Method for controlling vigorous growth of walnuts

Abstract

The invention discloses a walnut vigorous growth control method, and belongs to the technical field of walnut vigorous growth control, after walnut shoots grow to a certain length, a paclobutrazol solution is sprayed to treat walnut trees, paclobutrazol enters plant bodies to inhibit biosynthesis of gibberellin so as to reduce the gibberellin content, so that the elongation speed of plant cells is slowed down, and the yield of the walnut trees is increased. The vigorous growth situation of the plants is controlled, and effective vigorous growth control of the walnuts is achieved; in addition, a decomposer is prepared and applied to the soil, the decomposer efficiently decomposes paclobutrazol left in the soil, it is prevented that paclobutrazol is left in the soil for a long time, and later growth of walnuts is affected, and good application prospects are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of walnut growth control, in particular to a walnut growth control method. Background Art

[0002] Walnut (Juglans regia L.) is a plant of the genus Juglans in the family Juglandaceae. It is also known as "walnut" and "Qiang peach". It ranks first among the four major dried fruits in the world and is known as the "king of woody oil crops". It has extremely high nutritional value and good medical and health effects. It is an important dried fruit economic crop in the world and an important economic forest cultivated tree species in my country.

[0003] Walnut is a widely planted economic tree species. Seedlings are typically used for initial planting, resulting in large variations in individual tree yields. This, coupled with inappropriate variety selection and poor management, has resulted in many walnut forests becoming low-quality forests, significantly reducing yield and quality. Using high-grafting technology to transform low-quality walnut forests into walnut varieties with strong adaptability, disease resistance, and stable yields can effectively improve walnut yields and increase economic benefits. Some high-quality walnut varieties, such as "Yucheng No. 1," exhibit vigorous growth and strong shoot development after high-grafting, which are desirable traits for long-term fruiting. However, in the first year of high-grafting, due to the generally larger diameter of the rootstock and the high rainfall, new shoots grow vigorously, requiring multiple tying operations to prevent windbreaks. This labor-intensive process increases pruning and shaping during the first two years, further complicating and increasing the cost of cultivar conversion. Currently, the application of plant growth regulators can regulate shoot growth and promote branch lignification, effectively reducing the difficulty and cost of low-grafting walnut varieties.

[0004] In actual applications, it has been found that spraying high concentrations of paclobutrazol on walnut plants undergoing high-grafting can effectively slow the growth rate of new shoots and increase the degree of lignification of branches, thereby reducing the difficulty and cost of high-grafting. However, paclobutrazol is highly fat-soluble and easily adsorbed on soil particles. It is also highly stable and has a long half-life in the soil. The higher the concentration, the slower its degradation rate in the soil. After spraying walnut plants with high concentrations of paclobutrazol, it enters the soil and remains there for a long time, interfering with the metabolic function of soil microorganisms and inhibiting the growth of beneficial microorganisms, thereby reducing the ability of soil organic matter to decompose and release nutrients. Moreover, the long-term action of paclobutrazol residues in the soil on walnut plants can inhibit their normal growth in the later stages. In addition, it can easily pose a threat to human health after being transmitted through the food chain.

[0005] Therefore, it is currently necessary to find a method for controlling the vigorous growth of high-grafted walnuts to solve the problem that paclobutrazol remains in the soil when using paclobutrazol to control the vigorous growth of high-grafted walnuts, endangering soil safety and affecting the later growth of walnuts. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a method for controlling the vigorous growth of walnuts, so as to solve the problem that paclobutrazol remains in the soil when paclobutrazol is used to control the vigorous growth of high-grafted walnuts, endangering soil safety and affecting the later growth of walnuts.

[0007] The present invention solves the above technical problems through the following technical means:

[0008] A method for controlling the growth of walnuts, comprising the following steps:

[0009] (1) When the new shoots of high-grafted walnuts grow to 20-30 cm, spray the leaves of the walnut plants with 3000 mg / L paclobutrazol solution before 10 a.m. or after 5 p.m. on a sunny day. The spraying amount should be such that all leaf surfaces are wet and water drips. After an interval of 15 days, spray again using the same method, for a total of 2 sprays;

[0010] (2) One month after the second spraying of paclobutrazol solution, adjust the soil moisture content at 8-10 am on a sunny day, and then adjust the soil moisture content at 0.2-0.4 kg / m 2 Apply a certain amount of decomposer to the soil surface and rake it into the 1-5 cm soil layer to decompose paclobutrazol in the soil. Later, the walnut plants can be managed and maintained according to conventional methods.

[0011] Furthermore, the operation of adjusting the soil moisture content in step (2) is specifically as follows:

[0012] Check the soil moisture content. If the soil moisture content is greater than 45%, there is no need to spray water. If the soil moisture content is less than 40%, spray water to adjust the soil moisture content to 40-45%.

[0013] Furthermore, the decomposition agent includes the following raw materials:

[0014] Activated carbon, asparagine, laccase, peroxidase, lignin, ferric sulfate, calcium peroxide, xanthan gum, 4-tert-butylcyclohexanol, dicyclohexylcarbodiimide, 4-dimethylaminopyridine, locust bean gum.

[0015] Furthermore, the decomposition agent preparation method is as follows:

[0016] A: The lignin is ground through a 100-200 mesh sieve, then placed in a 10% by mass sodium hydroxide solution and heated to 60°C with stirring for 1-2 hours. The solution is then ultrasonically treated at a power of 100-300W and a frequency of 20-40kHz for 10 minutes. After the ultrasonic treatment, the filtrate is filtered and washed with water to obtain the activated lignin.

[0017] B: Add activated carbon to water, stir and disperse, then add asparagine, heat to 60-80°C and stir to react for 4-6 hours. After the reaction is complete, filter and remove the filtrate, wash with clean water, and dry to obtain modified activated carbon; Add modified activated carbon to water, stir and disperse, then add laccase and peroxidase, and stir and mix evenly at room temperature to obtain enzyme-loaded activated carbon;

[0018] C: Add xanthan gum to dimethyl sulfoxide and heat to 60°C with stirring to dissolve the xanthan gum. Then, add dicyclohexylcarbodiimide and 4-dimethylaminopyridine. Continue stirring and reacting for 20-30 minutes. Then, dissolve 4-tert-butylcyclohexanol in ethanol and add it. Continue stirring and reacting for 6-8 hours. After the reaction is complete, filter to remove the precipitate, and then vacuum dry to obtain modified xanthan gum.

[0019] D: Add modified xanthan gum and locust bean gum into water and stir thoroughly to disperse to obtain a suspension. Adjust the pH of the suspension to 7, then add calcium peroxide, ferric sulfate and activated lignin and stir thoroughly to mix. Heat to 80-90°C and keep warm for 15-30 minutes. Then cool to room temperature and transfer to 4°C and refrigerate overnight to allow the xanthan gum and locust bean gum to fully gel to obtain a composite gel. Add enzyme-loaded activated carbon to the composite gel, stir thoroughly to mix, and then granulate. After granulation, place in water to fully absorb water to obtain a decomposition agent.

[0020] After walnuts are grafted, new shoots tend to grow vigorously and are easily broken by the wind because the diameter of the rootstock is relatively large. Large amounts of spraying with a relatively high concentration of paclobutrazol solution can effectively control the growth of the new shoots. However, the relatively high concentration of paclobutrazol will remain in the soil for a long time after entering the soil, thereby destroying the soil microbial community structure and affecting the normal growth of walnuts in the later stage. Therefore, the present invention prepares a decomposition agent and applies it to the soil to efficiently decompose the residual paclobutrazol in the soil, thereby eliminating its adverse effects.

[0021] Specifically, the decomposition agent is prepared by coating calcium peroxide, iron sulfate and lignin with a composite gel prepared from xanthan gum and locust bean gum, and then granulating it with activated carbon loaded with laccase and peroxidase. The activated carbon in the decomposition agent can effectively adsorb paclobutrazol, and the loaded laccase and peroxidase can work together to catalyze the oxidative decomposition of paclobutrazol; at the same time, the lignin contains phenolic substances, which will convert Fe in iron sulfate into 3+ Converted to Fe 2+ Calcium peroxide continuously hydrolyzes to release H2O2, which can be further decomposed to release oxygen under the catalysis of ferric sulfate, peroxidase, etc., and the generated Fe 2+ Reacts with H2O2 to form hydroxyl radicals which in turn convert to Fe 3+ Hydroxyl free radicals will attack the chemical bonds in the paclobutrazol molecule to decompose it, and then work together with laccase and peroxidase to efficiently decompose paclobutrazol.

[0022] In order to improve the adsorption performance of activated carbon on paclobutrazol, the present invention uses asparagine to treat the activated carbon, and enhances the mutual binding effect between the activated carbon and paclobutrazol by adjusting its surface chemical properties, thereby adsorbing more paclobutrazol so that other components in the decomposer can decompose it more efficiently.

[0023] Calcium peroxide in the decomposition agent needs to be continuously supplied with water to effectively hydrolyze and release H2O2, ensuring that Fe 2+ It can continuously react with H2O2 and then continuously release hydroxyl radicals to decompose paclobutrazol. Therefore, the present invention uses a gel prepared by xanthan gum and locust bean gum to be added to the decomposition agent. The three-dimensional network structure of the gel has good water retention and can provide water for the hydrolysis of calcium peroxide for a long time. However, the existence of a tight gel network structure will limit the reaction substrates such as lignin, iron sulfate, enzymes, and H2O2, Fe 2+ Therefore, in order to allow the reaction substrates and reaction products in the decomposition agent to better contact each other to promote the reaction and generate more hydroxyl radicals to decompose paclobutrazol, the present invention uses tert-butyl cyclohexanol to treat xanthan gum, and reduces the interaction between the molecular chains of the formed gel network structure and improves the water retention by changing the molecular structure of xanthan gum, thereby obtaining a gel network structure with larger porosity, improving the diffusion and transport properties of the reaction substrates and reaction products in the decomposition agent in the gel network structure, improving the reaction efficiency, and then effectively decomposing the paclobutrazol remaining in the soil through the synergistic effect of the components in the decomposition agent, so as to eliminate its adverse effects on the soil and the later growth of walnuts.

[0024] Furthermore, in step B, the mass ratio of activated carbon to asparagine is (3-4): (0.3-0.5).

[0025] Furthermore, in step B, the mass ratio of modified activated carbon, laccase and peroxidase is (3-4): (0.01-0.02): (0.01-0.02).

[0026] Furthermore, in step C, the mass ratio of xanthan gum, dicyclohexylcarbodiimide, 4-dimethylaminopyridine and 4-tert-butylcyclohexanol is (0.06-0.15): (0.002-0.004): (0.001-0.002): (0.01-0.03).

[0027] Furthermore, the mass ratio of modified xanthan gum, locust bean gum and water in the suspension of step D is (0.04-0.12): (0.01-0.03): (10-15).

[0028] Furthermore, in step D, the mass ratio of the suspension, calcium peroxide, ferric sulfate, activated lignin, and enzyme-loaded activated carbon is (10-15): (0.5-1): (0.1-0.2): (1-2): (3-4).

[0029] Furthermore, the granulation particle size in step D is 5 to 10 mm.

[0030] Beneficial effects:

[0031] 1. The present invention treats walnut plants by spraying a specific concentration of paclobutrazol solution, which can effectively delay the elongation rate of plant cells, inhibit the excessive growth of new shoots, achieve a good control effect, promote the good growth of walnuts, and improve yield and quality.

[0032] 2. The present invention prepares a gel by co-preparing stable xanthan gum and locust bean gum, embeds lignin, iron sulfate, calcium peroxide and other components, and then granulates the gel with activated carbon loaded with laccase and peroxidase to prepare a decomposer. The components in the decomposer work synergistically to efficiently decompose the residual paclobutrazol in the soil, thereby ensuring soil safety and the normal growth of walnuts in the later stage. DETAILED DESCRIPTION

[0033] The present invention will be described in detail below with reference to specific embodiments:

[0034] Example 1: Preparation of decomposition agent

[0035] A: The lignin was ground through a 150-mesh sieve, then placed in a 10% sodium hydroxide solution (mass fraction) until the sodium hydroxide solution completely covered the lignin. The mixture was heated to 60°C and stirred for 1.5 hours. The mixture was then ultrasonicated at a power of 150 W and a frequency of 25 kHz for 10 minutes. After the ultrasonication, the filtrate was filtered and washed with water to obtain the activated lignin.

[0036] B: 3.5 kg of activated carbon was added to 17.5 kg of water, stirred and dispersed, and then 0.4 kg of asparagine was added. The temperature was raised to 70°C and stirred for reaction for 5 hours. After the reaction was completed, the filtrate was filtered out, washed with water, and dried to obtain modified activated carbon; 3.5 kg of modified activated carbon was added to 3.5 kg of water, stirred and dispersed, and then 0.015 kg of laccase and 0.015 kg of horseradish peroxidase were added. The mixture was stirred and mixed at room temperature to obtain enzyme-loaded activated carbon;

[0037] C: 0.1 kg of xanthan gum was added to 1 kg of dimethyl sulfoxide and the temperature was raised to 60°C with stirring to dissolve the xanthan gum. 0.003 kg of dicyclohexylcarbodiimide and 0.0015 kg of 4-dimethylaminopyridine were then added. The mixture was stirred and reacted for 25 minutes. 0.02 kg of p-tert-butylcyclohexanol was dissolved in 0.04 kg of ethanol and added. The mixture was stirred and reacted for 7 hours. After the reaction was completed, the precipitate was removed by filtration. The mixture was then vacuum dried at a vacuum degree of 0.1 MPa and a temperature of 40°C to obtain modified xanthan gum.

[0038] D: 0.08 kg of modified xanthan gum and 0.02 kg of locust bean gum were added together into 12 kg of water and stirred thoroughly to disperse to obtain a suspension. 12 kg of the suspension was taken and adjusted to pH 7, and then 0.6 kg of calcium peroxide, 0.15 kg of ferric sulfate and 1.5 kg of activated lignin were added and stirred thoroughly to mix evenly. The temperature was raised to 85°C and kept warm for 20 min. The mixture was then cooled to room temperature and refrigerated at 4°C overnight to allow the xanthan gum and locust bean gum to fully gel to obtain a composite gel. 3.5 kg of enzyme-loaded activated carbon was added to the composite gel, stirred thoroughly to mix evenly, and then granulated to prepare particles with a particle size of 6 mm. After granulation, the mixture was placed in water to fully absorb water to obtain a decomposition agent.

[0039] Example 2: Preparation of Decomposition Agent II

[0040] A: The lignin was ground through a 100-mesh sieve, then placed in a 10% sodium hydroxide solution (mass fraction) until the sodium hydroxide solution completely covered the lignin. The mixture was heated to 60°C and stirred for 1 hour. The mixture was then ultrasonically treated at a power of 100 W and a frequency of 20 kHz for 10 minutes. After the ultrasonic treatment, the filtrate was filtered and washed with water to obtain the activated lignin.

[0041] B: 3 kg of activated carbon was added to 15 kg of water with stirring and dispersed, and then 0.3 kg of asparagine was added. The temperature was raised to 60°C and stirred for reaction for 6 hours. After the reaction was completed, the filtrate was filtered out, washed with clean water, and dried to obtain modified activated carbon. 3 kg of modified activated carbon was added to 3 kg of water with stirring and dispersed, and then 0.01 kg of laccase and 0.01 kg of horseradish peroxidase were added. The mixture was stirred and mixed at room temperature to obtain enzyme-loaded activated carbon.

[0042] C: 0.06 kg of xanthan gum was added to 0.6 kg of dimethyl sulfoxide and the temperature was raised to 60°C with stirring to dissolve the xanthan gum. 0.002 kg of dicyclohexylcarbodiimide and 0.001 kg of 4-dimethylaminopyridine were then added. The mixture was stirred and reacted for 20 minutes. 0.01 kg of p-tert-butylcyclohexanol was dissolved in 0.02 kg of ethanol and added. The mixture was stirred and reacted for 6 hours. After the reaction was completed, the precipitate was removed by filtration. The mixture was then vacuum dried at a vacuum degree of 0.1 MPa and a temperature of 40°C to obtain modified xanthan gum.

[0043] D: 0.04 kg of modified xanthan gum and 0.01 kg of locust bean gum were added together into 10 kg of water and stirred thoroughly to disperse to obtain a suspension. 10 kg of the suspension was taken and adjusted to pH 7, and then 0.5 kg of calcium peroxide, 0.1 kg of ferric sulfate and 1 kg of activated lignin were added and stirred thoroughly to mix evenly. The temperature was raised to 80°C and kept warm for 30 minutes. The mixture was then cooled to room temperature and refrigerated at 4°C overnight to allow the xanthan gum and locust bean gum to fully gel to obtain a composite gel. 3 kg of enzyme-loaded activated carbon was added to the composite gel and stirred thoroughly to mix evenly. The mixture was then granulated to prepare particles with a particle size of 5 mm. After granulation, the mixture was placed in water to fully absorb water to obtain a decomposition agent.

[0044] Example 3: Decomposition agent preparation three

[0045] A: The lignin was ground through a 200-mesh sieve, then placed in a 10% sodium hydroxide solution (mass fraction) until the sodium hydroxide solution completely covered the lignin. The mixture was heated to 60°C and stirred for 2 hours. The mixture was then ultrasonically treated at a power of 300 W and a frequency of 40 kHz for 10 minutes. After the ultrasonic treatment, the filtrate was filtered and washed with water to obtain the activated lignin.

[0046] B: 4 kg of activated carbon was added to 20 kg of water with stirring and dispersed, and then 0.5 kg of asparagine was added. The temperature was raised to 80°C and stirred for reaction for 4 hours. After the reaction was completed, the filtrate was filtered out, washed with clean water, and dried to obtain modified activated carbon. 4 kg of modified activated carbon was added to 4 kg of water with stirring and dispersed, and then 0.02 kg of laccase and 0.02 kg of horseradish peroxidase were added. The mixture was stirred and mixed at room temperature to obtain enzyme-loaded activated carbon.

[0047] C: 0.15 kg of xanthan gum was added to 1.5 kg of dimethyl sulfoxide and the temperature was raised to 60°C with stirring to dissolve the xanthan gum. 0.004 kg of dicyclohexylcarbodiimide and 0.002 kg of 4-dimethylaminopyridine were then added. The mixture was stirred and reacted for 30 minutes. 0.03 kg of p-tert-butylcyclohexanol was dissolved in 0.06 kg of ethanol and added. The mixture was stirred and reacted for 8 hours. After the reaction was completed, the precipitate was removed by filtration. The mixture was then vacuum dried at a vacuum degree of 0.1 MPa and a temperature of 40°C to obtain modified xanthan gum.

[0048] D: 0.12 kg of modified xanthan gum and 0.03 kg of locust bean gum were added together into 15 kg of water and stirred thoroughly to disperse to obtain a suspension. 15 kg of the suspension was taken and adjusted to pH 7, followed by adding 1 kg of calcium peroxide, 0.2 kg of ferric sulfate and 2 kg of activated lignin and stirring thoroughly to mix evenly. The mixture was heated to 90°C and kept warm for 15 minutes. The mixture was then cooled to room temperature and refrigerated at 4°C overnight to allow the xanthan gum and locust bean gum to fully gel to obtain a composite gel. 3 to 4 kg of enzyme-loaded activated carbon was added to the composite gel and stirred thoroughly to mix evenly. The mixture was then granulated to prepare particles with a particle size of 8 mm. After granulation, the mixture was placed in water to fully absorb water to obtain a decomposition agent.

[0049] Comparative Example 1: Preparation of decomposition agent

[0050] In contrast to Example 1, the only difference is that the decomposition agent in Comparative Example 1 lacks the lignin activation treatment in step A, and instead directly uses conventional lignin, as shown below:

[0051] A: Same as step B in Example 1;

[0052] B: Same as step C in Example 1;

[0053] C: 0.08 kg of modified xanthan gum and 0.02 kg of locust bean gum were added together into 12 kg of water and stirred thoroughly to disperse to obtain a suspension. 12 kg of the suspension was taken and adjusted to pH 7, and then 0.6 kg of calcium peroxide, 0.15 kg of ferric sulfate and 1.5 kg of lignin were added and stirred thoroughly to mix evenly. The temperature was raised to 85°C and kept warm for 20 minutes. The mixture was then cooled to room temperature and refrigerated at 4°C overnight to allow the xanthan gum and locust bean gum to fully gel to obtain a composite gel. 3.5 kg of enzyme-loaded activated carbon was added to the composite gel, stirred thoroughly to mix evenly, and then granulated to prepare particles with a particle size of 6 mm. After granulation, the mixture was placed in water to fully absorb water to obtain a decomposition agent.

[0054] Comparative Example 2: Decomposition Agent Preparation

[0055] In contrast to Example 1, the only difference is that in the preparation of the decomposition agent in Comparative Example 2, in step B, asparagine is not used to treat the activated carbon, but conventional activated carbon is used, as shown below:

[0056] A: Same as Example 1;

[0057] B: 3.5 kg of activated carbon was added to 3.5 kg of water, stirred and dispersed, and then 0.015 kg of laccase and 0.015 kg of horseradish peroxidase were added. The mixture was stirred and mixed at room temperature to obtain enzyme-loaded activated carbon.

[0058] C to D: Same as Example 1.

[0059] Comparative Example 3: Preparation of decomposition agent

[0060] In contrast to Example 1, the only difference is that in Comparative Example 3, when preparing the decomposition agent, laccase and horseradish peroxidase are not added in step B, that is, modified activated carbon is added in step D, as shown below:

[0061] A: Same as Example 1;

[0062] B: Add 3.5 kg of activated carbon to 17.5 kg of water, stir and disperse, then add 0.4 kg of asparagine, heat to 70 ° C and stir to react for 5 hours. After the reaction is completed, filter and remove the filtrate, wash with water and dry to obtain modified activated carbon;

[0063] C: Same as Example 1;

[0064] D: 0.08 kg of modified xanthan gum and 0.02 kg of locust bean gum were added together into 12 kg of water and stirred thoroughly to disperse to obtain a suspension. 12 kg of the suspension was taken and adjusted to pH 7, followed by adding 0.6 kg of calcium peroxide, 0.15 kg of ferric sulfate and 1.5 kg of activated lignin and stirring thoroughly to mix uniformly. The mixture was heated to 85°C and kept warm for 20 min. The mixture was then cooled to room temperature and refrigerated at 4°C overnight to allow the xanthan gum and locust bean gum to fully gel to obtain a composite gel. 3.5 kg of modified activated carbon was added to the composite gel, stirred thoroughly to mix uniformly, and then granulated to prepare particles with a particle size of 6 mm. After granulation, the mixture was placed in water to fully absorb water to obtain a decomposition agent.

[0065] Comparative Example 4: Decomposition Agent Preparation

[0066] Compared with Example 1, the only difference is that the decomposition agent in Comparative Example 4 lacks the modification treatment of xanthan gum in step C, and conventional xanthan gum is used, as shown below:

[0067] A~B: Same as Example 1;

[0068] C: 0.08 kg of xanthan gum and 0.02 kg of locust bean gum were added together into 12 kg of water and stirred thoroughly to disperse to obtain a suspension. 12 kg of the suspension was adjusted to pH 7, and then 0.6 kg of calcium peroxide, 0.15 kg of ferric sulfate, and 1.5 kg of activated lignin were added and stirred thoroughly to mix evenly. The temperature was raised to 85°C and kept warm for 20 min. The mixture was then cooled to room temperature and refrigerated at 4°C overnight to allow the xanthan gum and locust bean gum to fully gel to obtain a composite gel. 3.5 kg of enzyme-loaded activated carbon was added to the composite gel, stirred thoroughly, and then granulated to prepare particles with a particle size of 6 mm. After granulation, the mixture was placed in water to fully absorb water to obtain a decomposition agent.

[0069] Comparative Example 5: Preparation of decomposition agent

[0070] In contrast to Example 1, the only difference is that calcium peroxide is not added in step D during the preparation of the decomposition agent in Comparative Example 5, and the remaining steps are the same as in Example 1.

[0071] Comparative Example 6: Preparation of decomposition agent

[0072] In contrast to Example 1, the only difference is that in the preparation of the decomposition agent in Comparative Example 6, ferric sulfate is not added in step D, and the remaining steps are the same as in Example 1.

[0073] Comparative Example 7: Preparation of decomposition agent

[0074] In contrast to Example 1, the only difference is that in Comparative Example 7, activated lignin is not added in step D when preparing the decomposition agent, as shown below:

[0075] A: Same as step B in Example 1;

[0076] B: Same as step C in Example 1;

[0077] C: 0.08 kg of modified xanthan gum and 0.02 kg of locust bean gum were added together into 12 kg of water and stirred thoroughly to disperse to obtain a suspension. 12 kg of the suspension was taken and adjusted to pH 7, and then 0.6 kg of calcium peroxide and 0.15 kg of ferric sulfate were added and stirred thoroughly to mix evenly. The temperature was raised to 85°C and kept warm for 20 min. The mixture was then cooled to room temperature and refrigerated at 4°C overnight to allow the xanthan gum and locust bean gum to fully gel to obtain a composite gel. 3.5 kg of enzyme-loaded activated carbon was added to the composite gel, stirred thoroughly to mix evenly, and then granulated to prepare particles with a particle size of 6 mm. After granulation, the mixture was placed in water to fully absorb water to obtain a decomposition agent.

[0078] Comparative Example 8: Preparation of decomposition agent

[0079] In contrast to Example 1, the only difference is that the amount of ferric sulfate added during the preparation of the decomposition agent in Comparative Example 8 is 0.08 kg.

[0080] Comparative Example 9: Preparation of decomposition agent

[0081] In contrast to Example 1, the only difference is that in the preparation of the decomposition agent in step D in Comparative Example 9, the amount of activated lignin added is 0.8 kg, and the remaining steps are the same as in Example 1.

[0082] Example 4: Walnut Growth Control Method

[0083] (1) After the new shoots of the grafted walnuts grow to 20 cm, spray the leaves of the walnut plants with 3000 mg / L paclobutrazol solution before 10 am on a sunny day. The spraying amount is based on the amount that all the leaf surfaces are wet and water drips. After an interval of 15 days, spray again using the same method, for a total of 2 sprays;

[0084] (2) One month after the second spraying of paclobutrazol solution, at about 9:00 a.m. on a sunny day, the soil moisture content was 42%. 2 The decomposition agent prepared according to the method of Example 2 is applied to the soil surface in an amount of 1 to 5 cm and raked into the soil layer to decompose paclobutrazol in the soil. The walnut plants can be managed and maintained according to conventional methods in the later stage.

[0085] Experiment 1: Paclobutrazol degradation experiment

[0086] The degradation effects of the decomposition agents prepared in Example 1 and Comparative Examples 1 to 9 on paclobutrazol were tested, and the specific method was as follows:

[0087] Soil was dug from a walnut forest, sterilized at 121°C for 30 min, and then dried in a 60°C oven to constant weight to obtain experimental soil; 2 kg of the experimental soil was placed in a flowerpot, water was added to adjust the moisture content to 45%, and then 0.1 g of paclobutrazol was added and mixed evenly (i.e., the initial paclobutrazol content of the experimental soil was 50 mg / kg). 20 g of a decomposer was then added and mixed evenly, and the soil was placed at a temperature of 25°C and a light intensity of 3000 lx for 24 h before the paclobutrazol content in the soil was detected.

[0088] The degradation effect of the decomposition agents prepared in Example 1 and Comparative Examples 1 to 9 on paclobutrazol was tested according to the above method. A blank control group was added to the experiment. No decomposition agent was added to the blank control group, but an equal amount of water was added. The experiment was repeated three times, and the average data of the paclobutrazol content in each group of soil were shown in Table 1.

[0089] Table 1

[0090]

[0091] According to the data analysis in Table 1, we can see that:

[0092] (1) In Example 1, the initial paclobutrazol content in the experimental soil was 50 mg / kg. After being treated with the decomposer of the present invention for 24 hours, the content was reduced to 6.2 mg / kg. In the blank control group, where no decomposer was applied, the paclobutrazol content remained at 49.6 mg / kg, with essentially no degradation. This indicates that the decomposer prepared according to the method of the present invention can be applied to the soil to efficiently decompose the residual paclobutrazol in the soil, thereby preventing the residual paclobutrazol from entering the soil from remaining in the soil for a long time, causing harm to soil safety and inhibiting the normal growth of walnuts in the later stage.

[0093] (2) In Comparative Example 1, lignin was not activated during the preparation of the decomposer, and no lignin was added during the preparation of the decomposer in Comparative Example 7. In Comparative Example 9, the amount of lignin added was reduced during the preparation of the decomposer. The decomposers prepared in Comparative Example 1, Comparative Example 7, and Comparative Example 9 respectively had the problems of low activity of phenolic substances in lignin, lack of reaction substrates, and insufficient substrate concentration, which affected the decomposition effect of the decomposer on paclobutrazol, and thus the residual paclobutrazol content in the experimental soil increased with different concentrations.

[0094] (3) In Comparative Example 2, the activated carbon was not modified during the preparation of the decomposition agent, but conventional activated carbon was used. The adsorption performance of the decomposition agent on paclobutrazol in the soil was reduced, thereby limiting the contact degradation rate of paclobutrazol by other components in the decomposition agent, and the residual paclobutrazol content in the soil was relatively high.

[0095] (4) In Comparative Example 3, laccase and peroxidase were not added during the preparation of the decomposition agent. The decomposition agent lacked the enzyme itself to degrade paclobutrazol. The lack of enzyme also affected the generation of hydrogen peroxide, greatly reducing the degradation effect of the decomposition agent on paclobutrazol.

[0096] (5) In Comparative Example 4, the xanthan gum was not modified during the preparation of the decomposer, and the water-holding gel in the decomposer was tightly bound, which affected the diffusion and transmission efficiency of the reaction substrates and reaction products in the decomposer, resulting in a decrease in the reaction efficiency and a certain degree of impact on the degradation of paclobutrazol.

[0097] (6) In Comparative Example 5, calcium peroxide was not added during the preparation of the decomposition agent, which failed to provide more sufficient hydrogen peroxide for the generation of hydroxyl radicals, greatly reducing the reaction efficiency and the degradation efficiency of paclobutrazol.

[0098] (7) In Comparative Example 6, no ferric sulfate was added during the preparation of the decomposer, and in Comparative Example 8, the amount of ferric sulfate added was reduced during the preparation of the decomposer. The lack of ferric sulfate and the insufficient amount of ferric sulfate greatly affected the formation of free radicals, and had a more significant impact on the degradation reaction of paclobutrazol.

[0099] Experiment 2: Walnut Growth Control Experiment

[0100] A walnut growth control experiment was conducted in Lingshang Village, Shijia Township, Shizhu County, Chongqing. The site is located at an altitude of 1,000 meters, with yellow-brown soil, an average annual temperature of approximately 14°C, average annual precipitation between 1,030 and 1,950 mm, and an average annual sunshine of 1,568.7 hours. The experiment was divided into 13 groups: experimental group 1, control groups 1 to 11, and a blank control group. Specific growth control methods for each group are as follows:

[0101] Experimental Group 1: The decomposition agent prepared in Example 1 and the growth control method of Example 4 were used;

[0102] Control groups 1 to 9: using the decomposition agents prepared in Comparative Examples 1 to 9 and the control method of Example 4 respectively;

[0103] Control group 10: This is an additional control group, using the decomposition agent prepared in Example 1. The concentration of the paclobutrazol solution was 1500 mg / L when controlling the growth of walnuts. The remaining steps were the same as those in Example 4.

[0104] Control group 11: This is an additional control group. The method of Example 4 was used to control the growth of walnuts, but no decomposition agent was applied. Instead, an equal amount of water was applied.

[0105] Blank control group: clean water was used instead of the paclobutrazol solution and decomposer in Example 4. That is, when spraying the paclobutrazol solution in the walnut growth control treatment method of Example 4, the paclobutrazol solution was not sprayed but an equal amount of clean water was sprayed. When applying decomposition, the decomposer was not applied but an equal amount of clean water was applied.

[0106] The test tree species in each group of experiments was the Chongqing local walnut variety "Yucheng No. 1" that was high-grafted and replaced that year. The rootstock was an 8-year-old local non-fruiting walnut tree with a breast diameter of about 12 cm. The rootstock row spacing was 5m×5m. The high-grafting and replacement grafting method was: on March 24, 22, the main trunk of the rootstock with consistent growth was cut off 100 cm from the ground, and a single-head high-grafting replacement was performed. Three healthy and high-quality spike buds of "Yucheng No. 1" were grafted on each rootstock by bark grafting. Then, after the new shoots grew to 20 cm, paclobutrazol solution was sprayed to control vigor. A second spray was applied after an interval of 15 days, and a decomposer was applied one month after the second spraying.

[0107] Each group of the experiment treated 10 walnut plants with 3 replicates. Twenty branches were randomly selected from each group of walnut plants for marking. The branch length, internode distance, and branch diameter of the marked one-year-old walnut branches in each group were tested in early December. The branch length and branch diameter of the marked two-year-old branches were tested again in September of the following year. The fruit setting rate, single-plant yield, and soluble sugar content of walnuts in each group were recorded, and the average data are shown in Table 2.

[0108] Table 2

[0109]

[0110]

[0111] According to the data analysis in Table 2:

[0112] (1) The method of the present invention was used to control the growth of walnuts grafted for transplantation, which effectively inhibited the vegetative growth of the new shoots of the grafted walnuts in the first year and promoted the lignification of the branches. Compared with the blank control group, the length of the one-year-old branches in experimental group 1 was reduced by 88.23 cm, and the internode distance between the branches was reduced by 2.41 cm, showing a significant growth control effect. The control group 10 was treated with a 1500 mg / L paclobutrazol solution for walnut growth control, but the growth control effect was far inferior to that of a 3000 mg / L paclobutrazol solution. To control the excessive vegetative growth of the new shoots of the grafted walnut plants in the first year, a higher amount of paclobutrazol solution must be sprayed to achieve a better effect.

[0113] (2) The control group 11 sprayed 3000 mg / L paclobutrazol solution to control the growth of walnuts, but no decomposers were applied. The decomposers remaining in the soil continued to act on the walnut plants. Although it further reduced the length of the one-year-old branches and increased the lignification of the branches, it also further affected the normal growth of the walnuts in the second year, resulting in a significant decrease in the yield and quality of the walnuts.

[0114] (4) Due to the lack of different raw materials or changes in conditions during the preparation of the decomposers in control groups 1 to 9, the decomposers had different degrees of reduction in the degradation efficiency of the residual paclobutrazol in the soil, resulting in more and different amounts of paclobutrazol residue in the soil, which in turn continued to inhibit the growth of the walnut plants in the later period, affecting the normal growth and flowering and fruiting of the walnuts in the second year, resulting in a decrease in walnut yield and quality. This shows that the use of a higher concentration of paclobutrazol solution can effectively control the vigorous growth of walnuts, and the decomposers prepared by the present invention can just degrade the higher concentration of paclobutrazol remaining in the soil to ensure the normal growth of walnuts in the later period. The combined use has good application prospects.

[0115] The above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art will appreciate that the technical solutions of the present invention may be modified or replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention, and such modifications or equivalents shall be encompassed by the claims of the present invention. Any techniques, shapes, and structures not described in detail herein are well known.

Claims

1. A method for controlling the growth of walnuts, characterized in that: The method comprises the following steps: (1) When the new shoots of high-grafted walnuts grow to 20-30 cm, spray the leaves of the walnut plants with 3000 mg / L paclobutrazol solution before 10 a.m. or after 5 p.m. on a sunny day. Spray again after 15 days, for a total of 2 sprays; (2) One month after the second spraying of paclobutrazol solution, adjust the soil moisture content at 8-10 am on a sunny day, and then adjust the soil moisture content at 0.2-0.4 kg / m 2 Apply a certain amount of decomposer to the soil surface and rake it into the 1-5 cm soil layer to decompose paclobutrazol in the soil. Later, the walnut plants can be managed and maintained according to conventional methods.

2. A method for controlling walnut growth according to claim 1, characterized in that: The operation of adjusting the soil moisture content in step (2) is specifically as follows: Check the soil moisture content. If the soil moisture content is greater than 45%, there is no need to spray water. If the soil moisture content is less than 40%, spray water to adjust the soil moisture content to 40-45%.

3. A method for controlling walnut growth according to claim 2, characterized in that: The decomposition agent comprises the following raw materials: Activated carbon, asparagine, laccase, peroxidase, lignin, ferric sulfate, calcium peroxide, xanthan gum, 4-tert-butylcyclohexanol, dicyclohexylcarbodiimide, 4-dimethylaminopyridine, locust bean gum.

4. A method for controlling walnut growth according to claim 3, characterized in that: The decomposition agent preparation method is as follows: A: The lignin is ground through a 100-200 mesh sieve, then placed in a 10% by mass sodium hydroxide solution and heated to 60°C with stirring for 1-2 hours. The solution is then ultrasonically treated at a power of 100-300W and a frequency of 20-40kHz for 10 minutes. After the ultrasonic treatment, the filtrate is filtered and washed with water to obtain the activated lignin. B: Add activated carbon to water, stir and disperse, then add asparagine, heat to 60-80°C, stir and react for 4-6 hours. After the reaction is complete, filter and remove the filtrate, wash with clean water, and dry to obtain modified activated carbon; The modified activated carbon is added into water and stirred to disperse, and then laccase and peroxidase are added, and the mixture is stirred and mixed at room temperature to obtain enzyme-loaded activated carbon; C: Add xanthan gum to dimethyl sulfoxide and heat to 60°C with stirring to dissolve the xanthan gum. Then, add dicyclohexylcarbodiimide and 4-dimethylaminopyridine. Continue stirring and reacting for 20-30 minutes. Then, dissolve 4-tert-butylcyclohexanol in ethanol and add it. Continue stirring and reacting for 6-8 hours. After the reaction is complete, filter to remove the precipitate, and then vacuum dry to obtain modified xanthan gum. D: Add modified xanthan gum and locust bean gum into water together, stir and disperse to obtain a suspension, adjust the pH of the suspension to 7, add calcium peroxide, ferric sulfate and activated lignin, stir and mix evenly, heat to 80-90°C and keep warm for 15-30 minutes, then cool to room temperature and transfer to 4°C and refrigerate overnight to allow the xanthan gum and locust bean gum to gel to obtain a composite gel, add enzyme-loaded activated carbon to the composite gel, stir and mix evenly, and then granulate. After granulation, put it into water to absorb water to obtain a decomposition agent.

5. A method for controlling walnut growth according to claim 4, characterized in that: The mass ratio of activated carbon to asparagine in step B is (3-4): (0.3-0.5).

6. A method for controlling walnut growth according to claim 5, characterized in that: The mass ratio of the modified activated carbon, laccase and peroxidase in the step B is (3-4): (0.01-0.02): (0.01-0.02).

7. A method for controlling walnut growth according to claim 6, characterized in that: In the step C, the mass ratio of xanthan gum, dicyclohexylcarbodiimide, 4-dimethylaminopyridine and p-tert-butylcyclohexanol is (0.06-0.15): (0.002-0.004): (0.001-0.002): (0.01-0.03).

8. A method for controlling walnut growth according to claim 7, characterized in that: The mass ratio of modified xanthan gum, locust bean gum and water in the suspension of step D is (0.04-0.12): (0.01-0.03): (10-15).

9. A method for controlling walnut growth according to claim 8, characterized in that: In the step D, the mass ratio of the suspension, calcium peroxide, ferric sulfate, activated lignin, and enzyme-loaded activated carbon is (10-15): (0.5-1): (0.1-0.2): (1-2): (3-4).

10. The method for controlling walnut growth according to claim 9, characterized in that: The granulation particle size in step D is 5 to 10 mm.

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