A management method for improving the cold resistance, drought resistance and increasing the flowering amount of macadamia

Abstract

The application discloses a management method for improving the cold resistance, drought resistance and flowering amount of macadamia nuts, which combines a four-stage dynamic management mode of soil improvement, cold resistance induction, drought resistance and shoot control and flowering period improvement, applies organic fertilizer, water retention agent and compound slow-release fertilizer, induces root development, simultaneously releases the fertilizer capacity of chemical fertilizer, prolongs the action time of the chemical fertilizer, applies brassinolide and potassium fulvate to activate the cold resistance gene expression of the macadamia nut plants, improves the cell membrane stability, thereby improving the cold resistance of the macadamia nut plants, applies melatonin and methyl jasmonate to double control the shoots, triggers the ABA signal path of the plants, improves the drought resistance of the plants, promotes the flower bud differentiation, the synergistic effect of brown algae oligosaccharide and gamma-aminobutyric acid enhances the pollen tube elongation capacity, the biological agent stimulation replaces the chemical agent stimulation, the use rate of the chemical agent is reduced, thereby reducing the negative influence of the chemical agent on the soil, and finally improving the fruit setting rate and the sustainable utilization of the soil.

Description

Technical Field

[0001] This invention belongs to the field of macadamia nut cultivation technology, and specifically relates to a management method for improving the cold and drought resistance and increasing flowering of macadamia nuts. Background Technology

[0002] Macadamia nuts, as a high-value crop, are significantly affected by abiotic stresses such as drought and low temperatures, leading to flower and fruit drop and severely impacting yield. In recent years, global climate change has resulted in frequent extreme weather events. Major macadamia-producing areas in my country, such as Yunnan and Guangxi, often suffer from the dual stresses of winter frost and seasonal drought, causing flower and fruit drop rates as high as 30%-50%, severely restricting the sustainable development of the industry. While current technologies have explored ways to improve the stress resistance of macadamia nuts, they still have the following shortcomings: 1. The methods are limited, focusing only on cold protection or drought resistance, lacking a systematic response to complex stresses. For example, patent CN104855206A proposes a solution of water-retaining agents plus organic fertilizers, which can alleviate drought stress but cannot address the effects of low temperatures; the frost damage index of macadamia nuts remains high under low-temperature conditions. 2. Over-reliance on chemical pesticides leads to excessive environmental residues, severely damaging the soil. For example, while the heavy application of paclobutrazol-based pesticides can inhibit new shoot growth, it causes an imbalance in the ratio of endogenous hormones, resulting in a lower flower bud differentiation rate the following year. The indiscriminate application of high concentrations of nitrogen and phosphorus in foliar fertilizers exacerbates nutrient leaching, leading to excessive nitrate content in the soil. 3. Inefficient nutrient supply during the flowering period leads to a combination of nutrient competition and environmental damage. The conventional method is to apply urea before flowering, which can promote the number of flowers, but the vigorous growth of new shoots consumes a large amount of photosynthetic assimilates, resulting in a very low actual effective flowering rate.

[0003] To address the above issues, there is an urgent need for a management method that can combine multiple benefits to improve the stress resistance of macadamia plants, effectively reduce the rate of flower and fruit drop, and thus improve economic benefits. Summary of the Invention

[0004] To address the shortcomings of existing macadamia nuts, which are susceptible to drought and low-temperature stress leading to reduced yields, this invention provides a management method to improve the cold and drought resistance of macadamia nuts and increase flowering, significantly enhancing their tolerance to harsh environments and maintaining stable yields.

[0005] This invention is achieved through the following technical solution: A management method to improve the cold and drought resistance and increase flowering of macadamia nuts includes the following steps: S1: In October-November, dig a circular trench 30-40cm deep, 50cm away from the trunk. At the bottom of the trench, lay 8-10kg / tree of organic fertilizer containing 18-24% macadamia nut green husk fermentation. In the middle layer of the trench, lay 0.4-0.6kg / tree of calcium magnesium phosphate fertilizer and 280-320g / tree of starch grafting acrylate water-retaining agent. At the top layer of the trench, lay 0.8-1.2kg / tree of compound slow-release fertilizer with N-P2O5-K2O=15-15-15. S2: From November to January of the following year, spray the leaves of the nut plants with a cold-resistant solution at a rate of 300-400 mL per plant. Spraying should be done on sunny days when the daytime temperature is ≥15℃. The aforementioned cold-resistant solution comprises the following components: proline 10-14 g / L, salicylic acid 140-160 mg / L, potassium humate 2-3 g / L, brassinolide 40-60 μg / L, and polyglycerol ester 0.4-0.6 g / L; S3: From October to December, alternately spray with a 600-fold dilution of 20% paclobutrazol and a 500-fold dilution of PBO containing 0.1% nano-silica carrier, with an interval of 12-15 days; simultaneously spray with a mixture containing 180-220 μmol / L melatonin and 240-260 μmol / L methyl jasmonate. S4: In January or February of the following year, spray a mixed solution containing 240-260 g / L of brown algae oligosaccharides, 40-60 g / L of 5-aminolevulinic acid, 340-360 g / L of γ-aminobutyric acid, 0.1-0.3% of potassium dihydrogen phosphate, 0.1-0.2% of fluid boron, and 0.1-0.2% of gibberellic acid, at a rate of 300-400 mL per plant.

[0006] This invention combines a four-stage dynamic management model: soil improvement, cold resistance induction, drought resistance shoot control, and flowering quality improvement. Organic fertilizer, calcium magnesium phosphate fertilizer, water-retaining agent, and compound slow-release fertilizer are applied to the plant roots. The Bacillus subtilis spores and fertilizer loaded on the surface of the compound slow-release fertilizer can induce root development, while the fertilizer's potency is slowly released, extending its duration of action. The combination of brassinolide and potassium humate can activate the expression of cold resistance genes in macadamia plants, enhancing cell membrane stability and thus improving their cold resistance. The dual shoot control of paclobutrazol and PBO diluted solution combined with melatonin and methyl jasmonate effectively reduces the use of chemical agents, triggers the ABA signaling pathway in plants to improve drought resistance, and promotes flower bud differentiation. The synergistic effect of fucoidan and γ-aminobutyric acid enhances pollen tube elongation. By using biological agents to stimulate instead of chemical agents, the use of chemical agents is reduced, thereby minimizing the negative impact of chemical agents on the soil and ultimately improving fruit set and sustainable soil use.

[0007] As a further improvement of the present invention, the method for preparing the compound slow-release fertilizer is as follows: (1) Dissolve potassium humate and polyvinyl alcohol in deionized water at 60℃ with a solid-liquid ratio of 1:8, add genipin crosslinking agent, adjust the pH to 7.5-8.0 and stir to form a homogeneous colloid with a viscosity of 800-1200 mPa·s; (2) Chitosan with a degree of deacetylation ≥90% was dissolved in 1% acetic acid solution to prepare a solution with a concentration of 30g / L. Then, nano-silica with a particle size of 30-50nm was added and ultrasonically dispersed for 20min to obtain a modified chitosan solution. (3) Place the N-P2O5-K2O=15-15-15 compound fertilizer granules in a fluidized bed, preheat to 50-55℃, atomize and spray the colloid prepared in step (1), and then let it stand to dry; spraying rate 8-10 mL / min; air inlet temperature 65-70℃; coating thickness 50-80μm; (4) Spray the dried granules from step (3) with the modified chitosan solution prepared in step (2) at 40-45℃, and then place them in an environment with a humidity of 60-70% and cure them with hot air circulation at 45℃ for 4-6 hours to obtain a composite slow-release fertilizer.

[0008] A slow-release compound fertilizer is prepared by combining nano-silica with chitosan as the slow-release outer layer and potassium humate with polyvinyl alcohol as the slow-release inner layer, together encapsulating compound fertilizer. When macadamia roots secrete organic acids, the potassium humate and compound fertilizer in the inner layer are released. The chitosan outer shell can release the compound fertilizer and potassium humate according to changes in soil temperature and humidity. The chitosan coating structure can ensure that the fertilizer and potassium humate can also be released and play their role during dry seasons, thereby improving the drought resistance of macadamia plants.

[0009] As a further improvement of the present invention, the outer surface of the composite slow-release fertilizer is loaded with 0.1%-0.2% by mass of Bacillus subtilis spore powder via electrostatic adsorption technology; the viable count of the Bacillus subtilis spore powder is ≥1×10⁻⁶. 8 CFU / g.

[0010] The outermost layer of Bacillus subtilis can activate soil phosphorus and potassium, forming a "chemical and biological dual slow-release" mechanism with potassium humate, thereby significantly improving fertilizer utilization and reducing the negative impact of chemical fertilizers on the soil.

[0011] As a further improvement of the present invention, the surface of the annular groove is covered with a water-retaining membrane, and the method for preparing the water-retaining membrane is as follows: (1) Soak the seeds of *Mentha pubescens* in a 2% w / v chitosan solution for 30 min, and then dry them to obtain coated seeds; the chitosan solution contains 0.1% by volume of gibberellic acid. (2) Mix polylactic acid particles with 8%-10% of its mass of acetylated tributyl citrate, dry in an oven at 60°C for 4 hours, then add 3%-5% of the mass of the mixed particles of nano-titanium dioxide, 1%-2% of nano-silver-supported montmorillonite, and 0.3%-0.5% of dicumyl peroxide, and premix at 800 rpm for 10 minutes to obtain a premix. (3) The premixed material is blended into a blend by a twin-screw extruder; the twin-screw extruder has a length-to-diameter ratio of 40:1, a screw speed of 120 rpm, a vacuum degassing pressure of -0.08 MPa, and a temperature gradient of 160℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3, and 180℃ in zone 4. (4) Add the coated seeds and blended material from step (1) into a mixer and mix at 95°C and 50 rpm for 5 min; the amount of coated seeds added is 10%-15% of the mass of the blended material; the mixed material is cast into a film, with a die temperature of 190°C, a cooling roller temperature of 25°C, a traction speed of 8-10 m / min, and the film thickness controlled to be 0.08-0.12 mm; (5) Micropores with a diameter of 50-100 μm are formed on the membrane surface using a pulsed laser with a wavelength of 1064 nm and a power of 20 W, resulting in 200-300 pores / cm. 2 .

[0012] The water-retaining membrane is loaded with seeds of the insect-repelling herb *Mentha haplocalyx*. The membrane surface has micropores that ensure air permeability while promoting the germination of the insect-repelling herb. The membrane body is infused with nano-titanium oxide and polylactic acid. The former degrades under light and the latter degrades in water. The released insect-repelling herb grows after degradation, forming a biological insect-repelling zone, which can reduce the amount of pesticides used.

[0013] As a further improvement of the present invention, the seeds of mint in step (1) are first frozen with liquid nitrogen and then crushed to 10-100 mesh.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention significantly enhances the antioxidant enzyme activity of macadamia nuts through multi-pathway activation of proline-salicylic acid-melatonin, thereby improving the plant's resistance to cold and drought cross-resistance.

[0015] 2. This invention uses brown algae oligosaccharides and γ-aminobutyric acid as biostimulants to replace chemical agents, and combines them with a biodegradable water-retaining film to release insect-repelling grass seeds to form an insect-repelling zone, thereby reducing the amount of pesticides used and forming an environmentally friendly protection.

[0016] 3. This invention uses compound slow-release fertilizer combined with organic fertilizer to promote plant root growth. The compound slow-release fertilizer can ensure the effective release of compound fertilizer and potassium humate during dry seasons, ensuring plant growth and thus improving the plant's drought resistance. Detailed Implementation

[0017] The present invention will be further described below with reference to the embodiments. Unless otherwise specified, the technical means used in the embodiments are all conventional technical means in the art.

[0018] The following examples all use the macadamia nut variety "JW", with an average tree age of 6-7 years; the planting locations are Zhoulu Town, Mashan County and Xingning District, Nanning City. Example 1

[0019] A management method to improve the cold and drought resistance and increase flowering of macadamia nuts includes the following steps: S1: In October and November, dig a circular trench 30cm deep 50cm away from the trunk. At the bottom of the trench, lay 8kg / tree of organic fertilizer containing 18% macadamia nut green husk fermentation. In the middle layer of the trench, lay 0.4kg / tree of calcium magnesium phosphate fertilizer and 280g / tree of starch grafting acrylate water-retaining agent. At the top layer of the trench, lay 0.8kg / tree of N-P2O5-K2O=15-15-15 compound slow-release fertilizer. S2: From November to January of the following year, spray the leaves of the nut plants with a cold-resistant solution at a rate of 300 mL / plant. Spraying should be done on sunny days when the daytime temperature is ≥15℃. The cold-resistant solution comprises the following components: proline 10g / L, salicylic acid 140mg / L, potassium humate 2g / L, brassinolide 40μg / L, and polyglycerol ester 0.4g / L; S3: From October to December, alternately spray with a 600-fold dilution of 20% paclobutrazol and a 500-fold dilution of PBO containing 0.1% nano-silica carrier, with a spraying interval of 12 days; simultaneously spray with a mixture containing 180 μmol / L melatonin and 240 μmol / L methyl jasmonate. S4: In January or February of the following year, spray a mixed solution containing 240 g / L brown algae oligosaccharides, 40 g / L 5-aminolevulinic acid, 340 g / L γ-aminobutyric acid, 0.1% potassium dihydrogen phosphate, 0.1% fluid boron, and 0.1% gibberellic acid, at a rate of 300 mL per plant.

[0020] The method for preparing the compound slow-release fertilizer is as follows: (1) Dissolve potassium humate and polyvinyl alcohol in deionized water at 60℃ with a solid-liquid ratio of 1:8, add genipin crosslinking agent, adjust the pH to 7.5 and stir to form a homogeneous colloid with a viscosity of 800 mPa·s; (2) Chitosan with a degree of deacetylation ≥90% was dissolved in 1% acetic acid solution to prepare a solution with a concentration of 30g / L. Then, nano-silica with a particle size of 30-50nm was added and ultrasonically dispersed for 20min to obtain a modified chitosan solution. (3) Place the N-P2O5-K2O=15-15-15 compound fertilizer granules in a fluidized bed, preheat to 50℃, atomize and spray the colloid prepared in step (1), and then let it stand to dry; spraying rate 8mL / min; air inlet temperature 65℃; coating thickness 50μm; (4) The granules dried in step (3) are sprayed with the modified chitosan solution prepared in step (2) at 40°C, and then placed in an environment with a humidity of 60% and cured by hot air circulation at 45°C for 6 hours to obtain a composite slow-release fertilizer.

[0021] The annular groove is covered with a water-retaining film, and the method for preparing the water-retaining film is as follows: (1) Soak the seeds of *Mentha pubescens* in a 2% w / v chitosan solution for 30 min, and then dry them to obtain coated seeds; the chitosan solution contains 0.1% by volume of gibberellic acid. (2) Mix polylactic acid particles with 8% of its mass of acetylated tributyl citrate, dry in an oven at 60°C for 4 hours, then add 3% of the mass of the mixed particles of nano-titanium dioxide, 1% of nano-silver-supported montmorillonite, and 0.3% of dicumyl peroxide, and premix at 800 rpm for 10 minutes to obtain a premix. (3) The premixed material is blended into a blend by a twin-screw extruder; the twin-screw extruder has a length-to-diameter ratio of 40:1, a screw speed of 120 rpm, a vacuum degassing pressure of -0.08 MPa, and a temperature gradient of 160℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3, and 180℃ in zone 4. (4) Add the coated seeds and blended material from step (1) into a mixer and mix at 95°C and 50 rpm for 5 min; the amount of coated seeds added is 10% of the mass of the blended material; the mixed material is cast into a film, with a die temperature of 190°C, a cooling roller temperature of 25°C, a traction speed of 8 m / min, and a film thickness of 0.08 mm. (5) Micropores with a diameter of 50 μm were drilled on the membrane surface using a pulsed laser with a wavelength of 1064 nm and a power of 20 W, resulting in 200 pores / cm². 2 . Example 2

[0022] A management method to improve the cold and drought resistance and increase flowering of macadamia nuts includes the following steps: S1: In October-November, dig a circular trench 40cm deep 50cm away from the trunk. At the bottom of the trench, lay 10kg / tree of organic fertilizer containing 24% macadamia nut green husk fermentation. In the middle layer of the trench, lay 0.6kg / tree of calcium magnesium phosphate fertilizer and 320g / tree of starch grafting acrylate water-retaining agent. At the top layer of the trench, lay 1.2kg / tree of compound slow-release fertilizer with N-P2O5-K2O=15-15-15. S2: From November to January of the following year, spray the leaves of the nut plants with a cold-resistant solution at a rate of 400 mL / plant. Spraying should be done on sunny days when the daytime temperature is ≥15℃. The cold-resistant solution comprises the following components: proline 14g / L, salicylic acid 160mg / L, potassium humate 3g / L, brassinolide 60μg / L, and polyglycerol ester 0.6g / L; S3: From October to December, alternately spray with a 600-fold dilution of 20% paclobutrazol and a 500-fold dilution of PBO containing 0.1% nano-silica carrier, with an interval of 12-15 days; simultaneously spray with a mixture containing 220 μmol / L melatonin and 260 μmol / L methyl jasmonate. S4: In January or February of the following year, spray a mixed solution containing 260 g / L brown algae oligosaccharides, 60 g / L 5-aminolevulinic acid, 360 g / L γ-aminobutyric acid, 0.3% potassium dihydrogen phosphate, 0.2% liquid boron, and 0.2% gibberellic acid, at a rate of 400 mL per plant.

[0023] The method for preparing the compound slow-release fertilizer is as follows: (1) Dissolve potassium humate and polyvinyl alcohol in deionized water at 60℃ with a solid-liquid ratio of 1:8, add genipin crosslinking agent, adjust the pH to 8.0 and stir to form a homogeneous colloid with a viscosity of 1200 mPa·s; (2) Chitosan with a degree of deacetylation ≥ 90% was dissolved in 1% acetic acid solution to prepare a solution with a concentration of 30 g / L. Then, nano-silica with a particle size of 50 nm was added and ultrasonically dispersed for 20 min to obtain a modified chitosan solution. (3) Place the N-P2O5-K2O=15-15-15 compound fertilizer granules in a fluidized bed, preheat to 55℃, atomize and spray the colloid prepared in step (1), and then let it stand to dry; spraying rate 10 mL / min; air inlet temperature 70℃; coating thickness 80μm; (4) Spray the dried granules from step (3) with the modified chitosan solution prepared in step (2) at 45°C, and then place them in an environment with a humidity of 60-70% and cure them with hot air circulation at 45°C for 4 hours to obtain a composite slow-release fertilizer.

[0024] The outer surface of the compound slow-release fertilizer is loaded with 0.1% (by mass) of Bacillus subtilis spore powder via electrostatic adsorption technology; the viable count of the Bacillus subtilis spore powder is ≥1×10⁻⁶. 8 CFU / g.

[0025] The annular groove is covered with a water-retaining film, and the method for preparing the water-retaining film is as follows: (1) The seeds of *Mentha pubescens* were first frozen with liquid nitrogen and then crushed to 10 mesh. They were then soaked in a 2% w / v chitosan solution for 30 min and then dried to obtain coated seeds. The chitosan solution contained 0.1% gibberellic acid by volume. (2) Mix polylactic acid particles with 10% of its mass of acetylated tributyl citrate, dry in an oven at 60°C for 4 hours, then add 5% of the mass of the mixed particles of nano-titanium dioxide, 2% of nano-silver-supported montmorillonite, and 0.5% of dicumyl peroxide, and premix at 800 rpm for 10 minutes to obtain a premix. (3) The premixed material is blended into a blend by a twin-screw extruder; the twin-screw extruder has a length-to-diameter ratio of 40:1, a screw speed of 120 rpm, a vacuum degassing pressure of -0.08 MPa, and a temperature gradient of 160℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3, and 180℃ in zone 4. (4) Add the coated seeds and blended material from step (1) into a mixer and mix at 95°C and 50 rpm for 5 min; the amount of coated seeds added is 15% of the mass of the blended material; the mixed material is cast into a film, with a die temperature of 190°C, a cooling roller temperature of 25°C, a traction speed of 10 m / min, and a film thickness of 0.12 mm. (5) Micropores with a diameter of 100 μm were drilled on the membrane surface using a pulsed laser with a wavelength of 1064 nm and a power of 20 W, resulting in 300 pores / cm. 2 . Example 3

[0026] A management method to improve the cold and drought resistance and increase flowering of macadamia nuts includes the following steps: S1: In October-November, dig a circular trench 32cm deep 50cm away from the trunk. At the bottom of the trench, lay 9kg / tree of organic fertilizer containing 18-24% macadamia nut green husk fermentation. In the middle layer of the trench, lay 0.4-0.6kg / tree of calcium magnesium phosphate fertilizer and 300g / tree of starch grafting acrylate water-retaining agent. At the top layer of the trench, lay 1.0kg / tree of compound slow-release fertilizer with N-P2O5-K2O=15-15-15. S2: From November to January of the following year, spray the leaves of the nut plants with a cold-resistant solution at a rate of 350 mL / plant. Spraying should be done on sunny days when the daytime temperature is ≥15℃. The cold-resistant solution comprises the following components: proline 12g / L, salicylic acid 150mg / L, potassium humate 2g / L, brassinolide 50μg / L, and polyglycerol ester 0.5g / L; S3: From October to December, alternately spray with a 600-fold dilution of 20% paclobutrazol and a 500-fold dilution of PBO containing 0.1% nano-silica carrier, with a spraying interval of 13 days; simultaneously spray with a mixture containing 200 μmol / L melatonin and 250 μmol / L methyl jasmonate. S4: In January or February of the following year, spray a mixed solution containing 250 g / L brown algae oligosaccharides, 50 g / L 5-aminolevulinic acid, 350 g / L γ-aminobutyric acid, 0.2% potassium dihydrogen phosphate, 0.15% liquid boron, and 0.15% gibberellic acid, at a rate of 350 mL per plant.

[0027] The method for preparing the compound slow-release fertilizer is as follows: (1) Dissolve potassium humate and polyvinyl alcohol in deionized water at 60℃ with a solid-liquid ratio of 1:8, add genipin crosslinking agent, adjust the pH to 7.8 and stir to form a homogeneous colloid with a viscosity of 1000 mPa·s; (2) Chitosan with a degree of deacetylation ≥ 90% was dissolved in 1% acetic acid solution to prepare a solution with a concentration of 30 g / L. Then, nano-silica with a particle size of 40 nm was added and ultrasonically dispersed for 20 min to obtain a modified chitosan solution. (3) Place the N-P2O5-K2O=15-15-15 compound fertilizer granules in a fluidized bed, preheat to 52℃, atomize and spray the colloid prepared in step (1), and then let it stand to dry; spraying rate 9 mL / min; air inlet temperature 66℃; coating thickness 70μm; (4) The granules dried in step (3) are sprayed with the modified chitosan solution prepared in step (2) at 42°C, and then placed in an environment with a humidity of 65% and cured by hot air circulation at 45°C for 5 hours to obtain a composite slow-release fertilizer. The outer surface of the composite slow-release fertilizer is loaded with 0.2% Bacillus subtilis spore powder by electrostatic adsorption technology; the viable count of the Bacillus subtilis spore powder is ≥1×10⁻⁶. 8 CFU / g.

[0028] The annular groove is covered with a water-retaining film, and the method for preparing the water-retaining film is as follows: (1) The seeds of *Mentha pubescens* were first frozen with liquid nitrogen and then crushed to 100 mesh. They were then soaked in a 2% w / v chitosan solution for 30 min and then dried to obtain coated seeds. The chitosan solution contained 0.1% gibberellic acid by volume. (2) Mix polylactic acid particles with 8%-10% of its mass of acetylated tributyl citrate, dry in an oven at 60°C for 4 hours, then add 4% of the mass of the mixed particles of nano-titanium dioxide, 1.5% of nano-silver-supported montmorillonite, and 0.4% of dicumyl peroxide, and premix at 800 rpm for 10 minutes to obtain a premix. (3) The premixed material is blended into a blend by a twin-screw extruder; the twin-screw extruder has a length-to-diameter ratio of 40:1, a screw speed of 120 rpm, a vacuum degassing pressure of -0.08 MPa, and a temperature gradient of 160℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3, and 180℃ in zone 4. (4) Add the coated seeds and blended material from step (1) into a mixer and mix at 95°C and 50 rpm for 5 min; the amount of coated seeds added is 12% of the mass of the blended material; the mixed material is cast into a film, with a die temperature of 190°C, a cooling roller temperature of 25°C, a traction speed of 9 m / min, and a film thickness of 0.10 mm. (5) Micropores with a diameter of 80 μm were drilled on the membrane surface using a pulsed laser with a wavelength of 1064 nm and a power of 20 W, resulting in 250 pores / cm. 2 . Example 4

[0029] A management method to improve the cold and drought resistance and increase flowering of macadamia nuts includes the following steps: S1: In October-November, dig a circular trench 38cm deep 50cm away from the trunk. At the bottom of the trench, lay 9kg / tree of organic fertilizer containing 22% macadamia nut green husk fermentation. In the middle layer of the trench, lay 0.6kg / tree of calcium magnesium phosphate fertilizer and 280-320g / tree of starch grafting acrylate water-retaining agent. At the top layer of the trench, lay 0.8kg / tree of N-P2O5-K2O=15-15-15 compound slow-release fertilizer. S2: From November to January of the following year, spray the leaves of the nut plants with a cold-resistant solution at a rate of 360 mL / plant. Spraying should be done on sunny days when the daytime temperature is ≥15℃. The cold-resistant solution comprises the following components: proline 13g / L, salicylic acid 150mg / L, potassium humate 2g / L, brassinolide 55μg / L, and polyglycerol ester 0.6g / L; S3: From October to December, alternately spray with a 600-fold dilution of 20% paclobutrazol and a 500-fold dilution of PBO containing 0.1% nano-silica carrier, with an interval of 12-15 days; simultaneously spray with a mixture containing 195 μmol / L melatonin and 245 μmol / L methyl jasmonate. S4: In January or February of the following year, spray a mixed solution containing 255 g / L of brown algae oligosaccharides, 55 g / L of 5-aminolevulinic acid, 350 g / L of γ-aminobutyric acid, 0.3% potassium dihydrogen phosphate, 0.1% fluid boron, and 0.1% gibberellic acid, at a rate of 400 mL per plant.

[0030] The method for preparing the compound slow-release fertilizer is as follows: (1) Dissolve potassium humate and polyvinyl alcohol in deionized water at 60℃ with a solid-liquid ratio of 1:8, add genipin crosslinking agent, adjust the pH to 8.0 and stir to form a homogeneous colloid with a viscosity of 1100 mPa·s; (2) Chitosan with a degree of deacetylation ≥ 90% was dissolved in 1% acetic acid solution to prepare a solution with a concentration of 30 g / L. Then, nano-silica with a particle size of 40 nm was added and ultrasonically dispersed for 20 min to obtain a modified chitosan solution. (3) Place the N-P2O5-K2O=15-15-15 compound fertilizer granules in a fluidized bed, preheat to 50℃, atomize and spray the colloid prepared in step (1), and then let it stand to dry; spraying rate 8mL / min; air inlet temperature 70℃; coating thickness 70μm; (4) The granules dried in step (3) are sprayed with the modified chitosan solution prepared in step (2) at 45°C, and then placed in an environment with a humidity of 60-70% and cured by hot air circulation at 45°C for 6 hours to obtain a composite slow-release fertilizer. The outer surface of the composite slow-release fertilizer is loaded with 0.2% Bacillus subtilis spore powder by electrostatic adsorption technology; the viable count of the Bacillus subtilis spore powder is ≥1×10⁻⁶. 8 CFU / g.

[0031] The annular groove is covered with a water-retaining film, and the method for preparing the water-retaining film is as follows: (1) The seeds of *Mentha pubescens* were first frozen with liquid nitrogen and then crushed to 50 mesh. They were then soaked in a 2% w / v chitosan solution for 30 min and then dried to obtain coated seeds. The chitosan solution contained 0.1% gibberellic acid by volume. (2) Mix polylactic acid particles with 9% of its mass of acetylated tributyl citrate, dry in an oven at 60°C for 4 hours, then add 3% of the mass of the mixed particles of nano-titanium dioxide, 2% of nano-silver-supported montmorillonite, and 0.5% of dicumyl peroxide, and premix at 800 rpm for 10 minutes to obtain a premix. (3) The premixed material is blended into a blend by a twin-screw extruder; the twin-screw extruder has a length-to-diameter ratio of 40:1, a screw speed of 120 rpm, a vacuum degassing pressure of -0.08 MPa, and a temperature gradient of 160℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3, and 180℃ in zone 4. (4) Add the coated seeds and blended material from step (1) into a mixer and mix at 95°C and 50 rpm for 5 min; the amount of coated seeds added is 15% of the mass of the blended material; the mixed material is cast into a film, with a die temperature of 190°C, a cooling roller temperature of 25°C, a traction speed of 8 m / min, and a film thickness of 0.12 mm. (5) Micropores with a diameter of 88 μm were drilled on the membrane surface using a pulsed laser with a wavelength of 1064 nm and a power of 20 W, resulting in 260 pores / cm. 2 .

[0032] Comparative Example The standard macadamia plant management methods are as follows: (1) October-November: Apply 5-10 kg of organic fertilizer, 0.5 kg of calcium magnesium phosphate fertilizer, and 1 kg of compound fertilizer; (2) During November-January: Spray with 20g / L potassium humate to improve cold resistance; (3) During October-December: spray with 20% paclobutrazol at 600-800 times dilution and 500 times PBO solution to improve drought resistance; (4) During January-February: spray with 0.2% potassium dihydrogen phosphate, 0.1% fluid boron, and 0.1% gibberellic acid.

[0033] The ratio of root depth to width is used as a standard for cold resistance: a ratio of 1.7-1.9 indicates strong cold resistance; a ratio of 1.5-1.6 indicates moderate cold resistance; and a ratio of 2.0-2.2 indicates weak cold resistance.

[0034] The flowering amount, drought resistance, chlorophyll content, and root depth to width ratio distribution of macadamia plants after Examples 1-3 and the comparative treatment are shown in Tables 1-4.

[0035] Table 1: Effects of different treatments on flowering quantity Comparative Example 2.9 22.6 23.8% Example 1 3.3 25.2 75.2% Example 2 3.2 24.8 68.3% Example 3 3.5 26.3 81.7% Example 4 3.3 27.4 69.5% Table 2: Physiological effects of different treatments on drought resistance Comparative Example 21.6 12.8 11.4 4.8 Example 1 39.4 31.3 28.2 7.5 Example 2 35.8 27.6 26.5 6.9 Example 3 37.1 28.7 19.8 8.2 Example 4 32.5 24.1 24.6 9.1 Table 3: Effects of different treatments on chlorophyll content Comparative Example 1.33 0.21 1.54 Example 1 1.78 0.31 2.09 Example 2 1.86 0.34 2.2 Example 3 1.92 0.39 2.31 Example 4 2.26 0.43 2.69 Table 4: Distribution of root depth to width ratio under different treatments Comparative Example 55% 29% 16% Example 1 70% 21% 9% Example 2 68% 32% 10% Example 3 72% 18% 10% Example 4 73% 18% 9% As shown in Tables 1-4, macadamia plants grown using the management method of this invention exhibit significantly increased flowering, high drought resistance, and high chlorophyll content in their branches and leaves, which enhances photosynthesis and provides more energy for the plants to cope with low-temperature stress. The proportion of plants with strong cold resistance is higher than 68%, while the proportion of plants with moderate cold resistance is lower than 10%.

[0036] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.

Claims

1. A management method for improving the cold and drought resistance and increasing flowering of macadamia nuts, characterized in that, Includes the following steps: S1: In October-November, dig a circular trench 30-40cm deep, 50cm away from the trunk. At the bottom of the trench, lay 8-10kg / tree of organic fertilizer containing 18-24% macadamia nut husk fermentation. In the middle layer, lay 0.4-0.6kg / tree of calcium magnesium phosphate fertilizer and 280-320g / tree of starch-grafted acrylate water-retaining agent. At the surface of the trench, lay 0.8-1.2kg / tree of N-P2O5-K2O=15-15-15 compound slow-release fertilizer. The surface of the trench is also covered with a water-retaining film. S2: From November to January of the following year, spray the leaves of the nut plants with a cold-resistant solution at a rate of 300-400 mL / plant. Spraying should be done on sunny days when the daytime temperature is ≥15℃. The aforementioned cold-resistant solution comprises the following components: proline 10-14 g / L, salicylic acid 140-160 mg / L, potassium humate 2-3 g / L, brassinolide 40-60 μg / L, and polyglycerol ester 0.4-0.6 g / L; S3: From October to December, alternately spray with a 600-fold dilution of 20% paclobutrazol and a 500-fold dilution of PBO containing 0.1% nano-silica carrier, with an interval of 12-15 days; simultaneously spray with a mixture containing 180-220 μmol / L melatonin and 240-260 μmol / L methyl jasmonate. S4: In January or February of the following year, spray a mixed solution containing 240-260 g / L of brown algae oligosaccharides, 40-60 g / L of 5-aminolevulinic acid, 340-360 g / L of γ-aminobutyric acid, 0.1-0.3% potassium dihydrogen phosphate, 0.1-0.2% liquid boron, and 0.1-0.2% gibberellic acid, at a rate of 300-400 mL per plant; The method for preparing the compound slow-release fertilizer is as follows: a1: Dissolve potassium humate and polyvinyl alcohol in deionized water at 60℃ at a solid-liquid ratio of 1:8, add genipin crosslinking agent, adjust the pH to 7.5-8.0 and stir to form a homogeneous colloid with a viscosity of 800-1200 mPa·s; a2: Chitosan with a degree of deacetylation ≥90% was dissolved in a 1% acetic acid solution to prepare a solution with a concentration of 30g / L. Then, nano-silica with a particle size of 30-50nm was added and ultrasonically dispersed for 20min to obtain a modified chitosan solution. a3: Place the N-P2O5-K2O=15-15-15 compound fertilizer granules in a fluidized bed, preheat to 50-55℃, atomize and spray the colloid prepared in step (1), and then let it stand to dry; spraying rate 8-10 mL / min; air inlet temperature 65-70℃; coating thickness 50-80μm; a4: The granules dried in step (3) are sprayed with the modified chitosan solution prepared in step (2) at 40-45℃, and then placed in an environment with a humidity of 60-70% and cured by hot air circulation at 45℃ for 4-6 hours to obtain a composite slow-release fertilizer. The method for preparing the water-retaining film is as follows: b1: Soak the seeds of *Mentha haplocalyx* in a 2% w / v chitosan solution for 30 min, and then dry them to obtain coated seeds; the chitosan solution contains 0.1% by volume of gibberellic acid. b2: Mix polylactic acid particles with 8%-10% of its mass of acetylated tributyl citrate, dry in an oven at 60°C for 4 hours, then add 3%-5% of the mass of the mixed particles of nano-titanium dioxide, 1%-2% of nano-silver-supported montmorillonite, and 0.3%-0.5% of dicumyl peroxide, and premix at 800 rpm for 10 minutes to obtain a premix. b3: The premixed material is blended into a blend using a twin-screw extruder; the twin-screw extruder has a length-to-diameter ratio of 40:1, a screw speed of 120 rpm, a vacuum degassing pressure of -0.08 MPa, and a temperature gradient of 160℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3, and 180℃ in zone 4. b4: Add the coated seeds and blend from step (1) to a mixer and mix at 95°C and 50 rpm for 5 minutes; the amount of coated seeds added is 10%-15% of the mass of the blend; the mixed material is cast into a film, with a die temperature of 190°C, a cooling roller temperature of 25°C, a traction speed of 8-10 m / min, and a film thickness of 0.08-0.12 mm. b5: Micropores with a diameter of 50-100 μm are created on the membrane surface using a pulsed laser with a wavelength of 1064 nm and a power of 20 W, resulting in 200-300 pores / cm. 2 .

2. The management method for improving the cold resistance, drought resistance, and increasing flowering of macadamia nuts according to claim 1, characterized in that: The outer surface of the compound slow-release fertilizer is loaded with 0.1%-0.2% by mass of Bacillus subtilis spore powder via electrostatic adsorption technology; the viable count of the Bacillus subtilis spore powder is ≥1×10⁻⁶. 8 CFU / g.

3. The management method for improving the cold and drought resistance and increasing flowering of macadamia nuts according to claim 1, characterized in that: The seeds of *Mentha pubescens* mentioned in step b1 are first frozen with liquid nitrogen and then crushed to 10-100 mesh.