Method for promoting rice field carbon sequestration and emission reduction and improving rice yield through deep soil air injection and oxygenation

Abstract

The invention belongs to the technical field of agriculture, and particularly relates to a method for promoting rice field carbon sequestration and emission reduction and improving the rice yield through deep soil air injection and oxygenation. According to the method provided by the invention, aiming at paddy field cultivation and tillage environment, paddy field methane emission characteristics and paddy field organic carbon library management design, a soil deep gas injection device is combined with paddy field production management, and soil oxygen content is increased to a corresponding threshold range through soil deep gas injection in combination with a soil organic carbon content background; the organic carbon content of rice field soil and the rice yield are increased while the methane emission of the rice field is reduced.

Description

Technical Field

[0001] The invention belongs to the field of agricultural resources and environment and rice cultivation and farming, and specifically relates to a method for promoting carbon fixation and emission reduction in rice fields and increasing rice yield by injecting air into deep soil to increase oxygen. Background Art

[0002] Methane is one of the important greenhouse gases, and its warming potential is 25-28 times that of carbon dioxide. Due to long-term flooding management, the anaerobic environment of rice fields has made rice fields one of the main sources of methane emissions recognized worldwide. The anaerobic environment is not conducive to the decomposition of rice straw, which limits the carbon sink function of rice fields. China is the world's largest rice producer, accounting for about 20% of the world's rice planting area. Enhancing the carbon sink function of rice field production is related to the achievement of the "dual carbon" goals.

[0003] Oxygenation management in rice fields can weaken the anaerobic decomposition of soil organic carbon to produce methane, promote methane oxidation, and promote the decomposition of exogenous carbon in organic materials such as straw to be fixed in the soil. However, the increase in soil oxygen content will also enhance the aerobic decomposition of soil organic carbon, causing the loss of soil carbon pool. At present, chemical oxygenation management methods such as the use of oxygenators in rice fields are difficult to control the range of soil oxygen content and are quickly ineffective. Physical oxygenation methods such as water oxygenation require high equipment investment costs, making it difficult to balance rice field methane emission reduction and economic benefits.

[0004] Therefore, there is an urgent need for a method that can promote carbon sequestration and emission reduction in rice fields and increase rice yields. Summary of the invention

[0005] The purpose of the present invention is to provide a method for promoting carbon fixation and emission reduction in paddy fields and increasing rice yield by deep soil gas injection and oxygenation. The method provided by the present invention can not only use the deep soil gas injection and oxygenation device to regulate the soil oxygen content to a corresponding range, taking into account methane emission reduction and soil carbon fixation, but also can increase paddy field yield by promoting crop root growth.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for promoting carbon sequestration and emission reduction in rice fields, which specifically comprises the following steps:

[0008] (1) Excessive return to the field and transplanting rice: The amount of rice straw returned to the field should be controlled at 4500-5000 kg hm -2 ; Select seedlings with 3-4 leaves and 10-14cm height for transplanting, with a transplanting density of 180,000-210,000 hm2 -2 ;

[0009] (2) Deep soil aeration and oxygenation management:

[0010] The gas injection device is used to perform deep soil gas injection and oxygenation management; the maximum soil oxygen content range is controlled according to the organic carbon background content; the gas injection device is placed every 400-500m 2 A silicone tube gas pipeline is laid at the center of the deep soil gas injection and oxygenation zone with the gas injection device as the center point; the gas injection device includes an air compressor, a gas storage tank and a gas injection spear;

[0011] (3) Field management: Regularly fertilize and irrigate rice fields and carry out pest and weed control.

[0012] Preferably, the air compressor in the gas injection device is connected to the air inlet of the gas storage tank, the gas outlet of the gas storage tank is connected to the gas flow rate control valve, and the gas injection spear is connected to the gas flow rate control valve through a silicone catheter.

[0013] More preferably, the air compressor has a minimum power of 550W and a minimum exhaust volume of 40L min -1 , minimum speed 1300rmin -1 .

[0014] Preferably, the minimum volume of the gas storage tank is 10L.

[0015] Preferably, the gas injection spear is a porous disc-shaped or cylindrical tubular port; the disc-shaped port has a diameter of 8-10 cm and a thickness of 1-3 cm; the cylindrical tubular port has a diameter of 3-5 cm and a length of 10-15 cm.

[0016] Preferably, the process of laying the silicone tube delivery channel should cover the entire deep soil gas injection and oxygenation zone, and each silicone tube gas delivery channel is equipped with a gas injection spear port at intervals of 3-5m using a branch pipe. The gas injection spear is buried 30-40cm deep in the soil, and the silicone pipe is buried in a 2-5cm soil layer.

[0017] Preferably, the deep soil aeration oxygenation management includes the following steps: within one month after returning the straw to the field, the interval between each aeration is 2-4 days, and then during the peak period of methane emission during the tillering and booting stages of rice, the interval between each aeration is 4-6 days, and the aeration is continued for 1 week. The interval between each aeration at other growth stages is 10-14 days, and the gas flow rate at each aeration point is controlled at 10-15 Lh -1 ;

[0018] Preferably, the soil oxygen content is regulated within the range of: soil organic carbon content is 25.0 g kg -1 Below, the soil oxygen content threshold range is 5.0-6.0 mg L -1 ; Soil organic carbon content is 25.0g kg -1 Above, the soil oxygen content threshold range is 3.0-4.0 mg L -1 .

[0019] Preferably, during the field management process, the total amount of fertilizer applied to the paddy field is in the range of 150-180 kgN hm -2 、60-90kgP2O5hm -2 With 120-150kg K2O hm -2 ; Nitrogen fertilizer is applied in the ratio of base fertilizer: tillering fertilizer: ear fertilizer = 5:2:3, and phosphorus fertilizer and potassium fertilizer are applied once as base fertilizer.

[0020] The present invention also provides application of the above method in promoting carbon fixation and emission reduction in paddy fields and increasing rice yield.

[0021] Beneficial effects of the present invention:

[0022] 1. Use deep soil aeration and oxygenation equipment to regulate soil oxygen content to the corresponding range, taking into account both methane emission reduction and soil carbon fixation, and increasing rice field yields by promoting crop root growth.

[0023] 2. The oxygen-enhancing equipment of the present invention has a simple structure, a wide range of equipment accessories to choose from, and low economic investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 This is a diagram of the gas injection and oxygenation device;

[0026] Figure 2 The appearance of the gas injection spear port is a porous round cake made by sintering pure titanium powder;

[0027] Figure 3 This is the field burial map of the silicone tube gas transmission channel. DETAILED DESCRIPTION

[0028] The present invention increases the oxygen content of flooded paddy field soil, promotes aerobic microorganisms to decompose and return straw to the field, accelerates the fixation of exogenous carbon in the straw organic material by the soil carbon pool, provides sufficient oxygen supply for plant root growth, promotes root growth and increases rice yield, inhibits anaerobic methanogenic microbial metabolism and promotes methane oxidation, thereby reducing methane emissions from paddy fields. At the same time, the soil oxygen content threshold range is controlled to avoid a reduction in soil organic carbon content and nutrient loss due to enhanced aerobic microbial decomposition of the soil organic carbon pool.

[0029] In order to increase rice yield, the present invention implements gas injection management on rice fields, provides sufficient oxygen supply to the rhizosphere of rice, and reduces the hindrance to the growth of the root system. According to the rice field production environment, every 400-500m 2 It is divided into a deep soil gas injection and oxygenation zone, and a gas injection device is placed in the center of the area. With the gas injection device as the center point, 8-10 silicone tube transmission channels are laid radially to cover the entire deep soil gas injection and oxygenation zone. Each silicone tube gas transmission channel is set with a gas injection spear port using a branch pipe at intervals of 3-5m. The gas injection spear is buried in a 30-40cm soil depth, and the silicone pipe is buried in a 2-5cm soil layer. Compared with the method of increasing soil oxygen content by laying aeration pipes in rice fields, this technology requires fewer aeration points per unit area, and the manpower and material investment in laying out the device is low.

[0030] The gas injection oxygenation device provided by the present invention is composed of three parts: an air compressor, an air storage tank and an air injection spear. The oxygenation equipment has a simple structure, a wide range of equipment accessories models to choose from, and low economic investment. The device utilizes the principle of air compression, with an air injection spear as the air injection port and a silicone catheter as the gas transmission channel to connect each air injection spear unit. The air injection spear is a porous disc-shaped or cylindrical tubular port sintered from pure titanium powder and other materials. The disc-shaped port has a diameter of 8-10cm and a thickness of 1-3cm. The cylindrical tubular port has a diameter of 3-5cm and a length of 10-15cm, which ensures gas circulation and deep soil gas injection oxygenation efficiency. The air injection flow rate of the air injection spear is regulated by the gas flow rate control valve of the air storage tank, and the flow rate range is 0-15Lh -1 .

[0031] This method of increasing the organic carbon content in paddy soil needs to be combined with the management of returning rice straw to the field. By increasing the oxygen content in flooded paddy fields, it can effectively promote the decomposition of straw and accelerate the fixation of exogenous carbon in the soil carbon pool. The amount of rice straw returned to the field can be increased by 20%-30% on the basis of the conventional amount of straw returned to the field, and the amount of rice straw returned to the field can be controlled at 4500-5000kg hm -2 The length of the straw returned to the field should be less than 10 cm, and the depth of the straw returned to the field should not exceed the burial depth of the gas-injected spears during the rice growing season.

[0032] To ensure that the method can achieve the effect of increasing rice field production, the basic range of rice seedlings for field transplanting is 180,000-210,000 hm2. -2 The seedling age can be shortened by 7-10 days according to the planting variety. The seedlings should have 3-4 leaves and be 10-14cm high. The planting density is 180,000-210,000 hm2. -2

[0033] Deep soil aeration and oxygenation management should be carried out after the straw is returned to the field and the soil is mixed with it, during the peak period of methane emission, and during different growth periods of rice to comprehensively regulate the frequency of deep soil aeration and oxygenation, so as to achieve the goals of soil carbon increase, methane emission reduction and rice field income increase. Deep soil aeration and oxygenation management should be carried out from 8:00 to 11:00 in the morning. Within 1 month after the straw is returned to the field and the soil is mixed with it, the interval between each aeration is 2-4 days. After that, during the peak period of methane emission during the tillering and booting stages of rice, the interval between each aeration is 4-6 days, and it lasts for at least 1 week. The interval between each aeration in other growth stages is 10-14 days.

[0034] The soil oxygen content threshold range is the optimal soil oxygen content range for rice fields to reduce methane emissions and increase carbon and yield. Beyond this threshold range, the soil organic carbon content and rice yield will not increase further and may even decrease due to aerobic decomposition of the soil carbon pool and nutrient loss. -1 Below, taking yellow soil paddy fields as an example, the soil oxygen threshold range is 5.0-6.0 mg L -1 , soil organic carbon content is 25.0g kg -1 The above, represented by black soil paddy fields, have a soil oxygen threshold range of 3.0-4.0 mg L -1 .

[0035] The production processes, experimental methods or detection methods involved in the embodiments of the present invention, unless otherwise specified, are all conventional methods in the prior art, and their names and / or abbreviations are all conventional names in the field, and are very clear and unambiguous in the relevant application fields. Technical personnel in the field can understand the conventional process steps based on the names and apply the corresponding equipment, and implement them according to conventional conditions or the conditions recommended by the manufacturer.

[0036] The various instruments, equipment, raw materials or reagents used in the embodiments of the present invention are not particularly limited in terms of their sources, and are all conventional products that can be purchased through regular commercial channels, or can be prepared according to conventional methods well known to those skilled in the art.

[0037] Example 1

[0038] This example carried out a production test at the Modern Agricultural Science and Technology Demonstration Base in Qianjiang City, Hubei Province from April to December 2023. The test site was a typical yellow loam soil in the Jianghan Plain, the planting mode was a mid-season rice fallow mode, and the soil organic carbon content was 18.2 g / kg -1 The demonstration base has complete rice field production management facilities, which are suitable for the use of this technical method. The specific implementation methods are as follows:

[0039] (1) The air compressor power of the air injection device is 450W and the exhaust volume is 30Lmin -1 , speed 1100r min -1The air tank has a capacity of 9L, and the air injection spear is a porous round cake-shaped port made of pure titanium powder, with a diameter of 10cm and a thickness of 2cm. The air compressor is powered by a lithium battery, and the air injection oxygen enrichment device is as follows Figure 1 As shown, Figure 2 The appearance of the gas injection spear port is a porous round cake made by sintering pure titanium powder.

[0040] (2) The rice fields are managed by no-till conservation tillage. Before burying the gas injection pipeline, the top 5 cm soil layer is manually plowed and tilled with a rake. 2 It is divided into a deep soil gas injection and oxygenation zone, and a gas injection device is placed in the center of the zone. With the gas injection device as the center point, 8 silicone gas pipelines are laid radially to cover the entire deep soil gas injection and oxygenation zone. A gas injection point is set on the silicone gas pipeline every 3m. The gas injection point is connected to the gas injection cake and buried horizontally in the 40cm deep soil layer of the paddy field. The silicone pipeline is buried in the 2cm soil layer on the surface of the bed to prevent the growth of the rice root system from being hindered. The silicone gas pipeline is buried in the field as follows: Figure 3 shown.

[0041] (3) After the rice was harvested last season, the amount of rice straw returned to the field was 4500 kg hm -2 , cut the straw manually, return it to the field with a length of 8-10cm, and evenly spread it on the soil surface, combined with broadcasting 30kgN hm -2 Nitrogen fertilizer promotes straw decomposition. During the spring ploughing period, the undecomposed straw from winter should be shallowly buried in the 2-5cm surface soil.

[0042] (4) Use a plow to level the field surface. Before transplanting the seedlings, spray conventional herbicides and insecticides, and irrigate to soak the field. Keep a 3-4 cm water layer in the field. The rice variety selected is Huanghuazhan, the seedlings are 28 days old, and transplanted by manual transplanting. The transplanting density is 180,000 hm2. -2 .

[0043] (5) The total amount of fertilizer applied to the paddy field is 180 kgN hm -2 、90kg P2O5hm -2 With 150kg K2O hm -2 . Nitrogen fertilizer is applied in the ratio of base fertilizer: tillering fertilizer: ear fertilizer = 5:2:3, and phosphorus fertilizer and potassium fertilizer are applied as base fertilizer at one time.

[0044] (6) After rice transplanting, deep soil aeration and oxygenation management was started at 8:30-10:30 in the morning. In the first month after rice transplanting, in order to promote the efficient decomposition of shallowly buried straw, the frequency of deep soil aeration and oxygenation was once every 2-3 days, and then the frequency was adjusted to once every 10-12 days. However, during the peak period of methane emission from rice fields during the tillering and booting stages of rice, the frequency of deep soil aeration and oxygenation was increased to once every 5-6 days. During the deep soil aeration and oxygenation process, the gas flow rate of each injection point was controlled at 8Lh -1 .

[0045] Set 4 ranges of plough layer oxygen content, 1.0-2.0 mg L -1 (O2), 3.0-4.0 mg L -1 (O4), 5.0-6.0 mg L -1 (O6) and 7.0-8.0 mg L -1 (O8). Three biological plots were set up for each treatment of topsoil oxygen content, with each plot area of ​​1000m 2 Two deep soil aeration and oxygenation devices were installed in 12 plots in total.

[0046] (7) The water management of rice fields adopts the local conventional flooding irrigation method. After rice is transplanted, the rice fields are kept at a water layer of 2-3 cm. If the water layer drops, water is irrigated in time to maintain the corresponding flooding state.

[0047] Comparative Example 1

[0048] This comparative example and Experimental Example 1 were used to carry out production trials at the same demonstration base during the same period. The field management such as rice variety selection, straw treatment, fertilization, transplanting, and irrigation were consistent with Experimental Example 1. The difference was that in Comparative Example 1, no deep soil aeration and oxygenation management was performed during the rice growth stage, and the oxygen content in the tillage layer ranged from 0.5 to 1.0 mg L -1 (CK). As in Experiment 1, three biological plots were set up for replication, each with an area of ​​1000m 2 , a total of 3 communities.

[0049] The experimental results are as follows:

[0050] Table 1 shows the changes in methane emissions, soil organic carbon content, root growth and yield of paddy fields in yellow loam soil in the Jianghan Plain under deep soil aeration management.

[0051] In terms of cumulative methane emissions, the application of deep aeration and oxygenation management technology in paddy field soil significantly reduced the cumulative methane emissions from paddy fields. Compared with control example 1, with the increase of oxygen content in the paddy field plough layer, the cumulative methane emissions decreased by 10.4%, 17.0%, 26.2% and 15.8% respectively. At the same time, deep aeration and oxygenation management in paddy field soil also significantly promoted the fixation of exogenous carbon from straw by the soil carbon pool. The oxygen content in the plough layer was 5.0-6.0 mg L -1 The soil organic carbon content in the range was significantly higher than that in the control case 1. However, when the oxygen content in the tillage layer of the black soil paddy field exceeded 6.0 mg L -1 Afterwards, the microbial aerobic decomposition of the soil organic carbon pool was enhanced. Under the conditions of deep soil aeration and oxygenation management, the soil organic carbon content did not increase further and the methane emission reduction effect was also weakened.

[0052] In addition, deep soil aeration and oxygenation technology also showed a significant yield-increasing effect, but consistent with the carbon fixation and emission reduction effect, the effects of deep soil aeration and oxygenation management on rice root growth and soil organic carbon pool nutrient decomposition were comprehensively considered. The rice yield was higher when the oxygen content in the tillage layer of the paddy field was 5.0-6.0 mg L -1 The range reached the maximum value, and the root surface area, root volume and yield of rice increased significantly by 32.3%, 23.4% and 26.9% respectively compared with the control case 1. The soil organic carbon content represented by the Jianghan Plain was 25.0 g kg -1 The following yellow loam paddy fields have soil oxygen content of 5.0-6.0 mg L -1 The regulatory threshold for deep soil aeration and oxygenation management in paddy fields to fix carbon emissions, reduce emissions and increase production.

[0053] Table 1 Changes in methane emissions, soil organic carbon content, root growth and yield in paddy fields with deep soil aeration in the yellow loam soil of the Jianghan Plain

[0054]

[0055] Different letters indicate differences among treatments at the p < 0.05 level.

[0056] Example 2

[0057] This example carried out a production test at the Baoan Village Cooperative Farm in Shanhe Town, Wuchang City, Heilongjiang Province from March to December 2023. The test site was a typical black soil in the Songnen Plain, a medium-season rice single-ripening rice production area, the second accumulated temperature zone in Heilongjiang Province, and the soil organic carbon content was 31.6 g kg -1 , the rice field production has a high degree of mechanization, which is suitable for the use of this technical method. The specific implementation method is as follows:

[0058] (1) The air compressor power is 550W and the exhaust volume is 40Lmin -1 , speed 1300r min-1 The air tank has a capacity of 10L, and the air injection spear is a porous cylindrical tubular port made of pure titanium powder, with a diameter of 3cm and a length of 15cm. The air compressor power supply is a hybrid of lithium battery and solar energy.

[0059] (2) The rice fields are managed by no-till conservation tillage. Before burying the gas injection pipeline, a small tiller is used to till only the top 5 cm of soil. 2 It is divided into a deep soil gas injection and oxygenation zone, and a gas injection device is arranged in the center of the area. With the gas injection device as the center point, 10 silicone tube gas transmission channels are laid radially to cover the entire deep soil gas injection and oxygenation zone, and a gas injection point is set on the silicone tube gas transmission channel at intervals of 5m. The gas injection point is connected to the gas injection spear and buried horizontally in the 40cm deep soil layer of the paddy field. The silicone tube gas transmission channel is buried in the 3cm soil layer to reduce the adverse effects on the growth of rice roots.

[0060] (3) After the rice was harvested last season, the amount of rice straw returned to the field was 5000 kg hm -2 The straw is cut into 3-5cm short sections by harvesting machinery and evenly spread on the soil surface. During the spring ploughing stage of the season, 7Lhm of conventional straw decomposition agent is sprayed. -2 And bury the undecomposed straw in the winter shallowly into the 2-5cm surface soil.

[0061] (4) Use a hoe to level the field surface. Before transplanting the seedlings, spray conventional herbicides and insecticides, and irrigate to soak the field. Keep a 3-4 cm water layer in the field. The rice variety selected is Yuanliang Daohuaxiang No. 2, with a seedling age of 30 days. The rice is transplanted by mechanical transplanting, and the transplanting density is 190,000 hm2. -2 .

[0062] (5) The total amount of fertilizer applied to the paddy field is 150 kg N hm -2 、60kg P2O5 hm -2 With 120kg K2O hm -2 . Nitrogen fertilizer is applied in the ratio of base fertilizer: tillering fertilizer: ear fertilizer = 5:2:3, and phosphorus fertilizer and potassium fertilizer are applied as base fertilizer at one time.

[0063] (6) After rice transplanting, deep soil aeration and oxygenation management was started from 8:00 to 11:00 in the morning. In the first month after rice transplanting, in order to promote the efficient decomposition of shallowly buried straw, the frequency of deep soil aeration and oxygenation was once every 3-4 days, and then the frequency was adjusted to once every 12-14 days. However, during the peak period of methane emission in rice fields during the tillering and booting stages of rice, the frequency of deep soil aeration and oxygenation was increased to once every 4-6 days. During the deep soil aeration and oxygenation process, the gas flow rate of each injection point was controlled at 10Lh -1 .

[0064] Set 4 ranges of plough layer oxygen content, 1.0-2.0 mg L -1 (O2), 3.0-4.0 mg L -1 (O4), 5.0-6.0 mg L -1 (O6) and 7.0-8.0 mg L -1 (O8). Three biological plots were set up for each treatment of topsoil oxygen content, with each plot area of ​​1000m 2 Two deep soil aeration and oxygenation devices were installed in 12 plots in total.

[0065] (7) Water management in rice fields adopts conventional dry-wet alternating irrigation. After rice is transplanted, water is irrigated to the soil saturated water holding capacity each time, and there is a 1-2 cm water layer. When the water is naturally consumed to the point where there is no visible water in the field, water is irrigated again to the soil saturated water holding capacity, and the process is repeated.

[0066] Comparative Example 2

[0067] This comparative example and Experimental Example 2 were conducted in the same farm during the same period. The field management such as rice variety selection, straw treatment, fertilization, transplanting, irrigation, etc. were consistent with Experimental Example 2. The difference was that in the comparative example 2, no deep soil aeration and oxygenation management was performed during the rice growth stage, and the oxygen content in the tillage layer ranged from 0.5 to 1.0 mg L -1 (CK). As in Experiment 2, three biological plots were set up for replication, each with an area of ​​1000m 2 , a total of 3 communities.

[0068] The test results are as follows:

[0069] Table 2 shows the changes in methane emissions, soil organic carbon content, root growth and yield of paddy fields in the black soil of the Songnen Plain under deep soil aeration management.

[0070] In terms of cumulative methane emissions, the application of deep aeration and oxygenation management technology in paddy field soil significantly reduced the cumulative methane emissions from paddy fields. Compared with control example 2, with the increase of oxygen content in the paddy field plough layer, the cumulative methane emissions decreased by 14.2%, 25.5%, 15.9% and 11.2% respectively. At the same time, deep aeration and oxygenation management in paddy field soil also significantly promoted the fixation of exogenous carbon from straw by the soil carbon pool. The oxygen content in the plough layer was 3.0-4.0 mg L -1 The soil organic carbon content in the range was significantly higher than that in the control case 2. However, when the oxygen content in the tillage layer of the black soil paddy field exceeded 4.0 mg L -1After that, the decomposition of soil carbon pool by aerobic microorganisms was promoted, and the content of soil organic carbon showed a downward trend. When the oxygen content of paddy field soil is beyond a certain range, the promotion of aerobic decomposition of soil carbon pool microorganisms will consume soil organic carbon and provide more substrates for methane production. In order to achieve carbon fixation and emission reduction management, it is necessary to pay attention to controlling the range of soil oxygen content.

[0071] In addition, deep soil aeration technology also showed a significant yield-increasing effect. However, consistent with the carbon fixation and emission reduction effect, affected by the decomposition of nutrients in the soil organic carbon pool, rice yield was significantly increased when the oxygen content in the paddy field was 3.0-4.0 mg L -1 The range reached the maximum value, and the rice root surface area, root volume and yield were significantly increased by 20.7%, 20.4% and 25.5% respectively compared with the control case 2. For higher organic carbon content, the content was 25.0 g kg -1 The above black soil paddy fields have soil oxygen content of 3.0-4.0 mg / L -1 The regulatory threshold for carbon fixation, emission reduction and yield increase in paddy field soil deep aeration and oxygenation management.

[0072] Table 2 Changes in methane emissions, soil organic carbon content, root growth and yield in black soil paddy fields in the Songnen Plain under deep aeration management

[0073]

[0074] 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 promoting carbon sequestration and emission reduction in rice fields, characterized in that: The following steps are involved: (1) Excessive return to the field and transplanting rice: The amount of rice straw returned to the field should be controlled at 4500-5000 kg hm -2 ; Select seedlings with 3-4 leaves and 10-14cm height for transplanting, with a transplanting density of 180,000-210,000 hm2 -2 ; (2) Deep soil aeration and oxygenation management: The gas injection device is used to perform deep soil gas injection and oxygenation management; the maximum soil oxygen content range is controlled according to the organic carbon background content; the gas injection device is placed every 400-500m 2 A silicone tube gas pipeline is laid at the center of the deep soil gas injection and oxygenation zone with the gas injection device as the center point; the gas injection device includes an air compressor, a gas storage tank and a gas injection spear; (3) Field management: Regularly fertilize and irrigate rice fields and carry out pest and weed control.

2. The method according to claim 1, characterized in that: The air compressor in the gas injection device is connected to the gas inlet of the gas storage tank, the gas outlet of the gas storage tank is connected to the gas flow rate control valve, and the gas injection spear is connected to the gas flow rate control valve through a silicone catheter.

3. The method according to claim 2, characterized in that: The minimum power of the air compressor is 550W, and the minimum exhaust volume is 40Lmin -1 , minimum speed 1300rmin -1 .

4. The method according to claim 1, characterized in that: The minimum volume of the gas storage tank is 10L.

5. The method according to claim 1, characterized in that: The gas injection spear is a porous round cake-shaped or cylindrical tubular port; the round cake-shaped port has a diameter of 8-10 cm and a thickness of 1-3 cm; the cylindrical tubular port has a diameter of 3-5 cm and a length of 10-15 cm.

6. The method according to claim 1, characterized in that: The process of laying the silicone tube delivery channel should cover the entire deep soil gas injection and oxygenation area. Each silicone tube gas delivery channel is equipped with a gas injection spear port at intervals of 3-5m using a branch pipe. The gas injection spear is buried 30-40cm deep in the soil, and the silicone pipe is buried in the 2-5cm soil layer.

7. The method according to claim 1, characterized in that: The deep soil aeration oxygenation management includes the following steps: within one month after returning the straw to the field, the interval between each aeration is 2-4 days; thereafter, during the peak period of methane emission during the tillering and booting stages of rice, the interval between each aeration is 4-6 days, and the aeration time is more than one week; during other growth stages, the interval between each aeration is 10-14 days, and the gas flow rate at each aeration point is controlled at 10-15 L / h -1 .

8. The method according to claim 1, characterized in that: The soil oxygen content control range is: soil organic carbon content is 25.0g kg -1 Below, the soil oxygen content threshold range is 5.0-6.0 mg L -1 ; Soil organic carbon content is 25.0g kg -1 Above, the soil oxygen content threshold range is 3.0-4.0 mg L -1 .

9. The method according to claim 1, characterized in that: During the field management process, the total amount of fertilizer applied to the paddy field ranged from 150-180 kg N hm -2 、60-90kg P2O5hm -2 With 120-150kg K2Ohm -2 ; Nitrogen fertilizer is applied in the ratio of base fertilizer: tillering fertilizer: ear fertilizer = 5:2:3, and phosphorus fertilizer and potassium fertilizer are applied once as base fertilizer.

10. Application of the method according to claim 1 in promoting carbon fixation and emission reduction in paddy fields and increasing rice yield.

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