A composite soil improver for gardening and preparation method thereof

Abstract

The invention relates to the technical field of soil improvement, and discloses a garden soil composite improver and a preparation method thereof. The soil composite improver comprises, by weight, 12-15 parts of fermented organic fertilizer, 9-20 parts of modified water-retaining adsorbent, 24-30 parts of biochar, 5-8 parts of plant ash, and 1.2-2 parts of a microbial mixture. The soil composite improver has good adsorption to heavy metal ions, can effectively remove heavy metal ions in the soil, and has excellent fertilizer and water retention, and can maintain the nutrients in the soil for a long time. It has excellent air permeability and water retention, can keep the soil loose and moist, improve soil compaction, improve soil air permeability and soil activity, provide necessary air and water for the growth of plant roots, and each component complements and promotes each other, synergizes and enhances efficiency, and can effectively improve the quality of garden soil.

Description

Technical Field

[0001] The invention relates to the technical field of soil improvement, in particular to a garden soil composite improver and a preparation method thereof. Background Art

[0002] With the rapid development of urban construction and the improvement of people's environmental awareness, the demand for gardening and greening is increasing. In the implementation of urban gardening and greening, soil, as an important part of the urban ecosystem, is the basis for the growth of garden plants and provides the necessary growth environment for plants. With the rapid development of industrialization, a large amount of industrial emissions and urban traffic and life pollution emissions have caused soil degradation. At the same time, there is pollution in irrigation water, which has caused a large amount of heavy metals to enter the soil environment, causing serious harm to soil quality. At the same time, there are multiple problems such as soil compaction and poor soil fertility, which seriously affect the growth of garden plants. Therefore, the application scope of garden soil conditioners is also expanding. There are many types and quantities of soil conditioners, including loosening agents, sand fixation agents, fertilizer agents, disinfectants, acid and alkali reducing agents, water retention agents, soil improvement regulators, etc., which play an important role in repairing and improving degraded soil and promoting the growth of green plants. Different conditioners have different effects, but single-component soil conditioners have poor improvement on the comprehensive performance of soil, and some soil conditioners have high costs. Therefore, comprehensive and cheap soil compound conditioners have a wide market and practical value.

[0003] Chinese patent application CN107473871A discloses a composite acidic garden soil conditioner, which is made of the following raw materials: straw powder, oyster shell powder, polyacrylamide, sodium alginate, minerals, microbial flora components, plant adjuvants, metal chelating agents, ammonium chloride, urea, sodium humate, sodium nitrophenolate, superphosphate, lime, activated carbon, bamboo charcoal, sea mud, sawdust, plant ash, polyhexamethylene guanidine, animal feces, which promotes the formation of a benign microecological environment in plant soil, inhibits the growth of harmful pathogens, improves soil aggregate structure, and reduces the content of toxic metals in the soil. However, the composite conditioner has complex ingredients, directly uses animal feces, has a strong odor, may contain harmful bacteria, and injures green plants, and the applicable soil environment is single. Chinese patent application CN107201233A discloses an eco-friendly soil conditioner, which includes the following raw materials: ore soil filler, coal gangue, straw, mixed grass powder, composite microorganisms, humate, livestock manure, desulfurized gypsum, biochar powder, and trace element additives. The soil conditioner can effectively overcome the imbalance of nutrient elements in the soil, improve soil fertility, loosen the soil, increase fertilizer efficiency, increase organic matter and nutrient content, and loosen compacted soil, but has poor removal effect on heavy metal ions and average water retention. Summary of the invention

[0004] 1. Technical issues to be solved

[0005] In order to solve the above technical problems, the present invention provides a garden soil composite improver and a preparation method thereof. The provided soil composite improver can reduce the heavy metal content in the soil, has good water retention, can also improve the soil structure, and has low cost.

[0006] (II) Technical solution

[0007] In order to achieve the above object, the present invention discloses a garden soil composite improver, which comprises, by weight, 12-15 parts of fermented organic fertilizer, 9-20 parts of modified water-retaining adsorbent, 24-30 parts of biochar, 5-8 parts of plant ash, and 1.2-2 parts of microbial mixture;

[0008] The fermented organic fertilizer is obtained by fermenting animal excrement and plant straw.

[0009] Preferably, the fermented organic fertilizer is prepared by the following steps:

[0010] S1, mixing the animal feces and the mixed acid evenly, adding them into a drum-type high-temperature furnace for drying, the drying temperature is 140-160°C, the drying time is 3-5h, and dry animal feces is obtained;

[0011] S2. Evenly mix the dried animal manure, plant straw and fermentation bacteria, pile them in a fermentation tank, introduce oxygen, and perform aerobic fermentation. Turn the pile during the fermentation process. After the fermentation is completed, obtain the fermented product, air-dry it until the moisture content of the fermented product is 18%-20%, and crush it to obtain fermented organic fertilizer.

[0012] Furthermore, the mass ratio of animal manure to mixed acid in S1 is 100:9-15, the animal manure is composed of chicken manure and pig manure in a mass ratio of 100:18, and the mixed acid is composed of oxalic acid and citric acid in a mass ratio of 5:1.

[0013] Furthermore, the fermentation bacteria in S2 are mixed with Bacillus subtilis and EM stock solution, wherein the mass ratio of dry animal feces, plant straw, Bacillus subtilis and EM stock solution is 21-30:100:1-3:4-9, the plant straw is composed of corn straw and wheat straw with a length of 1 cm and a mass ratio of 3:1, and during the aerobic fermentation process, air with an oxygen volume concentration of 65-75% is introduced, the fermentation temperature is 55-70°C, and the fermentation time is 25-30 days.

[0014] Preferably, the modified water-retaining adsorbent is prepared by the following steps:

[0015] (1) Ultrasonic dispersion of expanded vermiculite (EVMT) in N,N-dimethylacetamide to form a dispersion with a mass fraction of 10%, and then adding isophorone diisocyanate, heating, stirring and mixing, reacting, and after the reaction is completed, filtering, washing with anhydrous ethanol, and vacuum drying at 60° C. for 12 h to obtain isocyanate-modified expanded vermiculite;

[0016] (2) ultrasonically dispersing the isocyanate-modified expanded vermiculite in N,N-dimethylformamide, adding N-(3-aminopropyl)methacrylamide after the dispersion is uniform, heating, stirring and mixing, reacting, and after the reaction is completed, distilling under reduced pressure, washing with anhydrous ethanol, and vacuum drying at 60° C. for 12 h to obtain modified expanded vermiculite;

[0017] (3) N,N-dimethylformamide, modified expanded vermiculite, acrylamide, olefinic cyclodextrin, itaconic acid and initiator are mixed evenly, reacted at 60-70°C in a nitrogen atmosphere for 24 hours, filtered after the reaction, washed with anhydrous ethanol, and dried at 60°C for 6 hours to obtain a modified water-retaining adsorbent.

[0018] Furthermore, in the step (1), the mass ratio of expanded vermiculite to isophorone diisocyanate is 100:152-180, the reaction temperature is 80-90° C., and the reaction time is 5-8 hours.

[0019] Furthermore, in the step (2), the mass ratio of isocyanate-modified expanded vermiculite, N,N-dimethylformamide, and N-(3-aminopropyl)methacrylamide is 100:2500-3200:110-135, the reaction temperature is 75-85° C., and the reaction time is 10-12 h.

[0020] Furthermore, in the step (3), the initiator is azobisisobutyronitrile, and the mass ratio of N,N-dimethylformamide, modified expanded vermiculite, acrylamide, olefinic cyclodextrin, itaconic acid, and initiator is 2500-3200:15-35:9-14:100:2-4:3-7.

[0021] Furthermore, the microbial mixture consists of Bacillus megaterium, photosynthetic bacteria and Bacillus mucilaginosus in a mass ratio of 3:5:2.

[0022] A method for preparing a composite garden soil conditioner comprises the following steps: mixing fermented organic fertilizer, modified water-retaining adsorbent, biochar, plant ash and a microbial mixture, drying at 50°C to a constant weight after mixing evenly, and then crushing and passing through a 100-mesh sieve to obtain the composite garden soil conditioner.

[0023] (III) Beneficial technical effects

[0024] Expanded vermiculite can improve the structure of the soil, making it more loose and breathable, which is conducive to the growth and development of plant roots. At the same time, expanded vermiculite has excellent water storage capacity, which can improve the water retention capacity of the soil, reduce water evaporation and loss, and provide a stable water environment for plants. Expanded vermiculite can provide plants with its own K, Mg, Ca and trace elements, providing the necessary nutrients for plant growth. As a soil conditioner, it can prevent the rapid change of soil pH and improve acidic soil.

[0025] The hydrophobic cavity of cyclodextrin can coordinate or electrostatically attract heavy metal ions, adsorbing heavy metal ions on its surface or inside, reducing the mobility and bioavailability of heavy metal ions in the soil. At the same time, cyclodextrin can be used as a synergist to encapsulate nutrients through inclusion complexation to form a slow-release fertilizer, which gradually releases nutrients according to the needs of plant growth, improves fertilizer utilization, and reduces nutrient loss and waste. Cyclodextrin can be degraded in the soil, has no pollution to the environment, increases soil aggregate structure, improves soil water and fertilizer retention capacity, and reduces soil erosion.

[0026] Biochar has a loose and porous structure and a large specific surface area. It has strong adsorption and chelation capabilities and can effectively absorb nutrients, trace elements, medium elements and water. It plays a role in retaining fertilizer, water, and maintaining the long-term effectiveness of nutrients in the soil, thereby improving the utilization rate of nutrients in soil composite improvers.

[0027] Wood ash is rich in nutrients such as potassium, calcium, and magnesium, which are essential elements for plant growth. As a natural fertilizer, wood ash can directly provide nutrients to the soil and meet the nutritional needs of plants during growth. At the same time, it can also increase the permeability of the soil, improve the aeration and drainage of the soil, improve the water retention of the soil, help maintain moisture in the soil, and reduce water evaporation and loss. Furthermore, wood ash has a strong bactericidal effect, which can kill some pathogens and insect eggs in the soil, reduce the occurrence of plant diseases and insect pests, and effectively maintain the healthy growth of garden plants.

[0028] (1) In the present invention, chicken manure and pig manure are used as animal feces, mixed with deodorants, and the acidity of organic acids is used to neutralize various alkaline odor substances, thereby eliminating the peculiar smell in animal feces. Under the action of fermentation bacteria, the plant straw is fermented to effectively kill harmful bacteria, insect eggs and urokinase in the feces. The obtained fermented organic fertilizer contains rich organic matter, N, P, K and trace elements, which can supplement the nutrients in the soil, improve the biodiversity of the soil, and help maintain the ecological balance of the soil. The organic matter contained in the organic fertilizer can improve the adhesion between soil particles, make the soil more loose and permeable, and improve the water retention and air permeability of the soil. Animal feces and plant straw are agricultural wastes, which are rich in resources and easy to obtain. At the same time, they play a role in material reuse, conform to the principle of sustainable development, reduce production costs, and can effectively restore the fertility of garden soil, which is green and environmentally friendly. The fermented organic fertilizer and other ingredients work together to greatly improve the fertility release rate and have strong durability.

[0029] (2) In the present invention, isophorone diisocyanate is used to modify expanded vermiculite, and isocyanate groups are introduced on the surface of expanded vermiculite to obtain isocyanate-modified expanded vermiculite. The isocyanate groups on the isocyanate-modified expanded vermiculite react with the amino groups on N-(3-aminopropyl)methacrylamide, and a large number of imine groups are introduced to obtain modified expanded vermiculite. Carbon-carbon double bonds are introduced into the modified expanded vermiculite. Under the action of initiator azobisisobutyronitrile, the modified expanded vermiculite, acrylamide, olefinated cyclodextrin, and itaconic acid are polymerized to obtain a modified water-retaining adsorbent. The expanded vermiculite in the modified water-retaining adsorbent has good cation exchangeability and adsorption, and can well adsorb heavy metal ions. At the same time, a large number of carboxyl groups in the introduced itaconic acid can coordinate with heavy metal ions to form stable metal complexes, and further remove heavy metal ions. The nitrogen atoms in the imine groups introduced during the reaction can also form complexes with heavy metal ions to remove heavy metal ions in the soil. Polyacrylamide can form sticky substances at the water-soil interface, increase the shear strength of the soil, reduce the possibility of soil being washed away by water, and thus effectively prevent and control soil erosion. At the same time, it can also improve soil permeability and water retention, and improve soil quality. The modified water-retaining adsorbent obtained after polymerization has improved the inclusion of nutrients and heavy metal ions, further reducing the loss of nutrients, and has better adhesion and stability. It can more effectively bond soil particles together to form a stable soil structure, and improve the stability and anti-erosion ability of the soil.

[0030] (3) Bacillus megaterium, photosynthetic bacteria, and Bacillus colloidus are used as microbial mixtures in the present invention. The microbial mixture can improve the microecology of garden soil and adjust the structure of soil. At the same time, living microorganisms can metabolize heavy metal ions such as cadmium ions and lead ions through cell walls and cell membranes to enter the interior of cells, precipitate in cells or convert into other substances to form bioaccumulation to achieve the fixation of heavy metal ions, thereby repairing garden soil contaminated by heavy metal ions. Furthermore, the microbial composition can also achieve the degradation of organic pollutants in the soil, convert them into carbon sources, etc., and improve the fertility of the soil. The fermented organic fertilizer can promote the reproduction and activity of microorganisms in the microbial mixture, promote the decomposition of organic matter in the soil, release nutrients required by plants, and help prevent and control soil diseases.

[0031] (4) The raw materials used in the present invention are agricultural waste, which is environmentally friendly and safe. At the same time, the material cost used in the present invention is low, the raw materials are easy to obtain, and the process is simple, easy to operate and realize industrial production, and has high practical value and good application prospects. The soil composite improver has excellent fertilizer and water retention, and can keep the nutrients in the soil for a long time. It has excellent air permeability and water retention, can keep the soil loose and moist, improve soil compaction, improve soil permeability and soil activity, and provide necessary air and moisture for the growth of plant roots. The components complement and promote each other, and synergize to effectively improve the quality of garden soil. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] Example 1

[0034] A preparation method of a garden soil composite improver comprises the following steps: by weight, 12 parts of fermented organic fertilizer, 9 parts of modified water-retaining adsorbent, 24 parts of biochar, 5 parts of plant ash, and 1.2 parts of a microbial mixture are mixed, wherein the microbial mixture consists of Bacillus megaterium, photosynthetic bacteria, and Bacillus mucilaginosus in a mass ratio of 3:5:2; after uniform mixing, the mixture is dried at 50°C to a constant weight, crushed, and sieved through a 100-mesh sieve to obtain the garden soil composite improver.

[0035] The fermented organic fertilizer is prepared by the following steps:

[0036] S1, the mass ratio of 100:9 animal manure and mixed acid are mixed evenly, added into a drum type high temperature furnace for drying, the animal manure is composed of chicken manure and pig manure in a mass ratio of 100:18, the mixed acid is composed of oxalic acid and citric acid in a mass ratio of 5:1, the drying temperature is 140 ° C, the drying time is 5h, and the dried animal manure is obtained;

[0037] S2. Mix dry animal excrement, plant straw and fermentation bacteria, pile them in a fermentation tank, introduce oxygen and carry out aerobic fermentation, wherein the fermentation bacteria is mixed with Bacillus subtilis and EM stock solution, wherein the mass ratio of dry animal excrement, plant straw, Bacillus subtilis and EM stock solution is 21:100:1:4, and the plant straw is composed of corn straw and wheat straw with a mass ratio of 3:1 and a length of 1 cm. During the aerobic fermentation, air with an oxygen volume concentration of 65% is introduced, the fermentation temperature is 55°C, the fermentation time is 30d, and the pile is turned during the fermentation process. After the fermentation is completed, a fermentation product is obtained, which is air-dried to a moisture content of 18% and crushed to obtain a fermented organic fertilizer.

[0038] The modified water-retaining adsorbent is prepared by the following steps:

[0039] (1) ultrasonically dispersing expanded vermiculite in N,N-dimethylacetamide to form a dispersion with a mass fraction of 10%, then adding isophorone diisocyanate, wherein the mass ratio of expanded vermiculite to isophorone diisocyanate is 100:152, heating, stirring and mixing, reacting at 80° C. for 8 hours, and after the reaction is completed, filtering, washing with anhydrous ethanol, and vacuum drying at 60° C. for 12 hours to obtain isocyanate-modified expanded vermiculite;

[0040] (2) ultrasonically dispersing the isocyanate-modified expanded vermiculite in N,N-dimethylformamide, and after uniform dispersion, adding N-(3-aminopropyl)methacrylamide, wherein the mass ratio of the isocyanate-modified expanded vermiculite, N,N-dimethylformamide, and N-(3-aminopropyl)methacrylamide is 100:2500:110, heating, stirring and mixing, reacting at 75° C. for 12 hours, and after the reaction is completed, distilling under reduced pressure, washing with anhydrous ethanol, and vacuum drying at 60° C. for 12 hours to obtain modified expanded vermiculite;

[0041] (3) N,N-dimethylformamide, modified expanded vermiculite, acrylamide, olefinated cyclodextrin, itaconic acid and initiator azobisisobutyronitrile in a mass ratio of 2500:15:9:100:2:3 were mixed evenly, reacted at 60°C in a nitrogen atmosphere for 24 hours. After the reaction, the mixture was filtered, washed with anhydrous ethanol, and dried at 60°C for 6 hours to obtain a modified water-retaining adsorbent.

[0042] Example 2

[0043] A preparation method of a garden soil composite improver comprises the following steps: by weight, 13 parts of fermented organic fertilizer, 12 parts of modified water-retaining adsorbent, 26 parts of biochar, 6 parts of plant ash, and 1.5 parts of a microbial mixture are mixed, wherein the microbial mixture consists of Bacillus megaterium, photosynthetic bacteria, and Bacillus mucilaginosus in a mass ratio of 3:5:2; after uniform mixing, the mixture is dried at 50°C to a constant weight, crushed, and sieved through a 100-mesh sieve to obtain the garden soil composite improver.

[0044] The fermented organic fertilizer is prepared by the following steps:

[0045] S1, the mass ratio of 100:14 animal manure and mixed acid are mixed evenly, added into a drum type high temperature furnace for drying, the animal manure is composed of chicken manure and pig manure in a mass ratio of 100:18, the mixed acid is composed of oxalic acid and citric acid in a mass ratio of 5:1, the drying temperature is 150 ° C, the drying time is 4h, and the dried animal manure is obtained;

[0046] S2. Mix dry animal excrement, plant straw and fermentation bacteria, pile them in a fermentation tank, introduce oxygen and carry out aerobic fermentation, wherein the fermentation bacteria is mixed with Bacillus subtilis and EM stock solution, wherein the mass ratio of dry animal excrement, plant straw, Bacillus subtilis and EM stock solution is 25:100:2:7, and the plant straw is composed of corn straw and wheat straw with a mass ratio of 3:1 and a length of 1 cm. During the aerobic fermentation, air with an oxygen volume concentration of 70% is introduced, the fermentation temperature is 65°C, the fermentation time is 28d, the pile is turned during the fermentation process, and after the fermentation is completed, a fermentation product is obtained, which is air-dried to a moisture content of 19% and crushed to obtain a fermented organic fertilizer.

[0047] The modified water-retaining adsorbent is prepared by the following steps:

[0048] (1) ultrasonically dispersing expanded vermiculite in N,N-dimethylacetamide to form a dispersion with a mass fraction of 10%, then adding isophorone diisocyanate, wherein the mass ratio of expanded vermiculite to isophorone diisocyanate is 100:165, heating, stirring and mixing, reacting at 85° C. for 7 hours, and after the reaction is completed, filtering, washing with anhydrous ethanol, and vacuum drying at 60° C. for 12 hours to obtain isocyanate-modified expanded vermiculite;

[0049] (2) ultrasonically dispersing the isocyanate-modified expanded vermiculite in N,N-dimethylformamide, and after uniform dispersion, adding N-(3-aminopropyl)methacrylamide, wherein the mass ratio of the isocyanate-modified expanded vermiculite, N,N-dimethylformamide, and N-(3-aminopropyl)methacrylamide is 100:2800:120, heating, stirring and mixing, reacting at 80° C. for 11 hours, and after the reaction is completed, distilling under reduced pressure, washing with anhydrous ethanol, and vacuum drying at 60° C. for 12 hours to obtain modified expanded vermiculite;

[0050] (3) N,N-dimethylformamide, modified expanded vermiculite, acrylamide, olefinated cyclodextrin, itaconic acid and initiator azobisisobutyronitrile in a mass ratio of 2800:21:11:100:2.5:4.5 were mixed evenly, reacted at 65°C in a nitrogen atmosphere for 24 hours. After the reaction, the mixture was filtered, washed with anhydrous ethanol, and dried at 60°C for 6 hours to obtain a modified water-retaining adsorbent.

[0051] Example 3

[0052] A preparation method of a garden soil composite improver comprises the following steps: by weight, 13 parts of fermented organic fertilizer, 12 parts of modified water-retaining adsorbent, 26 parts of biochar, 6 parts of plant ash, and 1.5 parts of a microbial mixture are mixed, wherein the microbial mixture consists of Bacillus megaterium, photosynthetic bacteria, and Bacillus mucilaginosus in a mass ratio of 3:5:2; after uniform mixing, the mixture is dried at 50°C to a constant weight, crushed, and sieved through a 100-mesh sieve to obtain the garden soil composite improver.

[0053] The preparation method of the fermented organic fertilizer is the same as the preparation method of the fermented organic fertilizer in Example 2.

[0054] The modified water-retaining adsorbent is prepared by the following steps:

[0055] (1) ultrasonically dispersing expanded vermiculite in N,N-dimethylacetamide to form a dispersion with a mass fraction of 10%, then adding isophorone diisocyanate, wherein the mass ratio of expanded vermiculite to isophorone diisocyanate is 100:175, heating, stirring and mixing, reacting at 85° C. for 7 hours, and after the reaction is completed, filtering, washing with anhydrous ethanol, and vacuum drying at 60° C. for 12 hours to obtain isocyanate-modified expanded vermiculite;

[0056] (2) ultrasonically dispersing the isocyanate-modified expanded vermiculite in N,N-dimethylformamide, and after uniform dispersion, adding N-(3-aminopropyl)methacrylamide, wherein the mass ratio of the isocyanate-modified expanded vermiculite, N,N-dimethylformamide, and N-(3-aminopropyl)methacrylamide is 100:3000:130, heating, stirring and mixing, reacting at 80° C. for 11 hours, and after the reaction is completed, distilling under reduced pressure, washing with anhydrous ethanol, and vacuum drying at 60° C. for 12 hours to obtain modified expanded vermiculite;

[0057] (3) N,N-dimethylformamide, modified expanded vermiculite, acrylamide, olefinated cyclodextrin, itaconic acid and initiator azobisisobutyronitrile in a mass ratio of 3000:30:12:100:3.5:6 ​​were mixed evenly, reacted at 65°C in a nitrogen atmosphere for 24 hours. After the reaction, the mixture was filtered, washed with anhydrous ethanol, and dried at 60°C for 6 hours to obtain a modified water-retaining adsorbent.

[0058] Example 4

[0059] A preparation method of a garden soil composite improver comprises the following steps: by weight, 14 parts of fermented organic fertilizer, 16 parts of modified water-retaining adsorbent, 28 parts of biochar, 7 parts of plant ash, and 1.8 parts of a microbial mixture are mixed, wherein the microbial mixture consists of Bacillus megaterium, photosynthetic bacteria, and Bacillus mucilaginosus in a mass ratio of 3:5:2; after uniform mixing, the mixture is dried at 50°C to a constant weight, crushed, and sieved through a 100-mesh sieve to obtain the garden soil composite improver.

[0060] The preparation method of the fermented organic fertilizer is the same as the preparation method of the fermented organic fertilizer in Example 2.

[0061] The preparation method of the modified water-retaining adsorbent is the same as the preparation method of the modified water-retaining adsorbent in Example 3.

[0062] Example 5

[0063] A preparation method of a garden soil composite improver comprises the following steps: by weight, 15 parts of fermented organic fertilizer, 20 parts of modified water-retaining adsorbent, 30 parts of biochar, 8 parts of plant ash, and 2 parts of a microbial mixture are mixed, wherein the microbial mixture consists of Bacillus megaterium, photosynthetic bacteria, and Bacillus mucilaginosus in a mass ratio of 3:5:2; after uniform mixing, the mixture is dried at 50°C to a constant weight, crushed, and sieved through a 100-mesh sieve to obtain the garden soil composite improver.

[0064] The fermented organic fertilizer is prepared by the following steps:

[0065] S1, the mass ratio of 100:15 of animal feces and mixed acid was mixed evenly, added to a drum type high temperature furnace for drying, the animal feces consisted of chicken manure and pig manure in a mass ratio of 100:18, the mixed acid consisted of oxalic acid and citric acid in a mass ratio of 5:1, the drying temperature was 160 ° C, the drying time was 3h, and dried animal feces was obtained;

[0066] S2. Mix dry animal excrement, plant straw and fermentation bacteria, pile them in a fermentation tank, introduce oxygen and carry out aerobic fermentation, wherein the fermentation bacteria is mixed with Bacillus subtilis and EM stock solution, wherein the mass ratio of dry animal excrement, plant straw, Bacillus subtilis and EM stock solution is 30:100:3:9, and the plant straw is composed of corn straw and wheat straw with a mass ratio of 3:1 and a length of 1 cm. During the aerobic fermentation, air with an oxygen volume concentration of 75% is introduced, the fermentation temperature is 70°C, the fermentation time is 25d, the pile is turned during the fermentation process, and after the fermentation is completed, a fermentation product is obtained, which is air-dried to a moisture content of 20% in the fermentation product, and crushed to obtain a fermented organic fertilizer.

[0067] The modified water-retaining adsorbent is prepared by the following steps:

[0068] (1) ultrasonically dispersing expanded vermiculite in N,N-dimethylacetamide to form a dispersion with a mass fraction of 10%, then adding isophorone diisocyanate, wherein the mass ratio of expanded vermiculite to isophorone diisocyanate is 100:180, heating, stirring and mixing, reacting at 90° C. for 5 hours, and after the reaction is completed, filtering, washing with anhydrous ethanol, and vacuum drying at 60° C. for 12 hours to obtain isocyanate-modified expanded vermiculite;

[0069] (2) ultrasonically dispersing the isocyanate-modified expanded vermiculite in N,N-dimethylformamide, and after uniform dispersion, adding N-(3-aminopropyl)methacrylamide, wherein the mass ratio of the isocyanate-modified expanded vermiculite, N,N-dimethylformamide, and N-(3-aminopropyl)methacrylamide is 100:3200:135, heating, stirring and mixing, reacting at 85° C. for 10 hours, and after the reaction is completed, distilling under reduced pressure, washing with anhydrous ethanol, and vacuum drying at 60° C. for 12 hours to obtain modified expanded vermiculite;

[0070] (3) N,N-dimethylformamide, modified expanded vermiculite, acrylamide, olefinated cyclodextrin, itaconic acid and initiator azobisisobutyronitrile in a mass ratio of 3200:35:14:100:4:7 were mixed evenly, reacted at 70°C in a nitrogen atmosphere for 24 hours. After the reaction, the mixture was filtered, washed with anhydrous ethanol, and dried at 60°C for 6 hours to obtain a modified water-retaining adsorbent.

[0071] Comparative Example 1

[0072] A preparation method of a composite garden soil conditioner comprises the following steps: by weight, 2.8 parts of animal manure, 11.2 parts of plant straw, 16 parts of a modified water-retaining adsorbent, 28 parts of biochar, 7 parts of plant ash, and 1.8 parts of a microbial mixture are mixed, wherein the microbial mixture consists of Bacillus megaterium, photosynthetic bacteria, and Bacillus mucilaginosus in a mass ratio of 3:5:2; after uniform mixing, the mixture is dried at 50°C to a constant weight, crushed, and sieved through a 100-mesh sieve to obtain the composite garden soil conditioner.

[0073] The preparation method of the modified water-retaining adsorbent is the same as the preparation method of the modified water-retaining adsorbent in Example 3.

[0074] Comparative Example 2

[0075] A preparation method of a garden soil composite improver comprises the following steps: by weight, 14 parts of fermented organic fertilizer, 16 parts of modified water-retaining adsorbent, 28 parts of biochar, 7 parts of plant ash, and 1.8 parts of a microbial mixture are mixed, wherein the microbial mixture consists of Bacillus megaterium, photosynthetic bacteria, and Bacillus mucilaginosus in a mass ratio of 3:5:2; after uniform mixing, the mixture is dried at 50°C to a constant weight, crushed, and sieved through a 100-mesh sieve to obtain the garden soil composite improver.

[0076] The preparation method of the fermented organic fertilizer is the same as the preparation method of the fermented organic fertilizer in Example 2.

[0077] The modified water-retaining adsorbent is prepared by the following steps:

[0078] N,N-dimethylformamide, expanded vermiculite, acrylamide, olefinated cyclodextrin, itaconic acid and initiator azobisisobutyronitrile were mixed evenly in a mass ratio of 3000:30:12:100:3.5:6, reacted at 65°C in a nitrogen atmosphere for 24 hours. After the reaction, filtered, washed with anhydrous ethanol, and dried at 60°C for 6 hours to obtain a modified water-retaining adsorbent.

[0079] Comparative Example 3

[0080] A preparation method of a garden soil composite improver comprises the following steps: by weight, 14 parts of fermented organic fertilizer, 16 parts of modified expanded vermiculite, 28 parts of biochar, 7 parts of plant ash, and 1.8 parts of a microbial mixture are mixed, wherein the microbial mixture consists of Bacillus megaterium, photosynthetic bacteria, and Bacillus mucilaginosus in a mass ratio of 3:5:2; after uniform mixing, the mixture is dried at 50°C to a constant weight, crushed, and sieved through a 100-mesh sieve to obtain the garden soil composite improver.

[0081] The preparation method of the fermented organic fertilizer is the same as the preparation method of the fermented organic fertilizer in Example 2.

[0082] The modified expanded vermiculite is prepared by the following steps:

[0083] (1) ultrasonically dispersing expanded vermiculite in N,N-dimethylacetamide to form a dispersion with a mass fraction of 10%, then adding isophorone diisocyanate, wherein the mass ratio of expanded vermiculite to isophorone diisocyanate is 100:175, heating, stirring and mixing, reacting at 85° C. for 7 hours, and after the reaction is completed, filtering, washing with anhydrous ethanol, and vacuum drying at 60° C. for 12 hours to obtain isocyanate-modified expanded vermiculite;

[0084] (2) Ultrasonic dispersion of isocyanate-modified expanded vermiculite in N,N-dimethylformamide, and after uniform dispersion, adding N-(3-aminopropyl)methacrylamide, wherein the mass ratio of isocyanate-modified expanded vermiculite, N,N-dimethylformamide, and N-(3-aminopropyl)methacrylamide is 100:3000:130, heating, stirring and mixing, reacting at 80°C for 11 hours, and after the reaction is completed, vacuum distillation is performed, washing with anhydrous ethanol, and vacuum drying at 60°C for 12 hours to obtain modified expanded vermiculite.

[0085] The Bacillus subtilis described in the embodiments and comparative examples of the present invention was purchased from Jinan Qinghai Chemical Co., Ltd., with an effective live bacteria of ≥20 billion / g; EM stock solution was purchased from Jiangxi Tianyi Biotechnology Development Co., Ltd.; expanded vermiculite was purchased from Shijiazhuang Jinli Mining Co., Ltd., with a particle size of 300 mesh; wood ash was purchased from Shanghai Yiru Horticulture Co., Ltd., with the item number Longkang Ash; olefinated cyclodextrin was prepared according to the preparation method in "Lv Ling, Yuan Zhishun, Zeng Zhaorui, Journal of Mathematical Medicine, 1996, 4, 335"; biochar was purchased from Henan Houchang Environmental Protection Technology Co., Ltd., with the item number SWT002; Bacillus megaterium was purchased from Shandong Songguoyun Biotechnology Co., Ltd., model 20220325, with an effective live bacteria of ≥60 billion / g; photosynthetic bacteria were purchased from Shandong Xinzhuoyuan Chemical Co., Ltd.; Bacillus colloidus was purchased from Jinan Jinyuyuan Biotechnology Co., Ltd., with an effective live bacteria of ≥10 billion / g; other undisclosed reagents are all commercially available.

[0086] The soil composite improvers prepared in Examples 1-5 and Comparative Examples 1-3 were named Samples 1-8, respectively, and were subjected to corresponding tests. The test methods and test results are as follows:

[0087] (1) E. coli test: Samples 1-8 were tested for coliform bacteria, and the national standards for the tests were GB / T19524.1-2004;

[0088] (2) Determination of water retention: Weigh 50 g of loose and dry garden soil in a tea bag, weigh its mass as m0, add deionized water to make it adsorbed to saturation, weigh the sample mass as m1, place it in the garden soil, and then measure the total mass m2 after 1 day and 5 days respectively. Water retention rate (%) = (m2-m0) / m1;

[0089] (3) Determination of heavy metals: A 50m2 cadmium and lead contaminated garden soil site (average soil cadmium content of 80 mg / kg, average soil arsenic content of 150 mg / kg) was selected. 2 , the pollution depth is 1.5m, samples 1-8 are applied to the polluted site, and after a 6-month restoration period, the soil leaching toxicity test standard after restoration refers to HJ557-2009, and the leaching toxicity of cadmium and lead is tested. Decrease percentage (%);

[0090] (4) Determination of air permeability: The total porosity (%) of samples 1-8 was measured using STAS 7184 / 5-1978 "Determination of total porosity and air porosity of soil";

[0091] The above test results are shown in Table 1:

[0092] Table 1

[0093]

[0094] According to the test result of Table 1, it can be seen that the coliform bacteria in the animal feces used by the fermented organic fertilizer in the soil composite improver are effectively removed during the fermentation process, and mixed strains are added during the fermentation process, which effectively improves the quantity and activity of strains during the fermentation process, making the fermentation more complete. In Comparative Example 1, animal feces are directly added without processing and fermentation, and Escherichia coli is detected. Water retention rate, heavy metal ion leaching toxicity decline percentage and porosity are tested, indicating that the soil composite improver has excellent water retention rate and heavy metal ion removal power to garden soil, and the porosity is large, effectively improving the soil compaction problem, improving soil permeability and soil activity, and providing necessary air and moisture for the growth of plant root system. Expanded vermiculite is not modified in Comparative Example 2, and comprehensive performance decreases to some extent. In Comparative Example 3, modified expanded vermiculite is used to replace modified water-retaining adsorbent, and the water retention of soil and the removal ability of heavy metal ions are greatly reduced.

[0095] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A composite soil conditioner for gardening, characterized in that: By weight, it includes 12-15 parts of fermented organic fertilizer, 9-20 parts of modified water-retaining adsorbent, 24-30 parts of biochar, 5-8 parts of plant ash, and 1.2-2 parts of microbial mixture; The fermented organic fertilizer is obtained by fermenting animal excrement and plant straw; The fermented organic fertilizer comprises the following steps of preparing: S1, mixing the animal feces and the mixed acid evenly, adding them into a drum-type high-temperature furnace for drying, the drying temperature is 140-160°C, the drying time is 3-5h, and dry animal feces is obtained; S2, dry animal manure, plant straw, fermentation strains are mixed evenly, piled in a fermentation tank, oxygen is introduced, aerobic fermentation is carried out, the pile is turned during the fermentation process, and after the fermentation is completed, a fermentation product is obtained, air-dried to a moisture content of 18%-20% by mass of the fermentation product, and crushed to obtain a fermented organic fertilizer; The mass ratio of animal manure to mixed acid in S1 is 100:9-15, the animal manure is composed of chicken manure and pig manure in a mass ratio of 100:18, and the mixed acid is composed of oxalic acid and citric acid in a mass ratio of 5:1; The fermentation strain in S2 is a mixture of Bacillus subtilis and EM stock solution, wherein the mass ratio of dry animal feces, plant straw, Bacillus subtilis and EM stock solution is 21-30:100:1-3:4-9, the plant straw is composed of corn straw and wheat straw with a length of 1 cm and a mass ratio of 3:1, and during the aerobic fermentation process, air with an oxygen volume concentration of 65-75% is introduced, the fermentation temperature is 55-70°C, and the fermentation time is 25-30d; The modified water-retaining adsorbent is prepared by the following steps: (1) Ultrasonic dispersion of expanded vermiculite in N,N-dimethylacetamide to form a dispersion with a mass fraction of 10%, and then adding isophorone diisocyanate, heating, stirring and mixing to react. After the reaction is completed, suction filtration is performed, washing with anhydrous ethanol, and vacuum drying at 60°C for 12 hours to obtain isocyanate-modified expanded vermiculite; (2) Ultrasonic dispersion of isocyanate-modified expanded vermiculite in N,N-dimethylformamide, adding N-(3-aminopropyl)methacrylamide after uniform dispersion, heating, stirring and mixing to react, and after the reaction is completed, vacuum distillation, washing with anhydrous ethanol, and vacuum drying at 60°C for 12 hours to obtain modified expanded vermiculite; (3) N,N-dimethylformamide, modified expanded vermiculite, acrylamide, olefinic cyclodextrin, itaconic acid and initiator are mixed evenly, reacted at 60-70°C in a nitrogen atmosphere for 24 hours, filtered after the reaction, washed with anhydrous ethanol, and dried at 60°C for 6 hours to obtain a modified water-retaining adsorbent; In the step (1), the mass ratio of expanded vermiculite to isophorone diisocyanate is 100:152-180, the reaction temperature is 80-90° C., and the reaction time is 5-8 h; In step (2), the mass ratio of isocyanate-modified expanded vermiculite, N,N-dimethylformamide, and N-(3-aminopropyl)methacrylamide is 100:2500-3200:110-135, the reaction temperature is 75-85° C., and the reaction time is 10-12 h; In the step (3), the initiator is azobisisobutyronitrile, and the mass ratio of N,N-dimethylformamide, modified expanded vermiculite, acrylamide, olefinic cyclodextrin, itaconic acid, and initiator is 2500-3200:15-35:9-14:100:2-4:3-7.

2. The garden soil composite improver according to claim 1, characterized in that: The microbial mixture consists of Bacillus megaterium, photosynthetic bacteria and Bacillus mucilaginosus in a mass ratio of 3:5:

2.

3. A method for preparing the composite garden soil conditioner according to any one of claims 1 to 2, characterized in that: The method comprises the following steps: mixing fermented organic fertilizer, modified water-retaining adsorbent, biochar, plant ash and microbial mixture, drying at 50 DEG C to constant weight after uniform mixing, and then crushing and passing through a 100-mesh sieve to obtain a garden soil composite improver.

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