Preparation method of nano organic water-soluble fertilizer based on paper mulberry leaves

Abstract

The invention discloses a preparation method of a nano organic water-soluble fertilizer based on paper mulberry leaves. The preparation method comprises the following steps: S1, preparing raw materials: taking a plurality of healthy and mature paper mulberry leaves; s2, raw material pretreatment: crushing the prepared paper mulberry leaves, soaking the crushed paper mulberry leaves in a potassium fulvate solution, and adding xylanase; s3, staged temperature control decomposition; and S4, nano-chelating: filtering the decomposition liquid through a ceramic membrane, mixing the filtered decomposition liquid with 0.1% of sodium alginate and 0.05% of siloxane nanotubes, and carrying out self-assembly in a microfluidic reactor according to a flow rate ratio of 10: 1 to obtain a stable nano-fertilizer liquid. Through the combination of potassium fulvate and xylanase, the autolysis effect of cell walls of the paper mulberry leaves is activated, the degradation rate is increased, meanwhile, nano humic acid and plant endogenous stress-resistant factors are generated, then through temperature gradient regulation and control, staging product directional conversion is achieved, and finally, plasma activated water is adopted as a solvent, so that the growth of the paper mulberry leaves is promoted. And carrying out supramolecular self-assembly on the decomposition product, sodium alginate and siloxane nanotubes to form the nano-micelle.

Description

Technical Field

[0001] The invention relates to the technical field of organic agriculture, and in particular to a method for preparing a nano organic water-soluble fertilizer based on paper mulberry leaves. Background Art

[0002] Traditional organic fertilizers have the following defects: Solid organic fertilizers require slow mineralization by soil microorganisms, and their effectiveness lags (30-60 days); Liquid organic fertilizers generally have problems such as high impurities, easy precipitation, and nutrient imbalance; Hidden dangers of chemical water-soluble fertilizers: They rely on synthetic nitrogen, phosphorus and potassium salts, and long-term use can lead to soil compaction and ecological toxicity.

[0003] Plant-derived organic water-soluble fertilizers are difficult to degrade due to the difficulty in extracting high concentrations of active substances; Humic acid fertilizers have a large molecular weight (>1000 Da) and their foliar absorption rate is less than 5%.

[0004] Existing technologies focus on humic acid extraction, but do not address the following issues: The effect of temperature-FA-K synergistic decomposition mechanism on the efficiency of raw material pretreatment; Directed enrichment and stable chelation of nanoscale organic active substances (<100 nm); In situ generation technology of functional synergistic factors of water-soluble fertilizers (such as anti-adversity peptides and root-stimulating hormones). Summary of the Invention

[0005] In order to solve the above technical problems, the present invention proposes a method for preparing a nano organic water-soluble fertilizer based on paper mulberry leaves, comprising the steps of: S1. Raw material preparation: Take healthy, mature paper mulberry leaves; S2. Raw material pretreatment: The prepared paper mulberry leaves are crushed, then soaked in a potassium fulvic acid solution and xylanase is added; S3. Staged temperature control decomposition: The first stage: constant temperature at 30℃ for 24 hours to activate the hydrolysis of glycosidic bonds and release soluble sugars and small molecular organic acids; The second stage: the temperature was raised to 35°C and maintained for 48 hours, with ultrasound assistance activated to enhance the production of nano-humic acid; The third stage: heating to 40°C for 6 hours to terminate the reaction and inactivate the enzyme, triggering the enrichment of antioxidants such as flavonoids and polyphenols; S4. Nanochelation: The decomposed liquid from step S3 was filtered through a ceramic membrane with a molecular weight cutoff of 500 Da, mixed with 0.1% sodium alginate and 0.05% silicone nanotubes, and self-assembled in a microfluidic reactor at a flow rate ratio of 10:1 to obtain a stable nanofertilizer solution.

[0006] Furthermore, in step S1, the particle size of the paper mulberry leaves after crushing is ≤2 mm.

[0007] Furthermore, in step S2, the solid-liquid ratio of the crushed paper mulberry leaves to the potassium fulvic acid solution is 1:5, the concentration of the potassium fulvic acid solution is 1% to 7%, and the enzymatic activity of the added xylanase is 0.3 U / g to 0.8 U / g.

[0008] Furthermore, in step S2, the concentration of the potassium fulvic acid solution is 3%, and the enzymatic activity of the added xylanase is 0.5 U / g.

[0009] Furthermore, in step S3, the frequency of the second stage ultrasonic assistance is 20 KHz to 60 KHz.

[0010] Compared with the prior art, the advantages of the present invention are: The present invention uses a combination of potassium fulvic acid and xylanase to activate the autolysis effect of paper mulberry leaf cell walls, increase the degradation rate of lignin / cellulose, and simultaneously generate nano-humic acid (50-80 nm) and plant endogenous stress resistance factors (such as glutathione and jasmonic acid). Then, through temperature gradient control (30°C → 35°C → 40°C), phased product conversion is achieved: 30℃: Release soluble sugars and small molecular organic acids; 35℃: Generate nano-humic acid and amino acids; 40℃: triggers the accumulation of antioxidants such as flavonoids and polyphenols; Finally, plasma-activated water was used as a solvent to carry out supramolecular self-assembly of the decomposition products with sodium alginate and silicone nanotubes to form nanomicelles (particle size 20-50 nm), thereby improving the efficiency of organic macromolecules penetrating plant stomata. DETAILED DESCRIPTION

[0011] The present invention provides a method for preparing a nano organic water-soluble fertilizer based on paper mulberry leaves, comprising the steps of: S1. Raw material preparation: Take healthy, mature paper mulberry leaves; S2. Raw material pretreatment: The prepared paper mulberry leaves are crushed, then soaked in a potassium fulvic acid solution and xylanase is added; S3. Staged temperature control decomposition: The first stage: constant temperature at 30℃ for 24 hours to activate the hydrolysis of glycosidic bonds; The second stage: the temperature was raised to 35°C and maintained for 48 hours, with ultrasound assistance activated to enhance the production of nano-humic acid; The third stage: heating to 40℃ for 6 hours to terminate the reaction and inactivate the enzyme; S4. Nano-chelation: The decomposed liquid from step S3 was filtered through a ceramic membrane with a molecular weight cut-off of 500 Da, mixed with 0.1% sodium alginate and 0.05% siloxane nanotubes, and self-assembled in a microfluidic reactor at a flow rate ratio of 10:1 to obtain a stable nano-fertilizer solution. In step S1, the particle size of the paper mulberry leaves after crushing is ≤2 mm; In step S2, the solid-liquid ratio of the crushed paper mulberry leaves to the potassium fulvic acid solution is 1:5, the concentration of the potassium fulvic acid solution is 1% to 5%, and the enzymatic activity of the added xylanase is 0.3 U / g to 0.8 U / g. Preferably, the concentration of the potassium fulvic acid solution is 3%, and the enzymatic activity of the added xylanase is 0.5 U / g; In step S3, the frequency of the second stage ultrasonic assistance is 20 KHz to 60 KHz.

[0012] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with embodiments. The description in this section is only exemplary and explanatory and should not have any limiting effect on the scope of protection of the present invention.

[0013] Example 1 Raw material pretreatment: Several healthy and mature paper mulberry leaves were crushed. After the leaves were crushed (particle size ≤ 2 mm), they were soaked in 3% potassium fulvic acid solution with a solid-liquid ratio of 1:5 and 0.5 U / g xylanase was added.

[0014] Temperature control decomposition in stages: The first stage: constant temperature at 30℃ for 24 hours to activate the hydrolysis of glycosidic bonds; Phase 2: The temperature was raised to 35°C and maintained for 48 hours, with ultrasonic assistance (40KHz) turned on to enhance the production of nano-humic acid; The third stage: treatment at 40°C for 6 hours to terminate the reaction and inactivate the enzyme.

[0015] Nano Chelation: The decomposed liquid was filtered through a ceramic membrane (molecular weight cut-off 500 Da), mixed with 0.1% sodium alginate and 0.05% silicone nanotubes, and self-assembled in a microfluidic reactor at a flow rate ratio of 10:1 to obtain the nanofertilizer liquid of Example 1.

[0016] Example 2 The difference from Example 1 is that: The concentration of potassium fulvic acid solution was 1%, the enzyme activity of added xylanase was 0.3 U / g, the ultrasonic frequency was 20 kHz, and other preparation conditions were the same.

[0017] Example 3 The difference from Example 1 is that: The concentration of potassium fulvic acid solution was 5%, the enzyme content of added xylanase was 0.6 U / g, the ultrasonic frequency was 50 KHz, and other preparation conditions were the same.

[0018] Example 4 The difference from Example 1 is that: The concentration of the potassium fulvic acid solution was 7%, the enzyme content of the added xylanase was 0.8 U / g, the ultrasonic frequency was 60 KHz, and other preparation conditions were the same.

[0019] Comparative Example 1 The difference from Example 1 is that: Crushed paper mulberry leaves (particle size ≤ 2 mm) were soaked in clean water at a solid-liquid ratio of 1:5, and other preparation conditions were the same.

[0020] The decomposition rate of paper mulberry leaves was recorded during the preparation process, as shown in the following table: Decomposition rate Day 1 (%) Day 3 (%) Day 5 (%) Day 7 (%) Example 1 5.2±0.3 12.1±0.8 20.4±1.2 30.1±1.5 Example 2 6.8±0.4 15.3±1.0 25.1±1.5 35.8±1.8 Example 3 8.4±0.5 15.3±1.0 30.7±1.8 42.3±2.1 Example 4 7.9±0.4 17.8±1.1 28.5±1.7 39.2±2.0 Comparative Example 1 6.1±0.3 14.5±0.9 23.9±1.4 34.7±1.7 analyze: Decomposition rate: Compared with the control group, Examples 1 to 4 all significantly increased the decomposition rate of paper mulberry leaves. Among them, the 0.3% treatment group had the fastest decomposition rate, with the decomposition rate reaching 42.3% on the 7th day, which was 12.2% higher than that of the control group.

[0021] Concentration effect: As the concentration of potassium humate solution increases, the decomposition rate of paper mulberry leaves shows a trend of first increasing and then decreasing. The decomposition rate of Example 1 is the fastest, while the decomposition rate of higher concentrations (Examples 3 and 4) decreases instead. This may be due to the inhibitory effect of high concentration solutions on microorganisms.

[0022] The nano organic water-soluble fertilizer of the present invention is prepared according to the scheme of Example 1, which has the best effect and the highest efficiency. Example 1 is the best embodiment.

[0023] Functional synergy verification was performed using the nano fertilizer solution of Example 1: Stress resistance test: In tomato seedlings sprayed with the fertilizer solution of Example 1 under salt stress (NaCl 150 mM), the malondialdehyde content decreased by 62% and the superoxide dismutase (SOD) activity increased by 3.8 times.

[0024] Absorption efficiency comparison: 24 hours after foliar spraying of the fertilizer solution of Example 1, the accumulated amount of nano-humic acid in cucumber leaves was 17 times that of traditional humic acid fertilizer (ICP-MS detection).

[0025] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A method for preparing nano organic water-soluble fertilizer based on paper mulberry leaves, characterized in that: Including steps: S1. Raw material preparation: Take healthy, mature paper mulberry leaves; S2. Raw material pretreatment: The prepared paper mulberry leaves are crushed, then soaked in a potassium fulvic acid solution and xylanase is added; S3. Staged temperature control decomposition: The first stage: constant temperature at 30℃ for 24 hours to activate the hydrolysis of glycosidic bonds; The second stage: the temperature was raised to 35°C and maintained for 48 hours, with ultrasound assistance activated to enhance the production of nano-humic acid; The third stage: heating to 40℃ for 6 hours to terminate the reaction and inactivate the enzyme; S4. Nanochelation: The decomposed liquid from step S3 was filtered through a ceramic membrane with a molecular weight cutoff of 500 Da, mixed with 0.1% sodium alginate and 0.05% silicone nanotubes, and self-assembled in a microfluidic reactor at a flow rate ratio of 10:1 to obtain a stable nanofertilizer solution.

2. The method for preparing nano organic water-soluble fertilizer based on paper mulberry leaves according to claim 1, wherein In step S1, the particle size of the paper mulberry leaves after crushing is ≤2 mm.

3. The method for preparing nano organic water-soluble fertilizer based on paper mulberry leaves according to claim 1, wherein In step S2, the solid-liquid ratio of the crushed paper mulberry leaves to the potassium fulvic acid solution is 1:5, the concentration of the potassium fulvic acid solution is 1% to 7%, and the enzymatic activity of the added xylanase is 0.3 U / g to 0.8 U / g.

4. The method for preparing nano organic water-soluble fertilizer based on paper mulberry leaves according to claim 2, wherein In step S2, the concentration of the potassium fulvic acid solution is 3%, and the enzymatic activity of the added xylanase is 0.5 U / g.

5. The method for preparing nano organic water-soluble fertilizer based on paper mulberry leaves according to claim 1, wherein In step S3, the frequency of the second stage ultrasonic assistance is 20 KHz to 60 KHz.