A planting management method capable of reducing physiological fruit drop of macadamia in karst areas

Abstract

The application discloses a kind of planting management methods that can reduce physiological fruit drop of macadamia in karst area, and relates to the technical field of fruit tree planting management.The application embeds the mixture of composite water-retaining material and decomposed organic fertilizer in the hole dug at drip line during the flowering period of macadamia, sprays plant growth regulator, photosynthetic recovery agent and fruit retention fertilizer successively after 7-10 days of thanks to flower, and simultaneously root applies water-soluble high-potassium fertilizer and removes new shoots and a series of technical means, solves the problems that hormone combination and spraying fruit retention fertilizer are difficult to reduce physiological fruit drop of macadamia in karst area and difficult to increase fruit weight in the prior art.Using the management method of the application, the cumulative fruit drop rate in the early stage can be reduced from about 75% of the conventional method to 62-65%, the cumulative fruit drop rate in the later stage can be reduced from about 85% of the conventional method to 65-68%, and the size of fruit can be increased, and the weight of single fruit can be increased.

Description

Technical Field

[0001] This invention relates to the field of fruit tree planting and management technology, and in particular to a planting and management method that can reduce physiological fruit drop in macadamia nuts in karst regions. Background Technology

[0002] Macadamia nuts ( Macadamia Macadamia nut (spp.) is a high-end nut tree native to Australia. Its kernels are rich in various nutrients and have a delicious flavor, making it one of the world's best edible nuts, often referred to as the "Queen of Nuts." In my country, it is mainly distributed in Yunnan, Guangxi, and Guizhou provinces. With the continuous expansion of its planting area in my country, macadamia nuts are experiencing significant flower and fruit drop, especially early physiological fruit drop. A large number of immature fruits typically fall off 10-50 days after full bloom, severely impacting fruit yield.

[0003] The applicant's previous research found that the physiological fruit drop of macadamia nuts is related to the type and content of endogenous hormones (Li Mu et al. The relationship between the content of endogenous hormones in macadamia nuts and their physiological fruit drop [J]. Southern China Fruits, 2024, 53(03)); at the same time, the lack of available carbon nutrients such as sucrose and glucose in the fruit is an important reason for the early excessive fruit drop of macadamia nuts (Zeng Hui. Study on the fruit drop pattern and mechanism of early physiological fruit drop of macadamia nuts [D]. Guangzhou: South China Agricultural University, 2016). Therefore, the physiological fruit drop of macadamia nuts is also related to the insufficient carbon nutrition in the fruit. In the existing technology, the main methods to reduce the physiological fruit drop of macadamia nuts are to spray exogenous hormones (such as GA3) to preserve the fruit or to supplement foliar fertilizer to increase the carbon nutrition of the fruit, but both have the following defects: (1) While spraying exogenous hormones to protect the fruit, it will stimulate cell division in young fruit. If the nutrition is not up to par, it will lead to a decrease in the weight of a single fruit and a smaller fruit shape. In addition, some hormones will stimulate the elongation of new shoots, which will compete with the fruit for carbohydrates and aggravate fruit drop. (2) Supplementing foliar fertilizer to increase the carbon nutrition of the fruit can reduce the fruit drop rate of macadamia nuts to a certain extent. However, in karst areas, due to root damage, this method is not ideal and needs to be improved. The reasons are as follows: The soil moisture in karst areas is not very stable and does not retain water. It is very wet when it rains heavily, but it is easy to become relatively dry after the water is leached away. The roots are repeatedly subjected to drought and waterlogging stress, and the absorption function is damaged. The sugar synthesized by the leaves is difficult to transport to the fruit. Even if fertilizer is sprayed, it cannot be effectively accumulated in the fruit stalk. At the same time, the soil in karst areas is acidic but the parent material is rich in calcium, which can easily cause iron, zinc and boron deficiency, affecting sugar transport and photosynthesis. In addition, the soil layer is shallow and there are many gravels. The root system is shallow and has poor resistance. It wilts quickly during drought. After spraying fertilizer, the stomata close and the absorption efficiency is extremely low.

[0004] Therefore, reducing the physiological fruit drop of macadamia nuts in karst regions is a key issue that the industry urgently needs to address. Summary of the Invention

[0005] To address the above shortcomings, this invention provides a planting and management method for reducing physiological fruit drop in macadamia nuts in karst regions. It solves the problem in existing technologies where combining hormones with sprayed fruit-preserving fertilizers is insufficient to reduce physiological fruit drop and increase fruit weight in macadamia nuts in karst areas. The specific technical solution is as follows: A planting and management method to reduce physiological fruit drop in macadamia trees in karst areas includes: digging several holes along the drip line of the tree canopy when the macadamia trees are flowering, filling 2 / 3 of the holes with a mixture of composite water-retaining material and well-rotted organic fertilizer, watering thoroughly to allow the composite water-retaining material to fully expand, and then covering with soil. Spray a plant growth regulator 7-10 days after the macadamia tree flowers have faded. After the plant growth regulator treatment, spray a fruit-preserving fertilizer once on the 5th-7th day and again on the 12th-15th day. Begin removing new shoots 5-7 days after each application of the fruit-preserving fertilizer.

[0006] Furthermore, the number of acupoints is 3-4, and the diameter of each acupoint is 20-30 cm and the depth is 30-40 cm.

[0007] Further, the preparation method of the composite water-retaining material is as follows: Soak dried coconut coir in distilled water for 20-24 hours, remove and air-dry until the moisture content is 30-40%; soak the dried coconut coir in a 5-15% sodium hydroxide solution for 1-2 hours, filter, and wash with water until neutral to obtain alkalized coconut coir; add the alkalized coconut coir to a 70-75% ethanol solution and mix well, with a mass-to-volume ratio of alkalized coconut coir to ethanol solution of 1g:(2-3)mL; then add 20-30% (by weight) of chloroacetic acid from the alkalized coconut coir, and then heat to... The reaction was carried out at 60-70℃ with constant stirring for 1-2 hours. After the reaction was completed, the mixture was cooled to room temperature and washed 2-3 times with a 75% ethanol solution. Then it was washed with distilled water until neutral and dried at 60-65℃ to constant weight to obtain carboxymethylated modified coconut coir. The carboxymethylated modified coconut coir was added to a 2-5% chitosan solution and mixed and stirred evenly. The mass-volume ratio of carboxymethylated modified coconut coir to chitosan solution was 1g:(4-6)mL. The mixture was allowed to stand for 20-24 hours, filtered, and dried at 50-60℃ until the water content was <10%.

[0008] Furthermore, the mixture is made by mixing composite water-retaining material and decomposed organic fertilizer at a volume ratio of 1:(1-2).

[0009] Furthermore, the plant growth regulator is a mixture of chlorpyrifos and gibberellin, wherein the concentration of chlorpyrifos is 2-5 mg / L and the concentration of gibberellin is 20-50 mg / L.

[0010] Furthermore, the plant growth regulator is prepared by mixing chlorpyrifos with gibberellin at a pre-adjusted concentration and then spraying the mixture evenly onto the fruit and leaves until they are moist.

[0011] Furthermore, the fruit-preserving fertilizer comprises the following raw materials: 1 kg water, 1-3 g potassium dihydrogen phosphate, 0.5-1 g borax, 0.3-0.5 g zinc sulfate, 0.05-0.1 g ammonium molybdate, 0.2-0.5 g ferrous sulfate and 0.05-0.1 g alginic acid extract.

[0012] Furthermore, the application rate of the fruit-preserving fertilizer is 50-65 L / mu.

[0013] Furthermore, the planting management method also includes: spraying 20-30L / mu of photosynthesis restorer 1-2 days before applying the fruit-preserving fertilizer. The photosynthesis restorer includes the following raw materials: 100g water, 0.01-0.03g brassinolide, 0.1-0.3g ferrous sulfate and 0.05-0.15g magnesium sulfate.

[0014] Furthermore, the planting management method also includes: while spraying fruit-preserving fertilizer, simultaneously applying water-soluble high-potassium fertilizer to the roots. The specific root application method is: apply 50-100g of potassium sulfate and 20-30g of calcium nitrate per plant, and dilute with 10-20L of water and pour into the planting hole.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention solves the problem of physiological fruit drop in macadamia nuts in karst regions by burying a mixture of composite water-retaining material and decomposed organic fertilizer in holes dug at the drip line during the flowering period of macadamia nuts, and spraying plant growth regulators, photosynthetic restorers, and fruit-preserving fertilizer successively 7-10 days after flowering, while simultaneously applying water-soluble high-potassium fertilizer to the roots and removing new shoots. This reduces the cumulative fruit drop rate in the early stage from about 75% to 62-65%, and the cumulative fruit drop rate in the later stage from about 85% to 65-68%, while also increasing fruit size and weight.

[0016] 2. This invention involves burying a mixture of composite water-retaining material and well-rotted organic fertilizer at the drip line during the flowering period. The composite water-retaining material is made by modifying coconut coir and combining it with chitosan, which significantly improves the water absorption rate and extends the water retention time. This allows the soil in the planting hole to maintain its water-holding capacity for a long time, preventing the fruit tree roots from being repeatedly subjected to drought and waterlogging stress, and maintaining the normal absorption function of the roots. When fruit-preserving fertilizer is sprayed later to supplement sugar, the sugar accumulated in the leaves can be smoothly transported to the fruit and fruit stalk, thereby effectively reducing the physiological fruit drop rate of macadamia nuts.

[0017] 3. After spraying the plant growth regulator, the present invention sprays fruit-preserving fertilizer once on the 5th-7th day and once on the 12th-15th day. This can provide the fruit with sufficient nutrition in time and prevent the fruit from becoming smaller and less sized due to the stimulation of the plant growth regulator. After applying the fruit-preserving fertilizer, timely removal of new shoots can also prevent the new shoots from competing with the young fruit for carbohydrates, allowing the fruit to obtain more nutrients.

[0018] 4. This invention involves spraying a photosynthesis restorer before applying the fruit-preserving fertilizer, and simultaneously applying a water-soluble high-potassium fertilizer to the roots. The brassinolide in the photosynthesis restorer can regulate stomatal opening, while ferrous sulfate and magnesium sulfate can enhance photosynthetic capacity, thereby improving the absorption and utilization rate of the subsequent fruit-preserving fertilizer and promoting the synthesis of more sugars in the leaves. The high-potassium fertilizer applied to the roots can promote the transport of sugars to the fruit and supplement calcium to enhance the toughness of the fruit stalk, further reducing fruit drop. At the same time, it is adapted to the nutrient deficiency characteristics of karst soils, specifically supplementing elements such as iron, zinc, boron, and molybdenum (fruit-preserving fertilizer), solving the problem of element deficiency affecting photosynthesis and sugar transport in this region, and further ensuring the fruit preservation effect. Detailed Implementation

[0019] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Unless otherwise defined, all technical terms used below have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the scope of protection of the present invention. Unless otherwise specifically stated, all raw materials, reagents, instruments, and equipment used in the present invention are commercially available or can be prepared by existing methods.

[0020] Example 1 A planting management method to reduce physiological fruit drop in macadamia nuts in karst regions includes: (1) When the macadamia tree is flowering, dig three holes along the drip line of the canopy. Each hole should be 20cm in diameter and 30cm deep. Then mix the composite water-retaining material with well-rotted organic fertilizer in a 1:1 volume ratio to form a mixture. Fill the holes with the mixture until they are 2 / 3 full. Water thoroughly to allow the composite water-retaining material to expand fully and then cover with soil. The preparation method of the composite water-retaining material is as follows: Soak dried coconut coir in distilled water for 20 hours, remove and air-dry until the moisture content is 30%; soak the dried coconut coir in a 5% sodium hydroxide solution for 1 hour, filter, and wash with water until neutral to obtain alkalized coconut coir; add the alkalized coconut coir to a 70% ethanol solution and mix well, with a mass-to-volume ratio of alkalized coconut coir to ethanol solution of 1 g:2 mL; then add 20% (by weight) of chloroacetic acid from the alkalized coconut coir, and then heat to 60℃. The mixture was stirred at a constant temperature for 1 hour. After the reaction was completed, it was cooled to room temperature and washed twice with a 75% ethanol solution. Then it was washed with distilled water until neutral and dried at 60°C to constant weight to obtain carboxymethylated coconut coir. The carboxymethylated coconut coir was added to a 2% chitosan solution and mixed and stirred evenly. The mass-volume ratio of carboxymethylated coconut coir to chitosan solution was 1 g: 4 mL. The mixture was allowed to stand for 20 h, filtered, and dried at 50°C until the water content was <10%.

[0021] (2) Seven days after the macadamia flowers wither, spray a plant growth regulator. The plant growth regulator is a mixture of 2 mg / L chlorpyrifos and 20 mg / L gibberellin. After mixing, spray the mixture onto the fruit and leaves until the fruit and leaves are moist.

[0022] (3) After treatment with plant growth regulators, spray fruit-preserving fertilizer once on the 5th day and once on the 12th day. The fruit-preserving fertilizer includes the following ingredients: 1kg water, 1g potassium dihydrogen phosphate, 0.5g borax, 0.3g zinc sulfate, 0.05g ammonium molybdate, 0.2g ferrous sulfate and 0.05g alginic acid extract. The application rate of the fruit-preserving fertilizer is 50L / mu.

[0023] (4) While spraying the fruit-preserving fertilizer, apply water-soluble high-potassium fertilizer to the roots at the same time. The specific root application method is: apply 50g of potassium sulfate and 20g of calcium nitrate to each plant, and dilute with 10L of water and pour into the hole.

[0024] (5) One day before applying the fruit-preserving fertilizer, spray 20L / mu of photosynthesis restorer. The photosynthesis restorer includes the following ingredients: 100g water, 0.01g brassinolide, 0.1g ferrous sulfate and 0.05g magnesium sulfate. Five days after each application of the fruit-preserving fertilizer, start removing new shoots.

[0025] Example 2 A planting management method to reduce physiological fruit drop in macadamia nuts in karst regions includes: (1) When the macadamia tree is flowering, dig four holes along the drip line of the canopy. Each hole is 30cm in diameter and 40cm deep. Then mix the composite water-retaining material with the decomposed organic fertilizer in a volume ratio of 1:2 to form a mixture. Fill the holes with the mixture until they are 2 / 3 full. Water thoroughly to allow the composite water-retaining material to expand fully and cover with soil. The preparation method of the composite water-retaining material is as follows: Soak dried coconut coir in distilled water for 24 hours, remove and air-dry until the moisture content is 40%; soak the air-dried coconut coir in a 15% sodium hydroxide solution for 2 hours, filter, and wash with water until neutral to obtain alkalized coconut coir; add the alkalized coconut coir to a 75% ethanol solution and mix well, with a mass-volume ratio of alkalized coconut coir to ethanol solution of 1 g:3 mL; then add 30% (by weight) of chloroacetic acid from the alkalized coconut coir; heat to 70°C and stir at a constant temperature for 2 hours; after the reaction, cool to room temperature, wash the product three times with a 75% ethanol solution, wash with distilled water until neutral, and dry at 65°C to constant weight to obtain carboxymethylated modified coconut coir; add the carboxymethylated modified coconut coir to a 5% chitosan solution and mix well, with a mass-volume ratio of carboxymethylated modified coconut coir to chitosan solution of 1 g:6 mL. Let stand for 24 hours, filter, and dry at 60℃ until the moisture content is <10%.

[0026] (2) Spray a plant growth regulator 10 days after the macadamia flowers wither. The plant growth regulator is a mixture of chlorpyrifos at a concentration of 5 mg / L and gibberellin at a concentration of 50 mg / L. After mixing the two, spray them on the fruit and leaves until the fruit and leaves are moist.

[0027] (3) After treatment with plant growth regulators, spray fruit-preserving fertilizer once on the 7th day and once on the 15th day. The fruit-preserving fertilizer includes the following raw materials: 1kg water, 3g potassium dihydrogen phosphate, 1g borax, 0.5g zinc sulfate, 0.1g ammonium molybdate, 0.5g ferrous sulfate and 0.1g alginic acid extract. The application rate of the fruit-preserving fertilizer is 65L / mu.

[0028] (4) While spraying the fruit-preserving fertilizer, apply water-soluble high-potassium fertilizer to the roots at the same time. The specific root application method is: apply 100g of potassium sulfate and 30g of calcium nitrate to each plant, and dilute with 20L of water and pour into the hole.

[0029] (5) Two days before applying the fruit-preserving fertilizer, spray 30L / mu of photosynthesis restorer. The photosynthesis restorer includes the following ingredients: 100g water, 0.03g brassinolide, 0.3g ferrous sulfate and 0.15g magnesium sulfate. Seven days after each application of the fruit-preserving fertilizer, start removing new shoots.

[0030] Example 3 A planting management method to reduce physiological fruit drop in macadamia nuts in karst regions includes: (1) When the macadamia tree is flowering, dig four holes along the drip line of the canopy. Each hole is 30cm in diameter and 35cm deep. Then mix the composite water-retaining material with the decomposed organic fertilizer at a volume ratio of 1:1.5 to form a mixture. Fill the holes with the mixture until they are 2 / 3 full. Water thoroughly to allow the composite water-retaining material to expand fully and cover with soil. The preparation method of the composite water-retaining material is as follows: Soak dried coconut coir in distilled water for 22 hours, remove and air-dry until the moisture content is 35%; soak the dried coconut coir in a 10% sodium hydroxide solution for 1.5 hours, filter, and wash with water until neutral to obtain alkalized coconut coir; add the alkalized coconut coir to a 72% ethanol solution and mix well, with a mass-to-volume ratio of alkalized coconut coir to ethanol solution of 1 g: 2.5 mL; then add 25% (by weight) of chloroacetic acid from the alkalized coconut coir, and then heat to 65°C. The reaction was carried out at ℃ and stirred at a constant temperature for 1.5 hours. After the reaction was completed, it was cooled to room temperature and washed three times with a 75% ethanol solution. Then it was washed with distilled water until neutral and dried at 62℃ to constant weight to obtain carboxymethylated modified coconut coir. The carboxymethylated modified coconut coir was added to a 3% chitosan solution and mixed and stirred evenly. The mass-volume ratio of carboxymethylated modified coconut coir to chitosan solution was 1g:5mL. The mixture was allowed to stand for 22 hours, filtered, and dried at 55℃ until the water content was <10%.

[0031] (2) Spray a plant growth regulator 8 days after the macadamia flowers wither. The plant growth regulator is a mixture of chlorpyrifos at a concentration of 3 mg / L and gibberellin at a concentration of 40 mg / L. Spray the mixture onto the fruit and leaves until the fruit and leaves are moist.

[0032] (3) After treatment with plant growth regulators, spray fruit-preserving fertilizer once on the 6th day and once on the 13th day. The fruit-preserving fertilizer includes the following raw materials: 1kg water, 2g potassium dihydrogen phosphate, 0.8g borax, 0.4g zinc sulfate, 0.08g ammonium molybdate, 0.4g ferrous sulfate and 0.06g alginic acid extract. The application rate of the fruit-preserving fertilizer is 55L / mu.

[0033] (4) While spraying the fruit-preserving fertilizer, apply water-soluble high-potassium fertilizer to the roots at the same time. The specific root application method is: apply 70g of potassium sulfate and 25g of calcium nitrate to each plant, and dilute with 15L of water and pour into the hole.

[0034] (5) Two days before applying the fruit-preserving fertilizer, spray 25L / mu of photosynthesis restorer. The photosynthesis restorer includes the following ingredients: 100g water, 0.02g brassinolide, 0.25g ferrous sulfate and 0.09g magnesium sulfate. Six days after each application of the fruit-preserving fertilizer, start removing new shoots.

[0035] Comparative Example 1: No step (1), that is, no hole was dug and mixed material was filled along the drip line of the canopy when the macadamia tree was flowering. Other steps were the same as in Example 1.

[0036] Comparative Example 2: In step (1), coconut coir was used instead of composite water-retaining material, and the other steps were the same as in Example 1.

[0037] Comparative Example 3: Steps (2) and (3) were carried out simultaneously, that is, the plant growth regulator and the fruit-preserving fertilizer were mixed and sprayed at the same time, and the other steps were the same as in Example 1.

[0038] Comparative Example 4: No step (4). While spraying the fruit-preserving fertilizer, the root was not simultaneously fertilized with water-soluble high-potassium fertilizer. The other steps were the same as in Example 1.

[0039] Comparative Example 5: No step (5), that is, no photosynthesis restorer was sprayed 2 days before the fruit-preserving fertilizer was applied, and the other steps were the same as in Example 1.

[0040] Comparative Example 6: The photosynthetic restorer in step (5) does not contain ferrous sulfate, and the other steps are the same as in Example 1.

[0041] Comparative Example 7: The photosynthetic restorer in step (5) does not contain magnesium sulfate, and the other steps are the same as in Example 1.

[0042] To illustrate the effectiveness of the invention, the applicant conducted an experiment at a macadamia nut plantation in Longzhou County, Guangxi (karst landform). The experiment was divided into 11 groups. Groups 1 to 3 were managed using the methods of Examples 1 to 3, respectively; Groups 4 to 10 were managed using the methods of Comparative Examples 1 to 7, respectively; Group 11 was a blank control group, i.e., no management was carried out to prevent fruit drop. The experimental subjects were 8-year-old macadamia trees of the Guangxi main cultivar "Gui Re No. 1" with uniform tree vigor, good growth, reasonable branch layering, and good ventilation and light penetration. Each group consisted of 3 trees, with 3 replicates. The cumulative fruit drop rate was recorded on the 50th day after flowering (the early stage of fruit drop is generally 20-50 days after flowering) and the 100th day after flowering (the middle stage of fruit drop is generally 50-100 days after flowering) of each group. The transverse diameter, longitudinal diameter, and weight of the fruit at maturity were also recorded (20 fruits per group, 3 groups were randomly selected for a total of 60 fruits, the average weight of the fruit was measured using an electronic analytical balance, and the transverse diameter and longitudinal diameter of the fruit were measured using a digital vernier caliper). The results are shown in Table 1.

[0043] Five clusters of florets were selected from each of the four cardinal directions (east, south, west, and north) of the tested plants and tagged them. The number of fruits set was investigated on the 20th, 50th, and 100th day after flowering, for a total of three investigations. The number of fruits set on each tagged floret was recorded. The number of fruits set on the 20th day after flowering was taken as the initial number of fruits set, and the cumulative fruit drop rate was calculated on the 50th and 100th days after flowering. Cumulative fruit drop rate (%) = (cumulative number of fruits dropped on the day of investigation / initial number of fruits set) × 100.

[0044] Table 1. Cumulative fruit drop rate and phenotypic traits at maturity for each group. The data in Groups 1-3 of the table above show that the management method of this invention can reduce the early physiological fruit drop rate, reducing the cumulative fruit drop rate in the early stage from about 75% to 62-65%, and the cumulative fruit drop rate in the later stage from about 85% to 65-68%. At the same time, compared with the control group, the management method of this invention can increase fruit size and increase the weight of a single fruit.

[0045] The data in Groups 1, 4, and 5 of the table above illustrate that this invention involves burying a mixture of composite water-retaining material and well-rotted organic fertilizer at the drip line during the flowering period. The composite water-retaining material is made by modifying coconut coir and combining it with chitosan, which significantly improves the water absorption ratio and extends the water retention time. This allows the soil in the planting hole to maintain its water-holding capacity for a long time, preventing the fruit tree roots from being repeatedly subjected to drought and waterlogging stress, and maintaining the normal absorption function of the roots. When fruit-preserving fertilizer is sprayed later to supplement sugar, the sugar accumulated in the leaves can be smoothly transported to the fruit and fruit stalk, thereby effectively reducing the physiological fruit drop rate of macadamia nuts and increasing fruit weight.

[0046] The data in groups 1, 6, and 10 of the table above show that the order in which plant growth regulators and fruit-setting fertilizers are applied also affects the fruit drop rate. Spraying plant growth regulators first, followed by fruit-setting fertilizers, can promptly replenish the fruit with sufficient nutrients, preventing the fruit from losing weight and becoming smaller due to the stimulation of plant growth regulators. Simultaneously, using photosynthetic restorers before spraying fruit-setting fertilizers can improve the absorption and conversion efficiency of the fertilizers, thereby reducing the fruit drop rate and increasing fruit weight. Furthermore, simultaneous application of water-soluble high-potassium fertilizers to the roots can promote sugar transport to the fruit and supplement calcium to enhance the toughness of the fruit stalk, further reducing fruit drop.

[0047] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A planting and management method for reducing physiological fruit drop in macadamia nuts in karst regions, characterized in that, include: When the macadamia tree is flowering, dig several holes along the drip line of the canopy, then fill the holes with a mixture of composite water-retaining material and well-rotted organic fertilizer, water thoroughly, and cover with soil. Spray a plant growth regulator 7-10 days after the macadamia tree flowers have faded. After the plant growth regulator treatment, spray a fruit-preserving fertilizer once on the 5th-7th day and again on the 12th-15th day. Begin removing new shoots 5-7 days after each application of the fruit-preserving fertilizer.

2. The planting and management method for reducing physiological fruit drop in macadamia nuts in karst areas according to claim 1, characterized in that, The number of acupoints is 3-4, and the diameter of each acupoint is 20-30 cm and the depth is 30-40 cm.

3. The planting and management method for reducing physiological fruit drop in macadamia nuts in karst areas according to claim 1, characterized in that, The preparation method of the composite water-retaining material is as follows: Soak dried coconut coir in distilled water for 20-24 hours, remove and air-dry until the moisture content is 30-40%; soak the dried coconut coir in a 5-15% sodium hydroxide solution for 1-2 hours, filter, and wash with water until neutral to obtain alkalized coconut coir; add the alkalized coconut coir to a 70-75% ethanol solution and mix well, with a mass-to-volume ratio of alkalized coconut coir to ethanol solution of 1g:(2-3)mL; then add 20-30% (by weight) of chloroacetic acid from the alkalized coconut coir, and then heat to 60°C. The reaction was carried out at 70℃ with constant stirring for 1-2 hours. After the reaction was completed, the mixture was cooled to room temperature and washed 2-3 times with a 75% ethanol solution. Then it was washed with distilled water until neutral and dried at 60-65℃ to constant weight to obtain carboxymethylated modified coconut coir. The carboxymethylated modified coconut coir was added to a 2-5% chitosan solution and mixed and stirred evenly. The mass-volume ratio of carboxymethylated modified coconut coir to chitosan solution was 1g:(4-6)mL. The mixture was allowed to stand for 20-24 hours, filtered, and dried at 50-60℃ until the water content was <10%.

4. The planting and management method for reducing physiological fruit drop in macadamia nuts in karst areas according to claim 1, characterized in that, The mixture is made by mixing composite water-retaining material and decomposed organic fertilizer in a volume ratio of 1:(1-2).

5. A planting and management method for reducing physiological fruit drop in macadamia nuts in karst areas according to claim 1, characterized in that, The plant growth regulator is a mixture of chlorpyrifos and gibberellin, wherein the concentration of chlorpyrifos is 2-5 mg / L and the concentration of gibberellin is 20-50 mg / L.

6. A planting and management method for reducing physiological fruit drop in macadamia nuts in karst areas according to claim 5, characterized in that, The plant growth regulator is prepared by mixing chlorpyrifos and gibberellin at a pre-adjusted concentration and then spraying the mixture evenly onto the fruit and leaves until they are moist.

7. A planting and management method for reducing physiological fruit drop in macadamia nuts in karst areas according to claim 1, characterized in that, The fruit-preserving fertilizer comprises the following ingredients: 1 kg water, 1-3 g potassium dihydrogen phosphate, 0.5-1 g borax, 0.3-0.5 g zinc sulfate, 0.05-0.1 g ammonium molybdate, 0.2-0.5 g ferrous sulfate, and 0.05-0.1 g alginic acid extract.

8. A planting and management method for reducing physiological fruit drop in macadamia nuts in karst areas according to claim 7, characterized in that, The application rate of the fruit-preserving fertilizer is 50-65 L / mu.

9. A planting and management method for reducing physiological fruit drop in macadamia nuts in karst areas according to claim 1, characterized in that, The planting management method also includes: spraying 20-30L / mu of photosynthesis restorer 1-2 days before applying fruit-preserving fertilizer. The photosynthesis restorer includes the following raw materials: 100g water, 0.01-0.03g brassinolide, 0.1-0.3g ferrous sulfate and 0.05-0.15g magnesium sulfate.

10. A planting and management method for reducing physiological fruit drop in macadamia nuts in karst areas according to claim 1, characterized in that, The planting management method also includes: while spraying fruit-preserving fertilizer, water-soluble high-potassium fertilizer is also applied to the roots simultaneously. The specific root application method is: apply 50-100 g of potassium sulfate and 20-30 g of calcium nitrate per plant, and dilute with 10-20 L of water and pour into the hole.

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