Macadamia slow release fertiliser and method of making same

Abstract

The application provides a preparation method of macadamia nut slow-release fertilizer, which comprises the following steps: (1) dissolving chitosan in an acetic acid aqueous solution, then adding crabgrass extract under stirring, and then casting into a film after incubation; (2) mixing pleurotus eryngii residues and rape straw, and then soaking in an acid solution; then adding cellulase for enzymolysis; then calcining at 600-650 DEG C to obtain an active ingredient carrier; (3) uniformly mixing the crabgrass extract and mixed bacterial culture according to a weight ratio of 2:3-5 into the active ingredient carrier obtained in step (2), and then coating with the film obtained in step (1), so that the slow-release fertilizer is obtained. The slow-release fertilizer of the application is prepared from biological materials, has a slow-release effect, needs only a small number of fertilization times, has excellent fertilizer efficiency, and can significantly promote the yield increase of macadamia nuts.

Description

Technical Field

[0001] This invention belongs to the field of agricultural technology, and relates to slow-release fertilizer technology, specifically to a macadamia nut slow-release fertilizer and its preparation method. Background Technology

[0002] Currently, one of the important research directions for improving macadamia nut cultivation technology is the development of better fertilizers, including new chemical fertilizers and organic fertilizers. For example, Zhang Jinyun et al. studied the effects of different fertilizer formulations on macadamia nut cultivation in papers such as "The Influence of Formula Fertilizers on the Yield of Different Macadamia Nut Varieties" and "Application of Nutrient Balance Method in Formula Fertilization of Macadamia Nuts"; and Zheng Shufang et al. studied the effects of different organic fertilizers on the yield and kernel yield of macadamia nuts in their paper "The Influence of Four Commercial Organic Fertilizers on the Yield and Quality of Macadamia Nut 'Gui Re No. 1'".

[0003] However, while chemical fertilizers can effectively increase yield and nut quality, their effects are short-lived, their utilization rate is low, and excessive application can easily cause environmental pollution. On the other hand, common organic fertilizers are used in large quantities and have insufficient yield-promoting effects. As Zheng Shufang's aforementioned study showed, the relevant organic fertilizers only have a yield-promoting effect of 4.6% to 21.3%.

[0004] Therefore, how to develop an environmentally friendly, highly efficient, and low-volume slow-release fertilizer for macadamia nut cultivation is an important research topic in this field. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to solve the defects of the prior art, such as short fertilizer effect and low utilization rate when applying ordinary chemical fertilizers, and difficulty in obtaining the required fertilizer effect when applying general organic fertilizers. Therefore, this invention provides a macadamia nut slow-release fertilizer with slow-release effect, which uses biological materials as raw materials and requires fewer fertilization times, while having excellent fertilizer effect, and its preparation method.

[0006] The present invention provides the following technical solution to achieve the above objectives.

[0007] A method for preparing macadamia nut slow-release fertilizer, the method comprising the following steps:

[0008] (1) Chitosan is dissolved in an aqueous acetic acid solution, and then the crab extract is added while stirring. The mixture is incubated at 35-40°C for 1-2 hours. After standing to remove air bubbles, the mixture is cast into a film. The weight ratio of chitosan to crab extract is 10:1-3. The crab extract is obtained by hydrothermal extraction of crab.

[0009] (2) Mix the mushroom residue of king oyster mushroom and rapeseed straw at a weight ratio of 3 to 5:1, soak them in acid solution at 30 to 40°C for at least 1 hour, and then wash them with water until neutral; then add cellulase and enzymatically hydrolyze them at 30 to 35°C for at least 0.5 hours, and then wash away the residual enzyme with water; then calcine them at 600 to 650°C to obtain the active ingredient carrier.

[0010] (3) The extract of crabgrass and the mixed bacterial culture are mixed evenly into the active ingredient carrier obtained in step (2) at a weight ratio of 2:3 to 5, and then coated with the membrane obtained in step (1) to obtain the slow-release fertilizer.

[0011] The mixed bacterial culture was obtained by culturing Bacillus licheniformis strain 1x2-4 and Frankenstein's bacterium fgc6 separately in liquid medium to the plateau phase, and then mixing them at a volume ratio of 1:1. The preservation number of Bacillus licheniformis strain 1x2-4 is CGMCC No. 3911, and the preservation number of Frankenstein's bacterium fgc6 is CCTCC M207197.

[0012] Preferably, the volume fraction of acetic acid in the acetic acid aqueous solution is 1%, and the weight-volume ratio of chitosan to acetic acid is 2g:1mL.

[0013] Preferably, the crabgrass extract is prepared by the following hydrothermal extraction method: the whole crabgrass is added to water at a weight-volume ratio of 1g:10mL, extracted at 80℃ for 4 hours, and then the water is evaporated to obtain a dried powder.

[0014] Preferably, in step (1), the incubation temperature is 40°C and the incubation time is 1 hour.

[0015] Preferably, the weight ratio of chitosan to crabgrass extract is 10:2.

[0016] Preferably, the weight ratio of king oyster mushroom residue to rapeseed straw is 4:1.

[0017] Preferably, the king oyster mushroom residue and rapeseed straw are mixed, soaked in acidic solution at 40°C for 2 hours, then washed with water until neutral; then cellulase is added and enzymatic hydrolysis is carried out at 35°C for 0.5 hours.

[0018] Preferably, in step (2), the calcination temperature is 650°C and the calcination time is 1 hour.

[0019] Preferably, the weight ratio of crabgrass extract to mixed bacterial culture is 1:2, and the total weight of crabgrass extract and mixed bacterial culture accounts for 10% of the weight of the active ingredient carrier; after coating, the resulting slow-release fertilizer is composed of particles with an outer layer wrapped by a membrane and an inner layer consisting of crabgrass extract, mixed bacterial culture and active ingredient carrier.

[0020] A slow-release fertilizer for macadamia nuts, wherein the slow-release fertilizer is prepared by the aforementioned preparation method.

[0021] The beneficial effects of this invention are:

[0022] 1. The raw material of this invention is a biological material, which can effectively utilize the weeds that harm farmland, such as crabgrass, and at the same time effectively recycle and utilize agricultural waste such as mushroom residue and rapeseed straw.

[0023] 2. This invention creatively uses crabgrass extract to prepare chitosan membranes and achieves good anti-permeability effect, making it applicable for coating fertilizers to achieve slow release, avoiding the potential harm to crops and soil caused by using chemical substances to prepare chitosan membranes;

[0024] 3. This invention combines crabgrass extract and mixed bacterial fermentation product to achieve a synergistic effect in promoting macadamia nut yield.

[0025] 4. This invention uses king oyster mushroom residue and rapeseed straw as raw materials. After specific treatment, a carrier that can be used to carry fertilizer-active substances is prepared, which achieves a further slow-release effect and thus significantly reduces the number of fertilizations and the amount of fertilizer used. Detailed Implementation

[0026] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above-described invention are still within the scope of protection of the present invention.

[0027] Example 1

[0028] Preparation of macadamia nut slow-release fertilizer:

[0029] (1) Chitosan was dissolved in an aqueous acetic acid solution with a volume fraction of 1% v / v, and the weight-volume ratio of chitosan to acetic acid was 2g:1mL; then, the extract of Crataegus pinnatifida was added under stirring, and the mixture was incubated at 40°C for 1 hour. After standing to remove air bubbles, the mixture was evenly coated onto nylon cloth using a coater and dried at 50°C for 24 hours to obtain a membrane; wherein, the weight ratio of chitosan to Crataegus pinnatifida extract was 10:2; the Crataegus pinnatifida extract was prepared by the following hydrothermal extraction method: the whole Crataegus pinnatifida herb was added to water at a weight-volume ratio of 1g:10mL, and extracted at 80°C for 4 hours. Then, the water was evaporated to obtain a dried powder;

[0030] (2) Mix the mushroom residue of king oyster mushroom and rapeseed straw at a weight ratio of 4:1, soak them in acid solution at 40°C for 2 hours, and then wash them with water until neutral; then add cellulase (10000U / mL) and enzymatically hydrolyze them at 35°C for 0.5 hours, and then wash away the residual enzyme with water; then calcine them at 650°C for 1 hour to obtain the active ingredient carrier.

[0031] (3) The crab extract and mixed bacterial culture are mixed evenly into the active ingredient carrier obtained in step (2) at a weight ratio of 2:4, and then coated with the membrane obtained in step (1) to obtain the slow-release fertilizer; wherein, the total weight of the crab extract and mixed bacterial culture accounts for 10% of the weight of the active ingredient carrier; after coating, the obtained slow-release fertilizer has an outer layer wrapped by a membrane and an inner layer of crab extract, mixed bacterial culture and active ingredient carrier particles;

[0032] The mixed bacterial culture was prepared by culturing Bacillus licheniformis strain 1x2-4 and Frankenstein's bacterium fgc6 separately in liquid medium (LB medium) to the plateau phase, and then mixing them at a volume ratio of 1:1. The accession number of Bacillus licheniformis strain 1x2-4 is CGMCC No. 3911, and the accession number of Frankenstein's bacterium fgc6 is CCTCC M207197. Both strains were generously donated by colleagues, and their original sources were purchased by colleagues from their respective preservation centers (i.e., the China General Microbiological Culture Collection Center and the China Center for Type Culture Collection).

[0033] Example 2

[0034] Preparation of macadamia nut slow-release fertilizer:

[0035] (1) Chitosan was dissolved in an aqueous acetic acid solution with a volume fraction of 1% v / v, and the weight-volume ratio of chitosan to acetic acid was 2g:1mL; then, the extract of Crataegus pinnatifida was added under stirring, and the mixture was incubated at 35°C for 2 hours. After standing to remove air bubbles, the mixture was evenly coated onto nylon cloth using a coater and dried at 50°C for 24 hours to obtain a membrane; wherein, the weight ratio of chitosan to Crataegus pinnatifida extract was 10:3; the Crataegus pinnatifida extract was prepared by the following hydrothermal extraction method: the whole Crataegus pinnatifida herb was added to water at a weight-volume ratio of 1g:10mL, and extracted at 80°C for 4 hours. Then, the water was evaporated to obtain a dried powder;

[0036] (2) Mix the mushroom residue of king oyster mushroom and rapeseed straw at a weight ratio of 5:1, soak them in acid solution at 30°C for 3 hours, and then wash them with water until neutral; then add cellulase (10000U / mL) and enzymatically hydrolyze them at 30°C for 1 hour, and then wash away the residual enzyme with water; then calcine them at 600°C for 90 minutes to obtain the active ingredient carrier.

[0037] (3) The crab extract and mixed bacterial culture are mixed evenly into the active ingredient carrier obtained in step (2) at a weight ratio of 2:5, and then coated with the membrane obtained in step (1) to obtain the slow-release fertilizer; wherein, the total weight of the crab extract and mixed bacterial culture accounts for 10% of the weight of the active ingredient carrier; after coating, the obtained slow-release fertilizer has an outer layer wrapped by a membrane and an inner layer of crab extract, mixed bacterial culture and active ingredient carrier particles;

[0038] The mixed bacterial culture was prepared by culturing Bacillus licheniformis strain 1x2-4 and Frankenstein's bacterium fgc6 separately in liquid medium (LB medium) to the plateau phase, and then mixing them at a volume ratio of 1:1. The accession number of Bacillus licheniformis strain 1x2-4 is CGMCC No. 3911, and the accession number of Frankenstein's bacterium fgc6 is CCTCC M207197. Both strains were generously donated by colleagues, and their original sources were purchased by colleagues from their respective preservation centers (i.e., the China General Microbiological Culture Collection Center and the China Center for Type Culture Collection).

[0039] Example 3

[0040] Preparation of macadamia nut slow-release fertilizer:

[0041] (1) Chitosan was dissolved in an aqueous acetic acid solution with a volume fraction of 1% v / v, and the weight-volume ratio of chitosan to acetic acid was 2g:1mL; then, the extract of Crataegus pinnatifida was added under stirring, and the mixture was incubated at 30°C for 2 hours. After standing to remove air bubbles, the mixture was evenly coated onto nylon cloth using a coater and dried at 50°C for 24 hours to obtain a membrane; wherein, the weight ratio of chitosan to Crataegus pinnatifida extract was 10:1; the Crataegus pinnatifida extract was prepared by the following hydrothermal extraction method: the whole Crataegus pinnatifida herb was added to water at a weight-volume ratio of 1g:10mL, and extracted at 80°C for 4 hours. Then, the water was evaporated to obtain a dried powder;

[0042] (2) Mix the mushroom residue of king oyster mushroom and rapeseed straw at a weight ratio of 3:1, soak them in acid solution at 35°C for 2 hours, and then wash them with water until neutral; then add cellulase (10000U / mL) and enzymatically hydrolyze them at 32°C for 75 minutes, and then wash away the residual enzyme with water; then calcine them at 620°C for 75 minutes to obtain the active ingredient carrier.

[0043] (3) The crab extract and mixed bacterial culture are uniformly mixed into the active ingredient carrier obtained in step (2) at a weight ratio of 2:3, and then coated with the membrane obtained in step (1) to obtain the slow-release fertilizer; wherein, the total weight of the crab extract and mixed bacterial culture accounts for 10% of the weight of the active ingredient carrier; after coating, the obtained slow-release fertilizer has an outer layer wrapped by a membrane and an inner layer of crab extract, mixed bacterial culture and active ingredient carrier particles;

[0044] The mixed bacterial culture was prepared by culturing Bacillus licheniformis strain 1x2-4 and Frankenstein's bacterium fgc6 separately in liquid medium (LB medium) to the plateau phase, and then mixing them at a volume ratio of 1:1. The accession number of Bacillus licheniformis strain 1x2-4 is CGMCC No. 3911, and the accession number of Frankenstein's bacterium fgc6 is CCTCC M207197. Both strains were generously donated by colleagues, and their original sources were purchased by colleagues from their respective preservation centers (i.e., the China General Microbiological Culture Collection Center and the China Center for Type Culture Collection).

[0045] Comparative Example 1

[0046] The following scheme was adopted when preparing the chitosan membrane:

[0047] Chitosan was dissolved in an aqueous acetic acid solution (10% v / v) at a weight-volume ratio of 2g:1mL. The mixture was stirred until completely dissolved, and then 0.1mL of glutaraldehyde was added. The mixture was stirred continuously and then allowed to stand to completely remove air bubbles. The mixture was then evenly coated onto a nylon cloth using a coater and dried at 50°C for 24 hours to obtain a chitosan film.

[0048] Comparative Example 2

[0049] Compared with Example 1, the difference is that the mixed bacterial culture was replaced with a single bacterial culture (Frankella fgc6).

[0050] Preparation of macadamia nut slow-release fertilizer:

[0051] (1) Chitosan was dissolved in an aqueous acetic acid solution with a volume fraction of 1% v / v, and the weight-volume ratio of chitosan to acetic acid was 2g:1mL; then, the extract of Crataegus pinnatifida was added under stirring, and the mixture was incubated at 40°C for 1 hour. After standing to remove air bubbles, the mixture was evenly coated onto nylon cloth using a coater and dried at 50°C for 24 hours to obtain a membrane; wherein, the weight ratio of chitosan to Crataegus pinnatifida extract was 10:2; the Crataegus pinnatifida extract was prepared by the following hydrothermal extraction method: the whole Crataegus pinnatifida herb was added to water at a weight-volume ratio of 1g:10mL, and extracted at 80°C for 4 hours. Then, the water was evaporated to obtain a dried powder;

[0052] (2) Mix the mushroom residue of king oyster mushroom and rapeseed straw at a weight ratio of 4:1, soak them in acid solution at 40°C for 2 hours, and then wash them with water until neutral; then add cellulase (10000U / mL) and enzymatically hydrolyze them at 35°C for 0.5 hours, and then wash away the residual enzyme with water; then calcine them at 650°C for 1 hour to obtain the active ingredient carrier.

[0053] (3) The crab extract and Frankenstein's fgc6 culture are mixed evenly into the active ingredient carrier obtained in step (2) at a weight ratio of 2:4, and then coated with the membrane obtained in step (1) to obtain the slow-release fertilizer; wherein, the total weight of the crab extract and Frankenstein's fgc6 culture accounts for 10% of the weight of the active ingredient carrier; after coating, the obtained slow-release fertilizer has an outer layer wrapped by a membrane and an inner layer of crab extract, Frankenstein's fgc6 culture and active ingredient carrier particles;

[0054] The Frankenstein's fgc6 culture was obtained by culturing Frankenstein's fgc6 in liquid medium (LB medium) to the plateau phase; the accession number of Frankenstein's fgc6 is CCTCC M207197. This bacterium was kindly provided by a colleague, and its original source was purchased by a colleague from the China Center for Type Culture Collection.

[0055] Comparative Example 3

[0056] Compared with Example 1, the difference is that no crabgrass extract is added in step (3).

[0057] Preparation of macadamia nut slow-release fertilizer:

[0058] (1) Chitosan was dissolved in an aqueous acetic acid solution with a volume fraction of 1% v / v, and the weight-volume ratio of chitosan to acetic acid was 2g:1mL; then, the extract of Crataegus pinnatifida was added under stirring, and the mixture was incubated at 40°C for 1 hour. After standing to remove air bubbles, the mixture was evenly coated onto nylon cloth using a coater and dried at 50°C for 24 hours to obtain a membrane; wherein, the weight ratio of chitosan to Crataegus pinnatifida extract was 10:2; the Crataegus pinnatifida extract was prepared by the following hydrothermal extraction method: the whole Crataegus pinnatifida herb was added to water at a weight-volume ratio of 1g:10mL, and extracted at 80°C for 4 hours. Then, the water was evaporated to obtain a dried powder;

[0059] (2) Mix the mushroom residue of king oyster mushroom and rapeseed straw at a weight ratio of 4:1, soak them in acid solution at 40°C for 2 hours, and then wash them with water until neutral; then add cellulase (10000U / mL) and enzymatically hydrolyze them at 35°C for 0.5 hours, and then wash away the residual enzyme with water; then calcine them at 650°C for 1 hour to obtain the active ingredient carrier.

[0060] (3) The mixed bacterial culture is evenly mixed into the active ingredient carrier obtained in step (2), and then coated with the membrane obtained in step (1) to obtain the slow-release fertilizer; wherein, the total weight of the mixed bacterial culture accounts for 10% of the weight of the active ingredient carrier; after coating, the obtained slow-release fertilizer has an outer layer wrapped by a membrane and an inner layer of mixed bacterial culture and active ingredient carrier particles.

[0061] The mixed bacterial culture was prepared by culturing Bacillus licheniformis strain 1x2-4 and Frankenstein's bacterium fgc6 separately in liquid medium (LB medium) to the plateau phase, and then mixing them at a volume ratio of 1:1. The accession number of Bacillus licheniformis strain 1x2-4 is CGMCC No. 3911, and the accession number of Frankenstein's bacterium fgc6 is CCTCC M207197. Both strains were generously donated by colleagues, and their original sources were purchased by colleagues from their respective preservation centers (i.e., the China General Microbiological Culture Collection Center and the China Center for Type Culture Collection).

[0062] Comparative Example 4

[0063] Compared with Example 1, the difference is that rapeseed straw is not added in step (2).

[0064] Preparation of macadamia nut slow-release fertilizer:

[0065] (1) Chitosan was dissolved in an aqueous acetic acid solution with a volume fraction of 1% v / v, and the weight-volume ratio of chitosan to acetic acid was 2g:1mL; then, the extract of Crataegus pinnatifida was added under stirring, and the mixture was incubated at 40°C for 1 hour. After standing to remove air bubbles, the mixture was evenly coated onto nylon cloth using a coater and dried at 50°C for 24 hours to obtain a membrane; wherein, the weight ratio of chitosan to Crataegus pinnatifida extract was 10:2; the Crataegus pinnatifida extract was prepared by the following hydrothermal extraction method: the whole Crataegus pinnatifida herb was added to water at a weight-volume ratio of 1g:10mL, and extracted at 80°C for 4 hours. Then, the water was evaporated to obtain a dried powder;

[0066] (2) The mushroom residue of king oyster mushroom was soaked in acid solution at 40°C for 2 hours, and then washed with water until neutral; then cellulase (10000U / mL) was added and enzymatically hydrolyzed at 35°C for 0.5 hours, and then the residual enzyme was washed away with water; then calcined at 650°C for 1 hour to obtain the active ingredient carrier.

[0067] (3) The crab extract and mixed bacterial culture are mixed evenly into the active ingredient carrier obtained in step (2) at a weight ratio of 2:4, and then coated with the membrane obtained in step (1) to obtain the slow-release fertilizer; wherein, the total weight of the crab extract and mixed bacterial culture accounts for 10% of the weight of the active ingredient carrier; after coating, the obtained slow-release fertilizer has an outer layer wrapped by a membrane and an inner layer of crab extract, mixed bacterial culture and active ingredient carrier particles;

[0068] The mixed bacterial culture was prepared by culturing Bacillus licheniformis strain 1x2-4 and Frankenstein's bacterium fgc6 separately in liquid medium (LB medium) to the plateau phase, and then mixing them at a volume ratio of 1:1. The accession number of Bacillus licheniformis strain 1x2-4 is CGMCC No. 3911, and the accession number of Frankenstein's bacterium fgc6 is CCTCC M207197. Both strains were generously donated by colleagues, and their original sources were purchased by colleagues from their respective preservation centers (i.e., the China General Microbiological Culture Collection Center and the China Center for Type Culture Collection).

[0069] Experimental Example 1

[0070] The membranes obtained in steps (1) of Examples 1-3 and the membrane obtained in Comparative Example 1 were used for permeability testing, with urea as the permeate. The preparation of the colorimetric reagent, the urea standard solution, and the plotting of the standard curve were performed according to GB / T23348-2009. The testing apparatus was modified from an existing apparatus, specifically by drilling holes in the walls of two glass graduated cylinders, connecting the two holes with a glass conduit, and placing a flange in the glass conduit, on which the aforementioned membrane was loaded. 250 mL of a 100 g / L urea aqueous solution was added to graduated cylinder A, and the same volume of distilled water was added to graduated cylinder B. The liquid in graduated cylinder B was taken every other day, and the colorimetric reaction between urea and the colorimetric reagent was measured using a UV spectrophotometer at a wavelength of 430 nm. The urea permeation was calculated, and the cumulative urea permeation rate was calculated over 7 days.

[0071] Table 1

[0072]

[0073]

[0074] As shown in Table 1, the chitosan membrane obtained by this invention has low permeability, which can prevent urea release and achieve a slow-release effect. Compared with the glutaraldehyde cross-linking method, the use of crabgrass extract in Examples 1-3 of this invention also achieves a cross-linking effect. Although the amount of crabgrass extract used is relatively large, as shown in other experimental examples of this invention, the presence of crabgrass extract also contributes to the cultivation effect of macadamia nuts. Therefore, the use of crabgrass extract in this invention not only achieves the preparation of a slow-release membrane, but can also be used as an active ingredient in fertilizers.

[0075] Experiment Example 2

[0076] For 8-year-old macadamia trees, slow-release fertilizers obtained in Examples 1-3 and Comparative Examples 2-4 were applied in May and October, at a rate of 15 kg / tree. Yield (weight with shells) data were collected the following year when fruiting occurred. A control group was used, with the same application timing and amount of well-rotted chicken manure. The results are shown in Table 2.

[0077] Table 2

[0078]

[0079] As shown in Table 2, the slow-release fertilizers obtained in Examples 1-3 of this invention are significantly superior to those in Comparative Examples 2-4 and the control group in terms of yield promotion. Since Comparative Examples 2 and 3 lack a bacterial culture and a crabgrass extract, respectively, it is evident that the crabgrass extract and the bacterial culture have a significant synergistic effect in yield promotion. Furthermore, since rapeseed straw was not added during the preparation of the carrier in Comparative Example 4, it is clear that the addition of rapeseed straw, combined with subsequent special treatment methods, can prepare a carrier with excellent yield-promoting effects. The inventors speculate that Comparative Example 4's slow-release effect was less than that of Examples 1-3, resulting in macadamia trees not receiving timely fertilization under a longer fertilization cycle. Combining the experimental results of Example 1, it can be further speculated that the membrane coating of the corresponding carrier obtained in this invention enables further slow release of active ingredients, and the components exhibit a significant synergistic effect in yield promotion, making the slow-release fertilizer obtained in this invention particularly suitable for macadamia nut cultivation.

Claims

1. A method for preparing macadamia nut slow-release fertilizer, characterized in that, The preparation method includes the following steps: (1) Chitosan is dissolved in an aqueous acetic acid solution, and then the crab extract is added while stirring. The mixture is incubated at 35-40°C for 1-2 hours, and after standing to remove air bubbles, it is cast into a film. The weight ratio of chitosan to crab extract is 10:1-3. The crab extract is obtained by hydrothermal extraction of crab. (2) Mix the mushroom residue of king oyster mushroom and rapeseed straw at a weight ratio of 3~5:1, soak them in acid solution at 30~40℃ for at least 1 hour, and then wash them with water until neutral; then add cellulase and enzymatically hydrolyze them at 30~35℃ for at least 0.5 hours, and then wash away the residual enzyme with water; then calcine them at 600~650℃ to obtain the active ingredient carrier. (3) The extract of crabgrass and the mixed bacterial culture are mixed evenly into the active ingredient carrier obtained in step (2) at a weight ratio of 2:3~5, and then coated with the membrane obtained in step (1) to obtain the slow-release fertilizer. The mixed bacterial culture was obtained by culturing Bacillus licheniformis strain 1x2-4 and Frankenstein's bacterium fgc6 separately in liquid medium to the plateau phase, and then mixing them at a volume ratio of 1:1; the accession number of Bacillus licheniformis strain 1x2-4 is CGMCC No. 3911, and the accession number of Frankenstein's bacterium fgc6 is CCTCC M207197; The volume fraction of acetic acid in the acetic acid aqueous solution is 1%, and the weight-volume ratio of chitosan to acetic acid is 2g:1mL. The Crataegus pinnatifida extract is prepared by the following hydrothermal extraction method: whole Crataegus pinnatifida herb is added to water at a weight-volume ratio of 1g:10mL, extracted at 80℃ for 4 hours, and then the water is evaporated to obtain a dried powder.

2. The method for preparing a macadamia nut slow-release fertilizer according to claim 1, characterized in that, In step (1), the incubation temperature is 40℃ and the incubation time is 1 hour.

3. The method for preparing a macadamia nut slow-release fertilizer according to claim 1, characterized in that, The weight ratio of chitosan to crabgrass extract is 10:

2.

4. The method for preparing a macadamia nut slow-release fertilizer according to claim 1, characterized in that, The weight ratio of king oyster mushroom residue to rapeseed straw is 4:

1.

5. The method for preparing a macadamia nut slow-release fertilizer according to claim 4, characterized in that, Mix king oyster mushroom residue and rapeseed straw, soak them in acidic solution at 40°C for 2 hours, then wash with water until neutral; then add cellulase and enzymatically hydrolyze at 35°C for 0.5 hours.

6. The method for preparing a macadamia nut slow-release fertilizer according to claim 1, characterized in that, In step (2), the calcination temperature is 650℃ and the calcination time is 1 hour.

7. The method for preparing a macadamia nut slow-release fertilizer according to claim 1, characterized in that, The weight ratio of crabgrass extract to mixed bacterial culture is 1:2, and the total weight of crabgrass extract and mixed bacterial culture accounts for 10% of the weight of the active ingredient carrier. After coating, the resulting slow-release fertilizer has an outer layer wrapped by a membrane and an inner layer of crabgrass extract, mixed bacterial culture and active ingredient carrier particles.

8. A slow-release fertilizer for macadamia nuts, characterized in that, The slow-release fertilizer is prepared by the preparation method according to any one of claims 1 to 7.

Images