A green manure synergist for carbon sequestration and emission reduction in rice fields and its application

Abstract

The invention discloses a green manure synergist for carbon sequestration and emission reduction in paddy fields and an application thereof, belonging to the technical field of paddy field green manure. The green manure synergist for carbon sequestration and emission reduction in paddy fields in the invention comprises the following raw materials by mass: 3-5 kg ​​of composite sepiolite, 0.2-0.5 kg of sodium 2-chloroethane sulfonate, 0.5-1 kg of solidified bacteria biochar, and 0.3-0.5 kg of goethite. The green manure synergist is prepared by mixing the composite sepiolite, sodium 2-chloroethane sulfonate, solidified bacteria biochar, and goethite in a certain proportion, sowing the composite sepiolite in the paddy field when the milk vetch is in full bloom, and turning the composite sepiolite into the soil together with the milk vetch. The solidified bacteria biochar, sodium 2-chloroethane sulfonate, the composite sepiolite, and the goethite act together to reduce the emission of greenhouse gases such as methane and nitrous oxide during the decomposition process of the milk vetch, improve the soil carbon sequestration efficiency of the milk vetch after returning the field to the soil, promote the expansion of the carbon pool, and achieve carbon sequestration and emission reduction in green manure paddy fields.

Description

Technical Field

[0001] The present invention belongs to the technical field of paddy field green manure, and specifically relates to a green manure synergist for carbon sequestration and emission reduction in paddy fields and application thereof. Background Art

[0002] Green manure is the practice of using unused land, either seasonally or spatially, to plant (or stock) nitrogen-fixing or specialized soil-nourishing crops. The green plant matter of these crops is then turned over and returned to the fields or used as a mulch to provide nutrients and organic matter. This green plant matter and its stubble are known as green manure. Green manure is an integral part of traditional Chinese farming and has been a key technical and material tool for the sustainable utilization of arable land in my country for thousands of years. As a biofertilizer, green manure is primarily applied to the soil through turning and compaction to improve soil structure and provide nutrients. Its role in saving fertilizer, increasing yields, and improving soil fertility has garnered widespread attention from agricultural researchers and producers.

[0003] Publication number CN116267157A discloses a method for reducing the amount of chemical fertilizers in paddy fields based on green manure. The method comprises the following steps: sowing milk vetch seeds and ryegrass seeds in the paddy fields, and mixing the seeds with calcium magnesium phosphate fertilizer before sowing; leaving the rice stubble after late rice harvest, and opening trenches around the paddy fields; applying urea to the milk vetch and ryegrass at the seedling stage in the following year, and turning over and returning them to the fields together with the rice stubble during their peak flowering period, and spreading sesbania carbon and sepiolite; and after fermenting the fields, conventional harrowing, fertilization, and early rice transplanting are carried out, thereby reducing the input of chemical fertilizers in paddy fields and promoting increased rice production.

[0004] As the most commonly used leguminous green manure crop in rice fields, Chinese milk vetch is an efficient means of expanding the soil carbon pool after plowing and returning it to the field. The annual average carbon sequestration capacity (in terms of C) of winter fallow fields increases by 60 kg / mu. However, the polysaccharides such as cellulose and hemicellulose in its organic residues are hydrolyzed by aerobic bacteria and fungi to produce monosaccharides such as glucose and xylose, which are further metabolized into pyruvate through the glycolysis pathway and diverted to produce short-chain organic acids such as acetic acid and propionic acid. In an anaerobic microenvironment, some anaerobic bacteria will use these organic acids to synthesize a large amount of methane gas through the acetyl coenzyme A pathway, and its emission into the air will cause warming risks and environmental burdens.

[0005] How to turn over and return green manure, as a clean organic material, to the fields can not only improve the productivity of rice fields and synergistically improve soil fertility, but also reasonably control and reduce greenhouse gas emissions during rice production, further improve the carbon sequestration capacity of rice field soil and reduce greenhouse gas emissions, which has important ecological and environmental and practical production significance. Summary of the Invention

[0006] The present invention aims to provide a green manure synergist for carbon sequestration and emission reduction in paddy fields and its application. The synergist comprises the following steps: ferroferric oxide is compounded onto a degradable water-absorbing resin, the degradable water-absorbing resin is filled into the pores of modified biochar, and a DAMO archaea liquid is sprayed on the pores to obtain solidified bacterial biochar. The solidified biochar is then mixed with composite sepiolite introduced with thiol and amino groups, and the biochar is mixed with milk vetch for use. This achieves the goal of reducing greenhouse gas emissions while increasing the organic matter content in the soil, achieving the beneficial effects of carbon sequestration, nitrogen increase, and soil fertility, thereby solving the problem of milk vetch producing a large amount of greenhouse gases during its degradation process.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A green manure synergist for carbon sequestration and emission reduction in rice fields, comprising the following raw materials in parts by mass:

[0009] 3-5 parts of composite sepiolite, 0.2-0.5 parts of sodium 2-chloroethane sulfonate, 0.5-1 parts of solidified bacteria biochar and 0.3-0.5 parts of goethite.

[0010] The solidified bacteria biochar was prepared by the following steps:

[0011] Step 1: Add sorbitan monooleate, carboxymethyl cellulose, cyclohexane and modified ferrosoferric oxide into a reactor, react for 30-40 minutes under nitrogen protection and 40-50°C, add 2 mol / L sodium hydroxide solution and acrylic acid into the reactor, react for 20-30 minutes at 0-5°C and 200-300 r / min, then add acrylamide, potassium persulfate and N,N'-methylenebisacrylamide, react for 1-2 hours at 70-80°C, filter, wash, and dry to constant weight to obtain a composite degradable water-absorbing resin.

[0012] Step 2: Add the composite degradable water-absorbing resin, modified biochar, benzoyl peroxide and acetone into a reactor, vacuum impregnate for 4 hours, filter, wash and dry to obtain composite biochar.

[0013] Step 3: Spray the DAMO archaea suspension on 2-4 kg of composite biochar and dry it to obtain solidified bacterial biochar.

[0014] Furthermore, in step 1, the usage ratio of sorbitan monooleate, carboxymethyl cellulose, cyclohexane, modified ferrosoferric oxide, sodium hydroxide solution, acrylic acid, acrylamide, potassium persulfate and N,N'-methylenebisacrylamide is 6-8 kg: 15-20 kg: 1000-1200 L: 8-10 kg: 90-100 L: 40-50 L: 16-18 kg: 0.5-1 kg: 0.5-0.8 kg.

[0015] Furthermore, in step 2, the usage ratio of the composite degradable water-absorbing resin, modified biochar, benzoyl peroxide and acetone is 15-20 kg: 8-10 kg: 150 g: 800-1000 L.

[0016] Furthermore, the preparation process of modified biochar is as follows:

[0017] Biochar with a particle size of 0.5-1 mm and 2 mol / L nitric acid solution are added into a reactor, reacted for 22-25 hours at 80-120° C. and 200-500 r / min, centrifugally filtered, washed, and dried to obtain modified biochar.

[0018] Furthermore, the preparation process of the composite sepiolite is as follows:

[0019] Acidified sepiolite powder and 3-mercaptopropyltrimethoxysilane are added to a reaction kettle, and the mixture is reacted at 20-25° C. and 500-800 r / min for 11-14 hours. Tetraethylenepentamine, polyethyleneimine and methanol are added to the reaction kettle, and the mixture is stirred at 20-25° C. and 300-500 r / min for 20-24 hours. The mixture is filtered, washed and dried to obtain a composite sepiolite.

[0020] Furthermore, the usage ratio of the acidified sepiolite powder, 3-mercaptopropyltrimethoxysilane, tetraethylenepentamine, polyethyleneimine and methanol is 10-20 kg: 20-22 L: 8-10 L: 9-11 L: 80-100 L.

[0021] Furthermore, the preparation process of the acidified sepiolite powder is as follows:

[0022] Place sepiolite with a particle size of 0.5-1 mm in a muffle furnace at 150-180° C. for 3-5 hours, cool naturally to room temperature, transfer the sepiolite to a reactor, add 2 mol / L sulfuric acid solution, react at 70-90° C. and 300-500 r / min for 4-5 hours, filter, wash, dry, and grind to obtain acidified sepiolite powder.

[0023] Furthermore, the usage ratio of sepiolite and sulfuric acid solution is 10-20 kg: 100-200 L.

[0024] Furthermore, the preparation process of modified ferrosoferric oxide is as follows:

[0025] Add ferrosoferric oxide powder with a particle size of 30-50 nm, anhydrous ethanol and KH570 into a reactor, react for 5-6 hours at 70-90° C. and 300-500 r / min, filter, wash and dry to obtain modified ferrosoferric oxide.

[0026] The present invention also provides a green manure synergist for carbon sequestration and emission reduction in paddy fields, and its use in reducing greenhouse gas emissions from milk vetch green manure.

[0027] Beneficial effects of the present invention:

[0028] 1. The green manure synergist of the present invention mixes composite sepiolite, sodium 2-chloroethane sulfonate, solidified bacteria biochar and goethite in a certain proportion, and spreads them in paddy fields when the milk vetch is in full bloom, and turns them into the soil together with the milk vetch. The solidified bacteria biochar and the composite sepiolite jointly reduce the emission of greenhouse gases such as methane and nitrous oxide during the decomposition process of the milk vetch, or fix, absorb and decompose the greenhouse gases such as methane and nitrous oxide produced during the decomposition process of the milk vetch, and convert them into ammonium salts that are beneficial to the absorption of rice roots, thereby reducing the emission of greenhouse gases during the decomposition process of the milk vetch, and increasing the carbon and nitrogen nutrient content in the soil, achieving carbon fixation and capacity expansion, fertilizing the soil, and providing a material basis for increasing rice yield and efficiency.

[0029] 2. The immobilized bacterial biochar of the present invention first grafts the modified ferroferric oxide containing hydroxyl groups onto carboxymethyl cellulose through a silane coupling agent to obtain a composite degradable water-absorbing resin, which is then filled into the modified biochar. Utilizing its good water absorption and water retention effects, it can play a supporting role during volume expansion, making the spatial structure of the biochar more stable, helping to provide a good growth and reproduction space for DAMO archaea, helping to improve the fixation effect of greenhouse gases such as methane and nitrous oxide, and reducing greenhouse gas emissions; and the composite degradable water-absorbing resin is easy to degrade and more environmentally friendly. Modified ferroferric oxide has a large specific surface area and abundant adsorption sites. Through physical adsorption and electrostatic effects, it enhances the adsorption of particulate organic carbon in the soil by the composite biochar, achieving soil carbon fixation and fertilization, providing a material basis for increasing rice production. DETAILED DESCRIPTION

[0030] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] Example 1: This example provides a green manure synergist for carbon sequestration and emission reduction in rice fields, which is prepared by the following steps:

[0032] S1: 15 kg of biochar with a particle size of 0.5-1 mm and 150 L of 2 mol / L nitric acid solution were added to a reactor, reacted at 100°C and 350 r / min for 23.5 h, and centrifuged at 8000 r / min for 5 min. The precipitate was washed six times with deionized water and dried at 110°C to constant weight to obtain modified biochar.

[0033] S2: 9 kg of ferroferric oxide powder with a particle size of 30-50 nm, 220 L of anhydrous ethanol and 450 g KH570 was added to the reactor and reacted at 80°C and 400r / min for 5.5h. O-Si-O bonds were formed between the hydroxyl groups on the surface of ferroferric oxide and the Si-O bonds of KH570. The mixture was centrifuged and washed 4 times with deionized water. The mixture was vacuum dried at 70°C to constant weight to obtain modified ferroferric oxide. 7kg of sorbitan monooleate, 17.5kg of carboxymethyl cellulose, 1100L of cyclohexane and 9kg of modified ferroferric oxide were added to the reactor and reacted at 45°C and 400r / min for 35min under nitrogen protection. 95L of 2mol / L sodium hydroxide solution and 45L of acrylic acid were added to the reactor and reacted at 2°C and 250r / min for 25min. 17kg of acrylamide, 0.75kg of potassium persulfate and 0.65kg of N,N'-methylenebisacrylamide was added into a reaction kettle, and ferrosoferric oxide was grafted onto carboxymethyl cellulose. The reaction was carried out at 75°C for 1.5 hours, and the mixture was centrifuged and filtered. The filter cake was washed three times with anhydrous ethanol and dried in vacuo at 75°C to a constant weight to obtain a composite biodegradable water-absorbing resin.

[0034] S3: Add 17.5 kg of composite degradable water-absorbent resin, 9 kg of modified biochar, 150 g of benzoyl peroxide and 900 L of acetone solution into the reactor, vacuum impregnate for 4.5 h at 0.09 MPa and 50 ° C, centrifuge and filter, wash with deionized water 4 times, and dry at 45 ° C to constant weight to obtain composite biochar.

[0035] S4: Two groups of hollow fiber membrane modules are installed in the sequencing batch membrane biofilm reactor. The membrane modules are integrated by 80 hollow fibers, each fiber is 20m long, with an inner diameter of 180μm and an outer diameter of 280μm. A pneumatic pressure reducing valve is used to connect a high-pressure gas cylinder loaded with methane and carbon dioxide gas to one of the hollow fiber membrane gas paths, and the other hollow fiber membrane gas path is connected to a high-pressure gas cylinder loaded with oxygen. The sequencing batch membrane biofilm reactor is installed in a 700L inorganic salt culture medium. 120L of sludge containing DAMO archaea is inoculated in the inorganic salt culture medium at 30°C, and a concentrated culture medium containing ammonia nitrogen and nitrite nitrogen is added. Oxygen is introduced into the inorganic salt culture medium through the hollow fibers at 13-28d, and the dissolved oxygen content is 0.2mg / L. 0.5g / L of deoxidizer is added at 80-120d to obtain an enriched DAMO archaea liquid.

[0036] S5: 500mL of 4×10 8 The DAMO archaea suspension with a concentration of cfu / mL was sprayed on 3 kg of composite biochar and dried to a moisture content of 45% to obtain solidified bacterial biochar.

[0037] S6: 15 kg of sepiolite with a particle size of 0.5-1 mm was placed in a muffle furnace at 165° C. for 4 h, cooled naturally to room temperature, and the 15 kg of sepiolite was transferred to a reactor, 150 L of a 2 mol / L sulfuric acid solution was added, and the reaction was carried out at 80° C. and 400 r / min for 4.5 h, and the filter cake was washed with deionized water 4 times, dried at 105° C. to constant weight, and then ground and passed through a 100 mesh sieve to obtain acidified sepiolite powder; 15 kg of acidified sepiolite powder and 21 L of 3-Mercaptopropyltrimethoxysilane was added to a reactor and reacted at 20-25°C and 650 r / min for 12.5 h to graft the thiol group onto the sepiolite. 9 L of tetraethylene pentamine, 10 L of polyethylene imine and 90 L of methanol were added to the reactor and stirred at 20-25°C and 400 r / min for 22 h to insert the tetraethylene pentamine and polyethylene imine into the layered chain structure of the sepiolite. The mixture was centrifugally filtered, washed with methanol 3 times, and dried at 80°C to constant weight to obtain a composite sepiolite.

[0038] S7: 4 kg of composite sepiolite, 0.35 kg of sodium 2-chloroethane sulfonate, 0.75 kg of solidified bacteria biochar and 0.4 kg of goethite were mixed evenly to obtain a green manure synergist for carbon sequestration and emission reduction in rice fields.

[0039] Example 2: This example provides a green manure synergist for carbon sequestration and emission reduction in rice fields, which is prepared by the following steps:

[0040] S1: Add 10 kg of biochar with a particle size of 0.5-1 mm and 100 L of 2 mol / L nitric acid solution into a reactor, react at 80°C and 200 rpm for 22 h, centrifuge and filter at 8000 rpm for 5 min, wash the precipitate with deionized water five times, and dry it at 100°C to constant weight to obtain modified biochar.

[0041] S2: 8 kg of ferroferric oxide powder with a particle size of 30-50 nm, 200 L of anhydrous ethanol and 400 g of KH570 were added to a reactor, and the mixture was reacted at 70 ° C and 300 r / min for 5 h. O-Si-O bonds were formed between the hydroxyl groups on the surface of the ferroferric oxide and the Si-O bonds of KH570. The mixture was centrifuged and washed 3 times with deionized water. The mixture was vacuum dried at 60 ° C to constant weight to obtain modified ferroferric oxide; 6 kg of sorbitan monooleate, 15 kg of carboxymethyl cellulose, 1000 L of cyclohexane and 8 kg of modified ferroferric oxide were added to a reactor, and the mixture was reacted at 40 ° C and 300 r / min for 30 min under nitrogen protection. 90 L of 2 mol / L sodium hydroxide solution and 40 L of acrylic acid were added to the reactor, and the mixture was reacted at 0 ° C and 200 r / min for 20 min. Then 16 kg of acrylamide, 0.5 kg of potassium persulfate and 0.5 kg of N,N'-methylenebisacrylamide was added into a reaction kettle, and ferrosoferric oxide was grafted onto carboxymethyl cellulose. The reaction was carried out at 70°C for 1 hour, and the mixture was centrifuged and filtered. The filter cake was washed twice with anhydrous ethanol and dried in vacuo at 70°C to a constant weight to obtain a composite biodegradable water-absorbing resin.

[0042] S3: Add 15 kg of composite degradable water-absorbing resin, 8 kg of modified biochar, 150 g of benzoyl peroxide and 800 L of acetone solution into the reactor, vacuum impregnate for 4 h at 0.08 MPa and 40 ° C, centrifuge and filter, wash with deionized water three times, and dry at 40 ° C to constant weight to obtain composite biochar.

[0043] S4: Two groups of hollow fiber membrane modules are installed in the sequencing batch membrane biofilm reactor. The membrane modules are integrated by 80 hollow fibers, each fiber is 20m long, with an inner diameter of 180μm and an outer diameter of 280μm. A pneumatic pressure reducing valve is used to connect a high-pressure gas cylinder loaded with methane and carbon dioxide gas to one of the hollow fiber membrane gas paths, and the other hollow fiber membrane gas path is connected to a high-pressure gas cylinder loaded with oxygen. The sequencing batch membrane biofilm reactor is installed in a 700L inorganic salt culture medium. 120L of sludge containing DAMO archaea is inoculated in the inorganic salt culture medium at 29°C, and a concentrated culture medium containing ammonia nitrogen and nitrite nitrogen is added. Oxygen is introduced into the inorganic salt culture medium through the hollow fibers at 13-28d, and the dissolved oxygen content is 0.2mg / L. 0.5g / L of deoxidizer is added at 80-120d to obtain an enriched DAMO archaea liquid.

[0044] S5: 500mL of 4×10 8 The DAMO archaea suspension with a concentration of cfu / mL was sprayed on 2 kg of composite biochar and dried to a moisture content of 40% to obtain solidified bacterial biochar.

[0045] S6: Place 10 kg of sepiolite with a particle size of 0.5-1 mm in a muffle furnace at 150° C. for 3 h, cool naturally to room temperature, transfer 10 kg of sepiolite to a reactor, add 100 L of 2 mol / L sulfuric acid solution, react at 70° C. and 300 r / min for 4 h, centrifuge, wash the filter cake with deionized water 3 times, dry at 100° C. to constant weight, grind and pass through a 100 mesh sieve to obtain acidified sepiolite powder; 10 kg of acidified sepiolite powder and 20 L of 3-Mercaptopropyltrimethoxysilane was added to a reactor and reacted at 20-25°C and 500 r / min for 11 hours to graft the thiol group onto the sepiolite. 8 L of tetraethylene pentamine, 9 L of polyethylene imine and 80 L of methanol were added to the reactor and stirred at 20-25°C and 300 r / min for 20 hours to insert the tetraethylene pentamine and polyethylene imine into the layered chain structure of the sepiolite. The mixture was centrifuged and filtered, washed twice with methanol, and dried at 80°C to constant weight to obtain a composite sepiolite.

[0046] S7: 3 kg of composite sepiolite, 0.2 kg of sodium 2-chloroethane sulfonate, 0.5 kg of solidified bacteria biochar and 0.3 kg of goethite were mixed evenly to obtain a green manure synergist for carbon sequestration and emission reduction in rice fields.

[0047] Example 3: This example provides a green manure synergist for carbon sequestration and emission reduction in rice fields, which is prepared by the following steps:

[0048] S1: 20 kg of biochar with a particle size of 0.5-1 mm and 200 L of 2 mol / L nitric acid solution were added to a reactor, reacted at 120°C and 500 rpm for 25 h, and centrifuged at 8000 rpm for 5 min. The precipitate was washed 8 times with deionized water and dried at 120°C to constant weight to obtain modified biochar.

[0049] S2: 10 kg of ferroferric oxide powder with a particle size of 30-50 nm, 250 L of anhydrous ethanol and 500 g of KH570 were added to a reactor, and reacted at 90 ° C and 500 r / min for 6 h. O-Si-O bonds were formed between the hydroxyl groups on the surface of the ferroferric oxide and the Si-O bonds of KH570. The mixture was centrifuged and washed with deionized water 5 times. It was vacuum dried at 80 ° C to constant weight to obtain modified ferroferric oxide; 8 kg of sorbitan monooleate, 20 kg of carboxymethyl cellulose, 1200 L of cyclohexane and 10 kg of modified ferroferric oxide were added to a reactor, and reacted at 50 ° C and 500 r / min for 40 min under nitrogen protection. 100 L of 2 mol / L sodium hydroxide solution and 50 L of acrylic acid were added to the reactor, and reacted at 5 ° C and 300 r / min for 30 min. Then 18 kg of acrylamide, 1 kg of potassium persulfate and 0.8 kg N,N'-methylenebisacrylamide was added into a reaction kettle, and ferrosoferric oxide was grafted onto carboxymethyl cellulose. The reaction was carried out at 80°C for 2 hours, and the mixture was centrifuged and filtered. The filter cake was washed three times with anhydrous ethanol and dried in vacuum at 80°C to a constant weight to obtain a composite biodegradable water-absorbing resin.

[0050] S3: Add 20 kg of composite degradable water-absorbing resin, 10 kg of modified biochar, 150 g of benzoyl peroxide and 1000 L of acetone solution into the reactor, vacuum impregnate for 5 h at 0.1 MPa and 60 ° C, centrifuge and filter, wash with deionized water 5 times, and dry at 50 ° C to constant weight to obtain composite biochar.

[0051] S4: Two groups of hollow fiber membrane modules are installed in the sequencing batch membrane biofilm reactor. The membrane modules are integrated by 80 hollow fibers, each fiber is 20m long, with an inner diameter of 180μm and an outer diameter of 280μm. A pneumatic pressure reducing valve is used to connect a high-pressure gas cylinder loaded with methane and carbon dioxide gas to one of the hollow fiber membrane gas paths, and the other hollow fiber membrane gas path is connected to a high-pressure gas cylinder loaded with oxygen. The sequencing batch membrane biofilm reactor is installed in a 700L inorganic salt culture medium. 120L of sludge containing DAMO archaea is inoculated in the inorganic salt culture medium at 31°C, and a concentrated culture medium containing ammonia nitrogen and nitrite nitrogen is added. Oxygen is introduced into the inorganic salt culture medium through the hollow fibers at 13-28d, and the dissolved oxygen content is 0.2mg / L. 0.5g / L of deoxidizer is added at 80-120d to obtain an enriched DAMO archaea liquid.

[0052] S5: 500mL of 4×10 8 The DAMO archaea suspension with a concentration of cfu / mL was sprayed on 4 kg of composite biochar and dried to a moisture content of 50% to obtain solidified bacterial biochar.

[0053] S6: 20 kg of sepiolite with a particle size of 0.5-1 mm was placed in a muffle furnace at 180° C. for 5 h, cooled naturally to room temperature, and the 20 kg of sepiolite was transferred to a reactor, 200 L of a 2 mol / L sulfuric acid solution was added, and the mixture was reacted at 90° C. and 500 r / min for 5 h, and centrifuged. The filter cake was washed with deionized water 5 times, dried at 110° C. to constant weight, ground and sieved through a 100 mesh sieve to obtain acidified sepiolite powder; 20 kg of acidified sepiolite powder and 22 L of 3-Mercaptopropyltrimethoxysilane was added to a reactor and reacted at 20-25°C and 800 r / min for 14 hours to graft the thiol group onto the sepiolite. 11 L of tetraethylene pentamine, 11 L of polyethylene imine and 100 L of methanol were added to the reactor and stirred at 20-25°C and 500 r / min for 24 hours to insert the tetraethylene pentamine and polyethylene imine into the layered chain structure of the sepiolite. The mixture was centrifugally filtered, washed with methanol 5 times, and dried at 80°C to constant weight to obtain a composite sepiolite.

[0054] S7: 5 kg of composite sepiolite, 0.5 kg of sodium 2-chloroethane sulfonate, 1 kg of solidified bacteria biochar and 0.5 kg of goethite were mixed evenly to obtain a green manure synergist for carbon sequestration and emission reduction in rice fields.

[0055] Comparative Example 1: The difference from Example 1 is that ordinary biochar is used instead of solidified bacteria biochar in S7, and the other steps remain unchanged to prepare a green manure synergist for carbon sequestration and emission reduction in rice fields.

[0056] Comparative Example 2: The difference from Example 1 is that ordinary sepiolite is used instead of composite sepiolite in S7, and the other steps remain unchanged to prepare a green manure synergist for carbon sequestration and emission reduction in rice fields.

[0057] Comparative Example 3: The difference from Example 1 is that composite biochar is used instead of solidified bacterial biochar in S7, and the other steps remain unchanged to prepare a green manure synergist for carbon sequestration and emission reduction in rice fields.

[0058] The green manure synergist prepared in Example 1-Example 3 and Comparative Example 1-Comparative Example 3 was subjected to a fertilizer efficiency test. The test site was the experimental demonstration base in Luoshan County, Xinyang City, Henan Province. A plot with a medium or higher soil fertility level was selected. The green manure demonstration test field was divided into 7 areas, each area of ​​667 square meters. The green manure milk vetch variety planted was "Xin Zi No. 1", and the rice varieties were all local main varieties. They were planted by machine transplanting, and field management was carried out in accordance with conventional cultivation technology requirements. The prevention and control of pests and diseases and weeds were consistent with local farmland management measures. The green manure milk vetch needed to be measured before green manure was turned over, and the green manure yield needed to reach 1500 kg / mu or more. The green manure synergist prepared in Example 1-Example 3 and Comparative Example 1-Comparative Example 3 was scattered by drone one day before the green manure was turned over. The dosage is 20kg / mu, and a blank control group ck is set up. No green manure synergist is applied. During the flowering period of milk vetch, the milk vetch and the rice straw from the previous season are turned over and returned to the field together. The turning depth is 15-20cm to mix it thoroughly with the soil. 7-10 days after turning over, water is irrigated with 5-8cm of water to ferment the field. 10-15 days after fermenting, the field is harrowed and rice is planted. The initial soil data are: pH: 5.67, total nitrogen: 0.93g / kg, organic matter: 14.52g / kg, available phosphorus: 10.55mg / kg, and available potassium: 65.05mg / kg. The experimental data are averaged. The implementation period is 2021-2024. The cumulative emissions of methane and nitrous oxide gases are measured. GWP stands for global warming potential, and GHGI stands for greenhouse gas emission intensity.

[0059] The harvested rice yield data are shown in Table 1:

[0060] Table 1 Rice yield per mu data

[0061] project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 ck Yield per mu (kg / mu) 651.3 672.2 665.5 604.2 610.2 620.5 585.2 Number of effective ears (10,000 / mu) 18.08 18.12 18.05 17.64 17.72 17.83 17.45 Total number of grains per ear (grains) 176.9 179.8 177.5 171.2 171.6 172.3 168.2 Fruit setting rate (%) 90.9 90.8 90.7 89.5 89.7 89.6 88.1 Thousand-grain weight (g) 26.8 26.9 26.9 26.2 26.5 26.3 26.2

[0062] As can be seen from Table 1, the per mu yield of rice in Examples 1 to 3 is higher than that of ck, and the per mu yield of rice in Comparative Examples 1 to 3 is lower than that in Examples 1 to 3, which shows that the mixture of solidified bacteria biochar, composite sepiolite, etc. and Chinese milk vetch together with the soil can play a synergistic role in increasing the per mu yield of rice by increasing the effective panicles and the total number of grains per panicle in the rice yield structure, thereby increasing the per mu yield of rice to a certain extent.

[0063] Table 2 Effects of green manure synergists on greenhouse gas emissions

[0064]

[0065] As can be seen from Table 2, the cumulative emissions of methane and nitrous oxide during the growth of rice in Examples 1 to 3 are all less than those of the ck group. In Comparative Example 1, ordinary biochar was used instead of solidified bacteria biochar, and the cumulative emissions of methane and nitrous oxide decreased relative to those of the ck group. In Comparative Example 2, ordinary sepiolite was used instead of composite sepiolite, and the cumulative emissions of methane and nitrous oxide decreased relative to those of the ck group. In Comparative Example 3, composite biochar was used instead of solidified bacteria biochar, and the cumulative emissions of methane and nitrous oxide decreased compared to those of the ck group. Compared with Examples 1 to 3, the cumulative emissions of methane and nitrous oxide were higher, indicating that when the green manure synergist with solidified bacteria biochar and composite sepiolite is turned over and mixed with milk vetch, the emissions of methane, nitrous oxide and nitrous oxide can be effectively reduced throughout the entire process from turning over the milk vetch to rice harvesting.

[0066] Table 3 Effects of green manure synergists on soil nutrients

[0067] project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 ck Organic matter (g / kg) 16.79 17.14 16.88 14.21 13.25 13.45 14.21 Total nitrogen (g / kg) 1.05 1.11 1.08 0.95 1.03 0.91 0.95 Available phosphorus (mg / kg) 13.96 13.01 14.21 12.55 11.01 12.85 10.44 Fast-acting potassium (mg / kg) 81.11 79.25 80.15 75.04 78.14 80.04 65.21 pH 6.01 6.04 5.96 5.84 5.69 5.71 5.68

[0068] As can be seen from Table 3, the contents of organic matter, total nitrogen, available phosphorus and quick-acting potassium in the soil in Examples 1 to 3 are all higher than those in the ck group, indicating that the green manure synergist for carbon sequestration and emission reduction in paddy fields of the present invention can effectively improve soil nutrients after being mixed with milk vetch.

[0069] It is noted that, in this document, terms such as "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not explicitly listed, or elements that are inherent to such process, method, article, or apparatus.

[0070] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A green manure synergist for carbon sequestration and emission reduction in rice fields, characterized in that: The following raw materials are included in parts by mass: 3-5 parts of composite sepiolite, 0.2-0.5 parts of sodium 2-chloroethane sulfonate, 0.5-1 parts of solidified bacteria biochar and 0.3-0.5 parts of goethite; The solidified bacteria biochar is prepared by the following steps: Step 1: adding sorbitan monooleate, carboxymethyl cellulose, cyclohexane and modified ferrosoferric oxide into a reactor, reacting for 30-40 minutes under nitrogen protection and 40-50° C., adding a 2 mol / L sodium hydroxide solution and acrylic acid into the reactor, reacting for 20-30 minutes at 0-5° C. and 200-300 r / min, then adding acrylamide, potassium persulfate and N,N'-methylenebisacrylamide, reacting for 1-2 hours at 70-80° C., filtering, washing and drying to obtain a composite degradable water-absorbing resin; Step 2: adding the composite degradable water-absorbing resin, modified biochar, benzoyl peroxide and acetone into a reactor, vacuum impregnating for 4 hours, filtering, washing and drying to obtain composite biochar; Step 3: Spray the DAMO archaea suspension onto 2-4 kg of composite biochar and dry it to obtain solidified biochar; The preparation process of the modified biochar is as follows: Add biochar with a particle size of 0.5-1 mm and 2 mol / L nitric acid solution into a reactor, react at 80-120°C and 200-500 r / min for 22-25 hours, centrifuge, filter, wash, and dry to obtain modified biochar; The preparation process of the composite sepiolite is as follows: Adding acidified sepiolite powder and 3-mercaptopropyltrimethoxysilane to a reaction kettle, reacting at 20-25° C. and 500-800 r / min for 11-14 hours, adding tetraethylenepentamine, polyethyleneimine and methanol to the reaction kettle, stirring at 20-25° C. and 300-500 r / min for 20-24 hours, filtering, washing and drying to obtain a composite sepiolite; The preparation process of the modified ferrosoferric oxide is as follows: Add ferrosoferric oxide powder with a particle size of 30-50 nm, anhydrous ethanol and KH570 into a reactor, react for 5-6 hours at 70-90° C. and 300-500 r / min, filter, wash and dry to obtain modified ferrosoferric oxide.

2. A green manure synergist for carbon sequestration and emission reduction in paddy fields according to claim 1, characterized in that: The usage ratio of sorbitan monooleate, carboxymethyl cellulose, cyclohexane, modified ferrosoferric oxide, sodium hydroxide solution, acrylic acid, acrylamide, potassium persulfate and N,N'-methylenebisacrylamide in step 1 is 6-8kg: 15-20kg: 1000-1200L: 8-10kg: 90-100L: 40-50L: 16-18kg: 0.5-1kg: 0.5-0.8kg.

3. The green manure synergist for carbon sequestration and emission reduction in paddy fields according to claim 1, characterized in that: The usage ratio of the composite degradable water-absorbing resin, modified biochar, benzoyl peroxide and acetone in step 2 is 15-20 kg: 8-10 kg: 150 g: 800-1000 L.

4. The green manure synergist for carbon sequestration and emission reduction in paddy fields according to claim 1, characterized in that: The usage ratio of the acidified sepiolite powder, 3-mercaptopropyltrimethoxysilane, tetraethylenepentamine, polyethyleneimine and methanol is 10-20 kg: 20-22 L: 8-10 L: 9-11 L: 80-100 L.

5. The green manure synergist for carbon sequestration and emission reduction in paddy fields according to claim 1, characterized in that: The preparation process of the acidified sepiolite powder is as follows: Place sepiolite with a particle size of 0.5-1 mm in a muffle furnace at 150-180° C. for 3-5 hours, cool naturally to room temperature, transfer the sepiolite to a reactor, add 2 mol / L sulfuric acid solution, react at 70-90° C. and 300-500 r / min for 4-5 hours, filter, wash, dry, and grind to obtain acidified sepiolite powder.

6. The green manure synergist for carbon sequestration and emission reduction in paddy fields according to claim 5, characterized in that: The usage ratio of the sepiolite and the sulfuric acid solution is 10-20 kg: 100-200 L.

7. Use of the green manure synergist for carbon sequestration and emission reduction in rice fields according to claim 1 in reducing greenhouse gas emissions during the decomposition of Chinese milk vetch and rice growth.

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