Seedling raising substrate based on straw and cow dung and preparation method of seedling raising substrate

Abstract

The invention belongs to the technical field of seedling raising substrates, and particularly relates to a seedling raising substrate based on straw and cow dung and a preparation method thereof.The seedling raising substrate based on straw and cow dung is prepared from, by weight, 20-40 parts of dry cow dung, 20-40 parts of straw segments, 10-20 parts of ferroferric oxide composite water-absorbent resin, 6-8 parts of EM bacteria and 40-60 parts of field soil. The preparation method comprises the following steps: grafting a silane coupling agent on the surface of ferroferric oxide, then carrying out polymerization reaction on the surface of the ferroferric oxide grafted with the silane coupling agent and acrylic acid to generate ferroferric oxide-sodium polyacrylate particles, and the ferroferric oxide-sodium polyacrylate particles are magnetic particles. And the surfaces of the ferroferric oxide-sodium polyacrylate particles have abundant carboxyl (-COOH) and sodium carboxylate (-COONa) functional groups. The functional groups can form hydrogen bonds or ionic bonds with water molecules, so that the hydrophilicity and water absorption of the surfaces of the particles are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of seedling cultivation substrates, and in particular relates to a seedling cultivation substrate based on straw and cow dung and a preparation method thereof. Background Art

[0002] Seedling cultivation refers to the process of providing seeds with good growth conditions and support during the initial germination and seedling growth stages under suitable environmental conditions. This process usually takes place in a greenhouse, nursery room or planting pot in order to provide the best growth environment and promote seed germination and healthy growth of seedlings.

[0003] The seedling matrix is ​​crucial for the germination and growth of seeds. This is because the seedling matrix has appropriate air permeability and water retention, which can ensure that the seeds can absorb enough water and air, which is conducive to the rapid germination and root growth of seeds. In addition, the seedling matrix can also provide the basic nutrients required for plant germination and growth, such as nitrogen, phosphorus, potassium, etc., which is conducive to the healthy growth of seedlings and root development. Therefore, matrix seedling cultivation has become an emerging development direction in plant production and an indispensable link in the process of large-scale specialization of agricultural production.

[0004] Matrix seedling cultivation has some significant advantages over conventional soil seedling cultivation, especially in the early stages of seed germination and seedling growth. This is because (1) high-quality seedling cultivation substrates have been sterilized, which can greatly reduce the risk of seedling infection; (2) the seedling cultivation substrate can accurately control the supply of nutrients according to the needs of different plants. This method can better meet the specific nutritional needs of early plant growth than conventional soil seedling cultivation; (3) the substrate has a strong ability to regulate moisture, and the water retention performance of the substrate is usually better than that of soil, which can effectively maintain appropriate humidity and prevent seedlings from being damaged by drought or over-humidity.

[0005] The reason why the matrix has a stronger ability to regulate water than soil is that kaolin is added to the matrix. According to the characteristics of kaolin, the prepared matrix has a certain water retention capacity. However, for arid areas, the sunlight is strong and the evaporation is fast. In particular, kaolin usually has good air permeability, which is very beneficial for the root respiration of plants. However, high air permeability also means that the water in the matrix is ​​more likely to evaporate and lose, especially in arid environments, this situation may be more significant, so the use of kaolin-prepared matrix to cultivate seedlings is not conducive to a continuous supply of water, and will also hinder the germination and growth of seedlings, resulting in a long seedling raising cycle and a low germination rate. Therefore, it is necessary to develop a matrix for seedling cultivation in arid areas to improve the germination rate and shorten the seedling raising cycle. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a straw- and cow dung-based seedling medium and a preparation method thereof.

[0007] The first object of the present invention is to provide a seedling medium based on straw and cow dung, which is prepared from the following raw materials in parts by weight: 20 to 40 parts of dry cow dung, 20 to 40 parts of straw segments, 10 to 20 parts of ferrosoferric oxide composite water-absorbing resin, 6 to 8 parts of EM bacteria and 40 to 60 parts of garden soil.

[0008] Preferably, the seedling medium is prepared from the following raw materials in parts by weight: 25 to 38 parts of dry cow dung, 25 to 38 parts of straw segments, 12 to 18 parts of ferrosoferric oxide composite water-absorbing resin, 6.5 to 7.5 parts of EM bacteria, and 45 to 58 parts of garden soil.

[0009] Preferably, it is characterized in that the seedling medium is prepared from the following raw materials in parts by weight: 30 parts of dry cow dung, 30 parts of straw segments, 18 parts of ferrosoferric oxide composite water-absorbing resin, 7 parts of EM bacteria and 55 parts of garden soil.

[0010] The second object of the present invention is to provide a method for preparing a seedling medium based on straw and cow dung, which comprises accurately weighing dry cow dung, straw segments, ferroferric oxide composite water-absorbing resin, EM bacteria and garden soil according to weight proportions, and crushing the dry cow dung, straw segments and ferroferric oxide composite water-absorbing resin respectively, and then mixing the crushed cow dung, straw segments, ferroferric oxide composite water-absorbing resin and garden soil with EM bacteria.

[0011] Preferably, the method for preparing the ferrosoferric oxide composite water-absorbing resin comprises the following steps:

[0012] Ultrasonic dispersion of the silane coupling agent alcohol solution into the ferric hydroxide alcohol solution, and preparation of ferric hydroxide particles with the silane coupling agent grafted on the surface under a nitrogen atmosphere, wherein the molar ratio of the silane coupling agent to the ferric hydroxide is 1:1.1-1.3;

[0013] The ferric hydroxide particles with silane coupling agent inoculated on the surface are added to an alcohol solvent together with an acrylic acid monomer, and an initiator is added under a nitrogen atmosphere to obtain ferroferric oxide@polyacrylic acid particles through an in-situ polymerization reaction; then a NaOH solution of any concentration is added to the obtained solution of ferroferric oxide@polyacrylic acid particles for acid-base neutralization reaction to obtain ferroferric oxide@sodium polyacrylate particles, that is, ferroferric oxide composite water-absorbing resin is obtained, wherein the mass ratio of the initiator to the acrylic acid monomer is 0.3% to 0.6%:1; the mass ratio of the ferric hydroxide particles with silane coupling agent grafted on the surface to the acrylic acid monomer is 2 to 3:5.

[0014] Preferably, the silane coupling agent is a γ-methacryloxypropyltrimethoxysilanol solution or a vinyltrimethoxysilanol solution, wherein the mass ratio of the silane coupling agent to the alcohol solution is 6 to 7:100.

[0015] Preferably, the reaction temperature of the iron hydroxide surface grafted with a silane coupling agent is 60° C. to 90° C., and the reaction time is 7 h to 10 h.

[0016] Preferably, the initiator is azobisisobutyronitrile, the polymerization reaction temperature is 60 to 90° C., and the reaction time is 6 to 10 hours.

[0017] Preferably, the ferric hydroxide alcohol solution is prepared by dissolving ferric oxide in a hydrochloric acid solution with a volume ratio of 1:1 to obtain a ferric chloride solution, then dropping the prepared sodium hydroxide aqueous solution into the ferric chloride solution, stirring and reacting at 45° C. to 55° C. for 5 h to 8 h, filtering and washing to obtain ferric hydroxide, and then ultrasonically dispersing the ferric hydroxide in an anhydrous alcohol solution to obtain the ferric hydroxide alcohol solution.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention performs corresponding treatment on ferroferric oxide, grafts a silane coupling agent on the surface of ferroferric oxide, and then polymerizes the surface of ferroferric oxide grafted with the silane coupling agent with acrylic acid to generate ferroferric oxide@sodium polyacrylate particles, which are magnetic particles and have abundant carboxyl (-COOH) and sodium carboxylate (-COONa) functional groups on the surface of ferroferric oxide@sodium polyacrylate particles. These functional groups can form hydrogen bonds or ionic bonds with water molecules, thereby increasing the hydrophilicity and water absorption of the particle surface.

[0020] 2. The Fe3O4@PAA particles in the present invention generally have a high specific surface area and rich microporous structures. These microstructures provide more surface area for the adsorption and absorption of water molecules, thereby increasing the water retention capacity of the particles.

[0021] 3. The sodium polyacrylate in the Fe3O4@PAA particles of the present invention is a water-soluble polymer with good hydration and water absorption capacity. When PAA comes into contact with water, it can quickly absorb and retain water, forming a gel-like substance with strong water retention capacity, and the magnetic properties of the Fe3O4@PAA particles can help keep it in a favorable position, thereby effectively enhancing the overall water retention performance of the matrix and effectively prolonging the time that water acts in the matrix. This is especially important in arid or water-scarce areas, or when plants need to retain water for a long time.

[0022] 4. The research experiments of the present invention show that the components of dry cow dung, straw segments, ferroferric oxide composite water-absorbing resin, EM bacteria and garden soil cooperate with each other, thereby improving the germination rate of seedlings in arid areas and shortening the seedling raising period.

[0023] 5. The Fe3O4@PAA particles of the present invention have a network structure, a large specific surface area, and a stronger absorption capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the water absorption rate test result;

[0025] Figure 2 The results of the water release rate experiment. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. Since the steps and methods used are the same as those in Examples 1-5, in order to avoid redundancy, the present invention describes a preferred embodiment, but the present invention is not limited thereto, but can also be specifically implemented in other ways within the scope of the technical solution defined in the attached claims.

[0028] In the description of the present invention, unless otherwise specified, all reagents used are commercially available and all methods used are conventional techniques in the art.

[0029] In the description of the present invention, the EM bacterial powder is purchased from Jinan Juyi Trading Co., Ltd., and the effective live bacteria count is ≥ 10 billion per gram.

[0030] The seedling medium based on straw and cow dung is prepared from the following raw materials in parts by weight: 20-40 parts of dry cow dung, 20-40 parts of straw segments, 10-20 parts of ferrosoferric oxide composite water-absorbing resin, 6-8 parts of EM bacteria and 40-60 parts of garden soil.

[0031] Specifically, the seedling medium is prepared from the following raw materials in parts by weight: 25 to 38 parts of dry cow dung, 25 to 38 parts of straw segments, 12 to 18 parts of ferrosoferric oxide composite water-absorbing resin, 6.5 to 7.5 parts of EM bacteria, and 45 to 58 parts of garden soil.

[0032] Specifically, the seedling medium is prepared from the following raw materials in parts by weight: 30 parts of dry cow dung, 30 parts of straw segments, 18 parts of ferrosoferric oxide composite water-absorbing resin, 7 parts of EM bacteria and 55 parts of garden soil.

[0033] The preparation method of the seedling substrate based on straw and cow dung in the following embodiments and control examples is the same, and the preparation method of the seedling substrate based on straw and cow dung is to accurately weigh dry cow dung, straw segments, ferroferric oxide composite water-absorbing resin, EM bacteria and garden soil according to weight parts, and crush the dry cow dung, straw segments and ferroferric oxide composite water-absorbing resin respectively, and then mix the crushed cow dung, straw segments, ferroferric oxide composite water-absorbing resin and garden soil with EM bacteria.

[0034] The preparation method of the ferroferric oxide composite water-absorbing resin comprises the following steps:

[0035] The ferric hydroxide alcohol solution is prepared by dissolving ferric oxide in a hydrochloric acid solution with a volume ratio of 1:1 to obtain a ferric chloride solution, then dropping the prepared sodium hydroxide aqueous solution into the ferric chloride solution, stirring and reacting at 45° C. to 55° C. for 5 h to 8 h, filtering and washing to obtain ferric hydroxide, and then ultrasonically dispersing the ferric hydroxide in an anhydrous alcohol solution to obtain the ferric hydroxide alcohol solution.

[0036] Ultrasonic dispersion of a silane coupling agent alcohol solution into an iron hydroxide alcohol solution, and under a nitrogen atmosphere, the reaction temperature is 60°C to 90°C, the reaction time is 7h to 10h, and iron hydroxide particles with a silane coupling agent grafted on the surface are prepared, wherein the molar ratio of the silane coupling agent to the iron hydroxide is 1:1.1-1.3, the silane coupling agent is a γ-methacryloxypropyltrimethoxysilanol solution or a vinyltrimethoxysilanol solution, and the mass ratio of the silane coupling agent to the alcohol solution is: 6-7:100;

[0037] The ferric hydroxide particles with silane coupling agent inoculated on the surface are added to an alcohol solvent together with an acrylic acid monomer, and an initiator is added under a nitrogen atmosphere, wherein the initiator is azobisisobutyronitrile, and an in-situ polymerization reaction is performed at a polymerization reaction temperature of 60 to 90° C. and a reaction time of 6 to 10 hours to obtain ferroferric oxide @ polyacrylic acid particles; then a NaOH solution of any concentration is added to the obtained solution of ferroferric oxide @ polyacrylic acid particles for acid-base neutralization reaction to obtain ferroferric oxide @ sodium polyacrylate particles, that is, to obtain ferroferric oxide composite water-absorbing resin, wherein the mass ratio of the initiator to the acrylic acid monomer is 0.3% to 0.6%:1; and the mass ratio of the ferric hydroxide particles with silane coupling agent grafted on the surface to the acrylic acid monomer is 2 to 3:5.

[0038] The technical solution of the present invention is further illustrated below in the form of specific examples.

[0039] Example 1

[0040] The seedling medium based on straw and cow dung is prepared from the following raw materials in parts by weight: 20 parts of dry cow dung, 20 parts of straw segments, 10 parts of ferroferric oxide composite water-absorbing resin, 6 parts of EM bacteria and 40 parts of farmland soil. The above materials are mixed evenly to obtain the seedling medium.

[0041] The preparation method of the above-mentioned straw and cow dung based seedling medium is to accurately weigh dry cow dung, straw segments, ferroferric oxide composite water-absorbing resin and garden soil according to weight proportions, and crush the dry cow dung, straw segments and ferroferric oxide composite water-absorbing resin respectively, and then mix the crushed cow dung, straw segments, ferroferric oxide composite water-absorbing resin and garden soil with EM bacteria.

[0042] The preparation method of the ferroferric oxide composite water-absorbing resin comprises the following steps:

[0043] The ferric hydroxide alcohol solution is prepared by dissolving ferric oxide in a hydrochloric acid solution with a volume ratio of 1:1 to obtain a ferric chloride solution, then dropping the prepared sodium hydroxide aqueous solution into the ferric chloride solution, stirring and reacting at 55° C. for 8 hours, filtering and washing to obtain ferric hydroxide, and then ultrasonically dispersing the ferric hydroxide in an anhydrous alcohol solution to obtain the ferric hydroxide alcohol solution.

[0044] Ultrasonic dispersion of a silane coupling agent alcohol solution into an iron hydroxide alcohol solution, and under a nitrogen atmosphere, the reaction temperature is 80° C., the reaction time is 10 hours, and iron hydroxide particles with a silane coupling agent grafted on the surface are prepared, wherein the molar ratio of the silane coupling agent to the iron hydroxide is 1:1.1, the silane coupling agent is a γ-methacryloxypropyltrimethoxysilanol solution, and the mass ratio of the silane coupling agent to the alcohol solution is 6:100;

[0045] The ferric hydroxide particles with silane coupling agent inoculated on the surface are added to an alcohol solvent together with an acrylic acid monomer, and azobisisobutyronitrile is added under a nitrogen atmosphere, and an in-situ polymerization reaction is performed at a temperature of 80°C and a reaction time of 10 hours to obtain ferroferric oxide @ polyacrylic acid particles; then a NaOH solution of any concentration is added to the obtained solution of ferroferric oxide @ polyacrylic acid particles for acid-base neutralization reaction to obtain ferroferric oxide @ sodium polyacrylate particles, that is, to obtain ferroferric oxide composite water-absorbing resin, wherein the mass ratio of the initiator to the acrylic acid monomer is 0.5%:1; the mass ratio of the ferric hydroxide particles with silane coupling agent grafted on the surface to the acrylic acid monomer is 2:5.

[0046] Example 2

[0047] The seedling medium based on straw and cow dung is prepared from the following raw materials in parts by weight: 30 parts of dry cow dung, 30 parts of straw segments, 18 parts of ferroferric oxide composite water-absorbing resin, 7 parts of EM bacteria and 55 parts of farmland soil. The above materials are mixed evenly to obtain the seedling medium.

[0048] The preparation method of the above-mentioned straw and cow dung based seedling medium is to accurately weigh dry cow dung, straw segments, ferroferric oxide composite water-absorbing resin and garden soil according to weight proportions, and crush the dry cow dung, straw segments and ferroferric oxide composite water-absorbing resin respectively, and then mix the crushed cow dung, straw segments, ferroferric oxide composite water-absorbing resin and garden soil with EM bacteria.

[0049] The preparation method of the ferroferric oxide composite water-absorbing resin comprises the following steps:

[0050] The ferric hydroxide alcohol solution is prepared by dissolving ferric oxide in a hydrochloric acid solution with a volume ratio of 1:1 to obtain a ferric chloride solution, then dropping the prepared sodium hydroxide aqueous solution into the ferric chloride solution, stirring and reacting at 55° C. for 8 hours, filtering and washing to obtain ferric hydroxide, and then ultrasonically dispersing the ferric hydroxide in an anhydrous alcohol solution to obtain the ferric hydroxide alcohol solution.

[0051] Ultrasonic dispersion of a silane coupling agent alcohol solution into an iron hydroxide alcohol solution, and under a nitrogen atmosphere, the reaction temperature is 80° C., the reaction time is 10 hours, and iron hydroxide particles with a silane coupling agent grafted on the surface are prepared, wherein the molar ratio of the silane coupling agent to the iron hydroxide is 1:1.1, the silane coupling agent is a γ-methacryloxypropyltrimethoxysilanol solution, and the mass ratio of the silane coupling agent to the alcohol solution is 6:100;

[0052] The ferric hydroxide particles with silane coupling agent inoculated on the surface are added to an alcohol solvent together with an acrylic acid monomer, and azobisisobutyronitrile is added under a nitrogen atmosphere, and an in-situ polymerization reaction is performed at a temperature of 80°C and a reaction time of 10 hours to obtain ferroferric oxide @ polyacrylic acid particles; then a NaOH solution of any concentration is added to the obtained solution of ferroferric oxide @ polyacrylic acid particles for acid-base neutralization reaction to obtain ferroferric oxide @ sodium polyacrylate particles, that is, to obtain ferroferric oxide composite water-absorbing resin, wherein the mass ratio of the initiator to the acrylic acid monomer is 0.5%:1; the mass ratio of the ferric hydroxide particles with silane coupling agent grafted on the surface to the acrylic acid monomer is 2:5.

[0053] Example 3

[0054] The seedling medium based on straw and cow dung is prepared from the following raw materials in parts by weight: 40 parts of dry cow dung, 40 parts of straw segments, 20 parts of ferroferric oxide composite water-absorbing resin, 6 parts of EM bacteria and 60 parts of garden soil. The above materials are mixed evenly to obtain the seedling medium.

[0055] The preparation method of the above-mentioned straw and cow dung based seedling medium is to accurately weigh dry cow dung, straw segments, ferroferric oxide composite water-absorbing resin and garden soil according to weight proportions, and crush the dry cow dung, straw segments and ferroferric oxide composite water-absorbing resin respectively, and then mix the crushed cow dung, straw segments, ferroferric oxide composite water-absorbing resin and garden soil with EM bacteria.

[0056] The preparation method of the ferroferric oxide composite water-absorbing resin comprises the following steps:

[0057] The ferric hydroxide alcohol solution is prepared by dissolving ferric oxide in a hydrochloric acid solution with a volume ratio of 1:1 to obtain a ferric chloride solution, then dropping the prepared sodium hydroxide aqueous solution into the ferric chloride solution, stirring and reacting at 55° C. for 8 hours, filtering and washing to obtain ferric hydroxide, and then ultrasonically dispersing the ferric hydroxide in an anhydrous alcohol solution to obtain the ferric hydroxide alcohol solution.

[0058] Ultrasonic dispersion of a silane coupling agent alcohol solution into an iron hydroxide alcohol solution, and under a nitrogen atmosphere, the reaction temperature is 80° C., the reaction time is 10 hours, and iron hydroxide particles with a silane coupling agent grafted on the surface are prepared, wherein the molar ratio of the silane coupling agent to the iron hydroxide is 1:1.1, the silane coupling agent is a γ-methacryloxypropyltrimethoxysilanol solution, and the mass ratio of the silane coupling agent to the alcohol solution is 6:100;

[0059] The ferric hydroxide particles with silane coupling agent inoculated on the surface are added to an alcohol solvent together with an acrylic acid monomer, and azobisisobutyronitrile is added under a nitrogen atmosphere, and an in-situ polymerization reaction is performed at a temperature of 80°C and a reaction time of 10 hours to obtain ferroferric oxide @ polyacrylic acid particles; then a NaOH solution of any concentration is added to the obtained solution of ferroferric oxide @ polyacrylic acid particles for acid-base neutralization reaction to obtain ferroferric oxide @ sodium polyacrylate particles, that is, to obtain ferroferric oxide composite water-absorbing resin, wherein the mass ratio of the initiator to the acrylic acid monomer is 0.5%:1; the mass ratio of the ferric hydroxide particles with silane coupling agent grafted on the surface to the acrylic acid monomer is 2:5.

[0060] Comparative Example 1

[0061] There are differences between Control Example 1 and Example 2. The seedling medium based on straw and cow dung is prepared from the following raw materials in parts by weight: 30 parts of dry cow dung, 30 parts of straw segments, 18 parts of ferroferric oxide, 7 parts of EM bacteria and 55 parts of garden soil. The above materials are mixed evenly to obtain the seedling medium.

[0062] Comparative Example 2

[0063] There are differences between Control Example 2 and Example 2. The seedling medium based on straw and cow dung is prepared from the following raw materials in parts by weight: 30 parts of dry cow dung, 30 parts of straw segments, 18 parts of sodium polyacrylate, 7 parts of EM bacteria and 55 parts of garden soil. The above materials are mixed evenly to obtain the seedling medium.

[0064] Comparative Example 3

[0065] There are differences between Control Example 2 and Example 2. The seedling medium based on straw and cow dung is prepared from the following raw materials in parts by weight: 30 parts of dry cow dung, 30 parts of straw segments, 18 parts of kaolin, 7 parts of EM bacteria and 55 parts of garden soil. The above materials are mixed evenly to obtain the seedling medium.

[0066] Comparative Example 4

[0067] There is a difference between Control Example 4 and Example 2. The seedling medium based on straw and cow dung is prepared from the following raw materials in parts by weight: 30 parts of dry cow dung, 30 parts of straw segments, 18 parts of ferroferric oxide composite water-absorbing resin and 55 parts of garden soil. The above materials are mixed evenly to obtain the seedling medium.

[0068] (I) Repeated water absorption capacity test of the matrix

[0069] The water-retaining capacity of the seedling substrates prepared in the above-mentioned Examples 1 to 3 and Comparative Examples 1 to 4 was tested. The seedling substrates prepared in Examples 1 to 3 and Comparative Examples 1 to 4 of the same mass were weighed, which were recorded as A1, and then the seedling substrates of Examples 1 to 3 and Comparative Examples 1 to 4 were soaked in 2000 ml of deionized water, and after being fully soaked for 12 hours, they were filtered using gauze until no water dripped after filtration, which was recorded as A2, and then the obtained A2 was placed in an oven at 80°C for drying, and after drying, it was absorbed again, and then dried again, and this was repeated 10 times, and the mass of the substrate after each re-immersion was recorded as An, and 3 parallel samples were made for each sample.

[0070] Water absorption rate = (An-A1) / A1*100%

[0071] See also Figure 1 There are differences in water absorption between Examples 1 to 3 and Comparative Examples 1 to 4, wherein the water absorption of Examples 1 to 3 is not much different, while there is a great difference in water absorption between Example 2 and Comparative Examples 1 to 4.

[0072] This is because the components in Examples 1 to 4 assist each other and are related, and the surface of the ferroferric oxide@sodium polyacrylate particles has abundant carboxyl (-COOH) and sodium carboxylate (-COONa) functional groups. These functional groups can form hydrogen bonds or ionic bonds with water molecules, thereby increasing the hydrophilicity of the particle surface.

[0073] Although the absorption rates of control examples 1 and 2 are higher than those of control example 3 to a certain extent, the network structure of Fe3O4@PAA particles exposes a larger specific surface area and has a stronger water absorption capacity.

[0074] Compared with Example 2, the water absorption capacity of Control Example 4 is stronger than that of Control Examples 1-3 but weaker than that of Example 2, because there is a correlation between the components.

[0075] (II) Test of water retention capacity of substrate

[0076] The water-retention capacity of the seedling substrates prepared in the above-mentioned Examples 1 to 3 and Comparative Examples 1 to 4 was tested. The seedling substrates prepared in Examples 1 to 3 and Comparative Examples 1 to 4 of the same mass were weighed, which were recorded as B1, and were soaked in 2000 ml of deionized water. After being fully soaked for 12 hours, they were filtered using gauze until no water dripped after filtration. The mass was recorded as B2. The obtained B2 was placed in a beaker and weighed once every 24 hours in an oven at 35°C. The weighed weight was recorded as B3. Each sample was tested 5 times and the average value was calculated.

[0077] Water retention rate = (B3-B1) / (B2-B1)*100%

[0078] See also Figure 2 There are differences in water retention rates between Examples 1 to 3 and Comparative Examples 1 to 4, wherein the water retention rates of Examples 1 to 3 are not much different, while there is a great difference in water retention rates between Example 2 and Comparative Examples 1 to 4.

[0079] This is because the components in Examples 1 to 4 assist each other and are related, and the surface of the ferroferric oxide@sodium polyacrylate particles has abundant carboxyl (-COOH) and sodium carboxylate (-COONa) functional groups. These functional groups can form hydrogen bonds or ionic bonds with water molecules, thereby increasing the hydrophilicity of the particle surface.

[0080] Although the water retention rates of control examples 1 and 2 are higher than those of control example 3 to a certain extent, the network structure of Fe3O4@PAA particles exposes a larger specific surface area and has a stronger water retention capacity.

[0081] Compared with Example 2, the water retention capacity of Control Example 4 is stronger than that of Control Examples 1 to 3 but weaker than that of Example 2, because there is a correlation between the components.

[0082] (III) Seedling emergence rate

[0083] The test was conducted using the matrix prepared in Example 2 and Control Examples 1 to 4, using tomato (Improved Maofen 802F1) as the research object, using the direct seeding method, and using a 50-hole standard hole tray as one sample, and each seedling matrix was used to treat 3 samples. Fertilizer and water management and reasonable prevention and control of pests and diseases were consistent. After the seedlings emerged neatly, the emergence rate of each group was investigated.

[0084] Seedling rate (%) = number of seedlings / number of seeds sown*100%

[0085] Table 1 is the results of the emergence rate of Example 2 and Control Examples 1-4

[0086]

[0087] It can be concluded from Table 1 that the germination rate of Example 2 is much higher than that of Control Examples 1 to 4. This is because the matrix used in Example 2 is different from the matrix used in Control Examples 1 to 4, and the matrix in Example 2 has strong water retention and water absorption capabilities. Therefore, the germination rate of Example 2 is much higher than that of Control Examples 1 to 4.

[0088] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes a preferred embodiment. Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the attached claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0089] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A seedling substrate based on straw and cow dung, characterized in that: The invention is prepared from the following raw materials in parts by weight: 20-40 parts of dry cow dung, 20-40 parts of straw segments, 10-20 parts of ferroferric oxide composite water-absorbing resin, 6-8 parts of EM bacteria and 40-60 parts of farmland soil.

2. The straw and cow dung-based seedling substrate according to claim 1, characterized in that: The seedling culture medium is prepared from the following raw materials in parts by weight: 25 to 38 parts of dry cow dung, 25 to 38 parts of straw segments, 12 to 18 parts of ferroferric oxide composite water-absorbing resin, 6.5 to 7.5 parts of EM bacteria, and 45 to 58 parts of garden soil.

3. The seedling substrate based on straw and cow dung according to claim 1, characterized in that: The seedling culture medium is prepared from the following raw materials in parts by weight: 30 parts of dry cow dung, 30 parts of straw segments, 18 parts of ferroferric oxide composite water-absorbing resin, 7 parts of EM bacteria and 55 parts of garden soil.

4. The method for preparing a seedling medium based on straw and cow dung according to any one of claims 1 to 3, characterized in that: The dry cow dung, straw segments, ferroferric oxide composite water-absorbing resin, EM bacteria and farmland soil are accurately weighed according to weight, and the dry cow dung, straw segments and ferroferric oxide composite water-absorbing resin are crushed respectively, and then the crushed cow dung, straw segments, ferroferric oxide composite water-absorbing resin and farmland soil are mixed with EM bacteria.

5. The method for preparing the seedling medium based on straw and cow dung according to claim 4, characterized in that: The preparation method of the ferroferric oxide composite water-absorbing resin comprises the following steps: Ultrasonic dispersion of the silane coupling agent alcohol solution into the ferric hydroxide alcohol solution, and preparation of ferric hydroxide particles with the silane coupling agent grafted on the surface under a nitrogen atmosphere, wherein the molar ratio of the silane coupling agent to the ferric hydroxide is 1:1.1-1.3; The ferric hydroxide particles with silane coupling agent inoculated on the surface are added to an alcohol solvent together with an acrylic acid monomer, and an initiator is added under a nitrogen atmosphere to obtain ferroferric oxide@polyacrylic acid particles through an in-situ polymerization reaction; then a NaOH solution of any concentration is added to the obtained solution of ferroferric oxide@polyacrylic acid particles for acid-base neutralization reaction to obtain ferroferric oxide@sodium polyacrylate particles, that is, ferroferric oxide composite water-absorbing resin is obtained, wherein the mass ratio of the initiator to the acrylic acid monomer is 0.3% to 0.6%:1; the mass ratio of the ferric hydroxide particles with silane coupling agent grafted on the surface to the acrylic acid monomer is 2 to 3:

5.

6. The method for preparing the seedling substrate based on straw and cow dung according to claim 5, characterized in that: The silane coupling agent is a γ-methacryloxypropyl trimethoxysilanol solution or a vinyl trimethoxysilanol solution, wherein the mass ratio of the silane coupling agent to the alcohol solution is 6 to 7:

100.

7. The method for preparing the seedling medium based on straw and cow dung according to claim 5, characterized in that: The reaction temperature of the iron hydroxide surface grafted with the silane coupling agent is 60° C. to 90° C., and the reaction time is 7 h to 10 h.

8. The method for preparing the seedling medium based on straw and cow dung according to claim 5, characterized in that: The initiator is azobisisobutyronitrile, the polymerization reaction temperature is 60-90° C., and the reaction time is 6 h to 10 h.

9. The method for preparing the seedling medium based on straw and cow dung according to claim 5, characterized in that: The ferric hydroxide alcohol solution is prepared by dissolving ferric oxide in a hydrochloric acid solution with a volume ratio of 1:1 to obtain a ferric chloride solution, then dropping the prepared sodium hydroxide aqueous solution into the ferric chloride solution, stirring and reacting at 45° C. to 55° C. for 5 h to 8 h, filtering and washing to obtain ferric hydroxide, and then ultrasonically dispersing the ferric hydroxide in an anhydrous alcohol solution to obtain the ferric hydroxide alcohol solution.

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