Soil conditioner with good cold resistance and preparation method thereof

Abstract

The application relates to the field of fertilizers, and provides a soil conditioner with good cold resistance and a preparation method thereof.The soil conditioner comprises the following raw materials in proportion by weight: humic acid-based compound fertilizer 85-95 parts, modified brassinolide 0.1-0.5 part, beneficial bacteria 0.5-2 parts, dispersing agent 2-6 parts and water 50-100 parts.The soil conditioner can efficiently promote crop growth and has good cold resistance.

Description

Technical Field

[0001] This invention relates to the field of fertilizers, and in particular to a soil conditioner with good cold resistance and its preparation method. Background Technology

[0002] Soil, as a non-renewable resource, provides habitats and water sources for most organisms on Earth and is an important material basis for human survival. However, due to over-planting and improper management, agricultural planting has serious soil problems, such as soil compaction and shallowing of the topsoil, acidification and secondary salinization, and nutrient imbalance. Using green and natural biomass materials such as humic acid can not only improve the current state of soil degradation, enhance its physical and chemical properties, and increase soil nutrient content, but also promote crop growth and improve crop quality.

[0003] Chilling injury, also known as low-temperature chilling injury, is an agricultural meteorological disaster referring to the damage to crops caused by temperatures above 0°C during the crop growing season. Chilling injury hinders the physiological activities of crops, and in severe cases, it can lead to a series of physiological and biochemical changes, such as damage to plant cell membranes, decreased photosynthesis, disordered respiration, and accumulation of reactive oxygen species, ultimately affecting plant growth, development, and yield. Therefore, improving the cold resistance of plants is of great significance for agricultural production. However, although humic acid has many advantages, its cold resistance is limited, and it cannot function effectively in low-temperature environments.

[0004] Patent CN105399525A discloses a liquid fertilizer and its preparation method, but the raw materials in this patent do not contain any ingredients that can directly act as fertilizers. For plants, these substances enhance cold resistance through cold-resistant mechanisms, promoting plant growth and improving the crop's own resistance to cold. Patent CN 101607840 B discloses a multifunctional bio-organic fertilizer and its preparation method and application, which is prepared from the following raw materials in parts by weight: 50-70 parts fermentation raw materials, 0.5-2.0 parts fermentation bacteria powder, 0.3-0.8 parts brown sugar, and 0.05-0.2 parts brassinolide. This organic fertilizer can be directly applied to crops, and the addition of brassinolide can improve the fertilizer's cold resistance. However, the poor stability of natural brassinolide limits its widespread application in agricultural production.

[0005] Therefore, there is an urgent need in the market for a soil conditioner that can effectively promote crop growth while also having good cold resistance. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention discloses a soil conditioner with good cold resistance. It uses humic acid-based compound fertilizer as the main component, and modified brassinolide is designed to be added, along with beneficial bacteria and dispersants, so that it can effectively promote crop growth while also having good cold resistance.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention provides a soil conditioner with good cold resistance. By weight, the soil conditioner comprises the following raw materials: 85-95 parts of humic acid-based compound fertilizer, 0.1-0.5 parts of modified brassinolide, 0.5-2 parts of beneficial bacteria, 2-6 parts of dispersant, and 50-100 parts of water.

[0008] In some embodiments of the present invention, each part of the humic acid-based compound fertilizer comprises the following raw materials by weight: 30-40 parts of potassium nitrohumate slurry, 15-25 parts of monoammonium phosphate, 15-20 parts of urea, 5-10 parts of potassium dihydrogen phosphate, 3-5 parts of trace element chelation solution, and 0.5-1 part of sulfonate filtration loss reducer.

[0009] In some embodiments of the present invention, the method for preparing the potassium nitrohumate slurry includes the following steps: (1) Take lignite, crush it, sieve it, dry it, add 1.5-2.5 mol / L HCl aqueous solution, heat it, stir it, filter it, take the solid, wash it, add 1.5-2.5 mol / L HF aqueous solution, heat it, stir it, filter it, take the solid, wash it, dry it, and get product 1 for later use; (2) Take product 1 from step (1), add HNO3 aqueous solution, heat, stir, cool to room temperature, age, filter, take solid, wash, dry, and obtain product 2 for later use; (3) Take product 2 from step (2), add KOH aqueous solution, heat, stir, cool to room temperature, centrifuge, and take the liquid to obtain potassium nitrohumate slurry.

[0010] In some embodiments of the present invention, in step (1), the ratio of lignite, HCl aqueous solution and HF aqueous solution is 1g:(3.5-4.5)ml:(4.5-5.5)ml; in step (2), the ratio of product 1 and HNO3 aqueous solution is 1g:(9.5-10.5)ml, wherein the concentration of HNO3 aqueous solution is 10-20wt%; in step (3), the ratio of product 2 and KOH aqueous solution is 1g:(11-13)ml, wherein the concentration of KOH aqueous solution is 0.5-0.7mol / L.

[0011] The applicant chose to control the amount of acid and HF aqueous solution added to pre-treat lignite for ash removal, so as to fully remove impurities and improve purity. Furthermore, the applicant controlled the nitration reaction conditions to increase the number of active groups in potassium nitrohumate molecules and improve water solubility, thereby improving the efficiency and stability of subsequent chelation with nitrogen, phosphorus, potassium and trace elements, and thus improving the growth-promoting effect of humic acid compound fertilizer on crops.

[0012] In some embodiments of the present invention, the method for preparing the trace element chelate solution includes the following steps: Add EDTA to deionized water, stir, and set aside the liquid. Add the trace element mixture to deionized water, add the solution, stir, and you will get the trace element chelated solution.

[0013] In some embodiments of the present invention, the trace element mixture comprises ZnSO4·7H2O, FeSO4·7H2O, CuSO4·5H2O, and (NH4)6Mo7O. 24 It is composed of 4H2O and Na2B4O7·10H2O.

[0014] In some embodiments of the present invention, the trace element mixture contains ZnSO4·7H2O, FeSO4·7H2O, CuSO4·5H2O, and (NH4)6Mo7O. 24 The mass ratio of ·4H2O and Na2B4O7·10H2O is 1:(0.8-1):(0.7-9):(0.35-0.5):(0.6-0.8).

[0015] In some embodiments of the present invention, the sulfonate filtration reducer is sodium lignosulfonate.

[0016] In some embodiments of the present invention, the preparation method of the humic acid-based compound fertilizer includes the following steps: Add sulfonate filtration reducer to nitrohumate slurry, stir, heat to 55-65℃, and add monoammonium phosphate, urea, and potassium dihydrogen phosphate in sequence while stirring. Add trace element chelation solution, stir, filter, and age to obtain humic acid-based compound fertilizer.

[0017] In some embodiments of the present invention, the preparation method of the modified brassinolide includes the following steps: 1) Add zein to an ethanol aqueous solution and stir. At the same time, add Tris-HCl buffer to maintain pH=7.5-8.5, add ethylene glycol diglycidyl ether and stir. Add ethylenediamine-terminated polyethyleneimine, stir, dialyze, and freeze dry to obtain a solid for later use. 2) Add the solid from step 1) to an ethanol-water solution, stir, and set aside the liquid. Add glycine betaine to deionized water, stir, add carbodiimide and N-hydroxysuccinimide, stir, adjust the pH to 5-6, stir, add to the solution, stir, dialyze, and freeze dry under vacuum to obtain the carrier for later use. 3) Add the carrier and brassinolide from step 2) to an ethanol aqueous solution, sonicate, add deionized water, stir, and spray dry to obtain modified brassinolide.

[0018] In step 1), the mass ratio between zein and ethylenediamine-terminated polyethyleneimine is 1:(2.5-3.5).

[0019] In some embodiments of the present invention, in step 2), the mass ratio of solid to glycine betaine is 1:(0.4-0.6).

[0020] Preferably, in step 2), the mass ratio of the solid to glycine betaine is 1:0.5.

[0021] In some embodiments of the present invention, in step 3), the mass ratio of the carrier to brassinolide is 1:(0.02-0.06).

[0022] Preferably, in step 3), the mass ratio of the carrier to brassinolide is 1:0.04.

[0023] While humic acid can improve crop cold resistance to some extent by increasing the stability of crop cell membranes and reducing electrolyte leakage at low temperatures, the cold resistance of humic acid alone is limited. Brassinolide can activate crop stress-resistance genes and promote crop photosynthesis and nutrient metabolism, thereby effectively enhancing crop cold resistance. However, brassinolide is easily metabolized by the plant, resulting in insufficient stability and thus greatly reducing its cold resistance effect.

[0024] The applicant synthesized modified brassinolide by modifying zein with glycine betaine as a carrier. Zein is a natural protein with good biodegradability and excellent film-forming properties, which can form a dense protective film to encapsulate brassinolide, reducing its direct contact with external degradation factors such as oxygen, light, and high temperature. Glycine betaine can improve the water solubility and biocompatibility of the carrier, and its quaternary ammonium group can form hydrogen bonds with the hydroxyl groups of brassinolide, further enhancing the stability of the load. At the same time, glycine betaine has the function of an osmosis regulator, which can scavenge reactive oxygen species generated under adverse conditions, and synergize with the cold-resistant function of brassinolide, thereby enabling the modified brassinolide to exert highly efficient cold-resistant properties.

[0025] Furthermore, the combined use of modified brassinolide and potassium nitrohumate can synergistically improve soil structure, promote root growth, and enhance root vitality, thereby further improving crop yield and quality.

[0026] In some embodiments of the present invention, the beneficial bacteria are Bacillus subtilis.

[0027] In some embodiments of the present invention, the dispersant is a mixture of dodecyl betaine and triethanolamine dodecylbenzenesulfonate.

[0028] In some embodiments of the present invention, the mass ratio of dodecyl betaine to triethanolamine dodecylbenzenesulfonate is 1:(1-2).

[0029] Preferably, the mass ratio of dodecyl betaine to triethanolamine dodecylbenzenesulfonate is 1:1.5.

[0030] The applicant uses a certain proportion of dodecyl betaine and triethanolamine dodecylbenzenesulfonate as a dispersant, which can form a complementary system of amphoteric and anionic surfactants, with better dispersing and emulsifying properties, thereby enabling the soil conditioner to work more efficiently.

[0031] In another aspect, the present invention provides a method for preparing a soil conditioner with good cold resistance, comprising the following steps: Mix humic acid-based compound fertilizer, modified brassinolide, beneficial bacteria, dispersant and water, and stir for 1-2 hours at 40-50℃ and 400-600r / min to obtain a soil conditioner with good cold resistance.

[0032] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention discloses a soil conditioner with good cold resistance. It uses humic acid-based compound fertilizer as the main component, and designs the addition of modified brassinolide, along with beneficial bacteria and dispersants. Through the synergistic effect between the components, it can efficiently promote crop growth while also having good cold resistance.

[0033] (2) In this invention, a potassium nitrohumate slurry was designed and prepared in humic acid-based compound fertilizer. The purity was improved by a specific preparation method and the nitration reaction conditions were further controlled to increase the number of active groups in the potassium nitrohumate molecule and improve its water solubility. This improved the efficiency and stability of subsequent chelation with nitrogen, phosphorus, potassium and trace elements, thus making the humic acid compound fertilizer have a better effect on promoting crop growth.

[0034] (3) This invention designs and synthesizes a modified brassinolide. It uses glycine betaine-modified zein as a carrier to load brassinolide to synthesize the modified brassinolide, which solves the problem that natural brassinolide is easily metabolized by plants and thus has insufficient stability. It also synergistically improves the cold resistance of brassinolide. Furthermore, the modified brassinolide can be used in combination with potassium nitrohumate to synergistically improve soil structure, promote root growth and enhance root vitality, thereby further improving the yield and quality of crops. Detailed Implementation

[0035] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0036] In the following examples and comparative examples, except for potassium nitrohumate slurry, trace element chelate solution and modified brassinolide, all other compound monomers and related reagents used were commercially available. Among them, the CAS number of ethylenediamine-terminated polyethyleneimine was 25987-06-8, and the average weight-average molecular weight was 800; glycine betaine was purchased from Hangzhou Haixi Animal Husbandry Technology Co., Ltd.

[0037] Preparation Example 1 The synthesis method of potassium nitrohumate slurry A includes the following steps: (1) Take 50g of lignite, crush it, pass it through a 100-mesh sieve, dry it at 80℃ for 24h, add 200ml of 2mol / L HCl aqueous solution, heat it to 60℃, stir it for 8h, filter it, take the solid, wash it with deionized water until the filtrate is tested with 0.1mol / L AgNO3 aqueous solution until no precipitate is produced, add 250ml of 2mol / L HF aqueous solution, heat it to 60℃, stir it for 24h, filter it, take the solid, wash it with deionized water until the filtrate is tested with 0.1mol / L CaCl2 aqueous solution until no precipitate is produced, dry the solid at 80℃ for 24h to obtain product 1 for later use; (2) Take 10g of product 1 from step (1), add 100ml of 15wt% HNO3 aqueous solution, heat to 60℃, stir for 1h, cool to room temperature, age for 24h, filter, take the solid, wash with deionized water until the pH of the filtrate is 7, dry the solid at 80℃ for 24h, and obtain product 2 for later use. (3) Take 5g of product 2 from step (2), add 60ml of 0.6mol / L KOH aqueous solution, heat to 80℃, stir for 1h, cool to room temperature, centrifuge, and take the liquid to obtain potassium nitrohumate slurry A.

[0038] Preparation Example 2 The synthesis method of potassium nitrohumate slurry B includes the following steps: (1) Take 10g of lignite, crush it, pass it through a 100-mesh sieve, dry it at 80℃ for 24h, add 100ml of 15wt% HNO3 aqueous solution, heat it to 60℃, stir it for 1h, cool it to room temperature, age it for 24h, filter it, take the solid, wash it with deionized water until the pH of the filtrate is 7, dry it at 80℃ for 24h, and obtain the product for later use. (3) Take 5g of the product from step (2), add 60ml of 0.6mol / L KOH aqueous solution, heat to 80℃, stir for 1h, cool to room temperature, centrifuge, and take the liquid to obtain potassium nitrohumate slurry B.

[0039] Preparation Example 3 The method for synthesizing trace element chelate solutions includes the following steps: Add 4g EDTA to 40ml of deionized water at 40℃ and stir until completely dissolved to obtain a liquid for later use. Add 2.8g ZnSO4·7H2O, 2.7g FeSO4·7H2O, 2.5g CuSO4·5H2O, and 1.2g (NH4)6Mo7O 24 Add 4H2O and 2g Na2B4O7·10H2O to 50ml of deionized water, add liquid, stir well, and you will get a trace element chelate solution.

[0040] Preparation Example 4 The method for synthesizing modified brassinolide A includes the following steps: 1) Add 5g of zein to 200ml of 80wt% ethanol aqueous solution and stir for 1h. At the same time, add 0.1mol / L Tris-HCl buffer to maintain pH=8, add 2.5g of ethylene glycol diglycidyl ether, stir for 6h, add 15g of ethylenediamine-terminated polyethyleneimine, stir for 6h, dialyze with deionized water for 24h, freeze dry to obtain solid for later use; 2) Add 5g of the solid from step (1) to 200ml of 50wt% ethanol aqueous solution and stir for 1h to obtain a liquid for later use. Add 2.5g of glycine betaine to 50ml of deionized water and stir for 15min. Add 0.72g of carbodiimide and 0.45g of N-hydroxysuccinimide and stir for 15min. Adjust the pH to 5.5 with hydrochloric acid and stir for 2h. Add the solution and stir for 24h. Dialyze for 24h and freeze dry under vacuum to obtain a carrier for later use. 3) Add 10g of the carrier from step (2) and 0.4g of brassinolide to 200ml of 70wt% ethanol aqueous solution, sonicate for 10min, add 300ml of deionized water, stir for 10min, and spray dry (inlet air temperature is 100℃, outlet air temperature is 55℃) to obtain modified brassinolide A.

[0041] Preparation Example 5 Modified brassinolide B is implemented in the same way as modified brassinolide A, except that in step 2), the mass of glycine betaine is replaced with 1.5g.

[0042] Preparation Example 6 Modified brassinolide C is implemented in the same way as modified brassinolide A, except that in step 3), the mass of brassinolide is replaced with 0.1g.

[0043] Preparation Example 7 Modified brassinolide D is implemented in the same way as modified brassinolide A, except that in step 3), the mass of brassinolide is replaced with 0.7g.

[0044] Example 1 A soil conditioner with good cold resistance properties, comprising the following raw materials by weight: 90 parts of humic acid-based compound fertilizer, 0.3 parts of modified brassinolide A, 1.3 parts of Bacillus subtilis, 4 parts of dispersant, and 80 parts of water.

[0045] By weight, each part of humic acid-based compound fertilizer includes the following raw materials: 35 parts of potassium nitrohumate slurry A, 20 parts of monoammonium phosphate, 18 parts of urea, 7 parts of potassium dihydrogen phosphate, 4 parts of trace element chelation solution, and 0.8 parts of sodium lignosulfonate.

[0046] The dispersant is a mixture of dodecyl betaine and triethanolamine dodecylbenzenesulfonate in a mass ratio of 1:1.5.

[0047] The method for preparing the soil conditioner with good cold resistance in this embodiment includes the following steps: S1. Add sodium lignosulfonate to nitrohumate slurry A, stir for 30 min, heat to 60℃, add monoammonium phosphate, urea, and potassium dihydrogen phosphate in sequence while stirring, add trace element chelation solution, stir for 30 min, filter, and age for 24 h to obtain humic acid-based compound fertilizer for later use. S2. Mix humic acid-based compound fertilizer, modified brassinolide A, Bacillus subtilis, dispersant and water, and stir for 1.5 hours at 45℃ and 500r / min to obtain a soil conditioner with good cold resistance.

[0048] Example 2 A soil conditioner with good cold resistance properties, comprising the following raw materials by weight: 85 parts of humic acid-based compound fertilizer, 0.1 parts of modified brassinolide A, 0.5 parts of Bacillus subtilis, 2 parts of dispersant, and 50 parts of water.

[0049] The humic acid-based compound fertilizer is the same as in Example 1.

[0050] The dispersant is a mixture of dodecyl betaine and triethanolamine dodecylbenzenesulfonate in a mass ratio of 1:1.

[0051] The method for preparing the soil conditioner with good cold resistance in this embodiment includes the following steps: S1. Add sodium lignosulfonate to nitrohumate slurry A, stir for 30 min, heat to 60℃, add monoammonium phosphate, urea, and potassium dihydrogen phosphate in sequence while stirring, add trace element chelation solution, stir for 30 min, filter, and age for 24 h to obtain humic acid-based compound fertilizer for later use. S2. Mix humic acid-based compound fertilizer, modified brassinolide A, Bacillus subtilis, dispersant and water, and stir for 2 hours at 40℃ and 400r / min to obtain a soil conditioner with good cold resistance.

[0052] Example 3 A soil conditioner with good cold resistance properties, comprising the following raw materials by weight: 95 parts of humic acid-based compound fertilizer, 0.5 parts of modified brassinolide A, 2 parts of Bacillus subtilis, 6 parts of dispersant, and 100 parts of water.

[0053] The humic acid-based compound fertilizer is the same as in Example 1.

[0054] The dispersant is a mixture of dodecyl betaine and triethanolamine dodecylbenzenesulfonate in a mass ratio of 1:2.

[0055] The preparation method of the soil conditioner with good cold resistance in this embodiment is the same as in Example 1.

[0056] Example 4 This embodiment provides a soil conditioner with good cold resistance and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that potassium nitrohumate slurry B replaces potassium nitrohumate slurry A in an equal amount.

[0057] Example 5 This embodiment provides a soil conditioner with good cold resistance and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that modified brassinolide B replaces modified brassinolide A in an equal amount.

[0058] Example 6 This embodiment provides a soil conditioner with good cold resistance and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that modified brassinolide C is used to replace modified brassinolide A in an equal amount.

[0059] Example 7 This embodiment provides a soil conditioner with good cold resistance and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that modified brassinolide D is used to replace modified brassinolide A in an equal amount.

[0060] Comparative Example 1 This comparative example provides a soil conditioner with good cold resistance and its preparation method. The specific implementation method is the same as that in Example 1, except that brassinolide is used to replace modified brassinolide A in an equal amount.

[0061] Performance testing The relevant properties of the soil conditioners in Examples 1-7 and Comparative Example 1 were tested, and the test results are shown in Table 1.

[0062] The soil conditioners of Examples 1-7 and Comparative Example 1 were compared in a fertilization experiment. The test crop was cucumber. The experiment adopted a randomized block design. 8 mu of cucumbers were planted in the experimental field and randomly divided into 10 groups, with 1 mu in each group. The soil conditioners of Examples 1-9 and Comparative Example 1 were diluted with water at a mass ratio of 1:500 and sprayed evenly on the cucumbers. Foliar spraying was carried out once each at the cucumber seedling stage, the initial flowering stage, and the flowering and fruiting stage. The amount used each time was 5 kg per mu. The average yield of cucumbers at harvest (Y0) was calculated.

[0063] Low temperature treatment: Low temperature treatment (5℃ for 5 days) was carried out during the flowering and fruiting period. Other operations were the same as above. The average yield of cucumbers per mu at harvest time (Y1) was calculated.

[0064] The average yield loss rate of cucumbers after low-temperature treatment is calculated as (Y0-Y1) / Y0×100%.

[0065] Table 1

[0066] As shown in Table 1, the cucumber yield per mu (667 square meters) after application of the soil conditioner in Examples 1-3 of this invention was relatively high, and the yield loss rate per mu after low-temperature treatment was relatively small, indicating good growth-promoting effect and cold resistance of the crop. Specifically, Example 4, which used traditional methods to prepare potassium nitrohumate slurry, showed a significant decrease in the growth-promoting effect of the soil conditioner, but little impact on cold resistance. Examples 5-7 involved altering the proportion of key components in the synthesis of modified brassinolide, resulting in a significant decrease in the cold resistance of the soil conditioner, but little impact on the yield of crops not treated with low temperatures. Comparative Example 1, where brassinolide was used to replace modified brassinolide A in equal amounts, showed even worse cold resistance in the soil conditioner.

[0067] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A soil conditioner with good cold resistance, characterized in that, By weight, the soil conditioner comprises the following raw materials: The compound fertilizer contains 85-95 parts of humic acid, 0.1-0.5 parts of modified brassinolide, 0.5-2 parts of beneficial bacteria, 2-6 parts of dispersant, and 50-100 parts of water.

2. The soil conditioner with good cold resistance according to claim 1, characterized in that, By weight, each part of the humic acid-based compound fertilizer comprises the following raw materials: 30-40 parts of potassium nitrohumate slurry, 15-25 parts of monoammonium phosphate, 15-20 parts of urea, 5-10 parts of potassium dihydrogen phosphate, 3-5 parts of trace element chelation solution, and 0.5-1 part of sulfonate filtration loss reducer.

3. The soil conditioner with good cold resistance according to claim 2, characterized in that, The preparation method of the potassium nitrohumate slurry includes the following steps: (1) Take lignite, crush it, sieve it, dry it, add 1.5-2.5 mol / L HCl aqueous solution, heat it, stir it, filter it, take the solid, wash it, add 1.5-2.5 mol / L HF aqueous solution, heat it, stir it, filter it, take the solid, wash it, dry it, and get product 1 for later use; (2) Take product 1 from step (1), add HNO3 aqueous solution, heat, stir, cool to room temperature, age, filter, take solid, wash, dry, and obtain product 2 for later use; (3) Take product 2 from step (2), add KOH aqueous solution, heat, stir, cool to room temperature, centrifuge, and take the liquid to obtain potassium nitrohumate slurry.

4. The soil conditioner with good cold resistance according to claim 1, characterized in that, The preparation method of the modified brassinolide includes the following steps: 1) Add zein to an ethanol aqueous solution and stir. At the same time, add Tris-HCl buffer to maintain pH=7.5-8.5, add ethylene glycol diglycidyl ether and stir. Add ethylenediamine-terminated polyethyleneimine, stir, dialyze, and freeze dry to obtain a solid for later use. 2) Add the solid from step 1) to an ethanol-water solution, stir, and set aside the liquid. Add glycine betaine to deionized water, stir, add carbodiimide and N-hydroxysuccinimide, stir, adjust the pH to 5-6, stir, add to the solution, stir, dialyze, and freeze dry under vacuum to obtain the carrier for later use. 3) Add the carrier and brassinolide from step 2) to an ethanol aqueous solution, sonicate, add deionized water, stir, and spray dry to obtain modified brassinolide.

5. The soil conditioner with good cold resistance according to claim 4, characterized in that, In step 2), the mass ratio of solid to glycine betaine is 1:(0.4-0.6).

6. The soil conditioner with good cold resistance according to claim 4, characterized in that, In step 3), the mass ratio of the carrier to brassinolide is 1:(0.02-0.06).

7. The soil conditioner with good cold resistance according to claim 1, characterized in that, The beneficial bacteria are Bacillus subtilis.

8. The soil conditioner with good cold resistance according to claim 1, characterized in that, The dispersant is a mixture of dodecyl betaine and triethanolamine dodecylbenzenesulfonate.

9. The soil conditioner with good cold resistance as described in claim 8, characterized in that, The mass ratio of dodecyl betaine to triethanolamine dodecylbenzenesulfonate is 1:(1-2).

10. A method for preparing a soil conditioner with good cold resistance as described in any one of claims 1-9, characterized in that, Includes the following steps: Mix humic acid-based compound fertilizer, modified brassinolide, beneficial bacteria, dispersant and water, and stir for 1-2 hours at 40-50℃ and 400-600r / min to obtain a soil conditioner with good cold resistance.

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