Method for evaluating slope-to-terrace measure water and soil conservation carbon sequestration

Abstract

The invention discloses a method for evaluating water and soil conservation carbon sequestration of a slope-to-terrace measure. The method is specifically implemented according to the following steps: firstly, determining a datum line scene and a project scene of the slope-to-terrace measure; then respectively measuring the surface soil bulk density and the organic carbon content in the initial reference line scene and the project scene of slope-to-terrace measure implementation; respectively calculating the soil erosion amount of the reference line scene and the project scene in the project counting period, calculating the surface soil sampling thickness of the reference line scene and the project scene and the like, and finally calculating the water and soil conservation carbon sequestration amount of the slope-to-terrace measure. The method solves the problem that the carbon emission reduction benefit of the slope-to-terrace measure on the soil is not considered in the prior art; and when the soil carbon reserves are calculated, the surface soil eroded by the soil is not deducted, so that the problem that the water and soil conservation carbon sink quantity of the slope-to-terrace measure is undeducted is solved, a water and soil conservation carbon sink mechanism of the slope-to-terrace measure is perfected, and the water and soil conservation carbon sink quantity of the slope-to-terrace measure is estimated more systematically, comprehensively, objectively and accurately.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil and water conservation carbon sink, and in particular relates to a method for evaluating the soil and water conservation carbon sink amount of slope-to-terrace conversion measures. Background Art

[0002] In the context of global warming and my country's dual carbon goals, all walks of life are actively committed to reducing carbon emissions and increasing carbon sinks. As an important soil and water conservation measure, slope-to-terrace conversion has produced significant benefits in preventing soil erosion, reducing carbon emissions caused by soil erosion, and increasing soil carbon sinks. At present, research on the soil carbon sequestration benefits of slope-to-terrace conversion has emerged, but the existing research is not clear about the soil and water conservation carbon sink mechanism of slope-to-terrace conversion, lacks a systematic and comprehensive method for calculating the carbon sink of soil and water conservation in slope-to-terrace conversion measures, and does not consider the emission reduction benefits of soil and water conservation measures. When calculating soil carbon reserves, the surface soil eroded by soil erosion is not deducted, and the carbon sink of soil and water conservation in slope-to-terrace conversion measures is underestimated. Research on the evaluation method of soil and water conservation carbon sink in slope-to-terrace conversion measures is of great significance for objectively evaluating the soil and water conservation carbon sink benefits of slope-to-terrace conversion measures, exploring the huge emission reduction and sink increase benefits of soil carbon pools, and promoting the inclusion of soil and water conservation measures in CCER trading. Summary of the invention

[0003] The purpose of the present invention is to provide a method for evaluating the soil and water conservation carbon sink of slope-to-terrace measures, which solves the problem in the prior art that the emission reduction benefits of soil and water conservation measures are not considered and the carbon sink of soil and water conservation measures is underestimated.

[0004] The technical solution adopted by the present invention is a method for evaluating the carbon sink of soil and water conservation in slope-to-terrace conversion measures, which is specifically implemented according to the following steps:

[0005] Step 1: Clarify the baseline scenario and project scenario of the slope-to-terrace conversion measures;

[0006] Step 2: Determine the bulk density and organic carbon content of the surface soil in the initial baseline scenario and project scenario of the slope-to-terrace conversion measure respectively;

[0007] Step 3: Calculate the soil erosion amount during the project accounting period for the baseline scenario and the project scenario respectively;

[0008] Step 4: Calculate the surface soil sampling thickness of the baseline scenario and the project scenario respectively;

[0009] Step 5: Determine the soil bulk density and organic carbon content of each soil layer in the baseline scenario and the project scenario respectively;

[0010] Step 6: Calculate the carbon emissions of the baseline scenario and the project scenario respectively;

[0011] Step 7: Calculate the carbon storage of the baseline scenario and the project scenario respectively;

[0012] Step 8: Calculate the soil and water conservation carbon sink of the slope-to-terrace conversion measure.

[0013] The present invention is also characterized in that:

[0014] Step 1 is implemented as follows:

[0015] The baseline scenario of the slope-to-terrace measure is the scenario formed by the change of sloping farmland that has not been built into horizontal terraces over time without artificial protection measures, that is, the sloping farmland that has not been built into horizontal terraces will naturally change to a certain moment with artificial cultivation. The project scenario of the slope-to-terrace measure is the scenario formed by the change of sloping farmland into horizontal terraces over time. The original landforms of the sloping farmland determined as the baseline scenario and the terraces in the project scenario have basically the same slope, slope direction, and soil type.

[0016] Step 2 is implemented as follows:

[0017] Surface soil bulk density samples were collected from the initial baseline scenario and project scenario sample plots for the implementation of the slope-to-terracing measures, and their soil bulk density and organic carbon content were measured.

[0018] Step 3 is implemented as follows:

[0019] The soil erosion modulus of the baseline scenario is the multi-year average SE of the soil erosion modulus grid data in the dynamic monitoring results of soil and water loss in the corresponding year during the project inclusion period after removing the contribution of engineering measures factors. BSL,t , calculated according to formula (1):

[0020]

[0021] Where: SE BSL,i,t It represents the average amount of sediment produced by soil erosion per unit area of ​​sloping farmland in a year t, in tons per hectare per year, t·hm -2 a -1 ; A j It represents the grid average value of the soil erosion modulus grid data in the dynamic monitoring results of the jth year, in tons per hectare per year, t·hm -2 a -1 ; t represents the number of years since the start of the project, dimensionless; E represents the soil and water conservation engineering measures factor.

[0022] The soil erosion modulus of the project scenario is the multi-year average SE of the erosion modulus grid data in the dynamic monitoring results of soil and water loss in the corresponding year during the project inclusion period. PROJ,t , calculated according to formula (2):

[0023]

[0024] Where: SE PROJ,tIt represents the amount of sediment produced by soil erosion per unit area of ​​terraced fields in t years, in tons per hectare per year, t·hm -2 a -1 ; A j It represents the grid average value of the soil erosion modulus grid data in the dynamic monitoring results of the jth year, in tons per hectare per year, t·hm -2 a -1 ; t is the number of years since the start of the project, dimensionless.

[0025] Step 4 is implemented according to the following steps:

[0026] Under the baseline scenario, the surface soil of sloping farmland undergoes sediment migration due to soil erosion, resulting in a reduction in soil thickness. The reduction in soil thickness is calculated according to formula (3):

[0027] H BSL,SE,t =SE BSL,t ×t×ρ BSL,1，0 ×100 (3)

[0028] Where: H BSL,SE,t It represents the average reduction thickness of the soil in the baseline scenario within t years, in centimeters, cm; t represents the number of years since the start of the project, dimensionless; SE BSL,t It represents the amount of sediment produced by soil erosion per unit area of ​​sloping farmland in t years, in tons per hectare per year, t·hm -2 a -1 ρ BSL,1,0 Indicates the bulk density of the first layer of soil in sloping farmland, in grams per cubic centimeter, g·cm -3 .

[0029] The sampling depth of the first soil layer in the baseline scenario is calculated according to formula (4):

[0030] H BSL,1,t =H BSL,1,0 -H BSL,SE,t (4)

[0031] Where: H BSL,1，t represents the sampling depth of the first soil layer in the baseline scenario in year t, in centimeters (cm); t represents the number of years since the start of the project, dimensionless; H BSL,1，0 It indicates the sampling depth of the first soil layer in the baseline scenario in the year when the project was completed, in centimeters (cm); H BSL,SE,t It represents the average reduction thickness of the soil in the baseline scenario within t years, in centimeters (cm).

[0032] Under the project scenario, the surface soil of the terraced fields undergoes sediment migration due to soil erosion, resulting in a reduction in soil thickness. The reduction in soil thickness is calculated according to formula (5):

[0033]

[0034] Where: H PROJ,SE,t It represents the average reduction in soil thickness in the project scenario within t years, in centimeters, cm; t represents the number of years since the start of the project, dimensionless; SE PROJ,t It represents the amount of sediment produced by soil erosion per unit area of ​​terraces in t years, in tons per hectare per year, t·hm -2 a -1 ρ PROJ,1,0 It indicates the soil bulk density of the first layer of terraced fields in the year when the project was completed, in grams per cubic centimeter, g·cm -3 .

[0035] The depth of the first soil layer in the project scenario is calculated according to formula (6):

[0036] H PROJ,1,t =H PROJ,1,0 -H PROJ ,SE,t (6)

[0037] Where: H PROJ,1，t represents the sampling depth of the first soil layer in the project scenario in year t, in centimeters (cm); t represents the number of years since the start of the project, dimensionless; H PROJ,1，0 It indicates the sampling depth of the first soil layer in the project scenario in the year when the project was completed, in centimeters (cm); H PROJ,SE,t It represents the average reduction thickness of soil in the project scenario within t years, in centimeters (cm).

[0038] Step 5 is implemented according to the following steps:

[0039] According to the soil layer thickness determined in step 4, collect soil samples from each soil layer of the baseline scenario and the project scenario and bring them back to the laboratory for testing.

[0040] Step 6 is implemented according to the following steps:

[0041] Under the baseline scenario, during the transportation of sediment produced by soil erosion on sloping farmland, organic matter decomposes and mineralizes, emitting CO into the atmosphere. 2 , the baseline scenario carbon emissions are calculated according to formula (7):

[0042]

[0043] Where: C BSL,t It represents the carbon emissions of the baseline scenario in year t, in tons of carbon dioxide equivalent, t CO 2 e; t is the number of years since the start of the project, dimensionless; SE BSL,tIt represents the average amount of sediment produced by soil erosion per unit area of ​​sloping farmland in a year t, in tons per hectare per year, t·hm -2 a -1 ; AREA represents the field area, in hectares, hm 2 ;SOC BSL,1,0 Indicates the soil organic carbon content of the first soil layer of sloping farmland, in grams per kilogram, g·kg -1 ; P represents the decomposition ratio of sediment organic carbon produced by soil erosion during its migration process, in %.

[0044] In the project scenario, during the transportation of silt produced by terrace soil erosion, organic matter will decompose and mineralize, emitting CO into the atmosphere. 2 , the project carbon emissions are calculated according to formula (8):

[0045]

[0046] Where: C PROJ,t It represents the carbon emissions of the project scenario in t year, in tons of carbon dioxide equivalent, t CO 2 e; t is the number of years since the start of the project, dimensionless; SE PROJ,t It represents the amount of sediment produced by soil erosion per unit area of ​​terraces in t years, in tons per hectare per year, t·hm -2 a -1 ; AREA represents the project field area, in hectares, hm 2 ;SOC PROJ,1,0 Indicates the soil organic carbon content of the first soil layer of the terraced field in the year when the project was completed, in grams per kilogram, g·kg -1 ; P represents the decomposition ratio of sediment organic carbon produced by soil erosion during its migration process, in %.

[0047] Step 7 is implemented according to the following steps:

[0048] The carbon storage in the tth year of the baseline scenario is calculated according to formula (9):

[0049]

[0050] Where: CS BSL,t It represents the carbon storage in the tth year of the baseline scenario, in tons of carbon dioxide equivalent, tCO 2 e; l represents the number of stratified sampling layers of the baseline scenario, i = 1, 2, 3, ... dimensionless; AREA represents the field area, in hectares, hm 2 ;H BSL,l,t It represents the soil sampling depth of the lth layer in the baseline scenario in the tth year of the project, in centimeters, cm; ρ BSL,l,tIt represents the soil bulk density of the first layer of the baseline scenario in year t, in grams per cubic centimeter, g·cm -3 ;SOC BSL,l,ti It represents the soil organic carbon content in the first layer of the baseline scenario in year t, in grams per kilogram, g·kg -1 ;

[0051] The carbon storage in the tth year of the project scenario is calculated according to formula (10):

[0052]

[0053] Where: CS PROJ,t It represents the carbon storage in the tth year of the project scenario, in tons of carbon dioxide equivalent, tCO 2 e; l represents the number of layers of stratified sampling of project scenarios, i = 1, 2, 3, ... dimensionless; AREA represents the field area, in hectares, hm 2 ;H PROJ,l,t represents the soil sampling depth of the lth layer of the project scenario in the tth year, in centimeters, cm; ρ PROJ,l,t It represents the soil bulk density of the lth layer in the project scenario in year t, in grams per cubic centimeter, g·cm -3 ;SOC PROJ,l,t Indicates the soil organic carbon content in the lth layer of the project scenario in year t, in grams per kilogram, g·kg -1 .

[0054] Step 8 is implemented according to the following steps:

[0055] The soil and water conservation carbon sink after the implementation of the slope-to-terrace measure for t years is calculated according to formula (11):

[0056] CDR t =(C BSL,t -C PROJ,t )+(CS PROJ,t -CS BSL,t ) (11)

[0057] Where: CDR t It represents the carbon sink of soil and water conservation after the implementation of the project in year t, in tons of carbon dioxide equivalent, t CO 2 e; C BSL，t It represents the baseline emissions in year t, in tons of carbon dioxide equivalent, t CO 2 e; C PROJ,t It represents the project emissions in year t, in tons of carbon dioxide equivalent, t CO 2 e;CS BSL represents the baseline carbon storage in year t, in tons of carbon dioxide equivalent, t CO 2 e;CS PROJIt represents the carbon storage of the project in year t, in tons of carbon dioxide equivalent, t CO 2 e.

[0058] The beneficial effects of the present invention are that, compared with the existing methods, the method for evaluating the carbon sink of soil and water conservation in slope-to-terrace measures adds the calculation of soil carbon emission reduction for slope-to-terrace measures, that is, preventing soil erosion and reducing carbon emissions caused by soil erosion; when calculating soil carbon reserves, the surface soil eroded by soil erosion is deducted; the soil and water conservation carbon sink mechanism of slope-to-terrace measures is improved, and the soil and water conservation carbon sink of slope-to-terrace measures is estimated more systematically, comprehensively, objectively and accurately. This method is of great significance for objectively evaluating the soil and water conservation carbon sink benefits of slope-to-terrace measures, exploring the huge emission reduction and sink increase benefits of soil carbon pools, and promoting the inclusion of soil and water conservation measures carbon sinks into CCER trading. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is a method and step for evaluating soil and water conservation carbon sinks in slope-to-terrace conversion measures of the present invention;

[0060] Figure 2 It is a schematic diagram of soil layer depth division in different monitoring periods of the method for evaluating soil and water conservation carbon sinks in slope-to-terrace conversion measures of the present invention. DETAILED DESCRIPTION

[0061] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0062] The method for evaluating the soil and water conservation carbon sink of slope-to-terrace measures of the present invention is as follows: Figure 1 As shown, the specific implementation steps are as follows:

[0063] Step 1: Clarify the baseline scenario and project scenario of the slope-to-terrace conversion measures;

[0064] Step 1 is implemented as follows:

[0065] The baseline scenario of the slope-to-terrace measure is the scenario formed by the change of sloping farmland that has not been built into horizontal terraces over time without artificial protection measures, that is, the sloping farmland that has not been built into horizontal terraces will naturally change to a certain moment with artificial cultivation. The project scenario of the slope-to-terrace measure is the scenario formed by the change of sloping farmland into horizontal terraces over time. The original landforms of the sloping farmland determined as the baseline scenario and the terraces in the project scenario have basically the same slope, slope direction, and soil type.

[0066] Step 2: Determine the bulk density and organic carbon content of the surface soil in the initial baseline scenario and project scenario of the slope-to-terrace conversion measure respectively;

[0067] Step 2 is implemented as follows:

[0068] Surface soil bulk density samples were collected from the initial baseline scenario and project scenario sample plots for the implementation of the slope-to-terracing measures, and their soil bulk density and organic carbon content were measured.

[0069] Step 3: Calculate the soil erosion amount during the project accounting period for the baseline scenario and the project scenario respectively;

[0070] Step 3 is implemented as follows:

[0071] The soil erosion modulus of the baseline scenario is the multi-year average SE of the soil erosion modulus grid data in the dynamic monitoring results of soil and water loss in the corresponding year during the project inclusion period after removing the contribution of engineering measures factors. BSL,t , calculated according to formula (1):

[0072]

[0073] Where: SE BSL,i,t It represents the average amount of sediment produced by soil erosion per unit area of ​​sloping farmland in a year t, in tons per hectare per year, t·hm -2 a -1 ; A j It represents the grid average value of the soil erosion modulus grid data in the dynamic monitoring results of the jth year, in tons per hectare per year, t·hm -2 a -1 ; t represents the number of years since the start of the project, dimensionless; E represents the soil and water conservation engineering measures factor.

[0074] The soil erosion modulus of the project scenario is the multi-year average SE of the erosion modulus grid data in the dynamic monitoring results of soil and water loss in the corresponding year during the project inclusion period. PROJ,t , calculated according to formula (2):

[0075]

[0076] Where: SE PROJ,t It represents the amount of sediment produced by soil erosion per unit area of ​​terraced fields in t years, in tons per hectare per year, t·hm -2 a -1 ; A j It represents the grid average value of the soil erosion modulus grid data in the dynamic monitoring results of the jth year, in tons per hectare per year, t·hm -2 a -1 ; t is the number of years since the start of the project, dimensionless.

[0077] Step 4: Calculate the surface soil sampling thickness of the baseline scenario and the project scenario respectively;

[0078] Step 4 is implemented according to the following steps:

[0079] Under the baseline scenario, the surface soil of sloping farmland undergoes sediment migration due to soil erosion, resulting in a reduction in soil thickness. The reduction in soil thickness is calculated according to formula (3):

[0080] H BSL,SE,t =SE BSL,t ×t×ρ BSL,1，0 ×100 (3)

[0081] Where: H BSL,SE,t It represents the average reduction thickness of the soil in the baseline scenario within t years, in centimeters, cm; t represents the number of years since the start of the project, dimensionless; SE BSL,t It represents the amount of sediment produced by soil erosion per unit area of ​​sloping farmland in t years, in tons per hectare per year, t·hm -2 a -1 ρ BSL,1,0 Indicates the bulk density of the first layer of soil in sloping farmland, in grams per cubic centimeter, g·cm -3 .

[0082] The sampling depth of the first soil layer in the baseline scenario is calculated according to formula (4):

[0083] H BSL,1,t =H BSL,1,0 -H BSL,SE,t (4)

[0084] Where: H BSL,1，t represents the sampling depth of the first soil layer in the baseline scenario in year t, in centimeters (cm); t represents the number of years since the start of the project, dimensionless; H BSL,1，0 It indicates the sampling depth of the first soil layer in the baseline scenario in the year when the project was completed, in centimeters (cm); H BSL,SE,t It represents the average reduction thickness of the soil in the baseline scenario within t years, in centimeters (cm).

[0085] Under the project scenario, the surface soil of the terraced fields undergoes sediment migration due to soil erosion, resulting in a reduction in soil thickness. The reduction in soil thickness is calculated according to formula (5):

[0086]

[0087] Where: H PROJ,SE,t It represents the average reduction in soil thickness in the project scenario within t years, in centimeters, cm; t represents the number of years since the start of the project, dimensionless; SE PROJ,t It represents the amount of sediment produced by soil erosion per unit area of ​​terraces in t years, in tons per hectare per year, t·hm -2 a -1 ρ PROJ,1,0 It indicates the soil bulk density of the first layer of terraced fields in the year when the project was completed, in grams per cubic centimeter, g·cm-3 .

[0088] The depth of the first soil layer in the project scenario is calculated according to formula (6):

[0089] H PROJ,1,t =H PROJ,1,0 -H PROJ,SE,t (6)

[0090] Where: H PROJ,1，t represents the sampling depth of the first soil layer in the project scenario in year t, in centimeters (cm); t represents the number of years since the start of the project, dimensionless; H PROJ,1，0 It indicates the sampling depth of the first soil layer in the project scenario in the year when the project was completed, in centimeters (cm); H PROJ,SE,t It represents the average reduction thickness of soil in the project scenario within t years, in centimeters (cm).

[0091] Step 5: Determine the soil bulk density and organic carbon content of each soil layer in the baseline scenario and the project scenario respectively;

[0092] Step 5 is implemented according to the following steps:

[0093] According to the soil layer thickness determined in step 4, collect soil samples from each soil layer of the baseline scenario and the project scenario and bring them back to the laboratory for testing.

[0094] Step 6: Calculate the carbon emissions of the baseline scenario and the project scenario respectively;

[0095] Step 6 is implemented according to the following steps:

[0096] Under the baseline scenario, during the transportation of sediment produced by soil erosion on sloping farmland, organic matter decomposes and mineralizes, emitting CO into the atmosphere. 2 , the baseline scenario carbon emissions are calculated according to formula (7):

[0097]

[0098] Where: C BSL,t It represents the carbon emissions of the baseline scenario in year t, in tons of carbon dioxide equivalent, t CO 2 e; t is the number of years since the start of the project, dimensionless; SE BSL,t It represents the average amount of sediment produced by soil erosion per unit area of ​​sloping farmland in a year t, in tons per hectare per year, t·hm -2 a -1 ; AREA represents the field area, in hectares, hm 2 ;SOC BSL,1,0 Indicates the soil organic carbon content of the first soil layer of sloping farmland, in grams per kilogram, g·kg -1; P represents the decomposition ratio of sediment organic carbon produced by soil erosion during its migration process, in %.

[0099] In the project scenario, during the transportation of silt produced by terrace soil erosion, organic matter will decompose and mineralize, emitting CO into the atmosphere. 2 , the project carbon emissions are calculated according to formula (8):

[0100]

[0101] Where: C PROJ,t It represents the carbon emissions of the project scenario in t year, in tons of carbon dioxide equivalent, t CO 2 e; t is the number of years since the start of the project, dimensionless; SE PROJ,t It represents the amount of sediment produced by soil erosion per unit area of ​​terraces in t years, in tons per hectare per year, t·hm -2 a -1 ; AREA represents the project field area, in hectares, hm 2 ;SOC PROJ,1,0 Indicates the soil organic carbon content of the first soil layer of the terraced field in the year when the project was completed, in grams per kilogram, g·kg -1 ; P represents the decomposition ratio of sediment organic carbon produced by soil erosion during its migration process, in %.

[0102] Step 7: Calculate the carbon storage of the baseline scenario and the project scenario respectively;

[0103] Step 7 is implemented according to the following steps:

[0104] The carbon storage in the tth year of the baseline scenario is calculated according to formula (9):

[0105]

[0106] Where: CS BSL,t It represents the carbon storage in the tth year of the baseline scenario, in tons of carbon dioxide equivalent, tCO 2 e; l represents the number of stratified sampling layers of the baseline scenario, i = 1, 2, 3, ... dimensionless; AREA represents the field area, in hectares, hm 2 ;H BSL,l,t It represents the soil sampling depth of the lth layer in the baseline scenario in the tth year of the project, in centimeters, cm; ρ BSL,l,t It represents the soil bulk density of the first layer of the baseline scenario in year t, in grams per cubic centimeter, g·cm -3 ;SOC BSL,l,ti It represents the soil organic carbon content in the first layer of the baseline scenario in year t, in grams per kilogram, g·kg -1 ;

[0107] The carbon storage in the tth year of the project scenario is calculated according to formula (10):

[0108]

[0109] Where: CS PROJ,t It represents the carbon storage in the tth year of the project scenario, in tons of carbon dioxide equivalent, tCO 2 e; l represents the number of layers of stratified sampling of project scenarios, i = 1, 2, 3, ... dimensionless; AREA represents the field area, in hectares, hm 2 ;H PROJ,l,t represents the soil sampling depth of the lth layer of the project scenario in the tth year, in centimeters, cm; ρ PROJ,l,t It represents the soil bulk density of the lth layer in the project scenario in year t, in grams per cubic centimeter, g·cm -3 ;SOC PROJ,l,t Indicates the soil organic carbon content in the lth layer of the project scenario in year t, in grams per kilogram, g·kg -1 .

[0110] Step 8: Calculate the soil and water conservation carbon sink of the slope-to-terrace conversion measure.

[0111] Step 8 is implemented according to the following steps:

[0112] The soil and water conservation carbon sink after the implementation of the slope-to-terrace measure for t years is calculated according to formula (11):

[0113] CDR t =(C BSL,t -C PROJ,t )+(CS PROJ,t -CS BSL,t ) (11)

[0114] Where: CDR t It represents the carbon sink of soil and water conservation after the implementation of the project in year t, in tons of carbon dioxide equivalent, t CO 2 e; C BSL，t It represents the baseline emissions in year t, in tons of carbon dioxide equivalent, t CO 2 e; C PROJ,t It represents the project emissions in year t, in tons of carbon dioxide equivalent, t CO 2 e;CS BSL represents the baseline carbon storage in year t, in tons of carbon dioxide equivalent, t CO 2 e;CS PROJ It represents the carbon storage of the project in year t, in tons of carbon dioxide equivalent, t CO 2 e.

[0115] Example 1

[0116] The method for evaluating the soil and water conservation carbon sink of slope-to-terrace measures of the present invention is specifically implemented according to the following steps:

[0117] Step 1: Clarify the baseline scenario and project scenario of the slope-to-terrace conversion measures;

[0118] Step 2: Determine the bulk density and organic carbon content of the surface soil in the initial baseline scenario and project scenario of the slope-to-terrace conversion measure respectively;

[0119] Step 3: Calculate the soil erosion amount during the project accounting period for the baseline scenario and the project scenario respectively;

[0120] Step 4: Calculate the surface soil sampling thickness of the baseline scenario and the project scenario respectively;

[0121] Step 5: Determine the soil bulk density and organic carbon content of each soil layer in the baseline scenario and the project scenario respectively;

[0122] Step 6: Calculate the carbon emissions of the baseline scenario and the project scenario respectively;

[0123] Step 7: Calculate the carbon storage of the baseline scenario and the project scenario respectively;

[0124] Step 8: Calculate the soil and water conservation carbon sink of the slope-to-terrace conversion measure.

[0125] Example 2

[0126] The method for evaluating the soil and water conservation carbon sink of slope-to-terrace measures of the present invention is specifically implemented according to the following steps:

[0127] Step 1: Clarify the baseline scenario and project scenario of the slope-to-terrace conversion measures;

[0128] Step 1 is implemented as follows:

[0129] The baseline scenario of the slope-to-terrace measure is the scenario formed by the change of sloping farmland that has not been built into horizontal terraces over time without artificial protection measures, that is, the sloping farmland that has not been built into horizontal terraces will naturally change to a certain moment with artificial cultivation. The project scenario of the slope-to-terrace measure is the scenario formed by the change of sloping farmland into horizontal terraces over time. The original landforms of the sloping farmland determined as the baseline scenario and the terraces in the project scenario have basically the same slope, slope direction, and soil type.

[0130] Step 2: Determine the bulk density and organic carbon content of the surface soil in the initial baseline scenario and project scenario of the slope-to-terrace conversion measure respectively;

[0131] Step 2 is implemented as follows:

[0132] Surface soil bulk density samples were collected from the initial baseline scenario and project scenario sample plots for the implementation of the slope-to-terracing measures, and their soil bulk density and organic carbon content were measured.

[0133] Step 3: Calculate the soil erosion amount during the project accounting period for the baseline scenario and the project scenario respectively;

[0134] Step 3 is implemented as follows:

[0135] The soil erosion modulus of the baseline scenario is the multi-year average SE of the soil erosion modulus grid data in the dynamic monitoring results of soil and water loss in the corresponding year during the project inclusion period after removing the contribution of engineering measures factors. BSL,t , calculated according to formula (1):

[0136]

[0137] Where: SE BSL,i,t It represents the average amount of sediment produced by soil erosion per unit area of ​​sloping farmland in a year t, in tons per hectare per year, t·hm -2 a -1 ; A j It represents the grid average value of the soil erosion modulus grid data in the dynamic monitoring results of the jth year, in tons per hectare per year, t·hm -2 a -1 ; t represents the number of years since the start of the project, dimensionless; E represents the soil and water conservation engineering measures factor.

[0138] The soil erosion modulus of the project scenario is the multi-year average SE of the erosion modulus grid data in the dynamic monitoring results of soil and water loss in the corresponding year during the project inclusion period. PROJ,t , calculated according to formula (2):

[0139]

[0140] Where: SE PROJ,t It represents the amount of sediment produced by soil erosion per unit area of ​​terraced fields in t years, in tons per hectare per year, t·hm -2 a -1 ; A j It represents the grid average value of the soil erosion modulus grid data in the dynamic monitoring results of the jth year, in tons per hectare per year, t·hm -2 a -1 ; t is the number of years since the start of the project, dimensionless.

[0141] Step 4: Calculate the surface soil sampling thickness of the baseline scenario and the project scenario respectively;

[0142] Step 4 is implemented according to the following steps:

[0143] Under the baseline scenario, the surface soil of sloping farmland undergoes sediment migration due to soil erosion, resulting in a reduction in soil thickness. The reduction in soil thickness is calculated according to formula (3):

[0144] H BSL,SE,t =SE BSL,t ×t×ρ BSL,1，0 ×100 (3)

[0145] Where: H BSL,SE,t It represents the average reduction thickness of the soil in the baseline scenario within t years, in centimeters, cm; t represents the number of years since the start of the project, dimensionless; SE BSL,t It represents the amount of sediment produced by soil erosion per unit area of ​​sloping farmland in t years, in tons per hectare per year, t·hm -2 a -1 ρ BSL,1,0 Indicates the bulk density of the first layer of soil in sloping farmland, in grams per cubic centimeter, g·cm -3 .

[0146] The sampling depth of the first soil layer in the baseline scenario is calculated according to formula (4):

[0147] H BSL,1,t =H BSL,1,0 -H BSL,SE,t (4)

[0148] Where: H BSL,1，t represents the sampling depth of the first soil layer in the baseline scenario in year t, in centimeters (cm); t represents the number of years since the start of the project, dimensionless; H BSL,1，0 It indicates the sampling depth of the first soil layer in the baseline scenario in the year when the project was completed, in centimeters (cm); H BSL,SE,t It represents the average reduction thickness of the soil in the baseline scenario within t years, in centimeters (cm).

[0149] Under the project scenario, the surface soil of the terraced fields undergoes sediment migration due to soil erosion, resulting in a reduction in soil thickness. The reduction in soil thickness is calculated according to formula (5):

[0150]

[0151] Where: H PROJ,SE,t It represents the average reduction in soil thickness in the project scenario within t years, in centimeters, cm; t represents the number of years since the start of the project, dimensionless; SE PROJ,t It represents the amount of sediment produced by soil erosion per unit area of ​​terraces in t years, in tons per hectare per year, t·hm -2 a -1 ρ PROJ,1,0 It indicates the soil bulk density of the first layer of terraced fields in the year when the project was completed, in grams per cubic centimeter, g·cm-3 .

[0152] The depth of the first soil layer in the project scenario is calculated according to formula (6):

[0153] H PROJ,1,t =H PROJ,1,0 -H PROJ,SE,t (6)

[0154] Where: H PROJ,1，t represents the sampling depth of the first soil layer in the project scenario in year t, in centimeters (cm); t represents the number of years since the start of the project, dimensionless; H PROJ,1，0 It indicates the sampling depth of the first soil layer in the project scenario in the year when the project was completed, in centimeters (cm); H PROJ,SE,t It represents the average reduction thickness of soil in the project scenario within t years, in centimeters (cm).

[0155] Step 5: Determine the soil bulk density and organic carbon content of each soil layer in the baseline scenario and the project scenario respectively;

[0156] Step 5 is implemented according to the following steps:

[0157] According to the soil layer thickness determined in step 4, collect soil samples from each soil layer of the baseline scenario and the project scenario and bring them back to the laboratory for testing.

[0158] Step 6: Calculate the carbon emissions of the baseline scenario and the project scenario respectively;

[0159] Step 7: Calculate the carbon storage of the baseline scenario and the project scenario respectively;

[0160] Step 7 is implemented according to the following steps:

[0161] The carbon storage in the tth year of the baseline scenario is calculated according to formula (9):

[0162]

[0163] Where: CS BSL,t It represents the carbon storage in the tth year of the baseline scenario, in tons of carbon dioxide equivalent, tCO 2 e; l represents the number of stratified sampling layers of the baseline scenario, i = 1, 2, 3, ... dimensionless; AREA represents the field area, in hectares, hm 2 ;H BSL,l,t It represents the soil sampling depth of the lth layer in the baseline scenario in the tth year of the project, in centimeters, cm; ρ BSL,l,t It represents the soil bulk density of the first layer of the baseline scenario in year t, in grams per cubic centimeter, g·cm -3 ;SOC BSL,l,tiIt represents the soil organic carbon content in the first layer of the baseline scenario in year t, in grams per kilogram, g·kg -1 ;

[0164] The carbon storage in the tth year of the project scenario is calculated according to formula (10):

[0165]

[0166] Where: CS PROJ,t It represents the carbon storage in the tth year of the project scenario, in tons of carbon dioxide equivalent, tCO 2 e; l represents the number of layers of stratified sampling of project scenarios, i = 1, 2, 3, ... dimensionless; AREA represents the field area, in hectares, hm 2 ;H PROJ,l,t represents the soil sampling depth of the lth layer of the project scenario in the tth year, in centimeters, cm; ρ PROJ,l,t It represents the soil bulk density of the lth layer in the project scenario in year t, in grams per cubic centimeter, g·cm -3 ;SOC PROJ,l,t Indicates the soil organic carbon content in the lth layer of the project scenario in year t, in grams per kilogram, g·kg -1 .

[0167] Step 8: Calculate the soil and water conservation carbon sink of the slope-to-terrace conversion measure.

[0168] Step 8 is implemented according to the following steps:

[0169] The soil and water conservation carbon sink after the implementation of the slope-to-terrace measure for t years is calculated according to formula (11):

[0170] CDR t =(C BSL,t -C PROJ,t )+(CS PROJ,t -CS BSL,t ) (11)

[0171] Where: CDR t It represents the carbon sink of soil and water conservation after the implementation of the project in year t, in tons of carbon dioxide equivalent, t CO 2 e; C BSL，t It represents the baseline emissions in year t, in tons of carbon dioxide equivalent, t CO 2 e; C PROJ,t It represents the project emissions in year t, in tons of carbon dioxide equivalent, t CO 2 e;CS BSL represents the baseline carbon storage in year t, in tons of carbon dioxide equivalent, t CO 2 e;CS PROJ It represents the carbon storage of the project in year t, in tons of carbon dioxide equivalent, t CO2 e.

[0172] Example 3

[0173] In view of the demand for soil and water conservation carbon sink assessment of existing slope-to-terrace measures, the present invention provides a method for accurately assessing soil and water conservation carbon sinks of slope-to-terrace measures by taking into account the emission reduction benefits and sink enhancement benefits of soil and water conservation measures. Taking the terraces built in Wuqi County for 20 years as an example, the steps for assessing soil and water conservation carbon sinks of slope-to-terrace measures are described:

[0174] Step 1: Clarify the baseline scenario and project scenario of the slope-to-terrace conversion measure:

[0175] The baseline scenario for the slope-to-terrace measure is the scenario formed by the change of sloping farmland that has not been built into horizontal terraces over time without artificial protection measures, that is, the sloping farmland that has not been built into horizontal terraces will change into sloping farmland after 20 years of cultivation. The project scenario is the scenario formed by the conversion of sloping farmland into horizontal terraces after 20 years. The original landforms of the sloping farmland determined as the baseline scenario and the terraces in the project scenario have basically the same slope (15-20°), slope direction (southward), and soil type (loess soil).

[0176] Step 2: Determine the bulk density and organic carbon content of the surface soil in the initial baseline scenario and project scenario of the slope-to-terrace conversion measures:

[0177] The soil bulk density samples of the surface layer of 20 cm in the initial baseline scenario and project scenario of the slope-to-terrace measure were collected and their soil bulk density was measured. BSL,1,0 1.19 g·cm -3 , surface soil organic carbon content SOC BSL,1,0 2.53 g kg -1 ; Project scenario (terraces) surface soil bulk density ρ PROJ,1,0 1.47 g·cm -3 , surface soil organic carbon content SOC PROJ,1,0 2.18 g kg -1 .

[0178] Step 3: Calculate the soil erosion amount during the project accounting period for the baseline scenario and the project scenario respectively:

[0179] The soil erosion amount in the baseline scenario of the project implementation for 20 years is calculated according to the multi-year average value of the erosion modulus grid data in the national soil and water loss dynamic monitoring results after removing the contribution of engineering measures factors. The SE is calculated according to formula (1) BSL,t 4393t·hm -2 a -1 .

[0180] The soil erosion volume in the project scenario after 20 years of project implementation is calculated according to the multi-year average value of the erosion modulus grid data in the national soil and water loss dynamic monitoring results, and the SE is calculated according to formula (2): PROJ,t 369t·hm -2 a -1 .

[0181] Step 4: Calculate the surface soil sampling thickness for the baseline scenario and the project scenario respectively:

[0182] Under the baseline scenario, after 20 years, the sloping farmland without slope-to-terracing measures will experience sediment migration due to soil erosion, resulting in a reduction in soil thickness. The reduction in soil thickness in the baseline scenario is calculated according to formula (3): BSL,SE,t The first layer of soil sampling depth of sloping farmland is 7.3 cm. According to formula (4), the first layer of soil sampling depth of sloping farmland should be 20-7.3=12.7 cm. The second to fifth layers of soil sampling depths of the baseline scenario are 20 cm respectively.

[0183] Under the project scenario, 20 years after the terrace construction, the soil erosion causes the migration of sediment, resulting in a decrease in soil thickness. The reduction in soil thickness in the project scenario is calculated according to formula (5): PROJ,SE,t The first layer of soil sampling depth is 0.6 cm. According to formula (6), the first layer of soil sampling depth should be 20-0.5=19.5 cm. The second to fifth layers of soil sampling depths in the project scenario are 20 cm respectively.

[0184] Step 5: Determine the soil bulk density and organic carbon content of each soil layer in the baseline scenario and the project scenario respectively:

[0185] According to the soil layer thickness requirements in step 4, soil samples of each soil layer were collected for the baseline scenario and the project scenario, and brought back to the laboratory to test the soil bulk density and organic carbon content of each soil layer.

[0186] Step 6: Calculate the carbon emissions of the baseline scenario and the project scenario respectively:

[0187] Under the baseline scenario, during the transportation of sediment produced by soil erosion on sloping farmland, organic matter decomposes and mineralizes, emitting CO into the atmosphere. 2 , the sample area AREA is 1hm 2 The decomposition ratio P of sediment organic carbon produced by soil erosion during the migration process is 30%, and C is calculated according to formula (7): BSL,t 2.45t CO 2 e.

[0188] In the project scenario, during the transportation of sediment produced by terrace soil erosion, organic matter decomposes and mineralizes, emitting CO into the atmosphere. 2 , the sample area AREA is 1hm 2The decomposition ratio P of sediment organic carbon produced by soil erosion during the transport process is 30%, and C is calculated according to formula (8): PROJ,t 0.18t CO 2 e.

[0189] Step 7: Calculate the carbon storage of the baseline scenario and the project scenario respectively:

[0190] Combination Figure 2 According to the soil bulk density and soil organic carbon content of each soil layer in the baseline scenario and the project scenario determined in step 5, the soil carbon storage of each layer in the baseline scenario and the project scenario (Table 1) and the total carbon storage are calculated according to formula (9) and formula (10). 2 Soil carbon storage CS BSL,t 82.22t CO 2 e; Under the project scenario, 1hm 2 Soil carbon storage CS PROJ,t 141.63t CO 2 e.

[0191] Table 1 Calculation results of soil carbon storage in baseline scenario and project scenario

[0192]

[0193] Step 8: Calculate the soil and water conservation carbon sink of the slope-to-terrace conversion measure:

[0194] 1hm2 of slope-to-terrace measures implemented for 20 years 2 The carbon sink of soil and water conservation in the field is calculated according to formula (11): CDR t 61.68t CO 2 e.

Claims

1. A method for evaluating soil and water conservation carbon sinks in slope-to-terrace conversion measures, characterized in that: Follow the steps below to implement it: Step 1: Clarify the baseline scenario and project scenario of the slope-to-terrace conversion measures; Step 2: Determine the bulk density and organic carbon content of the surface soil in the initial baseline scenario and project scenario of the slope-to-terrace conversion measure respectively; Step 3: Calculate the soil erosion amount during the project accounting period for the baseline scenario and the project scenario respectively; Step 4: Calculate the surface soil sampling thickness of the baseline scenario and the project scenario respectively; Step 5: Determine the soil bulk density and organic carbon content of each soil layer in the baseline scenario and the project scenario respectively; Step 6: Calculate the carbon emissions of the baseline scenario and the project scenario respectively; Step 7: Calculate the carbon storage of the baseline scenario and the project scenario respectively; Step 8: Calculate the soil and water conservation carbon sink of the slope-to-terrace conversion measure.

2. The method for evaluating soil and water conservation carbon sinks in slope-to-terrace conversion measures according to claim 1 is characterized in that: The step 1 is specifically implemented according to the following steps: The baseline scenario of the slope-to-terrace measures is the scenario formed by the changes over time of sloping farmland that has not been built into horizontal terraces without any artificial protection measures. That is, the sloping farmland that has not been built into horizontal terraces will naturally change to a state at a certain moment due to artificial cultivation. The project scenario of the slope-to-terrace measures is the scenario formed by the construction of sloping farmland into horizontal terraces over time. The sloping farmland determined as the baseline scenario has the same slope, slope direction, and soil type as the original landform of the terraces in the project scenario.

3. The method for evaluating soil and water conservation carbon sinks in slope-to-terrace conversion measures according to claim 2 is characterized in that: The step 2 is specifically implemented according to the following steps: Surface soil bulk density samples were collected from the initial baseline scenario and project scenario sample plots for the implementation of the slope-to-terracing measures, and the soil bulk density and organic carbon content were measured.

4. The method for evaluating soil and water conservation carbon sinks in slope-to-terrace conversion measures according to claim 3 is characterized in that: The step 3 is specifically implemented according to the following steps: The soil erosion modulus of the baseline scenario is the multi-year average SE of the soil erosion modulus grid data in the dynamic monitoring results of soil and water loss in the corresponding year during the project inclusion period after removing the contribution of engineering measures factors. BSL,t , calculated according to formula (1): Where: SE BSL,i,t It represents the average amount of sediment produced by soil erosion per unit area of ​​sloping farmland in a year t, in tons per hectare per year, t·hm -2 a -1 ; A j It represents the grid average value of the soil erosion modulus grid data in the dynamic monitoring results of the jth year, in tons per hectare per year, t·hm -2 a -1 ; t represents the number of years since the start of the project, dimensionless; E represents the soil and water conservation engineering measures factor; The soil erosion modulus of the project scenario is the multi-year average SE of the erosion modulus grid data in the dynamic monitoring results of soil and water loss in the corresponding year during the project inclusion period. PROJ,t , calculated according to formula (2): Where: SE PROJ,t It represents the amount of sediment produced by soil erosion per unit area of ​​terraced fields in t years, in tons per hectare per year, t·hm -2 a -1 ; A j It represents the grid average value of the soil erosion modulus grid data in the dynamic monitoring results of the jth year, in tons per hectare per year, t·hm -2 a -1 ; t is the number of years since the start of the project, dimensionless.

5. The method for evaluating soil and water conservation carbon sinks in slope-to-terrace conversion measures according to claim 4 is characterized in that: The step 4 is specifically implemented according to the following steps: Under the baseline scenario, the surface soil of sloping farmland undergoes sediment migration due to soil erosion, resulting in a reduction in soil thickness. The reduction in soil thickness is calculated according to formula (3): H BSL,SE,t =SE BSL,t ×t×ρ BSL,1，0 ×100 (3) Where: H BSL,SE,t It represents the average reduction thickness of the soil in the baseline scenario within t years, in centimeters, cm; t represents the number of years since the start of the project, dimensionless; SE BSL,t It represents the amount of sediment produced by soil erosion per unit area of ​​sloping farmland in t years, in tons per hectare per year, t·hm -2 a -1 ; ρ BSL,1,0 Indicates the bulk density of the first layer of soil in sloping farmland, in grams per cubic centimeter, g·cm -3 ; The sampling depth of the first soil layer in the baseline scenario is calculated according to formula (4): H BSL,1,t =H BSL,1,0 -H BSL,SE,t (4) Where: H BSL,1，t represents the sampling depth of the first soil layer in the baseline scenario in year t, in centimeters; t represents the number of years since the start of the project, dimensionless; H BSL,1，0 Indicates the sampling depth of the first soil layer in the baseline scenario in the year when the project was completed, in centimeters; H BSL,SE,t It represents the average reduction thickness of the soil in the baseline scenario within t years, in centimeters; Under the project scenario, the surface soil of the terraced fields undergoes sediment migration due to soil erosion, resulting in a reduction in soil thickness. The reduction in soil thickness is calculated according to formula (5): Where: H PROJ,SE,t It represents the average reduction in soil thickness in the project scenario within t years, in centimeters, cm; t represents the number of years since the start of the project, dimensionless; SE PROJ,t It represents the amount of sediment produced by soil erosion per unit area of ​​terraces in t years, in tons per hectare per year, t·hm -2 a -1 ; ρ PROJ,1,0 It indicates the soil bulk density of the first layer of terraced fields in the year when the project was completed, in grams per cubic centimeter, g·cm -3 ; The depth of the first soil layer in the project scenario is calculated according to formula (6): H PROJ,1,t =H PROJ,1,0 -H PROJ,SE,t (6) Where: H PROJ,1，t represents the sampling depth of the first soil layer in the project scenario in year t, in centimeters (cm); t represents the number of years since the start of the project, dimensionless; H PROJ,1，0 It indicates the sampling depth of the first soil layer in the project scenario in the year when the project was completed, in centimeters (cm); H PROJ,SE,t It represents the average reduction thickness of soil in the project scenario within t years, in centimeters.

6. The method for evaluating soil and water conservation carbon sinks in slope-to-terrace conversion measures according to claim 5 is characterized in that: The step 5 is specifically implemented according to the following steps: According to the soil layer thickness determined in step 4, soil samples of each soil layer in the baseline scenario and project scenario are collected and tested.

7. The method for evaluating soil and water conservation carbon sinks in slope-to-terrace conversion measures according to claim 6 is characterized in that: The step 6 is specifically implemented according to the following steps: Under the baseline scenario, during the transportation of silt produced by soil erosion on sloping farmland, organic matter decomposes and mineralizes, emitting CO2 into the atmosphere. The carbon emissions under the baseline scenario are calculated according to formula (7): Where: C BSL,t It represents the carbon emissions of the baseline scenario in t years, in tons of carbon dioxide equivalent, tCO2e; t represents the number of years since the start of the project, dimensionless; SE BSL,t It represents the average amount of sediment produced by soil erosion per unit area of ​​sloping farmland in a year t, in tons per hectare per year, t·hm -2 a -1 ; AREA represents the field area, in hectares, hm 2 ;SOC BSL,1,0 Indicates the soil organic carbon content of the first soil layer of sloping farmland, in grams per kilogram, g·kg -1 ; P represents the decomposition ratio of sediment organic carbon produced by soil erosion during its migration process, in %; Under the project scenario, during the transportation process of the sediment produced by terrace soil erosion, the organic matter will decompose and mineralize, and emit CO2 into the atmosphere. The carbon emissions of the project are calculated according to formula (8): Where: C PROJ,t It represents the carbon emissions of the project scenario in t years, in tons of carbon dioxide equivalent, tCO2e; t represents the number of years since the start of the project, dimensionless; SE PROJ,t It represents the amount of sediment produced by soil erosion per unit area of ​​terraces in t years, in tons per hectare per year, t·hm -2 a -1 ; AREA represents the project field area, in hectares, hm 2 ;SOC PROJ,1,0 Indicates the soil organic carbon content of the first soil layer of the terraced field in the year when the project was completed, in grams per kilogram, g·kg -1 ; P represents the decomposition ratio of sediment organic carbon produced by soil erosion during its migration process, in %.

8. The method for evaluating soil and water conservation carbon sinks in slope-to-terrace conversion measures according to claim 7 is characterized in that: The step 7 is specifically implemented according to the following steps: The carbon storage in the tth year of the baseline scenario is calculated according to formula (9): Where: CS BSL,t represents the carbon storage in the tth year of the baseline scenario, in tons of carbon dioxide equivalent, tCO2e; l represents the number of stratified sampling layers of the baseline scenario, i = 1, 2, 3, ... dimensionless; AREA represents the field area, in hectares, hm 2 ; H BSL,l,t It represents the soil sampling depth of the lth layer in the baseline scenario in the tth year of the project, in centimeters, cm; ρ BSL,l,t It represents the soil bulk density of the first layer of the baseline scenario in year t, in grams per cubic centimeter, g·cm -3 ;SOC BSL,l,ti It represents the soil organic carbon content in the first layer of the baseline scenario in year t, in grams per kilogram, g·kg -1 ; The carbon storage in the tth year of the project scenario is calculated according to formula (10): Where: CS PROJ,t = represents the carbon storage in the tth year of the project scenario, in tons of carbon dioxide equivalent, tCO2e; l represents the number of layers of stratified sampling of the project scenario, i = 1, 2, 3, ... dimensionless; AREA represents the field area, in hectares, hm 2 ; H PROJ,l,t represents the soil sampling depth of the lth layer of the project scenario in the tth year, in centimeters, cm; ρ PROJ,l,t It represents the soil bulk density of the lth layer in the project scenario in year t, in grams per cubic centimeter, g·cm -3 ;SOC PROJ,l,t Indicates the soil organic carbon content in the first layer of the project scenario in year t, in grams per kilogram, g·kg -1 .

9. The method for evaluating soil and water conservation carbon sinks in slope-to-terrace conversion measures according to claim 8 is characterized in that: The step 8 is specifically implemented according to the following steps: The soil and water conservation carbon sink after the implementation of the slope-to-terrace measure for t years is calculated according to formula (11): CDR t =(C BSL,t -C PROJ,t )+(CS PROJ,t -CS BSL,t ) (11) Where: CDR t It represents the carbon sink of soil and water conservation after the project is implemented for t year, in tons of carbon dioxide equivalent, tCO2e; C BSL，t represents the baseline emissions in year t, in tons of carbon dioxide equivalent, tCO2e; C PROJ,t It represents the project emissions in year t, in tons of carbon dioxide equivalent, tCO2e; CS BSL represents the baseline carbon stock in year t, in tons of carbon dioxide equivalent, tCO2e; CS PROJ It represents the carbon storage of the project in year t, in tons of carbon dioxide equivalent, tCO2e.

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