Red soil hardening reduction conditioner based on modified straw adsorption carbon as well as preparation method and application thereof

Abstract

The invention relates to the technical field of agriculture, provides a red soil hardening reduction conditioner based on modified straw adsorption carbon as well as a preparation method and application thereof, and solves the problems that an existing red soil hardening conditioner is poor in soil improvement effect and does not have a slow release function. Comprising the following steps: (1) preparing oyster shell-biochar composite powder; (2) loading functional components; (3) directional immobilization of microorganisms; (4) coating a slow-release layer; (5) activating treatment; the red soil hardening reduction conditioner is prepared from the following raw materials in parts by weight: 80 to 100 parts of oyster shell powder, 100 to 200 parts of modified straw adsorption carbon, 10 to 30 parts of rice hull powder, 30 to 50 parts of nano dihydrate gypsum, 100 to 200 parts of a polyglutamic acid solution, 10 to 50 parts of acid-resistant bacillus, 15 to 30 parts of sodium alginate, 30 to 60 parts of humic acid, 10 to 30 parts of carbide slag and 30 to 60 parts of attapulgite.

Description

Technical Field

[0001] The present invention relates to the field of agricultural technology, and in particular to a red soil compaction reducing conditioner based on modified straw adsorbed carbon, and a preparation method and application thereof. Background Art

[0002] Red soil, as one of my country's important soil resources, is widely distributed in southern China and plays an important role in the production of horticultural crops such as citrus and tea. However, red soil is generally plagued by compaction, which has become one of the key factors limiting the yield and quality of horticultural crops. Red soil compaction can lead to poor soil aeration and water permeability, making it difficult for crop roots to obtain sufficient oxygen and water during growth, thereby affecting the normal growth and function of the root system and hindering the crop's absorption of nutrients and water. At the same time, red soil is usually acidic. Excessive acidity will affect the effectiveness of nutrients in the soil and the activity of microorganisms, reducing soil fertility and further restricting the growth and development of horticultural crops.

[0003] To improve the compaction of red soil and increase soil fertility and horticultural crop yields, several soil improvement methods and conditioners have been employed in existing technologies. Traditional soil improvement methods primarily include physical improvement (such as deep plowing and soil addition), chemical improvement (such as the application of lime and gypsum), and biological improvement (such as the inoculation of beneficial microorganisms). However, each of these methods has limitations. Physical improvement methods are labor-intensive, costly, and difficult to achieve sustained results. While chemical improvement methods can regulate soil pH and improve soil structure to a certain extent, long-term use may lead to increased soil compaction and environmental pollution. Biological improvement methods are significantly affected by environmental factors, making it difficult to ensure the survival and activity of microorganisms, resulting in unstable improvement results.

[0004] Chinese Patent Publication No. CN119842410A discloses a granular soil conditioner for acid-passivation aluminum and its preparation method, comprising the following steps: uniformly mixing alkaline phosphate tailings powder, silicon-based yellow phosphorus slag powder, silicate minerals and a carbon source conditioner to obtain a mixed powder material; soaking the mixed powder material in an alkaline solution for alkaline modification to obtain an alkaline-modified conditioner; soaking the alkaline-modified conditioner in a chitosan solution, reacting so that the functional groups of chitosan adhere to the surface of the alkaline-modified conditioner to obtain a chitosan-modified conditioner; adding a binder to the chitosan-modified conditioner and granulating it to obtain a granular soil conditioner for acid-passivation aluminum. The granular soil conditioner provided by this invention can effectively improve acidic soil and has a high ability to passivate aluminum. However, the granular soil conditioner does not have a slow-release function. During storage and transportation, it cannot effectively prevent microorganisms from being mechanically damaged, deactivated by drying, and invaded by external impurities. When applied to soil, it cannot prevent the microorganisms from being released into the soil in large quantities at one time and being affected by environmental pressure.

[0005] Chinese Patent Publication No. CN118125874A discloses a soil conditioner based on organic acid-activated oyster shells and its preparation method. The soil conditioner particles include an inner layer, a middle layer, and an outer layer. The inner layer includes phosphate tailings powder and oxalic acid, the middle layer includes roasted oyster shell powder and potassium alginate, and the outer layer includes unroasted oyster shell powder. This soil conditioner can effectively improve acidic soils, passivate various heavy metals such as lead, cadmium, copper, and zinc in the soil, and provide potassium and phosphate fertilizers to the soil, and the fertilizers can be released slowly. However, this conditioner has limited effect on improving soil porosity and reducing soil compaction. Summary of the Invention

[0006] Therefore, in response to the above problems, the present invention provides a red soil compaction reduction conditioner based on modified straw adsorbed carbon, and its preparation method and application, to solve the problems that the existing red soil compaction conditioners have poor soil improvement effect and the conditioners do not have a slow-release function.

[0007] To achieve the above object, the present invention adopts the following technical solutions: A method for preparing a red soil compaction reducing conditioner based on modified straw adsorbed carbon comprises the following steps: S1. Preparation of oyster shell-biochar composite powder: Fresh oyster shells are cleaned and calcined at 800-1000°C for 2-3 hours to obtain oyster shell powder containing highly active calcium oxide. Modified straw adsorption carbon and rice husk powder are added to the oyster shell powder and mixed evenly to obtain a composite carrier; S2. Functional component loading: mixing the composite carrier with nano-dihydrate gypsum, adding polyglutamic acid solution, and mixing evenly to obtain a functional mixture; S3. Directed immobilization of microorganisms: immersing the functional mixture in a culture medium containing acid-resistant Bacillus, and culturing at 25° C. for 48 hours to form a microbial-mineral complex; S4. Sustained-release layer coating: Using fluidized bed coating technology, with the microbial-mineral complex as the core, the following coating layers are sprayed in sequence: (a) an inner layer of a sodium alginate and humic acid composite film; (b) an outer layer of a porous coating of attapulgite modified with carbide slag; S5. Activation treatment: The coated particles are aged at 35°C and 80% relative humidity for 48-72 hours to allow microorganisms to colonize in the pores of the coating to obtain a red soil compaction reduction agent; The preparation process of the modified straw adsorption carbon is as follows: a. crushing the straw and then performing an amphoteric modification treatment, i.e., reacting the straw with 3-chloro-2-hydroxypropyltrimethylammonium chloride in an alkaline solution to graft cationic groups; b. reacting the straw with chloroacetic acid in a mixed solvent of ethanol and water to graft anionic groups to form an amphoteric adsorbent straw having both anions and cations; c. carbonizing the amphoteric adsorbent straw at a carbonization temperature of 400°C-600°C for 0.5h-2h to obtain the modified straw adsorption carbon; The nano dihydrate gypsum is prepared by ultrafine grinding of phosphogypsum after microwave-assisted acid washing, and the heavy metal content is ≤5 mg / kg, wherein the heavy metal is calculated as Pb; The preparation method of the carbide slag modified attapulgite is as follows: carbide slag and attapulgite are mixed, roasted at 400-600° C. for 1-2 hours, and activated with 0.1 mol / L sulfuric acid solution to obtain the mixture.

[0008] Furthermore: the red soil compaction reduction conditioner includes the following raw materials in parts by weight: 80-100 parts of oyster shell powder, 100-200 parts of modified straw adsorption carbon, 10-30 parts of rice husk powder, 30-50 parts of nano dihydrate gypsum, 100-200 parts of polyglutamic acid solution, 10-50 parts of acid-resistant Bacillus, 15-30 parts of sodium alginate, 30-60 parts of humic acid, 10-30 parts of carbide slag, and 30-60 parts of attapulgite.

[0009] Furthermore: the red soil compaction reduction conditioner is formed by a coating layer covering a microbial mineral complex, the coating layer includes an inner layer and an outer layer; the inner layer is a composite film of sodium alginate and humic acid, and the outer layer is a porous coating of attapulgite modified by carbide slag.

[0010] Furthermore: the inner layer thickness of the red soil compaction reducing conditioner is 50 μm-100 μm, and the porosity of the outer layer is ≥60%.

[0011] Further: A method for preparing a red soil compaction reducing conditioner based on modified straw adsorbed carbon, and application of the obtained red soil compaction reducing conditioner in horticultural crop planting to improve red soil compaction, the specific method is: (1) Soil pretreatment: Use a soil hardness tester to test the compaction degree of red soil. When the penetration resistance is greater than 25kg / cm 2 Initiate conditioning agent application when (2) Layered application: evenly spread the red soil compaction reducing agent at 30-50 kg / mu on the surface layer, and till the soil to a depth of 15-20 cm; add an additional 20 kg / mu to the bottom of the planting hole in the root layer and mix it with the hole soil; (3) Start the drip irrigation system: Start the drip irrigation system after application, maintain the soil moisture content at 60%-70%, and continue the action for 30 days.

[0012] Further: when the horticultural crop is citrus, the application is selected 15 days before the germination of spring shoots, and the horticultural ground is covered with weed control cloth.

[0013] Further: when the horticultural crop is tea tree, it is applied after autumn pruning.

[0014] Furthermore: the drip irrigation system includes an irrigation water pool, a fertilizing device, a primary filter device, a secondary filter device, a connection system, and several drip irrigation pipes. The irrigation water pool, fertilizing device, primary filter device, secondary filter device and drip irrigation pipes are connected by a connection system; the connection system includes a main pipe and a branch pipe; the branch pipe is connected to several drip irrigation pipes, and the connection system is provided with a check valve, a pressure gauge and several control valves; the main pipe between the secondary filter device and the drip irrigation pipe is provided with a pulse backwash device, which is controlled by a solenoid valve and a timer, and automatically backwashes the filter device every 24 hours; the water inlet end of the drip irrigation pipe is provided with a vortex debubbler, which destroys bubble aggregation through a rotating flow channel and reduces dripper blockage caused by air resistance.

[0015] By adopting the above technical solution, the beneficial effects of the present invention are: (1) The various components in the conditioner work synergistically to improve the physical structure of red soil. The calcium provided by oyster shell powder promotes the formation of soil aggregate structure, nano-dihydrate gypsum fills pores, and modified straw adsorbed carbon and rice husk powder increase soil organic matter. Together, they increase soil porosity, significantly improve air permeability and water permeability, effectively reduce the compaction of red soil, reduce soil penetration resistance, and promote the growth and development of crop roots. Among them, the modified straw adsorbed carbon has a good adsorption capacity for both anionic and cationic pollutants (such as heavy metal cations and anions such as phosphate) in red soil through amphoteric modification.

[0016] (2) The calcium oxide in oyster shell powder can neutralize the acidity of red soil and adjust the soil pH value to a range suitable for crop growth, providing a good growth environment for crop roots. It is also beneficial to the effectiveness of nutrients in the soil and the activity of microorganisms.

[0017] (3) The slow-release layer coats the microbial mineral complex. On the one hand, it plays a slow-release role: the sodium alginate and humic acid composite film can form a physical barrier on the surface of the microbial mineral complex, isolating microorganisms such as acid-resistant Bacillus from the adverse external environment. After application, the microorganisms can gradually diffuse into the soil with the degradation of the film and the release of nutrients; on the other hand, the porous coating of attapulgite modified by calcium carbide slag has a rich pore structure, which can increase the porosity of the soil and improve the air permeability and water permeability of the soil. Good air permeability is conducive to the respiration of microorganisms and the growth of the root system, while water permeability can prevent water accumulation in the soil and reduce the occurrence of soil compaction.

[0018] (4) The nano-dihydrate gypsum in the conditioner supplements nutrients such as calcium and sulfur, polyglutamic acid retains water and fertilizer, and acid-resistant Bacillus decomposes organic matter to release nutrients. The combined effect of each component improves the fertility of the soil, increases the effective nutrient content in the soil, and provides sufficient nutrition for crop growth.

[0019] (5) Agricultural waste and industrial waste residues such as oyster shells, rice husk powder, calcium carbide slag, and attapulgite are used in the conditioning agent, which realizes the resource utilization of waste, reduces the pollution of waste to the environment, and has good environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of the red soil compaction reduction conditioner in an embodiment of the present invention; Figure 2 This is a schematic structural diagram of a drip irrigation system according to an embodiment of the present invention; Figure 3 Schematic diagram of the structure of the vortex debubbler in an embodiment of the present invention; Explanation of the numbers in the figure: 1-irrigation water pool, 2-fertilization device, 3-primary filtration device, 4-secondary filtration device, 5-connection system, 6-drip irrigation pipe, 7-pulse backwash device, 11-microorganism mineral complex, 12-coating layer, 51-main pipe, 52-branch pipe, 61-vortex demister, 121-inner layer, 122-outer layer, 501-check valve, 502-pressure gauge, 503-control valve. DETAILED DESCRIPTION

[0021] Example 1

[0022] A method for preparing a red soil compaction reducing conditioner based on modified straw adsorbed carbon comprises the following steps: S1. Preparation of oyster shell-biochar composite powder: Fresh oyster shells were cleaned and calcined at 800° C. for 2 h to obtain oyster shell powder containing highly active calcium oxide. Modified straw adsorption carbon and rice husk powder were added to the oyster shell powder and mixed evenly to obtain a composite carrier. S2. Functional component loading: mixing the composite carrier with nano-dihydrate gypsum, adding polyglutamic acid solution, and mixing evenly to obtain a functional mixture; S3. Directed immobilization of microorganisms: immersing the functional mixture in a culture medium containing acid-resistant Bacillus, and culturing at 25° C. for 48 hours to form a microbial-mineral complex; S4, sustained-release layer coating: reference Figure 1 , using fluidized bed coating technology, with the microbial mineral complex 11 as the core, the following coating layers 12 are sprayed in sequence: a) an inner layer 121 is a sodium alginate and humic acid composite film with a thickness of 50 μm; b) an outer layer 122 is a porous coating of attapulgite modified with carbide slag with a porosity of 60%; S5. Activation treatment: The coated particles are aged at 35°C and 80% relative humidity for 72 hours to allow microorganisms to colonize in the pores of the coating to obtain a red soil compaction reduction agent; The preparation process of the modified straw adsorption carbon is as follows: a. crushing the straw and then performing an amphoteric modification treatment, i.e., reacting the straw with 3-chloro-2-hydroxypropyltrimethylammonium chloride in an alkaline solution to graft cationic groups; b. reacting the straw with chloroacetic acid in a mixed solvent of ethanol and water to graft anionic groups to form an amphoteric adsorbent straw having both anions and cations; c. carbonizing the amphoteric adsorbent straw at a carbonization temperature of 400°C for 0.5 hours to obtain the modified straw adsorption carbon; The nano dihydrate gypsum is prepared by ultrafine grinding of phosphogypsum after microwave-assisted acid washing, and has a heavy metal content of 5 mg / kg, where the heavy metal is calculated as Pb; The preparation method of the carbide slag modified attapulgite is as follows: mixing carbide slag with attapulgite, roasting at 400° C. for 1 hour, and activating with 0.1 mol / L sulfuric acid solution to obtain the obtained product; The red soil compaction reduction conditioner comprises the following raw materials in parts by weight: 80 parts of oyster shell powder, 100 parts of modified straw adsorbed carbon, 10 parts of rice husk powder, 30 parts of nano dihydrate gypsum, 100 parts of polyglutamic acid solution, 10 parts of acid-resistant Bacillus, 15 parts of sodium alginate, 30 parts of humic acid, 10 parts of carbide slag, and 30 parts of attapulgite.

[0023] The above-mentioned red soil compaction reducing conditioner based on modified straw adsorbed carbon is used in horticultural crop cultivation to improve red soil compaction. The specific method is as follows: (1) Soil pretreatment: The red soil hardness is tested by a soil hardness tester, and the penetration resistance is 30kg / cm 2 Initiate conditioning agent application when (2) Layered application: evenly spread the red soil compaction reducing agent at 30 kg / mu on the surface layer, and till the soil to a depth of 15 cm; add an additional 20 kg / mu to the bottom of the planting hole in the root layer and mix it with the hole soil; (3) Start the drip irrigation system: Start the drip irrigation system after application, maintain the soil moisture content at 60%, and continue the action for 30 days.

[0024] Wherein, the horticultural crop is citrus, and the application is selected 15 days before the spring shoots sprout, and the horticultural ground is covered with weed control cloth; Figures 2 to 3 The drip irrigation system includes an irrigation pool 1, a fertilizing device 2, a primary filter device 3, a secondary filter device 4, a connecting system 5, and a drip irrigation pipe 6. The irrigation pool 1, the fertilizing device 2, the primary filter device 3, the secondary filter device 4, and the drip irrigation pipe 6 are connected by the connecting system 5; the connecting system 5 includes a main pipe 51 and a branch pipe 52; the connecting system 5 is provided with a check valve 501, a pressure gauge 502 and several control valves 503; a pulse backwashing device 7 is provided on the main pipe between the secondary filter device 4 and the drip irrigation pipe 6, which is controlled by a solenoid valve and a timer to automatically backwash the filter device every 24 hours; a vortex debubbler 61 is provided at the water inlet end of the drip irrigation pipe 6, which destroys bubble aggregation through a rotating flow channel and reduces dripper clogging caused by air resistance.

[0025] The pulse backwash device can effectively prevent clogging of the filter device and ensure the normal operation of the drip irrigation system. The vortex debubbler destroys bubble accumulation through the rotating flow channel, reducing dripper blockage caused by air resistance and improving the uniformity and stability of drip irrigation.

[0026] Example 2

[0027] A method for preparing a red soil compaction reducing conditioner based on modified straw adsorbed carbon comprises the following steps: S1. Preparation of oyster shell-biochar composite powder: Fresh oyster shells were cleaned and calcined at 900° C. for 2.5 h to obtain oyster shell powder containing highly active calcium oxide. Modified straw adsorption carbon and rice husk powder were added to the oyster shell powder and mixed evenly to obtain a composite carrier. S2. Functional component loading: mixing the composite carrier with nano-dihydrate gypsum, adding polyglutamic acid solution, and mixing evenly to obtain a functional mixture; S3. Directed immobilization of microorganisms: immersing the functional mixture in a culture medium containing acid-resistant Bacillus, and culturing at 25° C. for 48 hours to form a microbial-mineral complex; S4. Sustained-release layer coating: Using fluidized bed coating technology, with the microbial mineral complex as the core, the following coating layers are sprayed in sequence: a) an inner layer of a sodium alginate and humic acid composite film with a thickness of 80 μm; b) an outer layer of a porous coating of attapulgite modified with carbide slag with a porosity of 60%; S5. Activation treatment: The coated particles are aged at 35°C and 80% relative humidity for 72 hours to allow microorganisms to colonize in the pores of the coating to obtain a red soil compaction reduction agent; The preparation process of the modified straw adsorption carbon is as follows: a) crushing the straw and then performing an amphoteric modification treatment, i.e., reacting the straw with 3-chloro-2-hydroxypropyltrimethylammonium chloride in an alkaline solution to graft cationic groups; b) reacting the straw with chloroacetic acid in a mixed solvent of ethanol and water to graft anionic groups to form an amphoteric adsorbent straw having both anions and cations; c) carbonizing the amphoteric adsorbent straw at a carbonization temperature of 500°C for 1 hour to obtain the modified straw adsorption carbon; The nano dihydrate gypsum is prepared by ultrafine grinding of phosphogypsum after microwave-assisted acid washing, and has a heavy metal content of 5 mg / kg, where the heavy metal is calculated as Pb; The preparation method of the carbide slag modified attapulgite is as follows: mixing carbide slag with attapulgite, calcining at 500° C. for 1.5 hours, and activating with 0.1 mol / L sulfuric acid solution to obtain the obtained product; The red soil compaction reduction conditioner comprises the following raw materials in parts by weight: 90 parts of oyster shell powder, 150 parts of modified straw adsorption carbon, 20 parts of rice husk powder, 40 parts of nano dihydrate gypsum, 150 parts of polyglutamic acid solution, 30 parts of acid-resistant Bacillus, 22 parts of sodium alginate, 45 parts of humic acid, 20 parts of carbide slag, and 45 parts of attapulgite.

[0028] The above-mentioned red soil compaction reducing conditioner based on modified straw adsorbed carbon is used in horticultural crop cultivation to improve red soil compaction. The specific method is as follows: (1) Soil pretreatment: The red soil hardness was tested by a soil hardness tester, and the penetration resistance was 28 kg / cm 2 Initiate conditioning agent application when (2) Layered application: evenly spread the red soil compaction reducing agent at 50 kg / mu on the surface layer, and till the soil to a depth of 20 cm; add an additional 20 kg / mu to the bottom of the planting hole in the root layer and mix it with the hole soil; (3) Start the drip irrigation system: Start the drip irrigation system after application, maintain the soil moisture content at 70%, and continue the action for 30 days.

[0029] When the horticultural crop is tea tree, it is applied after autumn pruning.

[0030] Example 3

[0031] A method for preparing a red soil compaction reducing conditioner based on modified straw adsorbed carbon comprises the following steps: S1. Preparation of oyster shell-biochar composite powder: Fresh oyster shells were cleaned and calcined at 1000° C. for 3 h to obtain oyster shell powder containing highly active calcium oxide. Modified straw adsorption carbon and rice husk powder were added to the oyster shell powder and mixed evenly to obtain a composite carrier. S2. Functional component loading: mixing the composite carrier with nano-dihydrate gypsum, adding polyglutamic acid solution, and mixing evenly to obtain a functional mixture; S3. Directed immobilization of microorganisms: immersing the functional mixture in a culture medium containing acid-resistant Bacillus, and culturing at 25° C. for 48 hours to form a microbial-mineral complex; S4. Sustained-release layer coating: Using fluidized bed coating technology, with the microbial mineral complex as the core, the following coating layers are sprayed in sequence: a) an inner layer of a sodium alginate and humic acid composite film with a thickness of 100 μm; b) an outer layer of a porous coating of attapulgite modified with carbide slag with a porosity of 60%; S5. Activation treatment: The coated particles are aged at 35°C and 80% relative humidity for 72 hours to allow microorganisms to colonize in the pores of the coating to obtain a red soil compaction reduction agent; The preparation process of the modified straw adsorption carbon is as follows: a. crushing the straw and then subjecting it to amphoteric modification treatment, i.e., reacting it with 3-chloro-2-hydroxypropyltrimethylammonium chloride in an alkaline solution to graft cationic groups; b. reacting it with chloroacetic acid in a mixed solvent of ethanol and water to graft anionic groups to form an amphoteric adsorbent straw with both anions and cations; c. carbonizing the amphoteric adsorbent straw at a carbonization temperature of 600°C for 2 hours to obtain the modified straw adsorption carbon; The nano dihydrate gypsum is prepared by ultrafine grinding of phosphogypsum after microwave-assisted acid washing, and has a heavy metal content of 5 mg / kg, where the heavy metal is calculated as Pb; The preparation method of the carbide slag modified attapulgite is as follows: mixing carbide slag with attapulgite, roasting at 600° C. for 2 hours, and activating with 0.1 mol / L sulfuric acid solution to obtain the obtained product; The red soil compaction reduction conditioner comprises the following raw materials in parts by weight: 90 parts of oyster shell powder, 150 parts of modified straw adsorption carbon, 20 parts of rice husk powder, 40 parts of nano dihydrate gypsum, 150 parts of polyglutamic acid solution, 30 parts of acid-resistant Bacillus, 22 parts of sodium alginate, 45 parts of humic acid, 20 parts of carbide slag, and 45 parts of attapulgite.

[0032] The above-mentioned red soil compaction reducing conditioner based on modified straw adsorbed carbon is used in horticultural crop cultivation to improve red soil compaction. The specific method is as follows: (1) Soil pretreatment: The red soil hardness was tested by a soil hardness tester, and the penetration resistance was 28 kg / cm 2 Initiate conditioning agent application when (2) Layered application: evenly spread the red soil compaction reducing agent at 40 kg / mu on the surface layer, and till the soil to a depth of 18 cm; add an additional 20 kg / mu to the bottom of the planting hole in the root layer and mix it with the hole soil; (3) Start the drip irrigation system: Start the drip irrigation system after application, maintain the soil moisture content at 65%, and continue the action for 30 days.

[0033] Wherein, the horticultural crop is citrus, and the application is selected 15 days before the germination of spring shoots, and the horticultural ground is covered with weed suppressant cloth.

[0034] Comparative Example 1 No modified straw adsorbed carbon was added, and other raw materials and amounts were the same as in Example 1. The preparation method was carried out according to the above steps. 2 ) was tested. The conditioner was evenly applied to the surface at a rate of 30 kg / mu, tilled to a depth of 15 cm. An additional 20 kg / mu was added to the bottom of the planting hole in the root zone and mixed thoroughly with the soil. After application, a drip irrigation system was activated, maintaining soil moisture at 60%, for 30 days.

[0035] The test data of Examples 1 to 3 and Comparative Example 1 are shown in Table 1.

[0036] Table 1

[0037] From the test data we can see that: Regarding soil compaction improvement: Examples 1-3, using the conditioner and drip irrigation system of the present invention, significantly reduced soil penetration resistance and significantly increased porosity, demonstrating effective reduction of red soil compaction. Comparative Example 1, which did not include the modified straw-adsorbed carbon, showed significantly poorer results.

[0038] In terms of soil acidity and alkalinity: Examples 1 to 3 can effectively adjust the soil pH value to make it closer to the range suitable for citrus growth, while the comparative example has a relatively weak adjustment effect.

[0039] Among them, soil porosity improvement rate is an important indicator to measure the degree of soil structure improvement. Its calculation formula and calculation steps are shown in formula (1): (1) The initial soil porosity was determined using the industry standard: NY / T 1121.22-2010 Soil Testing Part 22: Determination of Field Water Holding Capacity of Soils using the ring knife method.

[0040] Soil penetration resistance is an important indicator for measuring soil compaction and compaction conditions. Soil penetration resistance is measured using a soil compaction meter.

[0041] Although the present invention has been particularly shown and described in conjunction with preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims, and all such changes are within the scope of protection of the present invention.

Claims

1. A method for preparing a red soil compaction reducing conditioner based on modified straw adsorbed carbon, characterized in that: The following steps are involved: S1. Preparation of oyster shell-biochar composite powder: Fresh oyster shells are cleaned and calcined at 800-1000°C for 2-3 hours to obtain oyster shell powder containing highly active calcium oxide. Modified straw adsorption carbon and rice husk powder are added to the oyster shell powder and mixed evenly to obtain a composite carrier; S2. Functional component loading: mixing the composite carrier with nano-dihydrate gypsum, adding polyglutamic acid solution, and mixing evenly to obtain a functional mixture; S3. Directed immobilization of microorganisms: immersing the functional mixture in a culture medium containing acid-resistant Bacillus, and culturing at 25° C. for 48 hours to form a microbial-mineral complex; S4. Sustained-release layer coating: Using fluidized bed coating technology, with the microbial-mineral complex as the core, the following coating layers are sprayed in sequence: (a) an inner layer of a sodium alginate and humic acid composite film; (b) an outer layer of a porous coating of attapulgite modified with carbide slag; S5. Activation treatment: The coated particles are aged at 35°C and 80% relative humidity for 48-72 hours to allow microorganisms to colonize in the pores of the coating to obtain a red soil compaction reduction agent; The preparation process of the modified straw adsorption carbon is as follows: a. crushing the straw and then performing an amphoteric modification treatment, i.e., reacting the straw with 3-chloro-2-hydroxypropyltrimethylammonium chloride in an alkaline solution to graft cationic groups; b. reacting the straw with chloroacetic acid in a mixed solvent of ethanol and water to graft anionic groups to form an amphoteric adsorbent straw having both anions and cations; c. carbonizing the amphoteric adsorbent straw at a carbonization temperature of 400°C-600°C for 0.5h-2h to obtain the modified straw adsorption carbon; The nano dihydrate gypsum is prepared by ultrafine grinding of phosphogypsum after microwave-assisted acid washing, and the heavy metal content is ≤5 mg / kg, wherein the heavy metal is calculated as Pb; The preparation method of the carbide slag modified attapulgite is as follows: carbide slag and attapulgite are mixed, roasted at 400-600° C. for 1-2 hours, and activated with 0.1 mol / L sulfuric acid solution to obtain the mixture.

2. The red soil compaction reducing conditioner prepared by the method for preparing a red soil compaction reducing conditioner based on modified straw adsorbed carbon according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 80-100 parts of oyster shell powder, 100-200 parts of modified straw adsorption carbon, 10-30 parts of rice husk powder, 30-50 parts of nano dihydrate gypsum, 100-200 parts of polyglutamic acid solution, 10-50 parts of acid-resistant bacillus, 15-30 parts of sodium alginate, 30-60 parts of humic acid, 10-30 parts of carbide slag, and 30-60 parts of attapulgite.

3. The red soil compaction reducing conditioner prepared by the method for preparing a red soil compaction reducing conditioner based on modified straw adsorbed carbon according to claim 1, characterized in that: The red soil compaction reduction conditioner is formed by coating a microbial mineral complex, wherein the coating layer comprises an inner layer and an outer layer; the inner layer is a sodium alginate and humic acid composite film, and the outer layer is a porous coating of attapulgite modified by carbide slag.

4. The red soil compaction reducing agent prepared by the method for preparing a red soil compaction reducing agent based on modified straw adsorbed carbon according to claim 3, characterized in that: The thickness of the inner layer is 50 μm-100 μm, and the porosity of the outer layer is ≥60%.

5. The use of the red soil compaction reducing conditioner prepared by the method for preparing the red soil compaction reducing conditioner based on modified straw adsorbed carbon according to claim 1, characterized in that: It is used in horticultural crop planting to improve red soil compaction. The specific methods are: (1) Soil pretreatment: Use a soil hardness tester to test the compaction degree of red soil. When the penetration resistance is greater than 25kg / cm 2 Initiate conditioning agent application when (2) Layered application: evenly spread the red soil compaction reducing agent at 30-50 kg / mu on the surface layer, and till the soil to a depth of 15-20 cm; add an additional 20 kg / mu to the bottom of the planting hole in the root layer and mix it with the hole soil; (3) Start the drip irrigation system: Start the drip irrigation system after application, maintain the soil moisture content at 60%-70%, and continue the action for 30 days.

6. The use of the red soil compaction reducing conditioner prepared by the method for preparing the red soil compaction reducing conditioner based on modified straw adsorbed carbon according to claim 5, characterized in that: When the horticultural crop is citrus, the application is carried out 15 days before the spring shoots sprout, and the horticultural ground is covered with weed suppressant cloth.

7. The use of the red soil compaction reducing agent prepared by the method for preparing the red soil compaction reducing agent based on modified straw adsorbed carbon according to claim 5, characterized in that: When the horticultural crop is tea tree, it is applied after autumn pruning.

8. The use of the red soil compaction reducing agent prepared by the method for preparing the red soil compaction reducing agent based on modified straw adsorbed carbon according to claim 5, characterized in that: The drip irrigation system includes an irrigation pool, a fertilizing device, a primary filter device, a secondary filter device, a connection system, and several drip irrigation pipes. The irrigation pool, fertilizing device, primary filter device, secondary filter device and drip irrigation pipes are connected by the connection system; the connection system includes a main pipe and a branch pipe; the branch pipe is connected to the several drip irrigation pipes, and the connection system is provided with a check valve, a pressure gauge and several control valves; the main pipe between the secondary filter device and the drip irrigation pipe is provided with a pulse backwash device, which is controlled by a solenoid valve and a timer and automatically backwashes the filter device every 24 hours; the water inlet end of the drip irrigation pipe is provided with a vortex debubbler, which destroys bubble aggregation through a rotating flow channel and reduces dripper blockage caused by air resistance.

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