultivation environment is preferably 10-50%, more preferably 20-40 %. In the present invention, the time for culturing the microcosms is preferably 1-110 days, more preferably 6-85 days, still more preferably 12-78 days, most preferably 20-58 days.

After microcosm cultivation, the present invention respectively detects the abundance of ¹³ C in carbon dioxide emitted from microcosm cultivation in soils with high-labeled exogenous carbon and soil with low-labeled exogenous carbon. The present invention preferably further includes: separating and purifying the gas produced after microcosm cultivation before detection. In the present invention, the separation and purification method is preferably a cold trap. The invention separates the carbon dioxide from the gas produced after microcosm cultivation through 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.

The present invention is based on the abundance of ¹³ C in organic carbon and inorganic carbon in the original soil, the abundance of ¹³ C in high-abundance markers and low-abundance markers, soils with high-marked exogenous carbon and soils with low-marked exogenous carbon The ¹³ C abundance in carbon dioxide emitted by microcosm cultivation was calculated, and the contribution of organic carbon, inorganic carbon and exogenous carbon to carbon dioxide emitted by soil respiration was calculated. In the present invention, the contribution of the exogenous carbon to the emission of carbon dioxide by soil respiration is preferably calculated by formula 1:

Among them, δ ¹³ C ₁ is the abundance of ¹³ C in high-abundance markers, δ ¹³ C ₂ is the abundance of ¹³ C in low-abundance markers, and δ ¹³ CO _2Total-1 is the soil with high marker exogenous carbon ¹³ C abundance in carbon dioxide emitted by microcosm culture, δ ¹³ CO _2Total-2 is ^{the 13} C abundance in carbon dioxide emitted by soil microcosm culture with low label exogenous carbon, f _C is the contribution of exogenous carbon to carbon dioxide emitted by soil respiration share.

In the present invention, the contribution of the organic carbon to soil respiration to discharge carbon dioxide is preferably calculated by formula 2:

Among them, δ ¹³ C _SOC is the abundance of ¹³ C in the organic carbon in the original soil, δ ¹³ C _SIC is the abundance of ¹³ C in the inorganic carbon in the original soil, and f _SOC is the contribution of organic carbon to the emission of carbon dioxide by soil respiration .

In the present invention, the contribution of the inorganic carbon to soil respiration to discharge carbon dioxide is preferably calculated by formula 3:

f _SIC = 1-f _SOC -f _C formula 3;

Among them, f _SIC is the contribution of inorganic carbon to carbon dioxide emission from soil respiration.

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

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

Example 1

Tobacco biomass markers are prepared according to the following method:

Transplant the tobacco seedlings in Hoagland's nutrient solution, then place it in a transparent glass airtight box with a length of 50 cm, a width of 30 cm, and a height of 40 cm, and use a vacuum pump to draw the air into the transparent airtight box from the exhaust port. The air makes the vacuum degree in the transparent sealed box to be -0.02Mpa to _form a vacuum condition; the tobacco seedlings are subjected to starvation photosynthesis for 30 minutes under ^vacuum conditions; 2 days of marked photosynthesis; the marked photosynthetic plants were taken out of the transparent airtight box and placed in the air for 2.5 days of natural photosynthesis; the steps of starvation photosynthesis, marked photosynthesis and natural photosynthesis were repeated 5 times to obtain ¹³ C Carbon isotope markers with an abundance of 10526.35‰; carbon isotope markers with an abundance of ¹³ C of 10526.35‰ were dried at 50°C for 40 hours to obtain dry ¹³ C-labeled tobacco (abundance of ¹³ C was 10526.35‰); unlabeled tobacco 50 Dry at ℃ for 40 hours to obtain dry unlabeled tobacco (the abundance of ¹³ C is -23.78‰); dry ¹³ C labeled tobacco and dry unlabeled tobacco are mixed according to the ratio of 1:60, ground and passed through a 60-mesh sieve to obtain ¹³ C Tobacco biomass markers with an abundance of 144.26‰; dry ¹³ C labeled tobacco and dried unlabeled tobacco were mixed at a ratio of 1:120, ground and passed through a 60-mesh sieve to obtain tobacco raw tobacco with an abundance of ¹³ C of 67.01‰ substance markers;

Taking karst lime soil as the research object, the abundance values of ¹³ C in organic carbon (SOC) and inorganic carbon (SIC) detected by gas isotope mass spectrometer MAT252 in karst lime soil are: -23.15‰ and -0.07‰, respectively;

The karst lime soil was equally divided into two soil samples with a mass of 50.00g; 1.00g of tobacco biomass markers with an abundance of ¹³ C of 144.26‰ was added to one soil sample, and the soil with high marker exogenous carbon was obtained by mixing evenly ;

Add 1.00g ¹³ C abundance of 67.01‰ of tobacco biomass markers to another soil sample, and mix evenly to obtain soil with low marker exogenous carbon;

The soil with high-labeled exogenous carbon and the soil with low-labeled exogenous carbon were respectively cultured in microcosms at a temperature of 25°C and a relative humidity of 40%. After 6 days of cultivation, the gas produced after cultivation was separated by a cold trap. The carbon dioxide gas was obtained, and the abundance of ¹³ C in the separated carbon dioxide gas was detected by a gas isotope mass spectrometer MAT252, and the results are listed in Table 1.

Repeat the above detection process, the difference is that the time to detect the abundance of ¹³ C in the gas after microcosm cultivation is 26 days, 32 days, 52 days, 58 days, 78 days, 84 days and 104 days after microcosm cultivation, The results are listed in Table 1.

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

Table 1 According to the method of Example 1, the detection results of microcosm culture at different times

From the results in Table 1, it can be seen that CO ₂ emission from soil respiration during microcosm cultivation for 6 days mainly comes from soil organic carbon and exogenous carbon (tobacco biomass marker), of which organic carbon contributes 62.47%, exogenous The contribution share of carbon is 38.53%. With the increase of cultivation time, the proportion of CO ₂ in soil derived from exogenous carbon gradually increased, while the proportion derived from organic carbon gradually decreased. At the same time, there is also a small amount of _CO2 emission originating from inorganic carbon. The contribution shares of organic carbon, inorganic carbon and exogenous carbon to soil respiration CO ₂ emissions after 104 days of microcosm cultivation were 35.82%, 8.09% and 56.06%, indicating that inorganic carbon is also an important source of soil respiration CO ₂ emissions . At the same time, when tobacco biomass is used as exogenous carbon, it has a positive stimulating effect on soil organic carbon, which promotes the decomposition of soil organic carbon to produce CO ₂ , which is not conducive to carbon sequestration and emission reduction. The conclusion that tobacco biomass promotes the emission of soil organic carbon CO ₂ is consistent, indicating that the method provided by the present invention for obtaining the contribution of carbon dioxide emission from soil respiration is reliable.

Although the foregoing embodiment has described the present invention in detail, it is only a part of the embodiments of the present invention, rather than all embodiments, and people can also obtain other embodiments according to the present embodiment without inventive step, these embodiments All belong to the protection scope of the present invention.

Claims (10)

1. A method for obtaining soil respiration emission carbon dioxide contribution share, comprising the following steps: Detect the abundance of ¹³ C in the organic carbon and inorganic carbon in the original soil respectively; The original soil and high-abundance markers are first mixed to obtain soil with high-marked exogenous carbon; The original soil and the low-abundance marker are mixed for the second time to obtain the soil with low-mark exogenous carbon; the difference in ¹³ C abundance between the high-abundance marker and the low-abundance marker is 10-100‰; The soil with high labeled exogenous carbon and the soil with low labeled exogenous carbon were respectively cultured in microcosms under the same conditions; Detect the abundance of ¹³ C in carbon dioxide emitted from microcosm culture in the soil with high-labeled exogenous carbon and the soil with low-labeled exogenous carbon, respectively; According to the abundance of ¹³ C in organic carbon and inorganic carbon in the original soil, the abundance of ¹³ C in high-abundance markers and low-abundance markers, soils with high-labeled exogenous carbon and soil microcosms with low-labeled exogenous carbon The ¹³ C abundance in the carbon dioxide emitted was cultivated, and the contribution of organic carbon, inorganic carbon and exogenous carbon to the carbon dioxide emitted by soil respiration was calculated. 2. The method according to claim 1, characterized in that the abundance of ¹³ C in the high-abundance marker is 100-500‰. 3. The method according to claim 1, characterized in that, the ambient temperature of the microcosm cultivation is 10-30°C; the relative humidity of the microcosm cultivation environment is 10-50%. 4. The method according to claim 1 or 3, characterized in that, the time for culturing the microcosms is 1-110 days. 5. according to the described method of claim 1, it is characterized in that, the contribution share of described exogenous carbon to soil respiration discharge carbon dioxide is calculated by formula 1:

Among them, δ ¹³ C ₁ is the abundance of ¹³ C in high-abundance markers, δ ¹³ C ₂ is the abundance of ¹³ C in low-abundance markers, and δ ¹³ CO _2Total-1 is the soil with high marker exogenous carbon ¹³ C abundance in carbon dioxide emitted by microcosm culture, δ ¹³ CO _2Total-2 is ^{the 13} C abundance in carbon dioxide emitted by soil microcosm culture with low label exogenous carbon, f _C is the contribution of exogenous carbon to carbon dioxide emitted by soil respiration share. 6. according to the described method of claim 1 or 5, it is characterized in that, described organic carbon is calculated by formula 2 to the contribution share of carbon dioxide discharged by soil respiration:

Among them, δ ¹³ C _SOC is the abundance of ¹³ C in the organic carbon in the original soil, δ ¹³ C _SIC is the abundance of ¹³ C in the inorganic carbon in the original soil, and f _SOC is the contribution of organic carbon to the emission of carbon dioxide by soil respiration . 7. method according to claim 6, is characterized in that, described inorganic carbon is calculated by formula 3 to the contribution share of carbon dioxide discharged by soil respiration: f _SIC = 1-f _SOC -f _C formula 3; Among them, f _SIC is the contribution of inorganic carbon to carbon dioxide emission from soil respiration. 8. The method according to claim 1, characterized in that, before detecting the abundance of ¹³ C in organic carbon and inorganic carbon in the original soil, it also includes: carrying out impurity removal treatment on the original soil, and the impurities in the impurity removal process Includes fine roots, weeds and bugs. 9. The method according to claim 1, characterized in that, the original soil comprises lime-calcium soil, brown-calcium soil, volcanic ash soil, purple soil, stony soil or lime soil. 10. The method according to claim 9, characterized in that the lime soil is karst lime soil.