Mushroom bran, humic acid and attapulgite composite water-retaining slow-release organic fertilizer

Abstract

The invention relates to the technical field of organic slow-release fertilizers, in particular to a mushroom bran humic acid attapulgite composite water-retaining slow-release organic fertilizer which comprises an inner core, a coating layer and an outer functional layer from inside to outside, the inner core adopts a vacuum pressure swing method to deeply load mushroom bran source sodium humate into nanopore channels of purified attapulgite clay, and the coating layer is coated with the outer functional layer; the preparation method comprises the following steps of: firstly, forming a stable nutrient storage library which is not easy to lose, fundamentally improving the slow release performance and controllability of nutrients, secondly, constructing a coating layer of sodium alginate and chitosan outside an inner core through an electrostatic complexation reaction, controlling the permeation of water and the diffusion rate of the nutrients, ensuring the stability of a release curve, and finally, improving the slow release performance and controllability of the nutrients. The outer functional layer composed of the functional microbial agent, the plant stress resistance inducer and the adhesive is introduced into the outermost layer, so that the fertilizer is endowed with multifunctionality, and the requirements of modern agriculture on efficient, multifunctional and environment-friendly fertilizers are met.

Description

Technical Field

[0001] This invention relates to the field of organic slow-release fertilizer technology, and in particular to a composite water-retaining slow-release organic fertilizer made from bacterial bran, humic acid, and attapulgite. Background Technology

[0002] Humic acid fertilizers are widely used because they can improve soil and stimulate crop growth. However, conventional humic acid fertilizers are mostly fast-acting, and their nutrients are easily lost after irrigation or rainfall, resulting in low utilization rates and potential environmental pollution. Slow-release fertilizers are a key direction for solving this problem.

[0003] Existing technologies include attempts to extract humic acid from bacterial residues and combine it with attapulgite clay. These technologies typically employ simple mechanical mixing methods (such as ball milling) to physically blend sodium humate with attapulgite. While this method achieves a degree of slow nutrient release, its release curve is poorly controllable, the product is prone to clumping, and the pores of attapulgite are easily and rapidly blocked, leading to insufficient release momentum in later stages and difficulty in meeting the precise nutrient needs of crops throughout their entire growth cycle. Furthermore, these existing compound fertilizers have limited functionality, primarily relying on the fertilizer effect of humic acid itself and the physical adsorption of attapulgite, offering limited contribution to improving soil microbial communities and enhancing crop resistance (such as drought and disease resistance).

[0004] In summary, existing microbial bran humic acid attapulgite composite water-retaining slow-release organic fertilizers, due to their simple structure, single function, and uncontrollable slow-release performance, are unable to meet the urgent needs of modern agriculture for efficient, multifunctional, and environmentally friendly fertilizers. Summary of the Invention

[0005] The purpose of this invention is to provide a biomass humic acid attapulgite composite water-retaining slow-release organic fertilizer, which solves the problem that existing biomass humic acid attapulgite composite water-retaining slow-release organic fertilizers have simple structures, single functions, and uncontrollable slow-release performance, making it difficult to meet the urgent needs of modern agriculture for efficient, multifunctional, and environmentally friendly fertilizers.

[0006] To achieve the above objectives, the present invention provides a biomass-fungal humic acid-attapulgite composite water-retaining slow-release organic fertilizer, wherein the biomass-fungal humic acid-attapulgite composite water-retaining slow-release organic fertilizer comprises, from the inside out, a core, a coating layer, and an outer functional layer, wherein each component is expressed in the following parts by weight: The core is composed of purified attapulgite clay and bacterial bran-derived sodium humate through a vacuum pressure swinging method. The dry weight of the coating layer accounts for 3% to 15% of the dry weight of the core, and the coating layer is formed by sodium alginate and chitosan through an electrostatic complexation reaction; The dry weight of the outer functional layer accounts for 2% to 10% of the total dry weight of the core after the coating layer covers it. The outer functional layer contains functional microbial agents, plant stress resistance inducers, and adhesives. The weight ratio of purified attapulgite clay to bacterial bran-derived sodium humate in the core is 90:10. The dry weight ratio of sodium alginate to chitosan in the coating layer is 1:0.5 to 1:2. The weight ratio of functional microbial agents, plant stress-inducing agents, and adhesives in the outer functional layer is 5:3:2.

[0007] The sodium humate source is derived from one or more of the fermented substrate from the cultivation of shiitake mushrooms, king oyster mushrooms, or enoki mushrooms.

[0008] The functional microbial agent is at least one of phosphate-solubilizing bacteria, nitrogen-fixing bacteria, or Trichoderma harzianum. The plant stress resistance inducer is at least one of seaweed extract, betaine, or chitosan oligosaccharide; The adhesive is at least one of sodium carboxymethyl cellulose, polyvinyl alcohol, or soluble starch.

[0009] The specific preparation method of the bacterial bran humic acid attapulgite composite water-retaining slow-release organic fertilizer includes the following steps: The purified attapulgite clay was degassed under vacuum and then injected into the sodium humate solution. Pulsed pressure was applied, and the core was obtained after solid-liquid separation and drying. The core is placed in a fluidized bed, and sodium alginate and chitosan are alternately sprayed to make the two electrostatically complex on the surface of the core. After drying, the coating layer is formed on the surface of the core. A functional slurry containing the functional microbial agent, the plant stress inducer, and the adhesive is sprayed onto the surface of the coating layer. After drying, the organic slow-release fertilizer is prepared.

[0010] The specific method for preparing the kernel is as follows: The purified attapulgite clay was placed in a vacuum reactor; Evacuate the vacuum reactor to an absolute pressure of 10~30 kPa and maintain it for 20~40 minutes; Inject the bacterial bran-derived sodium humate solution with a concentration of 50~150 g / L; Return to normal pressure, apply a pulse pressure of 0.3~1.2 MPa, maintain the pressure for 1~5 minutes, then release the pressure. Repeat this cycle 3~8 times. Solid-liquid separation is performed, and the collected solid material is dried at 70~90℃ to obtain the core.

[0011] The purified attapulgite clay needs to be pulverized to pass through a 200-mesh standard sieve, and the liquid-to-solid volume ratio of the bacterial bran-derived sodium humate solution is 3:1 to 6:1.

[0012] The specific method for forming the coating layer is as follows: The core is placed in a fluidized bed coating machine and preheated to 40-60°C; The sodium alginate solution with a mass-volume concentration of 1.0% to 2.0% is sprayed. Alternately spray a chitosan acetate solution with a chitosan mass-volume concentration of 0.5%~1.5% and a crosslinking agent solution with a mass-volume concentration of 1.0%~3.0%; The coating layer is formed on the surface of the core by hot air curing at 50~70℃ for 1~2 hours.

[0013] Specifically, the crosslinking agent is a citric acid solution with a mass-volume concentration of 2.0%.

[0014] The specific method for forming the outer functional layer is as follows: The semi-finished product with the coating layer formed on the surface of the core is placed in a mixing device; A functional slurry composed of the aforementioned functional microbial agent, the aforementioned plant stress-inducing agent, and the aforementioned adhesive is sprayed on. The fertilizer is dried in a ventilated environment at 35-45°C, thereby forming the outer functional layer on the surface of the coating layer, thus completing the preparation of the organic slow-release fertilizer.

[0015] This invention discloses a microbial bran humic acid attapulgite composite water-retaining slow-release organic fertilizer, comprising a core, a coating layer, and an outer functional layer from the inside out. The core utilizes a vacuum pressure oscillation method to deeply load sodium humate derived from microbial bran into the nanopores of purified attapulgite clay, forming a stable and non-leaking nutrient reservoir. This fundamentally improves the slow-release performance and controllability of nutrients. Secondly, an electrostatic complexation reaction constructs a coating layer of sodium alginate and chitosan outside the core, controlling the rate of water penetration and nutrient diffusion, ensuring the stability of the release curve. Finally, the outermost functional layer, composed of the functional microbial agent, the plant stress-inducing agent, and the binder, is introduced, endowing the fertilizer with multifunctionality, thereby meeting the modern agricultural demand for efficient, multifunctional, and environmentally friendly fertilizers. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1This is a flowchart of the preparation method of the bacterial bran humic acid attapulgite composite water-retaining slow-release organic fertilizer provided by the present invention.

[0018] Figure 2 This is a flowchart illustrating the specific steps of the kernel preparation method provided by the present invention.

[0019] Figure 3 This is a flowchart illustrating the steps of a specific method for forming the coating layer provided by the present invention.

[0020] Figure 4 This is a flowchart illustrating the specific steps of the method for forming the outer functional layer provided by the present invention. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0022] Please see Figures 1 to 4 This invention provides a biomass-humic acid-attapulgite composite water-retaining slow-release organic fertilizer, which comprises, from the inside out, a core, a coating layer, and an outer functional layer, wherein each component is expressed in the following parts by weight: The core is composed of purified attapulgite clay and bacterial bran-derived sodium humate through a vacuum pressure swinging method. The dry weight of the coating layer accounts for 3% to 15% of the dry weight of the core, and the coating layer is formed by sodium alginate and chitosan through an electrostatic complexation reaction; The dry weight of the outer functional layer accounts for 2% to 10% of the total dry weight of the core after the coating layer covers it. The outer functional layer contains functional microbial agents, plant stress resistance inducers, and adhesives. The weight ratio of purified attapulgite clay to bacterial bran-derived sodium humate in the core is 90:10. The dry weight ratio of sodium alginate to chitosan in the coating layer is 1:0.5 to 1:2. The weight ratio of functional microbial agents, plant stress-inducing agents, and adhesives in the outer functional layer is 5:3:2.

[0023] In this embodiment, the core uses a vacuum pressure oscillation method to deeply load the sodium humate sourced from the bacterial bran into the nanopores of the purified attapulgite clay, forming a stable and non-leaking nutrient reservoir. This fundamentally improves the slow-release performance and controllability of nutrients. Secondly, an encapsulation layer of sodium alginate and chitosan is constructed outside the core through an electrostatic complexation reaction, controlling the rate of water penetration and nutrient diffusion and ensuring the stability of the release curve. Finally, an outer functional layer composed of the functional microbial agent, the plant stress inducer, and the binder is introduced on the outermost layer, endowing the fertilizer with multifunctionality, thereby meeting the needs of modern agriculture for efficient, multifunctional, and environmentally friendly fertilizers.

[0024] Furthermore, the sodium humate source is derived from one or more of the fermented substrate from the cultivation of shiitake mushrooms, king oyster mushrooms, or enoki mushrooms.

[0025] Furthermore, the functional microbial agent is at least one of phosphate-solubilizing bacteria, nitrogen-fixing bacteria, or Trichoderma harzianum; The plant stress resistance inducer is at least one of seaweed extract, betaine, or chitosan oligosaccharide; The adhesive is at least one of sodium carboxymethyl cellulose, polyvinyl alcohol, or soluble starch.

[0026] In this embodiment, the use of specific mushroom substrates such as shiitake mushrooms and king oyster mushrooms ensures a stable source and uniform quality of sodium humate; the introduction of compound functional microbial agents (phosphate-solubilizing bacteria, nitrogen-fixing bacteria, and Trichoderma harzianum) enables the fertilizer to have both the function of activating soil nutrients and biological control; and the combination of stress-inducing agents such as seaweed extract and betaine directly enhances the crop's resistance to adverse abiotic stresses.

[0027] Furthermore, the specific preparation method of the bacterial bran humic acid attapulgite composite water-retaining slow-release organic fertilizer includes the following steps: S1: The purified attapulgite clay is degassed under vacuum, injected into the sodium humate solution, pulsed pressure is applied, and the core is obtained after solid-liquid separation and drying; S2: The core is placed in a fluidized bed, and the sodium alginate and chitosan are alternately sprayed to make the two electrostatically complex on the surface of the core. After drying, the coating layer is formed on the surface of the core. S3: A functional slurry containing the functional microbial agent, the plant stress inducer, and the adhesive is sprayed onto the surface of the coating layer. After drying, the preparation of the organic slow-release fertilizer is completed.

[0028] In this embodiment, vacuum and pulse pressure technology ensures the deep and uniform loading of humic acid inside the carrier, laying the foundation for long-term sustained nutrient release; the electrostatic complexation process in the fluidized bed enables the coating layer to be uniformly and densely formed on the surface of the core, building a key barrier for precise controlled release; the final functional slurry spraying efficiently endows the product with additional biological promotion and stress resistance functions without damaging the structure of the core and the coating layer.

[0029] Furthermore, the specific preparation method of the kernel is as follows: S101: Place the purified attapulgite clay in a vacuum reactor; S102: Evacuate the vacuum reactor to an absolute pressure of 10~30 kPa and maintain it for 20~40 minutes; S103: Inject the bacterial bran-derived sodium humate solution with a concentration of 50~150 g / L; S104: Return to normal pressure, apply a pulse pressure of 0.3~1.2 MPa, hold the pressure for 1~5 minutes and then release the pressure, repeat 3~8 times; S105: Perform solid-liquid separation, collect the solid material and dry it at 70~90℃ to obtain the core.

[0030] The purified attapulgite clay needs to be pulverized to pass through a 200-mesh standard sieve, and the liquid-to-solid volume ratio of the bacterial bran-derived sodium humate solution is 3:1 to 6:1.

[0031] In this embodiment, the carrier (the purified attapulgite clay) is pulverized to 200 mesh and subjected to deep vacuum degassing at 10-30 kPa to completely eliminate air barriers within the nanopores. Subsequently, at a liquid-to-solid ratio of 3:1 to 6:1, a pulsed pressure cycle of 0.3-1.2 MPa is used to forcibly inject and firmly anchor the sodium humate solution into the deep pores of the purified attapulgite clay. This achieves deep, efficient, and stable nutrient loading, fundamentally constructing a nutrient reservoir and laying a solid and reliable structural foundation for subsequent controllable long-term sustained-release performance.

[0032] Furthermore, the specific method for forming the coating layer is as follows: S201: Place the core in a fluidized bed coating machine and preheat it to 40~60℃; S202: Spray an aqueous solution of sodium alginate with a mass-volume concentration of 1.0% to 2.0%; S203: Alternately spray a chitosan acetate solution with a chitosan mass-volume concentration of 0.5%~1.5% and a crosslinking agent solution with a mass-volume concentration of 1.0%~3.0%; S204: The coating layer is formed on the surface of the core by hot air curing at 50~70℃ for 1~2 hours.

[0033] Specifically, the crosslinking agent is a citric acid solution with a mass-volume concentration of 2.0%.

[0034] In this embodiment, under preheating conditions of 40-60°C, sodium alginate aqueous solution and chitosan acetate-citric acid solution of specific concentrations are sprayed alternately to allow the sodium alginate and chitosan to undergo sufficient electrostatic complexing and cross-linking reaction on the surface of the core; the subsequent hot air curing treatment at 50-70°C further enhances the stability of this composite gel network.

[0035] Furthermore, the specific method for forming the outer functional layer is as follows: S301: Place the semi-finished product with the coating layer formed on the surface of the core into a mixing device; S302: Spraying a functional slurry composed of the functional microbial agent, the plant stress-inducing agent, and the adhesive; S303: Dried in a ventilated environment at 35~45℃, thereby forming the outer functional layer on the surface of the coating layer, thus completing the preparation of the organic slow-release fertilizer.

[0036] In this embodiment, the preferred functional microbial agent, the plant stress-resistance inducer, and the adhesive are compounded into a slurry, which is then sprayed and cured under mild conditions of 35–45°C. This ensures that the activity of the functional microorganisms is not destroyed by high temperatures, and that the functional components are firmly adhered to the surface of the coating layer. The resulting active outer functional layer gives the fertilizer, in addition to its core slow-release function, multiple biological benefits, including promoting crop growth, inducing systemic stress resistance, and improving the plant rhizosphere microecology.

[0037] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A composite water-retaining slow-release organic fertilizer containing microbial residue, humic acid, and attapulgite, characterized in that... The microbial bran humic acid attapulgite composite water-retaining slow-release organic fertilizer comprises, from the inside out, a core, a coating layer, and an outer functional layer, wherein each component is expressed in the following parts by weight: The core is composed of purified attapulgite clay and bacterial bran-derived sodium humate through a vacuum pressure swinging method. The dry weight of the coating layer accounts for 3% to 15% of the dry weight of the core, and the coating layer is formed by sodium alginate and chitosan through an electrostatic complexation reaction; The dry weight of the outer functional layer accounts for 2% to 10% of the total dry weight of the core after the coating layer covers it. The outer functional layer contains functional microbial agents, plant stress resistance inducers, and adhesives. The weight ratio of purified attapulgite clay to bacterial bran-derived sodium humate in the core is 90:

10. The dry weight ratio of sodium alginate to chitosan in the coating layer is 1:0.5 to 1:

2. The weight ratio of functional microbial agents, plant stress-inducing agents, and adhesives in the outer functional layer is 5:3:

2.

2. The microbial bran humic acid attapulgite composite water-retaining slow-release organic fertilizer as described in claim 1, characterized in that, The sodium humate source is derived from one or more of the fermented substrate from the cultivation of shiitake mushrooms, king oyster mushrooms, or enoki mushrooms.

3. The microbial bran humic acid attapulgite composite water-retaining slow-release organic fertilizer as described in claim 2, characterized in that, The functional microbial agent is at least one of phosphate-solubilizing bacteria, nitrogen-fixing bacteria, or Trichoderma harzianum. The plant stress resistance inducer is at least one of seaweed extract, betaine, or chitosan oligosaccharide; The adhesive is at least one of sodium carboxymethyl cellulose, polyvinyl alcohol, or soluble starch.

4. The microbial bran humic acid attapulgite composite water-retaining slow-release organic fertilizer as described in claim 3, characterized in that, The specific preparation method of the bacterial bran humic acid attapulgite composite water-retaining slow-release organic fertilizer includes the following steps: The purified attapulgite clay was degassed under vacuum and then injected into the sodium humate solution. Pulsed pressure was applied, and the core was obtained after solid-liquid separation and drying. The core is placed in a fluidized bed, and sodium alginate and chitosan are alternately sprayed to make the two electrostatically complex on the surface of the core. After drying, the coating layer is formed on the surface of the core. A functional slurry containing the functional microbial agent, the plant stress inducer, and the adhesive is sprayed onto the surface of the coating layer. After drying, the organic slow-release fertilizer is prepared.

5. The microbial bran humic acid attapulgite composite water-retaining slow-release organic fertilizer as described in claim 4, characterized in that, The specific method for preparing the kernel is as follows: The purified attapulgite clay was placed in a vacuum reactor; Evacuate the vacuum reactor to an absolute pressure of 10~30 kPa and maintain it for 20~40 minutes; Inject the bacterial bran-derived sodium humate solution with a concentration of 50~150 g / L; Return to normal pressure, apply a pulse pressure of 0.3~1.2 MPa, maintain the pressure for 1~5 minutes, then release the pressure. Repeat this cycle 3~8 times. Solid-liquid separation is performed, and the collected solid material is dried at 70~90℃ to obtain the core.

6. The microbial bran humic acid attapulgite composite water-retaining slow-release organic fertilizer as described in claim 5, characterized in that, The purified attapulgite clay needs to be pulverized to pass through a 200-mesh standard sieve, and the liquid-to-solid volume ratio of the bacterial bran-derived sodium humate solution is 3:1 to 6:

1.

7. The microbial bran humic acid attapulgite composite water-retaining slow-release organic fertilizer as described in claim 6, characterized in that, The specific method for forming the coating layer is as follows: The core is placed in a fluidized bed coating machine and preheated to 40-60°C; The sodium alginate solution with a mass-volume concentration of 1.0% to 2.0% is sprayed. Alternately spray a chitosan acetate solution with a chitosan mass-volume concentration of 0.5%~1.5% and a crosslinking agent solution with a mass-volume concentration of 1.0%~3.0%; The coating layer is formed on the surface of the core by hot air curing at 50~70℃ for 1~2 hours.

8. The microbial bran humic acid attapulgite composite water-retaining slow-release organic fertilizer as described in claim 7, characterized in that, The crosslinking agent is specifically a citric acid solution with a mass-volume concentration of 2.0%.

9. The microbial bran humic acid attapulgite composite water-retaining slow-release organic fertilizer as described in claim 8, characterized in that, The specific method for forming the outer functional layer is as follows: The semi-finished product with the coating layer formed on the surface of the core is placed in a mixing device; A functional slurry composed of the aforementioned functional microbial agent, the aforementioned plant stress-inducing agent, and the aforementioned adhesive is sprayed on. The fertilizer is dried in a ventilated environment at 35-45°C, thereby forming the outer functional layer on the surface of the coating layer, thus completing the preparation of the organic slow-release fertilizer.

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