Soil conditioner for acidified soil remediation and preparation method thereof

Abstract

The invention provides a soil conditioner for acidified soil remediation and a preparation method thereof, and belongs to the technical field of soil conditioners. The invention discloses a soil conditioner for acidified soil remediation. The soil conditioner is prepared from the following raw materials in parts by weight: 25-30 parts of decomposed organic matters, 15-23 parts of calcined alkaline slag powder, 20-30 parts of a biochar-based composite material, 6-13 parts of a microbial agent and 10-20 parts of a bio-based adhesive. According to the soil conditioner for acidified soil remediation, the unbalance state of acidified soil is improved, and the acidification process is relieved.

Description

Technical Field

[0001] The invention belongs to the technical field of soil conditioners, and in particular relates to a soil conditioner for repairing acidified soil and a preparation method thereof. Background Art

[0002] Soil is the most basic means of production for obtaining food and other agricultural products. The production of all high-quality and high-yield crop varieties must rely on safe, fertile and harmonious soil. Long-term unreasonable farming systems and excessive application of nitrogen fertilizers have greatly accelerated the acidification process of soil. Soil acidification is a manifestation of soil degradation. Its essence is the H + The process of increasing concentration and decreasing base ions is caused by H + In the cycle, "production" and "consumption" are unbalanced, and "production" is greater than "consumption". According to existing research, the consequences of soil acidification include the following aspects: ① Acidic soil contains a large amount of H + and Al 3+ , the adsorption capacity of these two ions is stronger than that of base ions, resulting in the leaching of base ions, which significantly reduces soil fertility. At the same time, aluminum toxicity harms plants, inhibits plant growth, and affects the quality of crops; ② Soil microorganisms mainly include bacteria, fungi and actinomycetes. After soil acidification, some original microbial communities are inhibited, and the populations of some acid-loving or acid-resistant harmful microorganisms (such as some acidophilic denitrifying bacteria) increase rapidly; ③ After soil acidification, root-knot nematodes in acidic soils will reproduce rapidly, aggravating the harm to crop roots; ④ Soil acidification will also promote the activation and dissolution of heavy metal ions. Many studies have shown that soil pH is significantly correlated with the bioavailability of heavy metals in the soil. More effective heavy metals continue to pollute water sources after leaching, and these heavy metals may endanger human health through enrichment in the food chain.

[0003] At present, soil acidification in my country is showing a trend of widespread occurrence across the country, which has adverse effects on crop yields, agricultural product quality and biodiversity. Since the 1950s, my country has carried out a lot of work on acidic soils and achieved remarkable results. However, due to the unclear distribution details of acidic soils in my country, the controversial mechanism of soil acidification, the lack of stress-resistant crop varieties, the unclear threshold of crop acid damage, and the poor implementation of improved products and technologies, the use of acidic soils is still greatly restricted. Due to the influence of human activities, the progress of soil acidification is still accelerating and the degree of acidification is increasing. Therefore, it is urgent to improve acidified soils and alleviate the process of soil acidification.

[0004] Among the various strategies for dealing with soil acidification, the application of acidic soil conditioners is considered to be an effective method. However, the promotion and innovation of soil conditioners still face many difficulties and challenges. Nowadays, many soils often face complex problems such as heavy metal pollution, soil acidification / salinization, nutrient imbalance, structural imbalance, etc. These problems often exist at the same time and need to be solved at the same time. Most traditional acidic soil conditioners directly use quicklime, slaked lime and limestone powder, which have a significant effect on improving pH, but long-term application leads to potential "sub-ashing" or re-acidification risks in the soil; in addition, oyster shells are also widely used because of their easy access, low price and environmental friendliness, but they have potential heavy metal risks. Therefore, a variety of soil degradation problems can be solved in one package, and the application of soil conditioners with a higher safety factor can better meet current needs. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a soil conditioner for acidified soil repair in view of the deficiencies of the prior art, so as to improve the imbalance state of acidified soil and alleviate the acidification process.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: A soil conditioner for acidified soil remediation is prepared from the following raw materials in parts by weight: 25-30 parts of decomposed organic matter, 15-23 parts of calcined alkaline slag powder, 20-30 parts of biochar-based composite materials, 6-13 parts of microbial agents and 10-20 parts of bio-based adhesives.

[0007] Optionally, the soil conditioner for acidified soil remediation is made of 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 materials, 10 parts of microbial agents and 15 parts of bio-based adhesives.

[0008] Optionally, the method for preparing the decomposed organic matter is: crushing tea waste and straw, mixing them with biogas residue, adding EM bacterial agent, and making it through high-temperature composting, wherein: the mass ratio of the tea waste, straw and biogas residue is (1~2):2:1, and the amount of the EM bacterial agent added is 1~2% of the total mass of the tea waste, straw and biogas residue.

[0009] 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 in mass percentage: CaO 40~50%, SiO2 25~35%, Al2O3 10~20%, MgO 3~5%, Fe2O3 0.5~3.0%, MnO 0.5~1.5%, pH: 10~12.

[0010] Optionally, the biochar-based composite material is a composite material formed by biochar loaded with mineral powder, the mineral powder is one or more of fly ash, coal gangue, silicomanganese 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 husks, tea waste and peanut shells.

[0011] Optionally, the preparation method of the biochar-based composite material is: The mineral powder is calcined at 650-700°C for 2-3 hours to obtain the mineral calcined powder; The biochar is mixed with the mineral calcined powder, water is added, ultrasonic treatment is performed, and drying is performed to obtain a mixed powder; The mixed powder was pyrolyzed at 600-630°C for 40-50 min under inert gas protection to obtain a biochar-based composite material.

[0012] Optionally, the microbial agent is a composite agent of sulfur-loving Rhodomyces thiophilus, sulfate-reducing bacteria and Bacillus velez, the mass ratio of the three is 1:2:(2-3), and the total viable count of the microbial agent is ≥10 8 cfu / g.

[0013] Optionally, the bio-based adhesive is pregelatinized starch or molasses liquid.

[0014] The present invention also provides a method for preparing a soil conditioner for acidified soil remediation, which specifically comprises the following steps: S11, preparing decomposed organic matter, specifically: crushing tea waste and straw, mixing with biogas residue, adding EM bacterial agent, composting at high temperature, spreading and airing, and controlling the moisture content to be below 10%; S12, mixing the calcined alkaline slag powder with the decomposed organic matter, adding the first part of the bio-based binder, granulating, and drying to obtain a first granule; S13, mixing the biochar-based composite material, the second part of the bio-based adhesive and the first granules, granulating, and drying to obtain second granules; S14: Mix the microbial agent, the third part of the bio-based adhesive and the second granular agent, granulate, dry, control the moisture content to be below 5%, and sieve to obtain a soil conditioner.

[0015] Optionally, the mass ratio of the first part of bio-based adhesive, the second part of bio-based adhesive and the third part of bio-based adhesive is 6:3:1.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention prepares an acidified soil conditioner by organically combining decomposed organic matter, calcined alkaline slag powder, biochar-based composite materials and microbial agents. On the one hand, it avoids the potential risks to the soil caused by long-term single use of alkaline slag powder (such as quicklime, slaked lime and limestone powder). The soil conditioner of the present invention can be used for a long time to improve the imbalanced state of acidified soil and slowly increase its pH. On the other hand, it makes full use of solid waste resources, improves soil fertility while conditioning the soil, and promotes the proliferation of beneficial microorganisms in the soil.

[0017] The decomposed organic matter in the present invention is prepared by composting tea waste, straw and biogas residue, and the microorganisms in the used EM microbial agent can reproduce rapidly, decompose the organic matter in the tea waste, straw and biogas residue, generate bioheat, increase the temperature of the pile, and accelerate the compost decomposition process; under the action of high temperature, the EM microbial agent can inhibit or kill harmful organisms such as pathogens and insect eggs, and reduce the risks of pathogens and pests; in the humification process, the EM microbial agent helps to release effective nutrients such as nitrogen, phosphorus, potassium and trace elements in the tea waste, straw and biogas residue, and can absorb and decompose odor and harmful substances, improve the smell and safety of the compost; accelerate the composting maturity and shorten the composting cycle; after being applied to the soil, the EM microbial agent can improve the soil environment, inhibit harmful microorganisms, and enrich beneficial microorganisms; therefore, the nutrients of the decomposed organic matter are more comprehensive, rich in organic matter and microorganisms, can improve the soil aggregate structure, increase the water retention and air permeability of the soil, and also contain a variety of nutrients required for crop growth, such as nitrogen, phosphorus, potassium, etc., to improve soil fertility. Calcined alkaline slag powder is made by calcining alkaline slag powder. The chemical components it contains are easier for crops to use, with more pores, enhanced activity, and higher alkalinity. When mixed with decomposed organic matter, the nutrients in the decomposed organic matter can be absorbed by the pores on the surface of the calcined alkaline slag powder. As the core component of the granule, when applied to the soil, it can slowly release nutrients and increase soil alkalinity and condition the soil in long-term use. Biochar-based composite materials are composite materials formed by biochar loaded with mineral powder. As the coating material of the core, it further enhances its nutritional and slow-release conditioning properties. The microbial agent is a composite agent of sulfur-loving Rhodomyces oxysporum, sulfate-reducing bacteria and Bacillus velezii. Among them, the sulfur-loving Rhodomyces oxysporum has multiple functions such as disease resistance and insect pest resistance, and can also secrete beneficial ingredients, which are beneficial to crop growth and conducive to the formation of a beneficial cycle between the conditioner, soil and their functions; sulfate-reducing bacteria can reduce sulfate in the soil to generate sulfur, and sulfur can form sulfide with heavy metal ions to fix heavy metal ions, reduce the activity of heavy metals in the soil, and enable soil fertility to be more fully released; Bacillus velezii has strong adaptability, can survive in acidic soil, and can secrete a variety of extracellular enzymes (proteases, amylases and cellulases), making the conversion of cellulose, hemicellulose and starch possible, and also has significant antibacterial ability, promoting plant growth, thus improving the inhibitory effect of acidic soil on crop growth.

[0018] As is known, the microbial groups, organic matter and aggregate structure of the soil are an interactive and indispensable balanced system that determines the fertility and environment of the soil. Once the beneficial microorganisms are reduced, the structure is destroyed, and the soil quality declines, the crops will lose the source of life. Not only will the diseases increase, it will be difficult to obtain high yields, but also the service life of the cultivated land will be reduced. Therefore, the conditioning of the soil has the characteristics of integrity, systematization and timeliness. After the soil conditioner of the present invention is applied to the soil, the beneficial bacteria take the lead and form a dominant bacterial community around the soil or plant roots, crowding out and inhibiting the harmful bacteria in the soil, making it difficult for pathogenic microorganisms to reproduce; the bio-based adhesive and the internal components are slowly released and decomposed in the complex soil system, thereby forming tiny beneficial circles in the soil. After a certain period of improvement, the beneficial circles continue to expand and strengthen, and finally the overall environment of the soil is improved. DETAILED DESCRIPTION

[0019] In order to better understand the present invention, the content of the present invention is further clearly set forth in conjunction with the embodiments below, but the protection content of the present invention is not limited to the following embodiments. In the following description, a large number of specific details are provided in order to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details.

[0020] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0021] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0022] Unless otherwise specified, all raw materials are from commercially available products and do not contain other unspecified components except inevitable impurities unless otherwise specified.

[0023] In the following cases, the preservation number of R. sulfidophilus is CCTCCNO: M2012369; the preservation number of sulfate-reducing bacteria is CGMCC No.10072, and the preservation number of Bacillus velez is CGMCC No.30372. All of them are currently available strains, and bacterial agents with corresponding viable counts can be prepared by known culture methods.

[0024] Tea waste, straw, biogas residue, rice husks and peanut shells are all materials that have been naturally dried or dried, and their moisture content is less than 15%. Among them, tea waste refers to waste such as old leaves and tea stems generated during the planting and processing of tea trees.

[0025] The particle sizes of alkaline slag, lime slag, gypsum powder, fly ash, coal gangue, silicon manganese slag powder and iron tailings powder are all less than 300 meshes.

[0026] Embodiment 1: A soil conditioner for acidified soil remediation is prepared 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 materials, 10 parts of microbial agents and 15 parts of bio-based adhesives.

[0027] The preparation method of decomposed organic matter is as follows: tea waste and straw are crushed, mixed with biogas residue, EM bacterial agent is added, and high-temperature composting is performed, wherein: the mass ratio of tea waste, straw and biogas residue is 1:2:1, and the amount of EM bacterial agent added is 1.5% of the total mass of the tea waste, straw and biogas residue.

[0028] The calcined alkaline slag powder is a mixture of alkaline slag, lime slag and gypsum powder calcined at 650°C for 1h, wherein the mass ratio of alkaline slag, lime slag and gypsum powder is 1:2:1, and the calcined alkaline slag powder contains the following chemical components in mass percentage: CaO 42.3%, SiO2 28.6%, Al2O3 15.3%, MgO 4.2%, Fe2O3 1.4%, MnO 0.7%, and pH: 11.6.

[0029] The biochar-based composite material is a composite material formed by biochar loaded with mineral powder, the mineral powder is silicomanganese slag powder, and the biochar is a product obtained by decomposing straw at high temperature (500°C, 3h). The preparation method of the biochar-based composite material is: calcining the mineral powder at 700°C for 2h to obtain mineral calcined powder; mixing the biochar and the mineral calcined powder, adding water, ultrasonically treating (25kHz, 30min), and drying to obtain a mixed powder; pyrolyzing the mixed powder at 620°C for 45min under the protection of inert gas N2 to obtain the biochar-based composite material.

[0030] The microbial agent is a composite agent of sulfur-loving Rhodomyces thiophilus, sulfate-reducing bacteria and Bacillus velez. The mass ratio of the three is 1:2:2. The total number of viable bacteria in the microbial agent is ≥10 8 cfu / g.

[0031] The bio-based binder is pregelatinized starch.

[0032] A method for preparing a soil conditioner for acidified soil remediation comprises the following steps: S11, preparing decomposed organic matter, specifically: crushing tea waste and straw, mixing with biogas residue, adding EM bacterial agent, composting at high temperature, spreading and airing, and controlling the moisture content to be below 10%; S12, mixing the calcined alkaline slag powder with the decomposed organic matter, adding the first part of the bio-based binder, granulating, and drying to obtain a first granule; S13, mixing the biochar-based composite material, the second part of the bio-based adhesive and the first granules, granulating, and drying to obtain second granules; S14: Mix the microbial agent, the third part of the bio-based adhesive and the second granular agent, granulate, dry, control the moisture content to be below 5%, and sieve to obtain a soil conditioner.

[0033] The mass ratio of the first part of bio-based adhesive, the second part of bio-based adhesive and the third part of bio-based adhesive is 6:3:1.

[0034] The granulation is performed by disk granulation, and the drying is performed by natural air drying.

[0035] Embodiment 2: A soil conditioner for acidified soil remediation is prepared 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 materials, 12 parts of microbial agents and 10 parts of bio-based adhesives.

[0036] The preparation method of decomposed organic matter is as follows: tea waste and straw are crushed, mixed with biogas residue, EM bacterial agent is added, and high-temperature composting is performed, wherein: the mass ratio of tea waste, straw and biogas residue is 1.5:2:1, and the amount of EM bacterial agent added is 1% of the total mass of the tea waste, straw and biogas residue.

[0037] The calcined alkaline slag powder is a mixture of alkaline slag, lime slag and gypsum powder calcined at 650°C for 1 hour, wherein the mass ratio of alkaline slag, lime slag and gypsum powder is 1:2.5:1, and the calcined alkaline slag powder contains the following chemical components in mass percentage: CaO 40.5%, SiO2 30.6%, Al2O3 12.4%, MgO 4.7%, Fe2O3 2.6%, MnO 1.5%, and pH: 10.6.

[0038] The biochar-based composite material is a composite material formed by biochar loaded with mineral powder, the mineral powder is iron tailings powder, and the biochar is a product obtained by decomposing rice husk at high temperature (500°C, 3h).

[0039] The preparation method of biochar-based composite materials is as follows: calcining mineral powder at 680°C for 2 hours to obtain mineral calcined powder; mixing biochar and mineral calcined powder, adding water, ultrasonically treating (30kHz, 30min), and drying to obtain mixed powder; pyrolyzing the mixed powder at 630°C for 40min under the protection of inert gas N2 to obtain a biochar-based composite material.

[0040] The microbial agent is a composite agent of sulfur-loving Rhodomyces thiophilus, sulfate-reducing bacteria and Bacillus velez. The mass ratio of the three is 1:2:2.5. The total number of viable bacteria in the microbial agent is ≥10 8 cfu / g.

[0041] The bio-based binder is molasses liquid.

[0042] The preparation method of the soil conditioner for acidified soil remediation is shown in Example 1.

[0043] Embodiment 3: A soil conditioner for acidified soil remediation is prepared from the following raw materials in parts by weight: 30 parts of decomposed organic matter, 17 parts of calcined alkaline slag powder, 20 parts of biochar-based composite materials, 13 parts of microbial agents and 20 parts of bio-based adhesives.

[0044] The preparation method of decomposed organic matter is as follows: tea waste and straw are crushed, mixed with biogas residue, EM bacterial agent is added, and high-temperature composting is performed, wherein: the mass ratio of tea waste, straw and biogas residue is 2:2:1, and the amount of the EM bacterial agent added is 2% of the total mass of the tea waste, straw and biogas residue.

[0045] The calcined alkaline slag powder is a mixture of alkaline slag, lime slag and gypsum powder calcined at 650°C for 1 hour, wherein the mass ratio of alkaline slag, lime slag and gypsum powder is 1:3:1.5, and the calcined alkaline slag powder contains the following chemical components in mass percentage: CaO 48.1%, SiO2 26.3%, Al2O3 10.7%, MgO 3.8%, Fe2O3 0.7%, MnO 1.4%, and pH: 11.7.

[0046] The biochar-based composite material is a composite material formed by biochar loaded with mineral powder. The mineral powder is fly ash and gypsum powder, and the mass ratio of the two is 1:1. The biochar is a product obtained by high-temperature (400°C, 3h) decomposition of tea waste.

[0047] The preparation method of biochar-based composite materials is as follows: calcining mineral powder at 650°C for 3 hours to obtain mineral calcined powder; mixing biochar and mineral calcined powder, adding water, ultrasonically treating (30kHz, 25min), and drying to obtain mixed powder; pyrolyzing the mixed powder at 600°C for 50min under the protection of inert gas N2 to obtain a biochar-based composite material.

[0048] The microbial agent is a composite agent of sulfur-loving Rhodomyces thiophilus, sulfate-reducing bacteria and Bacillus velez. The mass ratio of the three is 1:2:3. The total number of viable bacteria in the microbial agent is ≥10 8 cfu / g.

[0049] The bio-based binder is pregelatinized starch.

[0050] The preparation method of the soil conditioner for acidified soil remediation is shown in Example 1.

[0051] Example 4 : A soil conditioner for acidified soil remediation, made from the following raw materials in parts by weight: 29 parts of decomposed organic matter, 15 parts of calcined alkaline slag powder, 30 parts of biochar-based composite materials, 9 parts of microbial agents and 17 parts of bio-based adhesives.

[0052] Among them, the biochar-based composite material is a composite material formed by biochar loaded with mineral powder, 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).

[0053] For other parameters and processes not mentioned, please refer to Example 1.

[0054] Example 5 : A soil conditioner for acidified soil remediation, made from the following raw materials in parts by weight: 30 parts of decomposed organic matter, 21 parts of calcined alkaline slag powder, 25 parts of biochar-based composite materials, 6 parts of microbial agents and 18 parts of bio-based adhesives.

[0055] Among them, the biochar-based composite material is a composite material formed by biochar loaded with mineral powder. 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. The biochar is the product obtained by high-temperature decomposition of straw and tea waste (mass ratio 2:1).

[0056] For other parameters and processes not mentioned, please refer to Example 1.

[0057] Example 6 : The difference from Example 1 is that the biochar-based composite material is a composite material formed by biochar loaded with mineral powder, the mineral powder is gypsum powder, the biochar is a product obtained by high-temperature decomposition of a mixture of straw, rice husks, tea waste and peanut shells, and the mass ratio of straw, rice husks, tea waste and peanut shells is 2:1:1:1.

[0058] Comparative Example 1 : The difference from Example 1 is that the method for preparing decomposed organic matter is: crushing the straw, mixing it, adding EM bacteria agent, and composting it at high temperature, wherein: the amount of EM bacteria agent added is 1.5% of the total mass of the straw.

[0059] Comparative Example 2 : The difference from Example 1 is that the calcined alkaline slag powder is replaced by a mixture of alkaline slag powder, lime slag powder and gypsum powder, and no calcination treatment is performed. The mass ratio of alkaline slag powder, lime slag powder and gypsum powder is 1:2:1.

[0060] Comparative Example 3 The difference from Example 1 is that the calcined alkaline slag powder is replaced by lime slag powder calcined at 650° C. for 1 h to form a product.

[0061] Comparative Example 4 : The difference from Example 1 is that the biochar-based composite material is replaced by biochar, and the biochar is a product obtained by decomposing straw at high temperature (500° C., 3 h).

[0062] Comparative Example 5 : The difference from Example 1 is that the microbial agent is sulfur-loving red oomycete.

[0063] Comparative Example 6 : The difference from Example 1 is that the microbial agent is sulfate-reducing bacteria.

[0064] Comparative Example 7 : The difference from Example 1 is that the microbial agent is Bacillus Velez.

[0065] In order to further demonstrate the effect of the acidified soil conditioner prepared by the present invention, the following content uses the soil conditioners prepared by Examples 1-6 and Comparative Examples 1-7 to conduct the following tests.

[0066] 1. Prepare 14 groups of acidified soil samples with the same conditions, with 3 parallels in each group. The weight of each parallel soil is 1kg. Add the corresponding soil conditioner (30g conditioner / kg soil) to each group of samples, mix them evenly, and set up a blank control group (CK) without conditioner. Cultivate for 90 days under the set experimental conditions (temperature 25℃, relative humidity 55%), take samples on the 0th day, 45th day and 90th day, and measure the soil pH. The experimental data are shown in the following table:

[0067] The above results show that the above soil conditioners can all increase the pH of the soil. The improvement of the soil pH by the embodiment of the present invention is higher than that by the comparative example, and the effect is more obvious.

[0068] 2. A typical acidified yellow-brown soil was selected in Xinyang City, Henan Province for field experiments, and the crop was tea. The amount of conditioner was 200kg / mu, and a blank control group (CK) was set up without adding soil conditioner. The experimental period was 6 months. At the end of the experimental period, the relevant parameters of soil properties were measured, as shown in the following table.

[0069]

[0070] The test results show that the treatment of the present invention is more beneficial to the improvement of soil pH. After 6 months of application, the soil pH value increased by about 1.2, and the improvement effect was significant. Under the same pH conditions, the actual application effect of the soil conditioner of the present invention is enhanced with the extension of time. This may be because the soil environment is in an open cycle in actual application, which is more conducive to the interaction of various components. This also further shows that the soil conditioner of the present invention has a good mutual coordination and promotion effect with the soil and crops in actual application, making the improvement and improvement effect of soil acidity more prominent. Secondly, after the use of the soil conditioner of the present invention, the exchange acid content of the soil is significantly reduced; the content of alkaline nitrogen, available phosphorus, available potassium and organic matter are all significantly improved to varying degrees. The above results all show that the soil conditioner of the present invention has a conditioning effect on acidified soil, can significantly increase the soil pH value, so that it approaches the normal range; at the same time, it can increase different nutrients in the soil to better meet the needs of crop growth.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in the field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A soil conditioner for acidified soil remediation, characterized in that: The invention is prepared from the following raw materials in parts by weight: 25-30 parts of decomposed organic matter, 15-23 parts of calcined alkaline slag powder, 20-30 parts of biochar-based composite materials, 6-13 parts of microbial agents and 10-20 parts of bio-based adhesives.

2. A soil conditioner for acidified soil remediation according to claim 1, characterized in that: The invention is prepared 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 materials, 10 parts of microbial agents and 15 parts of bio-based adhesives.

3. A soil conditioner for acidified soil remediation according to claim 2, characterized in that: The method for preparing the decomposed organic matter comprises: crushing tea waste and straw, mixing them with biogas residue, adding EM bacterial agent, and composting them at high temperature, wherein the mass ratio of the tea waste, straw and biogas residue is (1-2):2:1, and the amount of the EM bacterial agent added is 1-2% of the total mass of the tea waste, straw and biogas residue.

4. A soil conditioner for acidified soil remediation according to claim 3, characterized in that: The calcined alkaline slag powder is a mixture formed by calcining alkaline slag, lime slag and gypsum powder at high temperature, 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 in 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.

5. A soil conditioner for acidified soil remediation according to claim 4, characterized in that: The biochar-based composite material is a composite material formed by biochar loaded with mineral powder, wherein the mineral powder is one or more 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.

6. A soil conditioner for acidified soil remediation according to claim 5, characterized in that: The preparation method of the biochar-based composite material is: The mineral powder is calcined at 650-700°C for 2-3 hours to obtain the mineral calcined powder; The biochar is mixed with the mineral calcined powder, water is added, ultrasonic treatment is performed, and drying is performed to obtain a mixed powder; The mixed powder was pyrolyzed at 600-630°C for 40-50 min under inert gas protection to obtain a biochar-based composite material.

7. A soil conditioner for acidified soil remediation according to claim 6, characterized in that: The microbial agent is a composite agent of sulfur-loving Rhodomyces thiophilus, sulfate-reducing bacteria and Bacillus velez, the mass ratio of the three is 1:2:(2-3), and the total number of live bacteria of the microbial agent is ≥10 8 cfu / g.

8. A soil conditioner for acidified soil remediation according to claim 7, characterized in that: The bio-based adhesive is pregelatinized starch or molasses liquid.

9. A method for preparing a soil conditioner for acidified soil remediation according to any one of claims 1 to 8, characterized in that: The specific steps include: S11, preparing decomposed organic matter, specifically: crushing tea waste and straw, mixing with biogas residue, adding EM bacterial agent, composting at high temperature, spreading and airing, and controlling the moisture content to be below 10%; S12, mixing the calcined alkaline slag powder with the decomposed organic matter, adding the first part of the bio-based binder, granulating, and drying to obtain a first granule; S13, mixing the biochar-based composite material, the second part of the bio-based adhesive and the first granules, granulating, and drying to obtain second granules; S14: Mix the microbial agent, the third part of the bio-based adhesive and the second granular agent, granulate, dry, control the moisture content to be below 5%, and sieve to obtain a soil conditioner.

10. The method for preparing a soil conditioner for acidified soil remediation according to claim 9, characterized in that: The mass ratio of the first part of bio-based adhesive, the second part of bio-based adhesive and the third part of bio-based adhesive is 6:3:1.

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