A method for preventing early decline of densely-planted double-layered cone-shaped macadamia nut trees

Abstract

The application provides a method for preventing early decline of densely-planted double-layered circular table-shaped macadamia nut trees, and belongs to the technical field of fruit tree cultivation. The method for preventing early decline comprises hierarchical nutrient supply and flower and fruit protection management. The hierarchical nutrient supply comprises: deep application of calcium, magnesium and phosphorus fertilizer in the lower layer of more than 60cm soil, and covering with a root control device; application of organic fertilizer and biological bacteria agent in the middle layer of 30-60cm soil; and application of a large amount of elements, humic acid and seaweed extract water-soluble fertilizer in the upper layer of 0-30cm soil. The flower and fruit protection management comprises: spraying ABA and paclobutrazol during flower bud differentiation period; spraying brassinolide and fluid boron during full flowering period; spraying forchlorfenuron and amino acid during young fruit period; and spraying NAA and potassium dihydrogen phosphate during fruit swelling period. The application supplies nutrients hierarchically and protects flowers and fruits for densely-planted double-layered circular table-shaped macadamia nut trees, prevents early decline of the densely-planted macadamia nut trees, promotes the development of lower branches, balances tree vigor and maintains high yield.

Description

Technical Field

[0001] This invention belongs to the field of fruit tree cultivation technology, and in particular relates to a method for preventing premature aging of densely planted double-layered frustum macadamia trees. Background Technology

[0002] Macadamia nuts, a fruit tree with high economic value, are highly sought after in the international market due to their nutritious and crisp fruit. In recent years, with the increasing demand for macadamia nuts, their cultivation scale has been gradually expanding. Among the many cultivation techniques, CN115812504A discloses a high-density, dwarfing, and high-yield cultivation method for macadamia nuts. Through dense planting and pruning, this method effectively increases yield and advances the peak production period, providing important technical support for the efficient cultivation of macadamia nuts. However, with the deepening of planting practice, some drawbacks have gradually emerged from this cultivation method.

[0003] On the one hand, macadamia trees planted at high density are prone to premature aging. Due to the high planting density, competition for nutrients, water and light among the plants intensifies, and the rate of nutrient depletion in the soil accelerates. After bearing fruit for many consecutive years, the tree's nutrient reserves are insufficient to meet the dual needs of growth and fruiting, leading to a gradual weakening of the tree, yellowing and shedding of leaves, and a decline in fruit yield and quality.

[0004] On the other hand, this cultivation method is detrimental to the growth of lower branches. Although a double-layered, truncated cone-shaped plant form is achieved through pruning, in actual growth, the shading of the upper branches and leaves results in insufficient sunlight for the lower branches, limiting photosynthesis, causing them to become thin and weak, and making it difficult to form effective fruiting branches. Moreover, because nutrients are preferentially supplied to the vigorously growing upper parts, the lower branches are at a disadvantage in nutrient acquisition, further inhibiting their growth and development and affecting the overall yield. In some orchards, the fruit yield of lower branches accounts for only 30%-40% of the total yield, far below the expected level.

[0005] Therefore, although the cultivation method of CN115812504A has improved the yield and planting benefits of macadamia nuts to a certain extent, problems such as premature aging of the tree and growth of lower branches need to be solved urgently. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a method for preventing premature aging of densely planted double-layered frustum macadamia trees, thereby preventing premature aging of densely planted macadamia trees, promoting the development of lower branches, balancing tree vigor, and maintaining high yield.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] A method for preventing premature aging of densely planted double-layered frustum macadamia trees, including tiered nutrient supply and flower and fruit preservation management;

[0009] The stratified nutrient supply includes: applying calcium magnesium phosphate fertilizer to the bottom layer (>60cm) of soil and covering it with root control devices; applying organic fertilizer and biological agents to the middle layer (30-60cm) of soil; and applying water-soluble fertilizer containing macro-elements, humic acid, and seaweed extract to the top layer (0-30cm) of soil.

[0010] The management of flower and fruit preservation includes: spraying ABA and paclobutrazol during the flower bud differentiation period; spraying brassinolide and fluid boron during the full bloom period; spraying chlorpyrifos and amino acids during the young fruit period; and spraying NAA and potassium dihydrogen phosphate during the fruit expansion period.

[0011] Preferably, the macadamia tree is ≥7 years old, the planting density is 2-3m×2-3m, and the overall plant shape is a double-layered truncated cone with a main trunk.

[0012] Preferably, a circular trench with a depth of >60cm is dug at a distance of 90-110cm from the main stem of the macadamia nut, and 18-22kg / mu of calcium magnesium phosphate fertilizer is applied deeply, and a root control device is used to cover it. This deep application is repeated once every 2-3 years.

[0013] Preferably, the middle layer (30-60cm) of soil is treated with 1.5-2.5t / mu of organic fertilizer and 0.8-1.2kg / mu of biological agent.

[0014] Preferably, 8-12 kg / mu of water-soluble fertilizer is applied to the upper 0-30cm soil layer; the water-soluble fertilizer contains 13-17wt% N, 13-17wt% P2O5, 13-17wt% K2O, 4-6wt% humic acid and 2-4wt% seaweed extract.

[0015] Preferably, during the flower bud differentiation period, 0.01-0.03 wt% ABA and 0.005-0.008 wt% paclobutrazol are sprayed at a rate of 40-50 L / mu.

[0016] Preferably, during the full bloom period, 0.0001-0.0003 wt% brassinolide and 0.08-0.12 wt% fluid boron are sprayed at a rate of 60-70 L / mu.

[0017] Preferably, during the young fruit stage, 0.0001-0.0003 wt% chlorpyrifos and 0.25-0.35 wt% amino acids are sprayed at a rate of 50-60 L / mu.

[0018] Preferably, during the fruit expansion period, 0.0005-0.001 wt% NAA and 0.15-0.25 wt% potassium dihydrogen phosphate are sprayed at a rate of 60-70 L / mu.

[0019] Preferably, it also includes the management of the inner low-light zone, spraying zinc fertilizer, calcium fertilizer, molybdenum fertilizer and 6-BA after the spring shoots mature and before the autumn shoots sprout; injecting 6-BA and urea into the inner branches in the early spring bud sprouting period and in the autumn before the buds enter dormancy.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention precisely meets the nutrient needs of different layers of the tree's root system through tiered nutrient supply. The lower layer is deeply fertilized with calcium-magnesium-phosphate fertilizer and covered with root control devices to guide roots downwards, increase the proportion of vertical roots, enhance the tree's drought and lodging resistance, and provide a long-lasting supply of phosphorus to the roots. The middle layer is fertilized with organic fertilizer and biological agents to promote root branching, increase the nutrient absorption area, and improve the soil microbial environment. The upper layer is drip-irrigated with water-soluble fertilizer rich in various nutrients to prevent nutrient depletion in the surface layer and maintain root vitality. This tiered fertilization method effectively solves the problem of insufficient nutrient supply caused by intense root competition in densely planted orchards, fundamentally preventing premature aging of trees and extending their economic lifespan.

[0022] The fruit-preservation management measures of this invention, tailored to the growth characteristics of macadamia nuts, involve spraying appropriate plant growth regulators and nutrients at different stages, effectively promoting the development of lower branches. Furthermore, the management measures for the low-light areas within the canopy effectively improve light and nutrient conditions, delay leaf senescence, activate dormant buds, promote the growth of lower branches, and enhance their fruit-bearing capacity.

[0023] This invention integrates tiered nutrient supply and flower and fruit preservation management, which can significantly improve the yield and quality of macadamia nuts. Tiered nutrient supply provides sufficient nutrients for tree growth and fruiting, while flower and fruit preservation management improves fruit set rate, enabling the tree to maintain high yield. Simultaneously, through rational regulation of nutrient distribution, the fruit size is uniform, the weight of 100 fruits increases, the kernel yield is improved, and the fruit quality is significantly enhanced. Detailed Implementation

[0024] This invention provides a method for preventing premature aging of densely planted double-layered frustum macadamia trees, including tiered nutrient supply and flower and fruit preservation management.

[0025] In this invention, the macadamia trees are preferably ≥7 years old, planted at a density of 2-3m × 2-3m, and have an overall plant shape resembling a double-layered frustum of a main trunk. The specific planting method for densely planted double-layered frustum macadamia trees in this invention is carried out in accordance with the method disclosed in CN115812504A.

[0026] In this invention, the stratified nutrient supply includes: applying calcium magnesium phosphate fertilizer to the lower layer of soil (>60cm) and covering it with root control devices; applying organic fertilizer and biological agents to the middle layer of soil (30-60cm); and applying water-soluble fertilizer containing macro-elements, humic acid, and seaweed extract to the upper layer of soil (0-30cm).

[0027] In this invention, the application of calcium magnesium phosphate fertilizer to the lower soil layer (>60cm) and the application of root control devices are preferably carried out after autumn harvest, every 2-3 years. Preferably, a circular trench with a depth of >60cm is dug at a distance of 90-110cm from the main stem of the macadamia nut, more preferably at a distance of 1m from the main stem; the application of calcium magnesium phosphate fertilizer is preferably 18-22kg / mu, more preferably 20kg / mu; the root control device is preferably made of non-woven fabric, which is highly breathable and permeable, corrosion-resistant, and suitable for acidic red soil, more preferably buried at a depth of 60-80cm. In densely planted macadamia nut orchards, the vertical root ratio is <20%, resulting in weak drought and lodging resistance. Calcium magnesium phosphate fertilizer can slowly release phosphorus in acidic soil (solubility is 30% at pH 5.0), guiding the roots to grow deeper towards nutrient-rich soil; the root control device physically prevents excessive expansion of horizontal roots in macadamia nuts, forcing the roots to grow downwards and increasing the vertical root ratio.

[0028] In this invention, the application of organic fertilizer and biological agents to the middle 30-60cm soil layer is preferably carried out after autumn harvest. The preferred application rate of organic fertilizer is 1.5-2.5 t / mu, more preferably 2 t / mu, and even more preferably, the organic fertilizer is selected from commercial organic fertilizer or well-rotted organic fertilizer. The preferred application rate of biological agents is 0.8-1.2 kg / mu, more preferably 1 kg / mu, and even more preferably, the biological agent is an arbuscular mycorrhizal fungal inoculant. In densely planted macadamia orchards, the horizontal expansion of the root system is limited, and the deep root system is underdeveloped. The application of organic fertilizer to the middle soil layer provides slow-release organic matter, promotes root branching in the middle layer, induces auxin secretion from the root tips, and increases the nutrient absorption area. Arbuscular mycorrhizal fungi live in symbiosis with the roots, and their hyphal network extends into the soil pores, helping to absorb deep water and insoluble phosphorus.

[0029] In this invention, the preferred method is to apply a water-soluble fertilizer containing macro-elements, humic acid, and seaweed extract to the top 0-30cm soil layer via drip irrigation, once a month. The preferred application rate is 8-12 kg / mu of water-soluble fertilizer, more preferably 10 kg / mu. The preferred water-soluble fertilizer contains 13-17 wt% N, 13-17 wt% P2O5, 13-17 wt% K2O, 4-6 wt% humic acid (dry basis), and 2-4 wt% seaweed extract; more preferably, it contains 15 wt% N, 15 wt% P2O5, 15 wt% K2O, 5 wt% humic acid, and 3 wt% seaweed extract. In densely planted macadamia orchards, the surface root system is highly competitive, and conventional fertilization easily leads to nutrient depletion in the surface layer. Drip irrigation provides precise water and fertilizer supply, avoiding deep seepage, reducing fertilizer waste, and maintaining root vitality. Humic acid and seaweed extract stimulate macadamia root growth, activate fixed phosphorus and potassium in the soil, and improve the utilization rate of surface nutrients.

[0030] In this invention, the management of flower and fruit preservation includes: spraying ABA and paclobutrazol during the flower bud differentiation period; spraying brassinolide and fluid boron during the full bloom period; spraying chlorpyrifos and amino acids during the young fruit period; and spraying NAA and potassium dihydrogen phosphate during the fruit expansion period.

[0031] In this invention, it is preferred to spray 0.01-0.03 wt% ABA and 0.005-0.008 wt% paclobutrazol during the flower bud differentiation period, and more preferably, 0.02 wt% ABA and 0.0065 wt% paclobutrazol; the preferred spraying rate is 40-50 L / mu, and more preferably 45 L / mu. Macadamia nuts exhibit significant apical dominance, with apical flower buds easily differentiating during the flower bud differentiation period, leading to a decrease in the differentiation rate of inner flower buds. ABA can inhibit the polar transport of apical auxin, promoting nutrient allocation to inner flower buds; paclobutrazol can block gibberellin synthesis, shorten internode length, and reduce vegetative growth consumption.

[0032] In this invention, it is preferred to spray 0.0001-0.0003 wt% brassinolide and 0.08-0.12 wt% fluid boron during the full bloom period, and more preferably 0.0002 wt% brassinolide and 0.1 wt% fluid boron; the preferred spraying amount is 60-70 L / mu, and more preferably 65 L / mu.

[0033] In this invention, it is preferred to spray 0.0001-0.0003 wt% chlorpyrifos and 0.25-0.35 wt% amino acids during the young fruit stage, and more preferably 0.0002 wt% chlorpyrifos and 0.3 wt% amino acids; the preferred spraying rate is 50-60 L / mu, and more preferably 55 L / mu. In densely planted macadamia orchards, the inner fruits are prone to physiological fruit drop due to nutrient competition. Chlorpyrifos mimics cytokinin, promoting cell proliferation in young fruits and increasing the fruit set rate of inner fruits; amino acids provide an organic nitrogen source, avoiding competition between shoots and fruits caused by traditional nitrogen fertilizers.

[0034] In this invention, it is preferred to spray 0.0005-0.001 wt% NAA and 0.15-0.25 wt% potassium dihydrogen phosphate during the fruit expansion period, and more preferably 0.00075 wt% NAA and 0.2 wt% potassium dihydrogen phosphate; the preferred spraying rate is 60-70 L / mu, and more preferably 65 L / mu. In double-layered frustum macadamia trees, nutrients concentrate on the apical fruit, hindering the expansion of the inner fruit. NAA induces vascular bundle differentiation in the fruit, strengthens the inner fruit sink, and promotes assimilate input; potassium dihydrogen phosphate increases pericarp thickness and reduces sunburn cracking.

[0035] In this invention, the preferred method also includes management of the inner low-light zone. Zinc fertilizer, calcium fertilizer, molybdenum fertilizer, and 6-BA are sprayed after the spring shoots mature and before the autumn shoots sprout. More preferably, 0.1 wt% zinc fertilizer, 0.2 wt% calcium fertilizer, 0.05 wt% molybdenum fertilizer, and 0.005 wt% 6-BA are sprayed. More preferably, zinc sulfate is used as the zinc fertilizer, calcium nitrate as the calcium fertilizer, and ammonium molybdate as the molybdenum fertilizer. The spraying is applied to the back of the inner branches at a rate of 60 L / acre. In densely planted double-layered round macadamia trees, insufficient light leads to a reduction in photosynthetic assimilates in the inner leaves, causing branch dieback. Zinc fertilizer can activate carbonic anhydrase, improving CO2 fixation efficiency under low light and compensating for photosynthetic losses; calcium fertilizer can strengthen cell walls and delay mesophyll cell disintegration caused by low light; 6-BA can block leaf senescence signals (ethylene synthesis) and maintain chlorophyll content in the inner leaves.

[0036] In this invention, it is preferable to further include injecting 6-BA and urea into the inner branches before the buds sprout in spring and before the buds enter dormancy in autumn. More preferably, injecting 0.005wt% 6-BA and 0.1%wt urea. More preferably, select 1-2 year old branches with an inner diameter of 1-2 cm, full but unsprouted buds. Drill a hole at a 45° angle downwards with a 3mm drill bit on the shaded side of the branch base, 5-10 cm from the branching point, to the middle layer of the xylem. Slowly inject 2-3 mL of the solution using a medical syringe, avoiding spillage. After injection, seal the wound with a healing agent. Select 3-5 inner branches per tree for treatment, with a total single dose ≤15 mL / tree to prevent excessive hormones from causing malformed buds. Injection is performed when the macadamia tree has sufficient nutrient reserves and the buds are in a semi-dormant-to-budding critical state. 6-BA stimulates cell division, and urea provides a local nitrogen source, ensuring effective activation of dormant buds while avoiding competition for nutrients with fruits or new shoots.

[0037] In this invention, it is preferred to also include laying a silver reflective film between the rows of macadamia nut orchards, and more preferably the film width is 1.5-2m to increase the light intensity in the low light area of ​​the inner canopy; it is preferred to "open the skylight" pruning of the top branches that block the inner canopy in May every year, removing 1-2 upright branches, retaining 30% light-transmitting pores, increasing light transmittance, and extending the functional period of the inner canopy leaves.

[0038] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0039] Example 1

[0040] A method for cultivating macadamia nuts in a densely planted, double-layered, frustum shape includes the following steps:

[0041] (1) Layered nutrient supply: Select macadamia trees that are 7 years old, planted at a density of 2.5m × 2.5m, and have an overall tree shape with a double-layered truncated cone shape. After harvesting in autumn, dig a circular trench with a depth of >60cm at 1m away from the main trunk of the macadamia tree, apply 20kg / mu of calcium magnesium phosphate fertilizer, once every 3 years, and cover with a non-woven fabric root control device buried to a depth of 70cm. Apply 2t / mu of commercial organic fertilizer and 1kg / mu of arbuscular mycorrhizal fungi inoculant to the middle layer (30-60cm) of soil. Apply 10kg / mu of water-soluble fertilizer per month to the top layer (0-30cm) of soil via drip irrigation. This water-soluble fertilizer contains 15wt% N, 15wt% P2O5, 15wt% K2O, 5wt% humic acid, and 3wt% seaweed extract.

[0042] (2) During the flower bud differentiation period, spray with 0.02wt% ABA and 0.0065wt% paclobutrazol at a rate of 45L / mu; during the full bloom period, spray with 0.0002wt% brassinolide and 0.01wt% fluid boron at a rate of 65L / mu; during the young fruit stage, spray with 0.0002wt% chlorpyrifos and 0.3wt% amino acids at a rate of 55L / mu; during the fruit expansion stage, spray with 0.00075wt% NAA and 0.2wt% potassium dihydrogen phosphate at a rate of 65L / mu.

[0043] (3) Management of the inner canopy in low light: After the spring shoots mature and before the autumn shoots sprout, spray with 0.1wt% zinc sulfate, 0.2wt% calcium nitrate, 0.05wt% ammonium molybdate and 0.005wt% 6-BA on the back of the inner branches, at a rate of 60L / mu. In the early stage of spring bud sprouting and before autumn buds enter dormancy, select 1-2 year old branches with a diameter of 1.5cm and plump but unsprouted buds. At the base of the branch on the shaded side, 7.5cm from the branching point, drill a hole at a 45° angle downwards with a 3mm drill bit to the middle layer of the xylem. Slowly inject 2.5mL of the solution containing 0.005wt% 6-BA and 0.1wt% urea using a medical syringe. Select 4 inner branches per tree for treatment, and control the total amount of the solution per tree at 10mL. Meanwhile, a 1.5m wide silver reflective film is laid between the rows of macadamia nut orchards. Every May, the top branches that are blocking the inner canopy are pruned to "open the skylight", removing 1-2 upright branches and retaining 30% light-transmitting openings.

[0044] Example 2

[0045] A method for cultivating macadamia nuts in a densely planted, double-layered, frustum shape includes the following steps:

[0046] (1) Layered nutrient supply: Select macadamia trees that are 7 years old, planted at a density of 2m×2m, and have a double-layered truncated cone shape with a main trunk. After harvesting fruit in autumn, dig a circular trench with a depth of >60cm at 90cm from the main trunk, and apply 18kg / mu of calcium magnesium phosphate fertilizer. Repeat this application every 2 years, and cover with a non-woven fabric root control device buried 60cm deep. Apply 1.5t / mu of well-rotted organic fertilizer and 0.8kg / mu of arbuscular mycorrhizal fungi agent to the middle 30-60cm soil layer. Drip irrigate 8kg / mu of water-soluble fertilizer per month to the upper 0-30cm soil layer. The water-soluble fertilizer contains 13wt% N, 13wt% P2O5, 13wt% K2O, 4wt% humic acid, and 2wt% seaweed extract.

[0047] (2) Flower and fruit preservation management: During the flower bud differentiation period, spray 0.01wt% ABA and 0.005wt% paclobutrazol at a rate of 40L / mu; during the full bloom period, spray 0.0001wt% brassinolide and 0.08wt% fluid boron at a rate of 60L / mu; during the young fruit stage, spray 0.0001wt% chlorpyrifos and 0.25wt% amino acids at a rate of 50L / mu; during the fruit expansion period, spray 0.0005wt% NAA and 0.15wt% potassium dihydrogen phosphate at a rate of 60L / mu.

[0048] (3) The management of the low-light zone inside the bore is the same as in Example 1.

[0049] Example 3

[0050] A method for cultivating macadamia nuts in a densely planted, double-layered, frustum shape includes the following steps:

[0051] (1) Layered nutrient supply: Select macadamia trees that are 8 years old, planted at a density of 3m×3m, and have a double-layered truncated cone shape on the main trunk. After harvesting the fruit in autumn, dig a circular trench with a depth of >60cm at 110cm from the main trunk, and apply 22kg / mu of calcium magnesium phosphate fertilizer. Repeat this application every 3 years, and cover with a non-woven fabric root control device buried 80cm deep. Apply 2.5t / mu of commercial organic fertilizer and 1.2kg / mu of arbuscular mycorrhizal fungi inoculant to the middle 30-60cm soil layer. Drip irrigate 12kg / mu of water-soluble fertilizer monthly to the top 0-30cm soil layer. The water-soluble fertilizer contains 17wt% N, 17wt% P2O5, 17wt% K2O, 6wt% humic acid, and 4wt% seaweed extract.

[0052] (2) Flower and fruit preservation management: During the flower bud differentiation period, spray 0.03wt% ABA and 0.008wt% paclobutrazol at a rate of 50L / mu; during the full bloom period, spray 0.0003wt% brassinolide and 0.12wt% fluid boron at a rate of 70L / mu; during the young fruit stage, spray 0.0003wt% chlorpyrifos and 0.35wt% amino acids at a rate of 60L / mu; during the fruit expansion period, spray 0.001wt% NAA and 0.25wt% potassium dihydrogen phosphate at a rate of 70L / mu.

[0053] (3) The management of the low-light zone inside the bore is the same as in Example 1.

[0054] Experimental Example 1

[0055] The effects of different fertilization management methods on macadamia nut production and root growth

[0056] 1. Experimental Design

[0057] The macadamia nut variety is HiddenValleyA4, planted in acidic red soil at a density of 2×3m. The plant has a double-layered truncated cone shape with a main stem and is 8 years old.

[0058] A randomized block design was adopted, and three fertilization management methods were used as shown in Table 1. Fertilization was carried out continuously for 2 years, with 3 replicates, and each plot area was 0.5 mu.

[0059] Table 1 Different Fertilization Management Methods

[0060]

[0061] 2. Indicator Testing

[0062] Yield measurements were conducted for two years, and the annual yield per mu, weight of 100 fruits, and kernel yield were recorded. After harvesting in the second year, the root distribution (root mass percentage in the 0-30cm / 30-60cm / >60cm soil layer) was detected using a stratified excavation method.

[0063] 3. Test Results

[0064] As shown in Table 2, the yield, 100-fruit weight, and kernel yield of treatment group 2 were significantly higher than those of treatment group 1 and the control group CK in both years of testing (P < 0.05). Regarding root distribution, the proportion of lower root system in treatment group 2 was also significantly higher than that in treatment group 1 and the control group, indicating that the fertilization management method of treatment group 2 effectively guided root growth to deeper layers, enhanced the tree's nutrient absorption capacity and stability, and thus increased yield. Furthermore, the yield of CK decreased in the second year, exhibiting a clear "biennial bearing" phenomenon, while the production of treatment 2 remained relatively stable.

[0065] Table 2. Effects of different fertilization management methods on macadamia nut production and root growth.

[0066]

[0067] Note: Different letters in the table represent significant differences, P < 0.05.

[0068] Experimental Example 2

[0069] The impact of different flower and fruit preservation management methods on macadamia nut growth and yield

[0070] 1. Experimental Design

[0071] The macadamia nut variety is HiddenValleyA4, planted in acidic red soil at a density of 2×3m. The plant has a double-layered truncated cone shape with a main stem and is 8 years old.

[0072] A randomized block design was used, and two management methods for preserving flowers and fruits were shown in Table 3. The experiments were repeated three times, with each plot covering an area of ​​0.5 mu.

[0073] Table 3 Different methods of flower and fruit preservation

[0074] CK Example 1 of CN115812504A: Flower and Fruit Preservation Management 1 Example 1 of this invention: Flower and fruit preservation management + management of the inner canopy in low light conditions

[0075] Note: The fertilization and pest and disease management methods are the same for both treatments.

[0076] 2. Indicator Testing

[0077] During the fruit-setting period, five trees were randomly selected from each plot to investigate the total fruit-setting rate and the lower-layer fruit-setting rate. After harvest, five trees were randomly selected from each plot for yield measurement, and the total yield and the yield of the lower-layer fruit were calculated, along with the percentage of the lower-layer fruit yield.

[0078] 3. Test Results

[0079] As shown in Table 4, the total fruit set rate, lower layer fruit set rate, total yield, and lower layer fruit yield of treatment group 1 were significantly higher than those of the control group CK (P < 0.05). This indicates that the fruit preservation management method of the present invention, combined with the management of the inner canopy low-light area, can significantly improve the fruit set rate and yield of macadamia nuts, especially the yield of lower layer fruits, effectively improve the distribution of fruits, and enhance the overall planting benefits.

[0080] Table 4. Effects of different flower and fruit preservation methods on macadamia nut production in densely planted areas.

[0081]

[0082]

[0083] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preventing premature aging of densely planted double-layered frustum macadamia trees, characterized in that, This includes tiered nutrient supply and management for flower and fruit preservation; The stratified nutrient supply includes: applying 18-22 kg / mu of calcium magnesium phosphate fertilizer to the lower layer (>60cm) of soil after autumn harvest, and covering with root control devices; applying 1.5-2.5 t / mu of organic fertilizer and 0.8-1.2 kg / mu of arbuscular mycorrhizal biological agent to the middle layer (30-60cm) of soil after autumn harvest; and applying 8-12 kg / mu of water-soluble fertilizer containing macro-elements, humic acid, and seaweed extract to the upper layer (0-30cm) of soil, wherein the water-soluble fertilizer contains 13-17 wt% N, 13-17 wt% P2O5, 13-17 wt% K2O, 4-6 wt% humic acid, and 2-4 wt% seaweed extract, and drip irrigating once a month. The management of flower and fruit preservation includes: spraying 0.01-0.03wt% ABA and 0.005-0.008wt% paclobutrazol during the flower bud differentiation period, at a rate of 40-50L / mu; spraying 0.0001-0.0003wt% brassinolide and 0.08-0.12wt% fluid boron during the full bloom period, at a rate of 60-70L / mu; spraying 0.0001-0.0003wt% chlorpyrifos and 0.25-0.35wt% amino acids during the young fruit stage, at a rate of 50-60L / mu; and spraying 0.0005-0.001wt% NAA and 0.15-0.25wt% potassium dihydrogen phosphate during the fruit expansion period, at a rate of 60-70L / mu.

2. The method for preventing premature aging according to claim 1, characterized in that, The macadamia trees are ≥7 years old, planted at a density of 2-3m × 2-3m, and have an overall plant shape that resembles a double-layered truncated cone with a main trunk.

3. The method for preventing premature aging according to claim 1, characterized in that, Dig a circular trench with a depth of >60cm at a distance of 90-110cm from the main stem of the macadamia nut, and apply the trench deeply once every 2-3 years.

4. The method for preventing premature aging according to claim 1, characterized in that, It also includes the management of the low-light zone in the inner canopy, spraying zinc fertilizer, calcium fertilizer, molybdenum fertilizer and 6-BA after the spring shoots mature and before the autumn shoots sprout; injecting 6-BA and urea into the inner branches in the early spring bud sprouting period and in the autumn before the buds enter dormancy.

Images