A functional soil conditioner made from biomass pyrolysis products and its preparation method and application

Abstract

The invention provides a functional soil conditioner of a biomass pyrolysis product and a preparation method and application thereof. The functional soil conditioner is composed of the following materials in proportion by weight: 40-60 parts of a biochar-attapulgite composite material, 15-30 parts of humic acid, 5-10 parts of attapulgite clay, 3-5 parts of diammonium hydrogen phosphate, 8-10 parts of wood vinegar, 5-10 parts of polyaspartic acid, and 3-5 parts of a bioremediation bacterial agent. The invention utilizes agricultural waste such as honeydew melon stalks, sunflowers, corn, soybeans, wheat, rice straws, and agricultural mulch films as raw materials, and converts them into high-value-added soil conditioners through biomass pyrolysis technology, thereby realizing resource utilization of agricultural waste, reducing agricultural carbon emissions, and contributing to promoting the development of low-carbon agriculture.

Description

Technical Field

[0001] The present invention relates to the technical field of soil conditioning, and in particular to a functional soil conditioner produced by pyrolysis of biomass, and a preparation method and application thereof. Background Art

[0002] In the global carbon cycle, terrestrial ecosystems are important carbon pools with dual functions of source and sink. In terrestrial ecosystems, soil carbon pools are considered to be the largest carbon pool in terrestrial ecosystems, with global reserves reaching 2300Pg, which is about 3 times the atmospheric carbon pool and 4 times the biological carbon pool. Energy carbon emissions account for a large proportion of all types of carbon emissions and are the main force in energy conservation and emission reduction. They are of great significance for the realization of a low-carbon economy and the sustainable development of mankind. At present, agricultural greenhouse gas emissions have risen to the second place, second only to industrial greenhouse gas emissions. It is imperative to reduce agricultural carbon emissions. The agricultural production model is relatively fixed. Every year, crops will produce a large amount of agricultural waste in autumn, including crop straw, agricultural mulch, etc. Most of these materials will cause carbon emissions through combustion and other means, thereby increasing the concentration of greenhouse gases in the atmospheric environment. This proportion is relatively high in the entire agricultural production process, so the model of low-carbon utilization of agricultural waste to reduce agricultural carbon emissions cannot be delayed.

[0003] On the other hand, in agricultural production, soil quality is directly related to crop growth and yield. However, with the rapid development of modern agriculture, problems such as excessive use of fertilizers, pesticide residues, and soil erosion are becoming increasingly serious, leading to a decline in soil quality, damage to soil structure, and weakening of soil fertility, which in turn affects crop growth and the quality of agricultural products. Therefore, it is particularly important to develop a soil conditioner that can effectively improve soil, increase soil fertility, and promote healthy plant growth.

[0004] Therefore, there is an urgent need for a functional soil conditioner using a biomass pyrolysis product made from agricultural waste as a raw material. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a high-efficiency functional soil conditioner of biomass pyrolysis products, which is composed of the following materials in proportion by weight: 40-60 parts of biochar-attapulgite composite material, 15-30 parts of humic acid, 5-10 parts of attapulgite clay, 3-5 parts of diammonium hydrogen phosphate, 8-10 parts of wood vinegar, 5-10 parts of polyaspartic acid, and 3-5 parts of bioremediation bacteria agent.

[0006] Furthermore, the preparation method of the biochar-attapulgite composite material is as follows:

[0007] S1. Decompose agricultural waste by oxygen-deficient dry distillation in a biomass pyrolysis gasifier to generate biomass pyrolysis ash ( Figure 3)。 The biomass pyrolysis ash meets the following conditions: pH value is 7-10, organic matter content ≥10.73 wt%, total nitrogen content ≥6.01 wt%, total phosphorus content ≥7.13 wt%, total potassium content ≥10.5 wt%, silicon (Si) element ≤15 wt%;

[0008] S2, mixing the biomass pyrolysis ash and attapulgite clay, and grinding them to obtain a composite powder;

[0009] S3, grinding the attapulgite clay to obtain attapulgite fine soil;

[0010] S4, mixing the composite powder prepared in S2 with the attapulgite fine soil obtained in S3, pressing into granules and then drying;

[0011] S5, placing the dried material into a high temperature furnace for calcination to obtain a biochar-attapulgite composite material ( Figure 4 ), the calcination process helps to further improve the stability and activity of the composite material, enabling it to better play the role of soil improvement.

[0012] Furthermore, in step S1, the agricultural waste includes melon stems, sunflowers, corn, soybeans, wheat, rice straw and agricultural mulch film;

[0013] In the step S2, the particle size of the composite powder is 200 mesh.

[0014] Moreover, in the step S2, the mass ratio of biomass pyrolysis ash to attapulgite clay is 1-3:5-10.

[0015] Moreover, in the step S3, the particle size of the attapulgite fine soil is 200 meshes.

[0016] Moreover, in the step S4, the mass ratio of the composite powder to the attapulgite fine soil is 10-15:1.

[0017] Moreover, in the step S5, the calcination temperature is 400-500° C., and the calcination time is 30-50 min.

[0018] Moreover, according to the mass ratio, the bioremediation bacterial agent is: 1-2 parts of Trichoderma harzianum, 2-3 parts of Bacillus velezensis, 2-3 parts of Paenibacillus gelatinosa, and 2-3 parts of Lactobacillus plantarum.

[0019] Moreover, the preparation method of the highly efficient biomass pyrolysis product functional soil conditioner is as follows:

[0020] Step 1, mixing 5-10 parts of humic acid, attapulgite clay, diammonium hydrogen phosphate, wood vinegar, and polyaspartic acid, drying, and pressing into granules;

[0021] Step 2: After adding the biochar-attapulgite composite material and mixing evenly, add the bioremediation bacterial agent to obtain a soil conditioner.

[0022] Moreover, the pH value of the attapulgite clay is 7-8.5, and the components are calculated by mass content: organic matter ≥5wt%, carbon (C) element ≥23.63%, neodymium (Nd) element ≥7.72%, silicon (Si) element ≥4%, praseodymium (Pr) element ≥3.06%, cerium (Ce) element ≥3%, iron (Fe) element ≥2.79%, aluminum (Al) element ≥2.66%, potassium (K) element ≥0.92%, titanium (Ti) element ≥0.89%; the raw materials of the wood vinegar meet the following conditions: pH value is 3-4, acetic acid (CH3COOH) content ≥50.3%, organic matter ≥15%, hydroxyacetone (C3H6O2) ≥10%, propionic acid (CH3 CH2COOH) ≥2.39%, butyric acid (CH3 (CH2)2COOH) ≥1.73%.

[0023] On the other hand, the present invention provides an application of a high-efficiency functional soil conditioner produced by biomass pyrolysis, which is used to improve soil and promote plant growth.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention utilizes agricultural waste such as melon stems, sunflowers, corn, soybeans, wheat, rice straw and agricultural mulch as raw materials, and converts them into high-value-added soil conditioners through biomass pyrolysis technology, thereby realizing the resource utilization of agricultural waste, reducing agricultural carbon emissions, and helping to promote the development of low-carbon agriculture.

[0026] 2. The present invention forms composite powders from biomass pyrolysis ash and attapulgite clay, and then uses attapulgite fine soil as a binder to prepare a biochar-attapulgite composite material as the main component of the soil conditioner of the present invention: First, biomass pyrolysis ash itself has a highly developed pore structure and a huge specific surface area, which can adsorb and fix pollutants and nutrients in the soil. Attapulgite clay has a layered chain-like hydrated magnesium-rich, aluminum silicate structure, and also has a large specific surface area and microporous structure, showing strong surface activity and adsorption performance. The present invention prepares it into a composite material that combines the advantages of the two, further optimizes the pore structure and specific surface area, provides more adsorption sites, and improves the adsorption capacity for heavy metal ions and other pollutants; Second, attapulgite clay has a high cation exchange capacity, which can adsorb and fix heavy metal ions and other cations in the soil. In the composite material, biomass pyrolysis ash acts as a porous matrix to support and carry clay mineral nanoparticles. Rice particles further enhance the cation exchange capacity and improve the removal effect of harmful ions in the soil; third, during the preparation process, attapulgite clay can be used as a nutrient component or as a binder. After calcination, the organic matter contained in the attapulgite clay can also be carbonized at high temperature to form a stable carbonaceous structure, further enhancing the stability and durability of the composite material; fourth, attapulgite clay has a certain catalytic activity, which can promote the decomposition and transformation of organic matter in the soil. The organic matter and trace elements in the biomass pyrolysis ash can also be used as catalysts or co-catalysts to work together with attapulgite clay to promote the release and utilization of nutrients in the soil; that is to say, the biochar-attapulgite composite material, as the main component of the soil conditioner of the present invention, has excellent adsorption, ion exchange and water and fertilizer retention capabilities, can significantly improve soil structure, improve soil fertility, and promote soil microbial activity, which is beneficial to the growth and development of crops.

[0027] 4. The addition of humic acid, diammonium hydrogen phosphate, wood vinegar, polyaspartic acid, attapulgite clay and other ingredients in the present invention provides the soil with rich organic matter, nutrients such as nitrogen, phosphorus and potassium, and a variety of biologically active substances, which can meet the nutrient needs of crops during growth, promote the healthy growth of crops, and improve crop yield and quality. At the same time, attapulgite clay can also be used as a binder for granulation.

[0028] 5. The introduction of bioremediation agents in the present invention, such as Trichoderma harzianum, Bacillus velezensis, Bacillus gelatinus, and Lactobacillus plantarum, can significantly increase the types and quantity of microorganisms in the soil, thereby improving the microbial environment of the soil; the microorganisms in the bioremediation agents can rapidly multiply in the soil, forming a probiotic environment, inhibiting the growth and reproduction of harmful microorganisms, and can also decompose organic matter in the soil and convert it into nutrients that are easily absorbed by plants, such as nitrogen, phosphorus, potassium, etc., thereby improving the utilization rate of soil nutrients; the microorganisms in the microbial agents can also establish a symbiotic relationship with plants, enhance the resistance of plants to stress, such as drought resistance, disease resistance, cold resistance, etc., and reduce the occurrence of crop diseases and insect pests.

[0029] 6. The soil conditioner of the present invention uses natural agricultural waste as raw materials and is prepared through environmentally friendly technologies such as biomass pyrolysis. It does not contain chemical synthetic substances and is environmentally friendly. The preparation process is simple and easy to mass produce, which is in line with the concept of sustainable development.

[0030] 7. The soil conditioner of the present invention not only has the function of improving soil and increasing fertility, but also can promote plant growth, inhibit pests and diseases, and reduce the use of fertilizers and pesticides, thereby helping to reduce agricultural production costs and improve agricultural economic benefits.

[0031] 8. The soil conditioner prepared by the present invention has good slow-release effect, long fertilizer effect time, can be stored for a long time at room temperature, can be mixed with other organic and inorganic fertilizers for granulation and drying without being affected, and has obvious fertilizer synergistic effect. While effectively preventing and controlling soil-borne diseases, it also achieves the purpose of improving the soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the SEM image of biomass pyrolysis ash;

[0033] Figure 2 This is the SEM image of the biochar-attapulgite composite material;

[0034] Figure 3 Biomass pyrolysis ash prepared by the present invention;

[0035] Figure 4 The biochar-attapulgite composite material produced by the present invention;

[0036] Figure 5 The actual field test results of the soil conditioner provided by the present invention;

[0037] Figure 6 This is an actual field experiment to test the growth and development of honeydew melon during its growth period. DETAILED DESCRIPTION

[0038] Example 1

[0039] A highly efficient functional soil conditioner produced from biomass pyrolysis products is composed of the following materials in proportion by weight: 40 parts of a biochar-attapulgite composite material, 15 parts of humic acid, 5 parts of attapulgite clay, 3 parts of diammonium hydrogen phosphate, 8 parts of wood vinegar, 5 parts of polyaspartic acid, and 3 parts of a bioremediation bacterial agent.

[0040] Preferably, the preparation method of the biochar-attapulgite composite material is as follows:

[0041] S1. Decomposing agricultural waste by oxygen-deficient dry distillation in a biomass pyrolysis gasifier to generate biomass pyrolysis ash;

[0042] S2, mixing the biomass pyrolysis ash and attapulgite clay, and grinding them to obtain a composite powder;

[0043] S3, grinding the attapulgite clay to obtain attapulgite fine soil;

[0044] S4, mixing the composite powder prepared in S2 with the attapulgite fine soil obtained in S3, pressing into granules and then drying;

[0045] S5. The dried material is placed in a high-temperature furnace for calcination to obtain a biochar-attapulgite composite material.

[0046] Preferably, in step S1, the agricultural waste includes melon stems, sunflowers, corn, soybeans, wheat, rice straw and agricultural mulch film;

[0047] In the step S2, the particle size of the composite powder is 200 mesh.

[0048] Preferably, in step S2, the mass ratio of biomass pyrolysis ash to attapulgite clay is 1:5.

[0049] Preferably, in step S3, the particle size of the attapulgite fine soil is 200 mesh.

[0050] Preferably, in step S4, the mass ratio of the composite powder to the attapulgite fine soil is 10:1.

[0051] Preferably, in step S5, the calcination temperature is 400° C. and the calcination time is 30 min.

[0052] Preferably, in terms of mass ratio, the bioremediation bacterial agent comprises: 1 part of Trichoderma harzianum, 2 parts of Bacillus velezensis, 2 parts of Paenibacillus gelatinosa, and 2 parts of Lactobacillus plantarum.

[0053] Preferably, the preparation method of the soil conditioner is as follows:

[0054] Step 1, mixing humic acid, attapulgite clay, diammonium hydrogen phosphate, wood vinegar, and polyaspartic acid, drying, and pressing into granules;

[0055] Step 2: After adding the biochar-attapulgite composite material and mixing evenly, add the bioremediation bacterial agent to obtain a soil conditioner.

[0056] Preferably, the pH value of the attapulgite clay is 7, the organic matter content is ≥5wt%, the carbon content is ≥23.63%, the neodymium content is ≥7.72%, the silicon content is ≥4%, the praseodymium content is ≥3.06%, the cerium content is ≥3%, the iron content is ≥2.79%, the aluminum content is ≥2.66%, the potassium content is ≥0.92%, and the titanium content is ≥0.89%;

[0057] The pH value of the wood vinegar is 3, the acetic acid content is ≥50.3%, the organic matter content is ≥15%, the hydroxyacetone content is ≥10%, the propionic acid content is ≥2.39%, and the butyric acid content is ≥1.73%.

[0058] Example 2

[0059] A highly efficient functional soil conditioner produced from biomass pyrolysis products is composed of the following materials in proportion by weight: 60 parts of a biochar-attapulgite composite material, 30 parts of humic acid, 10 parts of attapulgite clay, 5 parts of diammonium hydrogen phosphate, 10 parts of wood vinegar, 10 parts of polyaspartic acid, and 5 parts of a bioremediation bacterial agent.

[0060] Preferably, the preparation method of the biochar-attapulgite composite material is as follows:

[0061] S1. Decomposing agricultural waste by oxygen-deficient dry distillation in a biomass pyrolysis gasifier to generate biomass pyrolysis ash;

[0062] S2, mixing the biomass pyrolysis ash and attapulgite clay, and grinding them to obtain a composite powder;

[0063] S3, grinding the attapulgite clay to obtain attapulgite fine soil;

[0064] S4, mixing the composite powder prepared in S2 with the attapulgite fine soil obtained in S3, pressing into granules and then drying;

[0065] S5. The dried material is placed in a high-temperature furnace for calcination to obtain a biochar-attapulgite composite material.

[0066] Preferably, in step S1, the agricultural waste includes melon stems, sunflowers, corn, soybeans, wheat, rice straw and agricultural mulch film;

[0067] In the step S2, the particle size of the composite powder is 200 mesh.

[0068] Preferably, in step S2, the mass ratio of biomass pyrolysis ash to attapulgite clay is 1-3:5-10.

[0069] Preferably, in step S3, the particle size of the attapulgite fine soil is 200 mesh.

[0070] Preferably, in step S4, the mass ratio of the composite powder to the attapulgite fine soil is 15:1.

[0071] Preferably, in step S5, the calcination temperature is 500° C. and the calcination time is 50 min.

[0072] Preferably, in terms of mass ratio, the bioremediation bacterial agent comprises: 2 parts of Trichoderma harzianum, 3 parts of Bacillus velezensis, 3 parts of Paenibacillus gelatinosa, and 3 parts of Lactobacillus plantarum.

[0073] Preferably, the preparation method of the soil conditioner is as follows:

[0074] Step 1, mixing humic acid, attapulgite clay, diammonium hydrogen phosphate, wood vinegar, and polyaspartic acid, drying, and pressing into granules;

[0075] Step 2: After adding the biochar-attapulgite composite material and mixing evenly, add the bioremediation bacterial agent to obtain a soil conditioner.

[0076] Preferably, the pH value of the attapulgite clay is 8.5, the organic matter content is ≥5wt%, the carbon content is ≥23.63%, the neodymium content is ≥7.72%, the silicon content is ≥4%, the praseodymium content is ≥3.06%, the cerium content is ≥3%, the iron content is ≥2.79%, the aluminum content is ≥2.66%, the potassium content is ≥0.92%, and the titanium content is ≥0.89%;

[0077] The pH value of the wood vinegar is 4, the acetic acid content is ≥50.3%, the organic matter content is ≥15%, the hydroxyacetone content is ≥10%, the propionic acid content is ≥2.39%, and the butyric acid content is ≥1.73%.

[0078] Example 3

[0079] A highly efficient functional soil conditioner produced from biomass pyrolysis products, comprising the following materials in proportion by weight: 50 parts of a biochar-attapulgite composite material, 28 parts of humic acid, 8 parts of attapulgite clay, 4 parts of diammonium hydrogen phosphate, 9 parts of wood vinegar, 8 parts of polyaspartic acid, and 4 parts of a bioremediation bacterial agent.

[0080] Preferably, the preparation method of the biochar-attapulgite composite material is as follows:

[0081] S1. Decomposing agricultural waste by oxygen-deficient dry distillation in a biomass pyrolysis gasifier to generate biomass pyrolysis ash;

[0082] S2, mixing the biomass pyrolysis ash and attapulgite clay, and grinding them to obtain a composite powder;

[0083] S3, grinding the attapulgite clay to obtain attapulgite fine soil;

[0084] S4, mixing the composite powder prepared in S2 with the attapulgite fine soil obtained in S3, pressing into granules and then drying;

[0085] S5. The dried material is placed in a high-temperature furnace for calcination to obtain a biochar-attapulgite composite material.

[0086] Preferably, in step S1, the agricultural waste includes melon stems, sunflowers, corn, soybeans, wheat, rice straw and agricultural mulch film;

[0087] In the step S2, the particle size of the composite powder is 200 mesh.

[0088] Preferably, in step S2, the mass ratio of biomass pyrolysis ash to attapulgite clay is 1:4.

[0089] Preferably, in step S3, the particle size of the attapulgite fine soil is 200 mesh.

[0090] Preferably, in step S4, the mass ratio of the composite powder to the attapulgite fine soil is 12:1.

[0091] Preferably, in step S5, the calcination temperature is 450° C. and the calcination time is 40 min.

[0092] Preferably, in terms of mass ratio, the bioremediation bacterial agent comprises: 1.5 parts of Trichoderma harzianum, 2.5 parts of Bacillus velezensis, 2.5 parts of Paenibacillus gelatinosa, and 2.5 parts of Lactobacillus plantarum.

[0093] Preferably, the preparation method of the soil conditioner is as follows:

[0094] Step 1, mixing humic acid, attapulgite clay, diammonium hydrogen phosphate, wood vinegar, and polyaspartic acid, drying, and pressing into granules;

[0095] Step 2: After adding the biochar-attapulgite composite material and mixing evenly, add the bioremediation bacterial agent to obtain a soil conditioner.

[0096] Preferably, the pH value of the attapulgite clay is 7.5, the organic matter content is ≥5wt%, the carbon content is ≥23.63%, the neodymium content is ≥7.72%, the silicon content is ≥4%, the praseodymium content is ≥3.06%, the cerium content is ≥3%, the iron content is ≥2.79%, the aluminum content is ≥2.66%, the potassium content is ≥0.92%, and the titanium content is ≥0.89%;

[0097] The pH value of the wood vinegar is 3.5, the acetic acid content is ≥50.3%, the organic matter content is ≥15%, the hydroxyacetone content is ≥10%, the propionic acid content is ≥2.39%, and the butyric acid content is ≥1.73%.

[0098] Comparative Example 1

[0099] The difference between this comparative example and Example 3 is that the biochar-attapulgite composite material is replaced with biomass pyrolysis ash and attapulgite clay, and the mass ratio is 10 parts of biomass pyrolysis ash and 40 parts of attapulgite clay, as follows:

[0100] A high-efficiency functional soil conditioner produced from biomass pyrolysis products is composed of the following materials in proportion by weight: 10 parts of biomass pyrolysis ash, 40 parts of attapulgite clay, 28 parts of humic acid, 8 parts of attapulgite clay, 4 parts of diammonium hydrogen phosphate, 9 parts of wood vinegar, 8 parts of polyaspartic acid, and 4 parts of a bioremediation bacterial agent.

[0101] The biomass pyrolysis ash is generated by oxygen-deficient carbonization and decomposition of agricultural waste using a biomass pyrolysis gasifier.

[0102] Preferably, the agricultural waste includes melon stems, sunflowers, corn, soybeans, wheat, rice straw and agricultural mulch.

[0103] Preferably, in terms of mass ratio, the bioremediation bacterial agent comprises: 1.5 parts of Trichoderma harzianum, 2.5 parts of Bacillus velezensis, 2.5 parts of Paenibacillus gelatinosa, and 2.5 parts of Lactobacillus plantarum.

[0104] Preferably, the preparation method of the soil conditioner is as follows:

[0105] Step 1, 10 parts of biomass pyrolysis ash, 40 parts of attapulgite clay, 28 parts of humic acid, 8 parts of attapulgite clay, 4 parts of diammonium hydrogen phosphate, 9 parts of wood vinegar, and 8 parts of polyaspartic acid are mixed, dried, and pressed into granules;

[0106] Step 2: Add the bioremediation agent to obtain a soil conditioner.

[0107] Comparative Example 2

[0108] The difference between this comparative example and Example 3 is that no bioremediation agent is added, as follows:

[0109] A highly efficient functional soil conditioner produced from biomass pyrolysis products is composed of the following materials in proportion by weight: 50 parts of a biochar-attapulgite composite material, 28 parts of humic acid, 8 parts of attapulgite clay, 4 parts of diammonium hydrogen phosphate, 9 parts of wood vinegar, and 8 parts of polyaspartic acid.

[0110] Preferably, the preparation method of the biochar-attapulgite composite material is as follows:

[0111] S1. Decomposing agricultural waste by oxygen-deficient dry distillation in a biomass pyrolysis gasifier to generate biomass pyrolysis ash;

[0112] S2, mixing the biomass pyrolysis ash and attapulgite clay, and grinding them to obtain a composite powder;

[0113] S3, grinding the attapulgite clay to obtain attapulgite fine soil;

[0114] S4, mixing the composite powder prepared in S2 with the attapulgite fine soil obtained in S3, pressing into granules and then drying;

[0115] S5. The dried material is placed in a high-temperature furnace for calcination to obtain a biochar-attapulgite composite material.

[0116] Preferably, in step S1, the agricultural waste includes melon stems, sunflowers, corn, soybeans, wheat, rice straw and agricultural mulch film;

[0117] In the step S2, the particle size of the composite powder is 200 mesh.

[0118] Preferably, in step S2, the mass ratio of biomass pyrolysis ash to attapulgite clay is 1:4.

[0119] Preferably, in step S3, the particle size of the attapulgite fine soil is 200 mesh.

[0120] Preferably, in step S4, the mass ratio of the composite powder to the attapulgite fine soil is 12:1.

[0121] Preferably, in step S5, the calcination temperature is 450° C. and the calcination time is 40 min.

[0122] Preferably, in terms of mass ratio, the bioremediation bacterial agent comprises: 1.5 parts of Trichoderma harzianum, 2.5 parts of Bacillus velezensis, 2.5 parts of Paenibacillus gelatinosa, and 2.5 parts of Lactobacillus plantarum.

[0123] Preferably, the preparation method of the soil conditioner is as follows:

[0124] Step 1, mixing humic acid, attapulgite clay, diammonium hydrogen phosphate, wood vinegar, and polyaspartic acid, drying, and pressing into granules;

[0125] Step 2: Add the biochar-attapulgite composite material and mix evenly to obtain a soil conditioner.

[0126] Experimental Section

[0127] Experiment 1

[0128] The biomass pyrolysis ash generated in step S1 of Example 3 and the biochar-attapulgite composite material obtained in step S5 were scanned using an electron scanning microscope. The results are shown in FIG. Figure 1 , Figure 2 , Figure 1 This is the SEM image of biomass pyrolysis ash. Figure 2 This is the SEM image of the biochar-attapulgite composite material. It can be seen from the figure that the biochar-attapulgite composite material has a more porous structure and a larger specific surface area than the biomass pyrolysis ash, and has more adsorption sites, which proves that it can improve its adsorption capacity for heavy metal ions and other pollutants.

[0129] from Figure 1 It can be seen that the morphology of biomass pyrolysis ash becomes irregular, presenting a honeycomb or mesh structure, with some microcracks and pores appearing on the surface, which can increase its specific surface area and provide more space for the attachment of attapulgite clay during material composite.

[0130] from Figure 2 It can be seen that the surface of the biochar-attapulgite composite material presents an obvious porous structure, including three types of pores: micropores (pore size <2nm), mesopores (2-50nm) and macropores (>50nm). Micropores and mesopores are particularly important for the adsorption of small molecules, and can effectively capture water-soluble pollutants or certain nutrients; while macropores are suitable for the adsorption of larger molecules or particles, such as some organic pollutants or water; the distribution of these pores is not completely uniform, and there are some large cracks and irregular holes. This is because during the pyrolysis process, the organic components of the biomass decompose, and some volatiles escape at high temperatures, leading to the formation of pores. These irregular pores will enhance the specific surface area of ​​the biomass ash, which helps to improve its adsorption performance.

[0131] Experiment 2

[0132] The soil conditioners prepared by Examples 1-3 and Comparative Examples 1-2 were used to improve the soil of moderately polluted farmland in Tuyou Banner, Baotou City, Inner Mongolia. Six areas were set up and marked as: control area (no soil conditioner was applied), implementation area 1-implementation area 3 (Examples 1-3), comparison area 1-comparison area 2 (Comparative Examples 1-2).

[0133] The soil conditioner was evenly sprinkled on the land surface, and then rotary tillage was performed to mix the soil conditioner and the land evenly. 600 kg of soil conditioner was added to each mu of land, and the soil was irrigated to allow it to be fully dissolved. After 2 months, the soil nitrogen, phosphorus, potassium content, organic matter content, total salt content, and heavy metal ion content (measured in Pb) were determined according to the "Soil Agrochemical Analysis". The results are shown in Table 1.

[0134] Table 1 Comparison before and after improvement

[0135]

[0136] As can be seen from Table 1, the soil nitrogen, phosphorus, potassium and organic matter contents in the implementation areas 1-3 are higher than those in the control area and the comparison area 1 and the comparison area 2. Compared with the control area and the comparison area 1 and the comparison area 2, the improvement of soil nutrients and organic matter content in the implementation areas further proves the effect of the soil conditioner of the present invention on soil improvement.

[0137] The total salt content of the soil in the implementation areas 1-3 was lower than that in the control area and the comparison area. Excessive soil salinity will have a negative impact on plant growth, such as increasing soil osmotic pressure, affecting plant absorption of water, and even causing plant physiological drought. The reduction of soil salinity will not only help the growth of current crops, but also have a positive impact on the long-term fertility and sustainability of the soil. By continuously implementing effective salt management measures, the soil structure can be gradually improved, the soil's ability to retain water and fertilizer can be improved, and the foundation for the sustainable development of agricultural production can be laid; therefore, the reduction in the total salt content of the soil in the implementation area can prove the effect of the soil conditioner of the present invention on soil improvement.

[0138] The Pb ion content of the soil in implementation areas 1-3 is lower than that in the control area and comparison area 1. Pb is a toxic heavy metal that has potential hazards to plant growth and human health. The reduction of the Pb ion content in the soil in the implementation area helps to improve the soil environmental quality, reduce the negative impact on the ecosystem, and reduce the risk of entering the human body through the food chain. The soil conditioner provided by the present invention has a certain fixing or reducing effect on heavy metals, which helps to improve the soil environment.

[0139] Experiment 3

[0140] The soil conditioner prepared in Examples 2 and 3 was applied before crop planting (April), and the application method of "manual broadcasting + rotary tillage" was adopted. A fertilizer spreader was used to evenly apply it on the soil surface, and a rotary tiller was used to turn it into the 0-20 cm soil layer (the application amount is shown in Table 2). After sufficient watering, the honeydew melon seedlings were transplanted. Typical representative plants were selected before transplanting (April), one week after planting (May), fruit setting period (June), expansion period (July) and after harvesting (early August), and their plant height, melon circumference, and leaf area were measured respectively. The results are shown in Table 2.

[0141] Table 2 Growth of honeydew melon

[0142]

[0143] As can be seen from Table 2, the best soil conditioner application amount for Example 2 is 600 kg / mu, and the best soil conditioner application amount for Example 3 is 1000 kg / mu. After harvest, all the produced melons were weighed. Compared with the control group without soil conditioner application (soil conditioner application amount 0), when the soil conditioner application amount for Example 2 was 600 kg / mu, the yield per mu could be increased by 23.42% relative to the control group without soil conditioner application (soil conditioner application amount 0); when the soil conditioner application amount for Example 3 was 1000 kg / mu, the yield per mu could be increased by 26.33% relative to the control group without soil conditioner application.

Claims

1. A functional soil conditioner made from biomass pyrolysis products, characterized in that: The invention is composed of the following materials in proportion by weight: 40-60 parts of biochar-attapulgite composite material, 15-30 parts of humic acid, 5-10 parts of attapulgite clay, 3-5 parts of diammonium hydrogen phosphate, 8-10 parts of wood vinegar, 5-10 parts of polyaspartic acid, and 3-5 parts of bioremediation bacterial agent; According to the mass ratio, the bioremediation bacterial agent is: 1-2 parts of Trichoderma harzianum, 2-3 parts of Bacillus velezensis, 2-3 parts of Paenibacillus gelatinosa, and 2-3 parts of Lactobacillus plantarum; The attapulgite clay has a pH value of 7-8.5, an organic matter content of ≥5wt%, a carbon content of ≥23.63%, a neodymium content of ≥7.72%, a silicon content of ≥4%, a praseodymium content of ≥3.06%, a cerium content of ≥3%, an iron content of ≥2.79%, an aluminum content of ≥2.66%, a potassium content of ≥0.92%, and a titanium content of ≥0.89%; The wood vinegar has a pH value of 3-4, an acetic acid content of ≥50.3%, an organic matter content of ≥15%, a hydroxyacetone content of ≥10%, a propionic acid content of ≥2.39%, and a butyric acid content of ≥1.73%; The preparation method of the biochar-attapulgite composite material is as follows: S1. Decomposing agricultural waste by oxygen-deficient dry distillation in a biomass pyrolysis gasifier to generate biomass pyrolysis ash; the agricultural waste includes melon stems, sunflowers, corn, soybeans, wheat, rice straw and agricultural mulch; S2, mixing the biomass pyrolysis ash and the attapulgite clay, and grinding them to obtain a composite powder; the particle size of the composite powder is 200 mesh, and the mass ratio of the biomass pyrolysis ash to the attapulgite clay is 1-3:5-10; S3, grinding the attapulgite clay to obtain attapulgite fine soil; the particle size of the attapulgite fine soil is 200 mesh; S4, mixing the composite powder prepared in S2 with the attapulgite fine soil obtained in S3, pressing into granules and then drying; the mass ratio of the composite powder to the attapulgite fine soil is 10-15:1; S5, placing the dried material into a high-temperature furnace for calcination to obtain a biochar-attapulgite composite material; the calcination temperature is 400-500° C., and the calcination time is 30-50 min; The preparation method of the soil conditioner is as follows: Step 1, mixing humic acid, attapulgite clay, diammonium hydrogen phosphate, wood vinegar, and polyaspartic acid, drying, and pressing into granules; Step 2: After adding the biochar-attapulgite composite material and mixing evenly, add the bioremediation bacterial agent to obtain a soil conditioner.

2. The use of a functional soil conditioner made from biomass pyrolysis products as claimed in claim 1, characterized in that: Used to improve soil and promote plant growth; the plant is honeydew melon, and the soil conditioner is turned into the 0-20 cm soil layer with a rotary tiller, and the application amount is 1000kg / mu.

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