High-absorption liquid compound fertilizer for direct drip irrigation application

Abstract

The invention relates to the technical field of agricultural fertilizers, and discloses a high-absorption liquid compound fertilizer for direct drip irrigation application, which comprises the following raw materials by weight: 45-50% of potassium nitrate; 10%-15% of monoammonium phosphate; 7%-11% of urea; 6%-9% of calcium nitrate; 8%-12% of ammonium sulfate; 4%-7% of magnesium sulfate heptahydrate; 3-5 parts of a seaweed extract; 2%-4% of boron humate; 1%-3% of EDTA disodium; 2%-5% of zinc polyphosphate; 0.5%-1% of ammonium thiosulfate; 0.5%-1% of ammonium molybdate; 1%-2% of amino acid manganese; 0.5%-1.5% of fulvic acid; 0.1%-0.5% of sodium diethylhexyl sulfosuccinate; 0.6%-0.9% of citric acid; 0.2%-0.7% of ascorbic acid; the liquid compound fertilizer is prepared according to the raw materials, the liquid compound fertilizer which is high in absorption, high in efficiency, stable and adaptive to a drip irrigation system is obtained, the growth vigor of crops, the fruit quality and the yield can be improved, meanwhile, blockage of the drip irrigation system is reduced, the service life of equipment is prolonged, and the liquid compound fertilizer has good application value.

Description

Technical Field

[0001] This invention relates to the field of agricultural fertilizer technology, specifically to a highly absorbent liquid compound fertilizer that can be applied directly via drip irrigation. Background Technology

[0002] Under the trend of precision and efficiency in modern agriculture, drip irrigation fertilization technology has become an important means to improve agricultural production efficiency due to its advantages of water and fertilizer saving and precise fertilizer supply. However, there are still many technical bottlenecks in the liquid compound fertilizers currently used for drip irrigation on the market. On the one hand, the nutrient ratio of traditional fertilizers often relies on experience to set, making it difficult to accurately match the nutritional needs of crops at different growth stages. This often leads to nutrient imbalance, resulting in slow crop growth, reduced fruit quality, and limited yield. For example, an improper ratio of nitrogen, phosphorus, and potassium can cause excessive vegetative growth or poor fruit development, reducing the fruit's storage and transportability. On the other hand, the lack or unreasonable addition of functional components in fertilizers results in poor fertilizer stability and limited effect on improving stress resistance. For example, the lack of chelating agents makes metal ions prone to precipitation, reducing fertilizer efficiency, and the absence of plant active ingredients makes it difficult to enhance the crop's resistance to adversity. In addition, non-standard preparation processes also cause a series of problems. Insufficient filtration leads to impurities clogging the drip irrigation system, and uncontrolled mixing reaction conditions cause a decrease in the stability of the fertilizer solution, seriously affecting the service life of drip irrigation equipment and fertilization effect, thus restricting the promotion and application of drip irrigation fertilization technology. Therefore, developing a highly absorbable liquid compound fertilizer with a scientific nutrient ratio, stable performance, and compatibility with drip irrigation systems has become an urgent industry challenge. Summary of the Invention

[0003] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a highly absorbable liquid compound fertilizer that can be directly applied via drip irrigation. It has the advantages of scientific nutrient ratio, high-efficiency absorption and utilization, stable performance, and compatibility with drip irrigation systems, thus solving the problems of nutrient imbalance, poor stability, drip irrigation system blockage, and poor fertilization effect of traditional fertilizers.

[0004] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a highly absorbent liquid compound fertilizer for direct drip irrigation, comprising the following steps: Step 1: Raw material selection and specific gravity: Potassium nitrate, monoammonium phosphate, urea, calcium nitrate, ammonium sulfate, magnesium sulfate heptahydrate, seaweed extract, boron humate, disodium EDTA, zinc polyphosphate, ammonium thiosulfate, ammonium molybdate, manganese amino acids, fulvic acid, sodium dioctyl sulfosuccinate, citric acid, ascorbic acid, compound trace element sugar alcohol and deionized water; Step 2, Raw material pretreatment: Dissolve calcium nitrate, ammonium sulfate, and magnesium sulfate heptahydrate. Step 3, Mixing reaction: Add potassium nitrate, monoammonium phosphate and urea to the reaction vessel and stir evenly. Then add the dissolved calcium nitrate solution, ammonium sulfate solution and magnesium sulfate heptahydrate solution dropwise from step 2 to fully mix the raw materials and obtain a mixed reaction solution. Step 4: Adding additives: In the reaction vessel, add seaweed extract, boron humate, disodium EDTA, zinc polyphosphate, ammonium thiosulfate, ammonium molybdate, manganese amino acids, fulvic acid, sodium dioctyl sulfosuccinate, citric acid, ascorbic acid and compound trace element sugar alcohol in sequence to make the additives evenly dispersed in the mixture. Step 5, pH adjustment: Use a pH meter to monitor the online pH value of the solution in the reaction vessel in real time; Step 6, Post-processing: After pH adjustment, the mixed solution is filtered three times to control the final viscosity between 1-4 cP, thus obtaining liquid compound fertilizer.

[0005] Preferably, the raw materials and their proportions of the compound fertilizer in step one are as follows: potassium nitrate 45%–50%; monoammonium phosphate 10%–15%; urea 7%–11%; calcium nitrate 6%–9%; ammonium sulfate 8%–12%; magnesium sulfate heptahydrate 4%–7%; seaweed extract 3–5%; boron humate 2%–4%; disodium EDTA 1%–3%; zinc polyphosphate 2%–5%; ammonium thiosulfate 0.5%–1%; ammonium molybdate 0.5%–1%; manganese amino acids 1%–2%; fulvic acid 0.5%–1.5%; sodium dioctyl sulfosuccinate 0.1%–0.5%; citric acid 0.6%–0.9%; ascorbic acid 0.2%–0.7%; compound trace element sugar alcohol 1%–2%; and the remainder is deionized water.

[0006] Preferably, the magnesium sulfate heptahydrate is prepared by reacting a magnesium source with sulfuric acid, and its chemical reaction formula is as follows: MgO + H₂SO₄ + 6H₂O → MgSO₄·7H₂O In the formula, MgO represents magnesium oxide, H2SO4 represents sulfuric acid, H2O represents water, and MgSO4·7H2O represents magnesium sulfate heptahydrate.

[0007] Preferably, the seaweed extract is prepared by: S1.1 Select fresh, unpolluted seaweed and wash it with clean water; S1.2. Chop the seaweed into pieces with a diameter of 3-5mm; S1.3 Add deionized water at 5-8 times the dry weight of seaweed, adjust the pH to 7.5-8, stir and extract at 65-70℃ for 3-4 hours, and filter to obtain the extract; S1.4 Add 0.2% to 0.4% of the total mass of seaweed to the extract, and enzymatically hydrolyze at 38-45℃ for 2-5 hours to break down the cell walls. Filter to obtain the enzymatic hydrolysate. S1.5. Concentrate the enzymatic hydrolysate under vacuum at 55-60℃ and 0.08-0.09MPa for 2-3 hours until the volume is reduced to 1 / 10-1 / 5 of the original volume.

[0008] Preferably, in step two, the raw material pretreatment involves adding calcium nitrate, ammonium sulfate, and magnesium sulfate heptahydrate to deionized water and heating it to 50-55°C for later use.

[0009] Preferably, the mixing reaction conditions in step three are: controlling the temperature of the mixed solution between 40-50℃, and stirring the reaction at a speed of 40-50 r / min for 1-2 hours.

[0010] Preferably, the mixing conditions for the additives in step four are: stirring at 100-200 r / min for 30-60 minutes in an environment below 35°C.

[0011] Preferably, in step five, pH adjustment involves adding 5%–10% potassium hydroxide or 2%–5% sodium hydroxide solution dropwise when the pH meter detects that the online pH value of the solution in the reactor is not within the target range. The target pH range is 5.8–6.2.

[0012] Preferably, the three-stage filtering in step six: S2.1 Coarse filtration: Pass the pH-adjusted mixed solution through an 80-100 mesh sieve; S2.2 Fine filtration: The mixed solution after coarse filtration is passed through a 5μm filter cartridge; S2.3, Ultrafiltration: The mixed solution after fine filtration is passed through a 0.22μm sterile filter membrane.

[0013] Preferably, the composite trace element sugar alcohol is composed of mannitol chelated iron, xylitol chelated copper, and sorbitol chelated zinc in a ratio of 3:2:2.

[0014] Compared with the prior art, the present invention provides a highly absorbent liquid compound fertilizer for direct drip irrigation, which has the following beneficial effects: 1. This invention achieves beneficial effects of promoting crop growth, improving fruit quality and yield by scientifically proportioning potassium nitrate, monoammonium phosphate and urea within a reasonable range. Within the set proportion range, the main nutrients can meet the needs of crops at different growth stages, improve crop growth vitality and fruit quality, and enhance storage and transportation resistance.

[0015] 2. This invention achieves the beneficial effects of enhancing plant stress resistance and stabilizing the fertilizer system by adding functional components such as seaweed extract and disodium EDTA. Among them, seaweed extract is rich in natural plant hormones and active ingredients, which can stimulate crop growth, enhance its stress resistance, and effectively prevent root diseases and poor growth. Disodium EDTA, on the other hand, prevents precipitation by chelating metal ions, improves the stability of fertilizer solution and the availability of elements, and ensures that the fertilizer maintains high efficiency during storage and application. The synergistic effect of the two components helps to improve the overall performance of the fertilizer.

[0016] 3. This invention achieves the beneficial effects of ensuring high stability of fertilizer solution and compatibility with drip irrigation systems by strictly standardizing the process flow of raw material pretreatment, mixing reaction conditions, pH adjustment, and three-stage filtration. By precisely controlling the temperature, stirring speed, and pH value of the mixing reaction, and by adopting a three-stage filtration process, undissolved particles and impurities are effectively removed to ensure the clarity and sterility of the fertilizer solution. This not only improves the fertilizer absorption efficiency but also avoids clogging of the drip irrigation system, thereby extending the service life of the drip irrigation equipment and ensuring that fertilizer can be applied to crops safely and efficiently. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the preparation process of the liquid compound fertilizer of this invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Please see Figure 1 A highly absorbable liquid compound fertilizer for direct drip irrigation includes the following steps: Step 1: Raw material selection and specific gravity: Potassium nitrate, monoammonium phosphate, urea, calcium nitrate, ammonium sulfate, magnesium sulfate heptahydrate, seaweed extract, boron humate, disodium EDTA, zinc polyphosphate, ammonium thiosulfate, ammonium molybdate, manganese amino acids, fulvic acid, sodium dioctyl sulfosuccinate, citric acid, ascorbic acid, compound trace element sugar alcohol and deionized water; Step 2, Raw material pretreatment: Dissolve calcium nitrate, ammonium sulfate, and magnesium sulfate heptahydrate. Step 3, Mixing reaction: Add potassium nitrate, monoammonium phosphate and urea to the reaction vessel and stir evenly. Then add the dissolved calcium nitrate solution, ammonium sulfate solution and magnesium sulfate heptahydrate solution dropwise from step 2 to fully mix the raw materials and obtain a mixed reaction solution. Step 4: Adding additives: In the reaction vessel, add seaweed extract, boron humate, disodium EDTA, zinc polyphosphate, ammonium thiosulfate, ammonium molybdate, manganese amino acids, fulvic acid, sodium dioctyl sulfosuccinate, citric acid, ascorbic acid and compound trace element sugar alcohol in sequence to make the additives evenly dispersed in the mixture. Step 5, pH adjustment: Use a pH meter to monitor the online pH value of the solution in the reactor in real time. When the monitored pH value is not in the target range, add 5% to 10% potassium hydroxide or 2% to 5% sodium hydroxide solution dropwise to control the pH within the target range. Step 6, Post-processing: After pH adjustment, the mixed solution is filtered three times to control the final viscosity between 1-4 cP, thus obtaining liquid compound fertilizer.

[0020] The advantages are: by strictly regulating the process of raw material pretreatment, mixing reaction conditions, pH adjustment, and three-stage filtration, the high stability of the fertilizer solution and compatibility with drip irrigation systems are ensured. By precisely controlling the temperature, stirring speed, and pH value of the mixing reaction, and by using a three-stage filtration process, undissolved particles and impurities are effectively removed to ensure the clarity and sterility of the fertilizer solution. This not only improves the fertilizer absorption efficiency but also avoids clogging of the drip irrigation system, thereby extending the service life of the drip irrigation equipment and ensuring that the fertilizer can be applied to crops safely and efficiently.

[0021] Specifically, the raw materials and their proportions for the compound fertilizer in step one are as follows: potassium nitrate 45%–50%; monoammonium phosphate 10%–15%; urea 7%–11%; calcium nitrate 6%–9%; ammonium sulfate 8%–12%; magnesium sulfate heptahydrate 4%–7%; seaweed extract 3–5%; boron humate 2%–4%; disodium EDTA 1%–3%; zinc polyphosphate 2%–5%; ammonium thiosulfate 0.5%–1%; ammonium molybdate 0.5%–1%; manganese amino acids 1%–2%; fulvic acid 0.5%–1.5%; sodium dioctyl sulfosuccinate 0.1%–0.5%; citric acid 0.6%–0.9%; ascorbic acid 0.2%–0.7%; compound trace element sugar alcohol 1%–2%; and the remainder is deionized water.

[0022] The advantages are: by scientifically proportioning potassium nitrate, monoammonium phosphate and urea within a reasonable range, it achieves the beneficial effects of promoting crop growth, improving fruit quality and yield. Within the set proportion range, the main nutrients can meet the needs of different growth stages of crops, improve crop growth vitality and fruit quality, and improve storage and transportation resistance.

[0023] Specifically, the raw materials and their functions are as follows: Table 1

[0024] Specifically, magnesium sulfate heptahydrate (MgSO4·7H2O) is prepared by reacting a magnesium source with sulfuric acid, and its chemical reaction formula is as follows: MgO + H₂SO₄ + 6H₂O → MgSO₄·7H₂O In the formula, MgO represents magnesium oxide (magnesium source, from magnesite, dolomite, etc.), H2SO4 represents sulfuric acid (providing sulfate ions), and H2O represents water (reaction medium, participating in the formation of crystalline hydrates).

[0025] Specifically, the preparation method of seaweed extract is as follows: S1.1 Select fresh, uncontaminated seaweed, wash it with clean water to remove mud, salt and other impurities, and ensure it is uncontaminated; S1.2. Chop the seaweed into pieces with a diameter of 3-5mm to increase the contact area of ​​the raw materials; S1.3 Add deionized water at 5-8 times the dry weight of seaweed, adjust the pH to 7.5-8, stir and extract at 65-70℃ for 3-4 hours, and filter to obtain the extract; S1.4 Add 0.2% to 0.4% of the total mass of seaweed to the extract, and enzymatically hydrolyze at 38-45℃ for 2-5 hours to break down the cell walls. Filter to obtain the enzymatic hydrolysate, which fully releases the active ingredients (such as polysaccharides, amino acids and minerals) in the seaweed. S1.5. Concentrate the enzymatic hydrolysate under vacuum at 55-60℃ and 0.08-0.09MPa for 2-3 hours until the volume is reduced to 1 / 10-1 / 5 of the original volume, in order to remove most of the water, increase the concentration of the active ingredients, and facilitate storage and compounding.

[0026] The advantages are: by adding functional ingredients such as seaweed extract and disodium EDTA, the plant's stress resistance and fertilizer system can be enhanced. Seaweed extract is rich in natural plant hormones and active ingredients, which can stimulate crop growth, enhance its stress resistance, and effectively prevent root diseases and poor growth. Disodium EDTA, on the other hand, prevents precipitation by chelating metal ions, improves the stability of the fertilizer solution and the availability of elements, and ensures that the fertilizer maintains high efficiency during storage and application. The synergistic effect of the two components helps to improve the overall performance of the fertilizer.

[0027] Specifically, in step two, the raw material pretreatment involves adding calcium nitrate, ammonium sulfate, and magnesium sulfate heptahydrate to deionized water and heating it to 50-55°C for later use.

[0028] Specifically, the mixing reaction conditions in step three are as follows: control the temperature of the mixed solution between 40-50℃, and stir the reaction at a speed of 40-50 r / min for 1-2 hours to ensure that the raw materials are fully mixed.

[0029] Specifically, the mixing conditions for the additives in step four are as follows: continue stirring at 100-200 r / min for 30-60 minutes in an environment below 35℃ to ensure that the additives are evenly dispersed in the mixture.

[0030] Specifically, in step five, pH adjustment: when the pH meter detects that the online pH value of the solution in the reactor is not in the target range, add 5% to 10% potassium hydroxide or 2% to 5% sodium hydroxide solution dropwise. The target pH range is 5.8-6.2.

[0031] Specifically, step six involves three levels of filtering: S2.1 Coarse filtration: Pass the pH-adjusted mixed solution through an 80-100 mesh sieve to remove undissolved particles; S2.2 Fine filtration: The mixed solution after coarse filtration is passed through a 5μm filter element to remove colloidal impurities; S2.3 Ultrafiltration: The mixed solution after fine filtration is passed through a 0.22μm sterile filter membrane to ensure sterility. Through three-stage filtration (coarse filtration → fine filtration → ultrafiltration), the clarity, microbial safety and compatibility of the liquid fertilizer with drip irrigation system are ensured. The final product is free of impurities and sterile, and is suitable for direct drip irrigation.

[0032] Specifically, the compound trace element sugar alcohol is composed of mannitol chelated iron, xylitol chelated copper, and sorbitol chelated zinc in a ratio of 3:2:2. The trace elements chelated by sugar alcohol are not easily fixed or precipitated in the soil and can remain stable over a wide pH range, thus ensuring the effectiveness of the fertilizer under different soil conditions.

[0033] The above formulas were prepared into finished products, Examples 1-6. Based on Examples 1-6, corresponding reference groups / comparative examples 1-10 were listed, with their raw material ratios and preparation processes shown in Tables 2-3 below. Table 2 shows the raw material ratios and preparation process for Examples 1-3.

[0034] Table 3 shows the raw material ratios and preparation process for Comparative Examples 1-10.

[0035] The liquid compound fertilizers prepared in the examples and comparative examples were then applied to specific environments. The effectiveness period was 1-2 months, and the observation data are shown in Table 3 below:

[0036] Analysis of Table 2-4 yields the following results: (1) Exploring the effect of raw material ratio on crops: In the examples, when the main nutrients (potassium nitrate, monoammonium phosphate and urea) are reasonably matched within the set range, the crops show excellent growth performance. In Examples 1-3, tomatoes, cucumbers and strawberries all showed significant improvement in plant height, fruit quality and yield. However, in Comparative Example 1, the crop growth was slow and the fruit development was poor due to the reduction of the main nutrient content. This shows that the nutrient ratio within the specified range is the basis for ensuring fertilizer efficiency.

[0037] (2) Explore the effects of seaweed extract and disodium EDTA in the raw materials on fertilizer performance: Since seaweed extract was not added in Comparative Example 1, the cucumber root development was poor and the roots were prone to rot; while in Comparative Example 3, since disodium EDTA was not used for chelation, the strawberry flower bud differentiation was delayed and the fruit was not resistant to storage and transportation. This shows that seaweed extract and disodium EDTA can promote plant growth and stabilize the fertilizer system.

[0038] (3) Explore the impact of standardized preparation process on fertilizer quality: Comparative Example 5 only performed coarse filtration, which caused the drip irrigation system to be blocked, affecting fertilizer efficiency; while Comparative Example 6 increased the mixing reaction temperature, which caused strawberry seedlings to burn, indicating that process parameters such as temperature and filtration need to be strictly controlled, otherwise the applicability and safety of fertilizer will be reduced.

[0039] In summary, this invention, through the scientific design of the raw material ratio of compound fertilizer, rationally combines the main nutrients of potassium nitrate, monoammonium phosphate, and urea with functional components such as seaweed extract and disodium EDTA, providing comprehensive nutrition for crop growth. By strictly regulating the preparation process of raw material pretreatment, mixing reaction, and pH adjustment, the fertilizer solution is ensured to have high stability and few impurities, allowing for direct drip irrigation application. As verified by Examples 1-6, the fertilizer of this invention can significantly promote crop growth, improve fruit quality and yield. Compared with the adverse effects caused by missing components or improper processes in the comparative examples, this invention has the advantages of high absorption, high efficiency, and strong applicability, demonstrating good application value in agricultural production. It can effectively contribute to the development of green and efficient agriculture and reduce resource waste and environmental pollution caused by the unreasonable use of fertilizers.

[0040] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A highly absorbent liquid compound fertilizer for direct drip irrigation, characterized in that, Includes the following steps: Step 1: Raw material selection and specific gravity: Potassium nitrate, monoammonium phosphate, urea, calcium nitrate, ammonium sulfate, magnesium sulfate heptahydrate, seaweed extract, boron humate, disodium EDTA, zinc polyphosphate, ammonium thiosulfate, ammonium molybdate, manganese amino acids, fulvic acid, sodium dioctyl sulfosuccinate, citric acid, ascorbic acid, compound trace element sugar alcohol and deionized water; Step 2, Raw material pretreatment: Dissolve calcium nitrate, ammonium sulfate, and magnesium sulfate heptahydrate. Step 3, Mixing reaction: Add potassium nitrate, monoammonium phosphate and urea to the reaction vessel and stir evenly. Then add the dissolved calcium nitrate solution, ammonium sulfate solution and magnesium sulfate heptahydrate solution dropwise from step 2 to fully mix the raw materials and obtain a mixed reaction solution. Step 4: Adding additives: In the reaction vessel, add seaweed extract, boron humate, disodium EDTA, zinc polyphosphate, ammonium thiosulfate, ammonium molybdate, manganese amino acids, fulvic acid, sodium dioctyl sulfosuccinate, citric acid, ascorbic acid and compound trace element sugar alcohol in sequence to make the additives evenly dispersed in the mixture. Step 5, pH adjustment: Use a pH meter to monitor the online pH value of the solution in the reaction vessel in real time; Step 6, Post-processing: After pH adjustment, the mixed solution is filtered three times to control the final viscosity between 1-4 cP, thus obtaining liquid compound fertilizer.

2. The highly absorbent liquid compound fertilizer for direct drip irrigation according to claim 1, characterized in that: The raw materials and their proportions for the compound fertilizer in step one are as follows: potassium nitrate 45%–50%; monoammonium phosphate 10%–15%; urea 7%–11%; calcium nitrate 6%–9%; ammonium sulfate 8%–12%; magnesium sulfate heptahydrate 4%–7%; seaweed extract 3–5%; boron humate 2%–4%; disodium EDTA 1%–3%; zinc polyphosphate 2%–5%; ammonium thiosulfate 0.5%–1%; ammonium molybdate 0.5%–1%; manganese amino acids 1%–2%; fulvic acid 0.5%–1.5%; sodium dioctyl sulfosuccinate 0.1%–0.5%; citric acid 0.6%–0.9%; ascorbic acid 0.2%–0.7%; compound trace element sugar alcohol 1%–2%; and the remainder is deionized water.

3. The highly absorbent liquid compound fertilizer for direct drip irrigation according to claim 1, characterized in that: The magnesium sulfate heptahydrate is prepared by reacting a magnesium source with sulfuric acid, and its chemical reaction formula is as follows: MgO + H₂SO₄ + 6H₂O → MgSO₄·7H₂O In the formula, MgO represents magnesium oxide, H2SO4 represents sulfuric acid, H2O represents water, and MgSO4·7H2O represents magnesium sulfate heptahydrate.

4. The highly absorbent liquid compound fertilizer for direct drip irrigation according to claim 1, characterized in that: The preparation method of the seaweed extract is as follows: S1.1 Select fresh, unpolluted seaweed and wash it with clean water; S1.

2. Chop the seaweed into pieces with a diameter of 3-5mm; S1.3 Add deionized water at 5-8 times the dry weight of seaweed, adjust the pH to 7.5-8, stir and extract at 65-70℃ for 3-4 hours, and filter to obtain the extract; S1.4 Add 0.2% to 0.4% of the total mass of seaweed to the extract, and enzymatically hydrolyze at 38-45℃ for 2-5 hours to break down the cell walls. Filter to obtain the enzymatic hydrolysate. S1.

5. Concentrate the enzymatic hydrolysate under vacuum at 55-60℃ and 0.08-0.09MPa for 2-3 hours until the volume is reduced to 1 / 10-1 / 5 of the original volume.

5. The highly absorbent liquid compound fertilizer for direct drip irrigation according to claim 1, characterized in that: In step two, the raw material pretreatment involves adding calcium nitrate, ammonium sulfate, and magnesium sulfate heptahydrate to deionized water and heating it to 50-55°C for later use.

6. The highly absorbent liquid compound fertilizer for direct drip irrigation according to claim 1, characterized in that: The mixing reaction conditions in step three are as follows: control the temperature of the mixed solution between 40-50℃, and stir the reaction at a speed of 40-50 r / min for 1-2 hours.

7. The highly absorbent liquid compound fertilizer for direct drip irrigation according to claim 1, characterized in that: The mixing conditions for the additives in step four are as follows: stirring at 100-200 r / min for 30-60 minutes in an environment below 35°C.

8. The highly absorbent liquid compound fertilizer for direct drip irrigation according to claim 1, characterized in that: In step five, pH adjustment: when the pH meter detects that the online pH value of the solution in the reactor is not in the target range, add 5% to 10% potassium hydroxide or 2% to 5% sodium hydroxide solution dropwise. The target pH range is 5.8-6.

2.

9. A highly absorbent liquid compound fertilizer for direct drip irrigation according to claim 1, characterized in that: The three-stage filtering in step six: S2.1 Coarse filtration: Pass the pH-adjusted mixed solution through an 80-100 mesh sieve; S2.2 Fine filtration: The mixed solution after coarse filtration is passed through a 5μm filter cartridge; S2.3, Ultrafiltration: The mixed solution after fine filtration is passed through a 0.22μm sterile filter membrane.

10. A highly absorbent liquid compound fertilizer for direct drip irrigation according to claim 1, characterized in that: The compound trace element sugar alcohol is composed of mannitol chelated with iron, xylitol chelated with copper, and sorbitol chelated with zinc in a ratio of 3:2:2.

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