A soil conditioner for acidified soil remediation and a method of preparing the same

Abstract

The application provides a soil conditioner for acidification soil remediation and a preparation method thereof, and belongs to the technical field of soil conditioners. The soil conditioner for acidification soil remediation is prepared from the following raw materials in parts by weight: 25-30 parts of mature organic matter, 15-23 parts of calcined alkaline residue powder, 20-30 parts of biochar-based composite material, 6-13 parts of microbial inoculum and 10-20 parts of bio-based adhesive. The soil conditioner for acidification soil remediation can improve the imbalance of acidification soil and relieve the acidification process.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of soil conditioners, and particularly relates to a soil conditioner for acidification soil remediation and a preparation method thereof. BACKGROUND

[0002] Soil is the most basic production material for obtaining food and other agricultural products. All high-quality and high-yield crop production must rely on safe, fertile and coordinated soil. Long-term unreasonable cultivation system and excessive application of nitrogen fertilizer greatly accelerate the acidification process of soil. Soil acidification is a manifestation of soil degradation, and its essence is the process of increasing the concentration of H + and reducing the concentration of base ions in the surface soil, and the fundamental reason is that the "production" and "consumption" of H + in the soil H + cycle are unbalanced, and the "production" is more than the "consumption". According to existing research, the results of soil acidification include the following aspects: ① Acid soil contains a large amount of H 3+ and Al 3+ , the adsorption capacity of these two ions is stronger than that of base ions, resulting in the loss of base ions, which significantly reduces soil fertility, and aluminum toxicity harms plants and inhibits plant growth, affecting crop quality; ② After soil acidification, some original microbial communities are inhibited, and some acidophilic or acid-tolerant harmful microorganisms (such as some acidophilic denitrifying bacteria) populations rapidly increase; ③ After soil acidification, acidophilic soil nematodes will rapidly reproduce and cause more harm to crop roots; ④ Soil acidification also promotes the activation and dissolution of heavy metal ions, and many studies have shown that soil pH is significantly related to the bioavailability of heavy metals in soil. More effective heavy metals continue to pollute water sources, and these heavy metals may harm human health through the enrichment of the food chain.

[0003] At present, soil acidification in China is showing a trend of occurring throughout the country, which has a negative impact on crop yield, agricultural product quality and biodiversity. Since the 1950s, China has carried out a lot of work on acid soil and achieved remarkable results, but due to the unknown details of acid soil distribution in China, the controversy over the mechanism of soil acidification, the lack of stress-tolerant crop varieties, the unclear acid damage threshold of crops, and the poor landing of improvement products and technologies, the use of acid soil is still greatly limited. Due to the influence of human activities, the progress of soil acidification is still accelerating, and the degree of acidification is increasing, so it is urgent to improve acidified soil and slow down the process of soil acidification.

[0004] Among the various strategies to cope with soil acidification, the application of acid soil conditioner is considered an effective method. However, the promotion and innovation of soil conditioner still face many difficulties and challenges. Now many soils often face the problems of heavy metal pollution, soil acidification / salinity, nutrient imbalance, structure imbalance and other complex problems, which often exist at the same time and need to be solved at the same time. However, the traditional acid soil conditioner mostly directly uses quicklime, slaked lime and limestone powder, which has a significant effect on increasing pH, but long-term application may lead to potential "secondary calcification" or re-acidification risk; in addition, oyster shells are also widely used due to their easy acquisition, low price and environmental friendliness, but they have potential heavy metal risks. Therefore, a "package" solution to various soil degradation problems can be provided, and soil conditioners with higher safety factors can better meet current needs. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a soil conditioner for acid soil remediation, which can improve the imbalance of acid soil and alleviate the acidification process.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is:

[0007] A soil conditioner for acid soil remediation is prepared from the following raw materials by weight: 25-30 parts of composted organic matter, 15-23 parts of calcined alkaline slag powder, 20-30 parts of biochar-based composite material, 6-13 parts of microbial inoculant and 10-20 parts of bio-based adhesive.

[0008] Optionally, the soil conditioner for acid soil remediation is prepared from the following raw materials by weight: 28 parts of composted organic matter, 20 parts of calcined alkaline slag powder, 27 parts of biochar-based composite material, 10 parts of microbial inoculant and 15 parts of bio-based adhesive.

[0009] Optionally, the preparation method of the composted organic matter is: crushing tea waste and straw, blending with biogas residue, adding EM inoculant, and preparing by high-temperature composting, wherein: the mass ratio of tea waste, straw and biogas residue is (1-2):2:1, and the addition amount of EM inoculant is 1-2% of the total mass of tea waste, straw and biogas residue.

[0010] Optionally, the calcined alkaline slag powder is a mixture formed by high-temperature calcination of alkaline slag, lime slag and gypsum powder, wherein: the mass ratio of alkaline slag, lime slag and gypsum powder is 1:(2-3):(1-2), and the calcined alkaline slag powder contains the following chemical components by mass percentage: CaO 40-50%, SiO2 25-35%, Al2O3 10-20%, MgO 3-5%, Fe2O3 0.5-3.0%, MnO 0.5-1.5%, and pH: 10-12.

[0011] Optionally, the biochar-based composite material is a composite material formed by loading the biochar with mineral powder, the mineral powder is one or more than two of fly ash, coal gangue, silicon manganese slag powder, iron tailings powder, and gypsum powder, and the biochar is a product obtained by high-temperature decomposition of at least one of straw, rice husk, tea waste, and peanut shell.

[0012] Optionally, the preparation method of the biochar-based composite material comprises the following steps:

[0013] mineral powder is calcined at a high temperature of 650-700°C for 2-3 hours to obtain mineral calcined powder;

[0014] the biochar is mixed with the mineral calcined powder, water is added, ultrasonic treatment is performed, and drying is performed to obtain mixed powder;

[0015] the mixed powder is pyrolyzed at 600-630°C under the protection of inert gas for 40-50 minutes to obtain the biochar-based composite material.

[0016] Optionally, the microbial agent is a composite microbial agent of Rhodovulum sulfidophilum, sulfate-reducing bacteria, and Bacillus velezensis, and the mass ratio of the three is 1:2:(2-3), and the total viable bacterial count of the microbial agent is ≥10 8 cfu / g.

[0017] Optionally, the bio-based binder is pregelatinized starch or molasses liquid.

[0018] The application further provides a preparation method of a soil conditioner for acidified soil remediation, specifically comprising the following steps:

[0019] S11, preparing composted organic matter, specifically: crushing tea waste and straw, blending with biogas residue, adding an EM microbial agent, and preparing by high-temperature composting, and airing to control the water content to be less than 10%;

[0020] S12, mixing the calcined alkaline residue powder with the composted organic matter, adding a first part of bio-based binder, granulating, and drying to obtain a first granule;

[0021] S13, mixing the biochar-based composite material, a second part of bio-based binder, and the first granule, granulating, and drying to obtain a second granule;

[0022] S14: mixing the microbial agent, a third part of bio-based binder, and the second granule, granulating, drying to control the water content to be less than 5%, and screening to obtain the soil conditioner.

[0023] Optionally, the mass ratio of the first part of bio-based binder, the second part of bio-based binder, and the third part of bio-based binder is 6:3:1.

[0024] Compared with the prior art, the present application has the following advantages:

[0025] The acidified soil conditioner is prepared by organically combining rotten organic matter, calcined alkaline residue powder, biochar-based composite material and microbial inoculum, which can avoid the potential risks of long-term single use of alkaline residue powder (such as quicklime, slaked lime and limestone powder) on the soil, and can be used for a long time to improve the imbalance of acidified soil and slowly increase the pH value of the soil, and on the other hand, the solid waste resources can be fully utilized to improve the soil fertility and promote the multiplication of beneficial microorganisms in the soil.

[0026] The humic organic matter is prepared by composting tea waste, straw and biogas residue, the microorganisms in the EM microbial agent can rapidly reproduce, decompose the organic matter in the tea waste, straw and biogas residue, produce biological heat energy, and increase the temperature of the composting material, thereby accelerating the composting decomposition process; under the action of high temperature, the EM microbial agent can inhibit or kill harmful organisms such as pathogens and insect eggs, thereby reducing the risk of pathogens and pests; in the humification process, the EM microbial agent can help release the effective nutrients such as nitrogen, phosphorus, potassium and trace elements in the tea waste, straw and biogas residue, and can absorb and decompose odorous and harmful substances, thereby improving the odor and safety of the compost; the composting process is accelerated, and the composting period is shortened; after being applied to the soil, the EM microbial agent can improve the soil environment, inhibit harmful microorganisms, and enrich beneficial microorganisms; therefore, the humic organic matter is more comprehensive in nutrients, rich in organic matter and microorganisms, can improve the soil aggregate structure, increase the water retention and air permeability of the soil, and also contains various nutrient elements required for crop growth, such as nitrogen, phosphorus, potassium and the like, thereby improving the soil fertility. The calcined alkaline residue powder is prepared by calcining the alkaline residue powder, the chemical components contained in the alkaline residue powder are more easily utilized by crops, the porosity is increased, the activity is enhanced, and the alkalinity is higher; when the humic organic matter is mixed with the calcined alkaline residue powder, the nutrient components in the humic organic matter can be absorbed by the pores on the surface of the calcined alkaline residue powder, and the calcined alkaline residue powder can be used as the core component of the granular agent; when the granular agent is applied to the soil, the nutrient components can be slowly released in a long-term use, and the alkalinity of the soil can be improved, thereby conditioning the soil. The biological carbon-based composite material is a composite material formed by loading the mineral powder on the biological carbon, which is used as the coating material of the core, thereby further enhancing the nutrient and slow-release conditioning performance of the composite material. The microbial agent is a composite microbial agent of S. luteola, SRB and B. velezensis; the S. luteola has multiple effects such as disease resistance and pest resistance, can secrete beneficial components, is beneficial to crop growth, and is conducive to forming a beneficial cycle among the conditioning agent, the soil and the effects; the SRB can reduce the sulfate in the soil to generate sulfur, the sulfur can form sulfide with heavy metal ions to fix the heavy metal ions, thereby reducing the activity of the heavy metals in the soil and enabling the soil fertility to be more fully released; the B. velezensis has strong adaptability, can survive in acidic soil, can secrete various extracellular enzymes (protease, amylase and cellulase), can make the conversion of cellulose, hemicellulose and starch possible, has significant antibacterial ability, and can promote plant growth, thereby improving the inhibitory effect of the acidic soil on crop growth.

[0027] It is known that the soil microbial group, organic matter and aggregate structure are an interaction, indispensable balance system, which determines the soil fertility and environment. Once the beneficial microorganisms are reduced, the structure is destroyed, and the soil quality is decreased, the crops lose the source of life, not only the diseases increase, it is difficult to obtain high yield, but also the service life of arable land is reduced. Therefore, the soil conditioning has the characteristics of integrity, system and time. After the soil conditioner of the application is applied to the soil, the beneficial bacteria are first in command, the dominant bacterial group is formed around the soil or plant root system, the harmful bacteria in the soil are excluded and inhibited, so that the pathogenic microorganisms are difficult to reproduce; the biological base adhesive and internal components are slowly released and decomposed in the complex soil system, so that a small beneficial circle is formed in the soil, after a certain time of improvement, the beneficial circle is continuously expanded and enhanced, and finally the overall environment of the soil is improved. DETAILED DESCRIPTION

[0028] For better understanding of the present application, the content of the present application is further clarified below in combination with examples, but the protection content of the present application is not limited to the following examples. In the following description, a large number of specific details are given in order to provide a more thorough understanding of the present application. However, it is obvious to those skilled in the art that the present application can be implemented without one or more of these details.

[0029] All other examples obtained by those skilled in the art on the basis of the examples in the present application without creative labor belong to the scope of protection of the present application.

[0030] In all examples shown and discussed herein, any specific value is to be interpreted as merely exemplary and not as a limitation. Thus, other examples of the example embodiments can have different values.

[0031] Unless otherwise specified, all raw materials are obtained from commercially available products, and unless otherwise specified, do not contain other components other than unavoidable impurities without explicit indication.

[0032] In the following cases, the preservation number of Rhodovulum sulfidophilum is CCTCC NO: M2012369, the preservation number of sulfate-reducing bacteria is CGMCC No. 10072, and the preservation number of Bacillus velezensis is CGMCC No. 30372, which are existing available strains, and the corresponding viable bacterial agent in the range can be prepared by known culture method.

[0033] The tea waste, straw, biogas residue, rice husk and peanut shell are all materials after natural drying or drying processing, and the water content is less than 15%. Among them, the tea waste is the waste such as old leaves and tea stems generated in the process of tea tree planting and processing.

[0034] The particle size of alkaline slag, lime slag, gypsum powder, fly ash, coal gangue, ferromanganese slag powder, and iron tailings powder is less than 300 mesh.

[0035] Example 1 A soil conditioner for the remediation of acidified soil is made from the following raw materials in parts by weight: 28 parts of decomposed organic matter, 20 parts of calcined alkaline slag powder, 27 parts of biochar-based composite material, 10 parts of microbial inoculant, and 15 parts of bio-based binder.

[0036] The method for preparing decomposed organic matter is as follows: tea waste and straw are crushed, mixed with biogas residue, EM agent is added, and composted at high temperature. The mass ratio of tea waste, straw and biogas residue is 1:2:1, and the amount of EM agent added is 1.5% of the total mass of tea waste, straw and biogas residue.

[0037] Calcined alkaline slag powder is a mixture formed by calcining alkaline slag, lime slag, and gypsum powder at 650℃ for 1 hour. The mass ratio of alkaline slag, lime slag, and gypsum powder is 1:2:1. The calcined alkaline slag powder contains the following chemical components by mass percentage: CaO 42.3%, SiO2 28.6%, Al2O3 15.3%, MgO 4.2%, Fe2O3 1.4%, MnO 0.7%, pH: 11.6.

[0038] The biochar-based composite material is a composite material formed by loading mineral powder onto biochar. The mineral powder is ferrosilicon manganese slag powder, and the biochar is a product obtained by decomposing straw at high temperature (500℃, 3h). The preparation method of the biochar-based composite material is as follows: the mineral powder is calcined at 700℃ for 2h to obtain calcined mineral powder; the biochar and calcined mineral powder are mixed, water is added, ultrasonic treatment (25kHz, 30min) is performed, and the mixture is dried to obtain a mixed powder; the mixed powder is pyrolyzed at 620℃ for 45min under inert gas N2 protection to obtain the biochar-based composite material.

[0039] The microbial agent is a compound of sulfur-loving red oomycetes, sulfate-reducing bacteria, and Bacillus belye, with a mass ratio of 1:2:2. The total viable count of the microbial agent is ≥10. 8 cfu / g.

[0040] The bio-based binder is pregelatinized starch.

[0041] A method for preparing a soil conditioner for acidified soil remediation specifically includes the following steps:

[0042] S11. Preparation of decomposed organic matter, specifically: crush tea waste and straw, mix with biogas residue, add EM bacteria, compost at high temperature, spread out to dry, and control the moisture content to below 10%.

[0043] S12. The calcined alkaline slag powder is mixed with the decomposed organic matter, the first part of the bio-based binder is added, granulated, and dried to obtain the first granule.

[0044] S13. Mix the biochar-based composite material, the second part of the bio-based adhesive and the first granule, granulate, and dry to obtain the second granule.

[0045] S14: Mix the microbial inoculant, the third part of the bio-based binder, and the second granule, granulate, dry, control the moisture content to be below 5%, and sieve to obtain the soil conditioner.

[0046] The mass ratio of the first part of the bio-based adhesive, the second part of the bio-based adhesive, and the third part of the bio-based adhesive is 6:3:1.

[0047] The above granulation method uses disc granulation, and natural air drying is selected for drying.

[0048] Example 2 A soil conditioner for the remediation of acidified soil is made from the following raw materials in parts by weight: 25 parts of decomposed organic matter, 23 parts of calcined alkaline slag powder, 30 parts of biochar-based composite material, 12 parts of microbial inoculant, and 10 parts of bio-based binder.

[0049] The method for preparing decomposed organic matter is as follows: tea waste and straw are crushed, mixed with biogas residue, EM microbial agent is added, and composted at high temperature. The mass ratio of tea waste, straw and biogas residue is 1.5:2:1, and the amount of EM microbial agent added is 1% of the total mass of the tea waste, straw and biogas residue.

[0050] Calcined alkaline slag powder is a mixture formed by calcining alkaline slag, lime slag, and gypsum powder at 650℃ for 1 hour. The mass ratio of alkaline slag, lime slag, and gypsum powder is 1:2.5:1. The calcined alkaline slag powder contains the following chemical components by mass percentage: CaO 40.5%, SiO2 30.6%, Al2O3 12.4%, MgO 4.7%, Fe2O3 2.6%, MnO 1.5%, pH: 10.6.

[0051] Biochar-based composite materials are composite materials formed by loading mineral powder onto biochar. The mineral powder is iron tailings powder, and the biochar is a product obtained by decomposing rice husks at high temperature (500℃, 3h).

[0052] The preparation method of biochar-based composite material is as follows: mineral powder is calcined at 680℃ for 2 hours to obtain calcined mineral powder; biochar and calcined mineral powder are mixed, water is added, ultrasonic treatment (30kHz, 30min) is performed, and dried to obtain mixed powder; the mixed powder is pyrolyzed at 630℃ for 40min under inert gas N2 protection to obtain biochar-based composite material.

[0053] The microbial agent is a compound microbial agent of Rhodovulum sulfidophilum, sulfate-reducing bacteria and Bacillus velezensis, and the mass ratio of the three is 1:2:2.5, and the total viable bacterial count of the microbial agent is ≥10 8 cfu / g.

[0054] The bio-based adhesive is molasses liquid.

[0055] The preparation method of the soil conditioner for acidified soil remediation is described in Example 1.

[0056] Example 3 A soil conditioner for acidified soil remediation is prepared from the following raw materials by weight: 30 parts of composted organic matter, 17 parts of calcined alkaline slag powder, 20 parts of biochar-based composite material, 13 parts of microbial agent and 20 parts of bio-based adhesive.

[0057] The preparation method of the composted organic matter is as follows: tea waste and straw are crushed, blended with biogas residue, and added with EM microbial agent to produce high-temperature compost, wherein the mass ratio of the tea waste, straw and biogas residue is 2:2:1, and the amount of the EM microbial agent added is 2% of the total mass of the tea waste, straw and biogas residue.

[0058] The calcined alkaline slag powder is a mixture formed by calcining alkaline slag, lime slag and gypsum powder at a high temperature of 650℃ for 1h, wherein the mass ratio of the alkaline slag, lime slag and gypsum powder is 1:3:1.5, and the calcined alkaline slag powder contains the following chemical components in the following mass percentages: CaO 48.1%, SiO2 26.3%, Al2O3 10.7%, MgO 3.8%, Fe2O3 0.7%, MnO 1.4%, and pH: 11.7.

[0059] The biochar-based composite material is a composite material formed by loading mineral powder on biochar, wherein the mineral powder is fly ash and gypsum powder, and the mass ratio of the two is 1:1, and the biochar is a product obtained by decomposing tea waste at a high temperature (400℃, 3h).

[0060] The preparation method of the biochar-based composite material is as follows: the mineral powder is calcined at a high temperature of 650℃ for 3h to obtain mineral calcined powder; the biochar is mixed with the mineral calcined powder, water is added, ultrasonic treatment (30kHz, 25min) is performed, and drying is performed to obtain a mixed powder; the mixed powder is pyrolyzed at 600℃ for 50min under the protection of inert gas N2 to obtain the biochar-based composite material.

[0061] The microbial agent is a compound microbial agent of Rhodovulum sulfidophilum, sulfate-reducing bacteria and Bacillus velezensis, and the mass ratio of the three is 1:2:3, and the total viable bacterial count of the microbial agent is ≥10 8 cfu / g.

[0062] The bio-based adhesive is pre-gelatinized starch.

[0063] The preparation method of the soil conditioner for acidified soil remediation is referred to Example 1.

[0064] Example 4 The soil conditioner for acidified soil remediation is prepared from the following raw materials in parts by weight: 29 parts of matured organic matter, 15 parts of calcined alkaline residue powder, 30 parts of biochar-based composite material, 9 parts of microbial agent, and 17 parts of bio-based binder.

[0065] The biochar-based composite material is a composite material formed by loading mineral powder on biochar, the mineral powder is a mixture of coal gangue and silicon-manganese slag powder, the mass ratio of the two is 1:1, and the biochar is a product obtained by high-temperature decomposition of straw and peanut shells (mass ratio 1:1).

[0066] The remaining parameters and processes not mentioned are referred to Example 1.

[0067] Example 5 The soil conditioner for acidified soil remediation is prepared from the following raw materials in parts by weight: 30 parts of matured organic matter, 21 parts of calcined alkaline residue powder, 25 parts of biochar-based composite material, 6 parts of microbial agent, and 18 parts of bio-based binder.

[0068] The biochar-based composite material is a composite material formed by loading mineral powder on biochar, the mineral powder is a mixture of silicon-manganese slag powder, iron tailings powder, and gypsum powder, the mass ratio of the three is 1:1:2, and the biochar is a product obtained by high-temperature decomposition of straw and tea waste (mass ratio 2:1).

[0069] The remaining parameters and processes not mentioned are referred to Example 1.

[0070] Example 6 The biochar-based composite material is a composite material formed by loading mineral powder on biochar, the mineral powder is gypsum powder, and the biochar is a product obtained by high-temperature decomposition of a mixture of straw, rice husk, tea waste, and peanut shells, the mass ratio of the four is 2:1:1:1.

[0071] Comparative Example 1 The preparation method of the matured organic matter is as follows: the straw is crushed, mixed, and EM microbial agent is added, and then high-temperature composting is performed, wherein: the addition amount of the EM microbial agent is 1.5% of the total mass of the straw.

[0072] Comparative Example 2 The calcined alkaline residue powder is replaced by a mixture of alkaline slag powder, lime slag powder, and gypsum powder, which is not subjected to calcination treatment, and the mass ratio of the alkaline slag powder, lime slag powder, and gypsum powder is 1:2:1.

[0073] Comparative Example 3 : Different from example 1, the calcined alkaline residue powder is replaced by lime residue powder calcined at 650℃ for 1h to form the product.

[0074] Comparative Example 4 : Different from example 1, the biochar-based composite material is replaced by biochar, which is a product obtained by decomposing straw at high temperature (500℃, 3h).

[0075] Comparative Example 5 : Different from example 1, the microbial agent is Rhodovulum sulfidophilum.

[0076] Comparative Example 6 : Different from example 1, the microbial agent is sulfate-reducing bacteria.

[0077] Comparative Example 7 : Different from example 1, the microbial agent is Bacillus velezensis.

[0078] In order to further prove the effect of the acidified soil conditioner prepared by the present application, the following tests are carried out on the soil conditioners prepared in examples 1-6 and comparative examples 1-7.

[0079] 1. Prepare 14 groups of acidified soil samples under the same conditions, with 3 parallels in each group, and the weight of soil in each parallel is 1 kg. Add the corresponding soil conditioner (30g conditioner / kg soil) to each group of samples, mix uniformly, and set up a blank control group (CK) without adding conditioner. Cultivate under the set experimental conditions (temperature 25℃, relative humidity 55%) for 90 days. Take samples at 0th day, 45th day and 90th day, and measure the soil pH. The experimental data are shown in the following table:

[0080]

[0081] The above results show that the above soil conditioners can all improve the pH of the soil, and the pH improvement range of the examples of the present application is higher than that of the comparative examples, and the effect is more obvious.

[0082] 2. Select typical acidified yellow-brown soil in Xinyang City, Henan Province to carry out field test, and plant tea trees as crops. The dosage of the conditioner is 200kg / acre, and a blank control group (CK) is set without adding soil conditioner. The experimental period is 6 months, and the related parameters of soil properties are measured at the end of the experimental period, as shown in the following table.

[0083]

[0084] The test results show that the treatment of the application is more beneficial to the increase of the soil pH, and the soil pH value is increased by about 1.2 after 6 months of application, and the increase effect is remarkable. Under the same pH condition, the practical application effect of the soil conditioner of the application is enhanced with the extension of time, which may be because the soil environment in the practical application is in an open cycle, which is more conducive to the interaction of various components, which further shows that the soil conditioner of the application has a good mutual cooperation and promotion effect with the soil and crops in the actual application, so that the improvement and increase effect of the soil acidity is more outstanding. Secondly, after the application of the soil conditioner of the application, the exchange acid content of the soil is obviously decreased; the alkali hydrolysis nitrogen, available phosphorus, available potassium and organic matter contents are obviously increased in different degrees. The above results show that the soil conditioner of the application has a conditioning effect on the acidified soil, can significantly increase the soil pH value, and make it tend to be in the normal range; and can increase different nutrients in the soil, and better meet the growth demand of crops.

[0085] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the application but not limit the application, and other modifications or equivalent replacements of the technical solutions of the application made by those skilled in the art should be covered in the scope of the claims of the application, as long as they do not deviate from the spirit and scope of the technical solutions of the application.

Claims

1. A soil conditioner for use in acidified soil remediation, characterised in that: The soil conditioner is prepared from the following raw materials by weight: 28 parts of decomposed organic matter, 20 parts of calcined alkaline slag powder, 27 parts of biochar-based composite material, 10 parts of microbial inoculant, and 15 parts of bio-based binder. The preparation method of the decomposed organic matter comprises the following steps: crushing tea waste and straw, blending with biogas residue, adding EM microbial inoculant, and preparing by high-temperature composting, wherein the mass ratio of the tea waste, straw and biogas residue is (1-2):2:1, and the addition amount of the EM microbial inoculant is 1-2% of the total mass of the tea waste, straw and biogas residue. The calcined alkaline slag powder is a mixture formed by high-temperature calcination of alkaline slag, lime slag and gypsum powder, wherein the mass ratio of the alkaline slag, lime slag and gypsum powder is 1:(2-3):(1-2). The biochar-based composite material is a composite material formed by loading mineral powder on biochar, wherein the mineral powder is one or more than two of fly ash, coal gangue, silicon manganese slag powder, iron tailings powder and gypsum powder, and the biochar is a product obtained by high-temperature decomposition of at least one of straw, rice husk, tea waste and peanut shell, and the preparation method of the biochar-based composite material comprises the following steps: high-temperature calcination of the mineral powder at 650-700 DEG C for 2-3 hours to obtain mineral calcined powder; mixing the biochar with the mineral calcined powder, adding water, ultrasonic treatment, drying to obtain a mixed powder; pyrolysis of the mixed powder at 600-630 DEG C under inert gas protection for 40-50 minutes to obtain the biochar-based composite material. The microbial inoculant is a composite inoculant of S. luteola, sulfate-reducing bacteria and Bacillus velezensis, and the mass ratio of the three is 1:2:(2-3).

2. A soil conditioner for acidified soil remediation as claimed in claim 1, characterized in that: The soil conditioner is prepared from the following raw materials by weight: 28 parts of decomposed organic matter, 20 parts of calcined alkaline slag powder, 27 parts of biochar-based composite material, 10 parts of microbial inoculant, and 15 parts of bio-based binder.

3. A soil conditioner for acidified soil remediation as claimed in claim 2, characterised in that: The calcined alkaline slag powder contains the following chemical components by mass percentage: CaO 40-50%, SiO2 25-35%, Al2O3 10-20%, MgO 3-5%, Fe2O3 0.5-3.0%, MnO 0.5-1.5%, and pH: 10-12.

4. A soil conditioner for acidified soil remediation as claimed in claim 3, characterised in that: The total viable bacterial count of the microbial inoculant is ≥ 10 8 cfu / g.

5. A soil conditioner for acidified soil remediation as claimed in claim 4, characterised in that: The bio-based binder is pre-gelatinized starch or molasses liquid.

6. A method of preparing a soil conditioner for acidified soil remediation as claimed in any one of claims 1 to 5, characterised in that: Specifically comprises the following steps: S11, preparing decomposed organic matter, specifically: crushing tea waste and straw, blending with biogas residue, adding EM microbial inoculant, and preparing by high-temperature composting, airing, and controlling the water content to be below 10%; S12, mixing the calcined alkaline slag powder with the decomposed organic matter, adding the first part of bio-based binder, granulating, drying to obtain the first granules; S13, mixing the biochar-based composite material, the second part of bio-based binder with the first granules, granulating, drying to obtain the second granules; S14: mixing the microbial inoculant, the third part of bio-based binder with the second granules, granulating, drying, controlling the water content to be below 5%, screening to obtain the soil conditioner.

7. A method of preparing a soil conditioner for acidified soil remediation as claimed in claim 6, characterised in that: The mass ratio of the first part of bio-based binder, the second part of bio-based binder and the third part of bio-based binder is 6:3:1.

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