A method for planting selenium-rich oolong tea

Abstract

The application belongs to the field of oolong tea planting, and particularly relates to a selenium-rich oolong tea planting method. Sodium t-butyl alcohol is mixed with degradable polybutylene succinate to modify the polybutylene succinate. The modified polybutylene succinate is mixed with modified medical stone by calcium hydroxide through hydrogen bond interaction, and then is subjected to freeze spray drying. The obtained viscous soil conditioner can efficiently and continuously adjust the pH value of soil. The base fertilizer mixture is subjected to sufficient enzymolysis by a mixed bacterial agent, and then is mixed with calcium selenate, selenomethionine, sodium selenite and pig excrement to obtain a selenium absorption promoting compound fertilizer which can promote the absorption of selenium by oolong tea. The oolong tea seedlings soaked in hydroponic nutrient solution are planted in soil which is conditioned by the viscous soil conditioner and contains the selenium absorption promoting compound fertilizer. The planted oolong tea is rich in selenium and stable in quality, and the planting method is simple and efficient, so the method can be widely promoted for large-scale planting.

Description

Technical Field

[0001] This invention belongs to the field of oolong tea cultivation, specifically referring to a method for cultivating selenium-rich oolong tea. Background Technology

[0002] Oolong tea, also known as green tea or semi-fermented tea, is a unique and distinctive category of tea among China's major tea types. It is made from the new shoots of Camellia sinensis trees at a suitable maturity level, and undergoes a series of processing steps including withering, shaking and cooling, fixation, shaping, and drying. Oolong tea offers various health benefits, such as fat breakdown, weight loss, mental alertness, and antioxidant properties. Long-term consumption of oolong tea can improve health and prevent various diseases.

[0003] Oolong tea cultivation refers to the process of nurturing and managing tea trees under specific ecological and soil conditions using scientific cultivation techniques to obtain high-quality tea leaves, which are then used to produce superior oolong tea. The cultivation process includes multiple stages such as site selection, tea variety selection, planting, tea garden management, and harvesting. Oolong tea is typically planted in mountainous or semi-mountainous areas with abundant vegetation. Scientific tea garden management helps protect the soil, prevent soil erosion, and maintain ecological balance. The improved ecological environment of the tea garden provides habitats for various organisms, promoting biodiversity. Oolong tea cultivation is a major source of income for farmers in many tea-producing regions. Through scientific cultivation and management, improving the yield and quality of oolong tea can significantly increase farmers' income.

[0004] Currently, existing methods for cultivating oolong tea have the following problems: First, the cultivation of selenium-rich oolong tea has specific requirements for the selenium content of the soil, which greatly limits the planting area and makes it difficult to promote large-scale cultivation; Second, existing cultivation techniques cannot increase the selenium content in tea leaves and may even cause soil selenium pollution, affecting tea tree growth and tea quality, and even having adverse effects on the surrounding environment; Third, the current cultivation of selenium-rich oolong tea is complex, and improper operation in any step may lead to poor tea tree growth and unstable quality of the cultivated selenium-rich oolong tea. Summary of the Invention

[0005] In response to the above-mentioned situation and to overcome the shortcomings of existing technologies, this invention provides a method for cultivating selenium-enriched oolong tea. To address the problems of existing oolong tea cultivation methods being difficult to scale up, unable to increase the selenium content in tea leaves, and producing inconsistent quality of the resulting selenium-enriched oolong tea, this invention uses hydroponic nutrient solution to treat oolong tea seedlings, a clay soil conditioner to condition the soil, and a compound fertilizer to promote selenium absorption. The resulting method is simple to operate, can be scaled up, effectively increases the selenium content in oolong tea, and produces selenium-enriched oolong tea of ​​stable quality.

[0006] To achieve the above objectives, the technical solution adopted by this invention is as follows: This invention proposes a method for cultivating selenium-rich oolong tea, specifically including the following steps:

[0007] Step 1: Soil conditioning before planting: Select a gentle slope of brown soil with a slope of less than 15 degrees. Use a clay soil conditioner to condition the brown soil on the gentle slope. The application rate is 70-90 kg / mu. After application, till the soil evenly and let it remain naturally for 8-13 days to obtain the conditioned soil.

[0008] Step 2, meticulous cultivation: Apply the selenium-enriching compound fertilizer to the soil prepared in Step 1 at a rate of 80-100 kg / mu, till it evenly, harrow and level the land, and let it remain naturally for 4-7 days to obtain a selenium-rich soil matrix.

[0009] Step 3: Hydroponic tea seedlings: Soak oolong tea seedlings with a height of 25-30 cm in hydroponic nutrient solution and cultivate them at a temperature of 28℃ for 15-20 days to obtain strong oolong tea seedlings.

[0010] Step 4, Tea seedling planting: Plant the robust oolong tea seedlings obtained in Step 3 into planting holes with a depth of 5-10 cm and a diameter of 30 cm, with a plant spacing of 40 cm and a row spacing of 1.5 m. The robust oolong tea seedlings are then planted into the selenium-rich soil substrate obtained in Step 2 to obtain the planted oolong tea seedlings.

[0011] Step 5, Water and Fertilizer Management: Water, fertilize, and spray pesticides on the oolong tea seedlings after planting in Step 4. After 3 years of planting, selenium-rich oolong tea will be obtained.

[0012] Preferably, in step three, the hydroponic nutrient solution is prepared by mixing 1-1.2 parts by weight of ammonium chloride, 0.8-1.3 parts by weight of sodium nitrophenolate, 0.6-0.8 parts by weight of calcium nitrate, 1.1-1.3 parts by weight of magnesium nitrate, 0.6-0.9 parts by weight of zinc chloride, 0.4-0.8 parts by weight of potassium acetate, 0.3-0.7 parts by weight of 5-aminolevulinic acid, and 400-500 parts by weight of ultrapure water in a mixing tank with a power of 1.5-1.8 kW, a mixing temperature of 28-33°C, a mixing time of 20-26 min, and a mixing speed of 500 r / min.

[0013] Preferably, in step five, the water and fertilizer management is as follows: during the first month of growth of the oolong tea seedlings after planting, water once a day, and then once a week thereafter. Each irrigation should bring the soil moisture content to 80%. After planting, apply a compound fertilizer that promotes selenium absorption every two months, with an application rate of 30-50 kg / mu.

[0014] Preferably, in step one, the preparation method of the cohesive soil conditioner specifically includes the following steps:

[0015] S1. Place 10-12 parts by weight of sodium tert-butoxide, 13-17 parts by weight of polybutylene succinate, 80-100 parts by weight of tetrahydrofuran, and 100-110 parts by weight of chloroform into a reactor with a power of 2.4-3.5 kW. The reaction temperature is 100℃, the reaction rate is 300-600 r / min, and the reaction time is 6-8 h. Mix and react to obtain modified polybutylene succinate.

[0016] S2. Place 25-30 parts by weight of maifanite, 18-26 parts by weight of calcium hydroxide, and 200-300 parts by weight of glycerol into a reactor with a power of 2.4-3.5 kW. The reaction temperature is 75-85℃, the reaction rate is 300-400 r / min, and the reaction time is 1.5-2 h. Mix and react to carry out modification to obtain modified maifanite.

[0017] S3. The modified maifanite prepared in S2, the modified polybutylene succinate prepared in S1, and 350-400 parts of dichloromethane are placed in a stirring tank with a power of 1.5-1.8 kW. The stirring temperature is 75℃, the stirring time is 1-2 h, and the stirring speed is 400-600 r / min. After stirring and mixing, the mixture is filtered with sterile gauze and washed 2-3 times with anhydrous ethanol. Then, it is dried in an oven with a power of 2.2 kW at a temperature of 60℃ for 30-40 min to obtain the composite.

[0018] S4. Place 15-19 parts by weight of *Ipomoea purpurea*, 21-23 parts of *Senecio scandens*, and 36-38 parts of *Vegetariana* into a pulverizer with a power of 1.5-1.8 kW. Pulverize at a temperature of 23-28℃ for 15-20 minutes and at a speed of 3500-4500 r / min. After pulverization, place the pulverizer into a grinder with a power of 1.8-2.4 kW. Grind at a temperature of 30-36℃ for 15-25 minutes and at a speed of 18000-20000 r / min to obtain a viscous slurry.

[0019] S5. The composite prepared in S3 is placed in a vacuum freeze-spray dryer with a power of 2.3-2.8 kW, a vacuum degree of -0.05 MPa, a freeze-spray drying temperature of -40℃, a freeze-spray drying particle size of 100 nm, and a freeze-spray drying time of 2.5-3 h to obtain composite nanoparticles.

[0020] S6. Place the composite nanoparticles prepared in S5, the viscous slurry prepared in S4, 7-11 parts of ferric hydroxide, and 6-9 parts of sodium percarbonate into a mixing tank with a power of 1.5-1.8 kW. The mixing temperature is 30-36℃, the mixing time is 30-40 min, and the mixing speed is 300-400 r / min. Mix evenly to obtain a viscous soil conditioner.

[0021] Preferably, in step two, the preparation method of the selenium absorption-promoting compound fertilizer specifically includes the following steps:

[0022] L1. Place 26-34 parts by weight of Vitex negundo, 35-42 parts of Sophora flavescens, and 31-37 parts of Lorrae rubra into a 1.5 kW pulverizer. Pulverize at 23°C for 15 minutes and at 3500 r / min to obtain a base fertilizer mixture.

[0023] L2. Inoculate 1.2-1.4 parts by weight of the mixed bacterial agent into a 5% sterile glucose solution and place it in a constant temperature shaking incubator with a power of 2.2 kW. The constant temperature shaking incubation temperature is 25℃, the constant temperature shaking incubation time is 24 h, and the constant temperature shaking incubation speed is 210 r / min. After constant temperature shaking incubation, put it into an enzymatic hydrolysis tank with a power of 1.6-2.2 kW with the base fertilizer mixture prepared in L1. The enzymatic hydrolysis temperature is 30℃, the enzymatic hydrolysis time is 2-3 days, and the enzymatic hydrolysis speed is 70-90 r / min. After enzymatic hydrolysis and fermentation, a composition that promotes plant absorption of selenium is obtained.

[0024] L3. The plant-absorbing selenium-promoting composition prepared in L2 is mixed with 3.4-5.3 parts of calcium selenate, 6.8-7.4 parts of selenomethionine, 9.6-11.8 parts of sodium selenite, and 18-23 parts of pig manure in a mixing tank with a power of 1.5-1.8 kW. The mixing temperature is 33-36℃, the mixing time is 38-46 min, and the mixing speed is 400-600 r / min to obtain a selenium-absorbing compound fertilizer.

[0025] Further, in L2, the mixed bacterial agent consists of *Bacillus spheroides*, *Serratia depigmentosus*, and *Pseudomonas putida*, with a weight ratio of 1.2:0.9:1. The *Bacillus spheroides* was purchased from the China General Microbiological Culture Collection Center (CGMCC) under accession number CGMCC1.8369, the *Serratia depigmentosus* under accession number CGMCC1.1857, and the *Pseudomonas putida* under accession number CGMCC1.8829. The inoculum size of the mixed bacterial agent in 5% sterile glucose solution is 1%.

[0026] The beneficial effects achieved by this invention are as follows:

[0027] This invention employs a mixed reaction of sodium tert-butoxide and biodegradable polybutylene succinate. Sodium tert-butoxide introduces tert-butoxy groups onto the surface of polybutylene succinate, enabling it to chemically bond with acidic groups in acidic compounds in the soil, forming stable chemical bonds. The modified polybutylene succinate has a higher specific surface area and more porous structure, forming adsorption, neutralizing soil acidity, and increasing the soil pH. A higher pH facilitates the dissolution and movement of selenium, increasing its bioavailability and allowing plants to more effectively absorb selenium from the soil. Calcium hydroxide reacts with maifanite; the modified maifanite has a larger specific surface area, providing more adsorption space for the adsorbed compounds. After being applied to the soil, it provides a rich calcium source, increasing the content of available calcium in the soil. It also combines with heavy metal ions in the soil to form insoluble calcium metal compounds, avoiding competitive absorption between heavy metals and selenium, and improving soil aeration and permeability. *Gynostemma pentaphyllum*, *Senecio scandens*, and *Vegetariana* are pulverized and ground into a viscous slurry, which then reacts with the soil... The soil particles combine to form stable aggregates, which also contain abundant nutrients that can be absorbed and utilized by soil microorganisms and plants. This promotes the formation of clay minerals in the soil. Clay minerals have a large specific surface area and abundant surface active sites, which can adsorb selenium in the soil, increasing the concentration of selenium in the soil. Iron hydroxide forms a stable complex with selenium in the soil, fixing the selenium and preventing its loss. Sodium percarbonate decomposes in water to produce hydrogen peroxide and sodium carbonate, which can oxidize insoluble selenium in the soil into soluble selenium, improving the solubility and bioavailability of selenium. Modified maifanite and modified polybutylene succinate interact through hydrogen bonds to form stable chemical bonds. After freeze spray drying, the resulting composite nanoparticles are mixed with viscous slurry, iron hydroxide, and sodium percarbonate. The resulting viscous soil conditioner effectively and continuously regulates soil pH, improves soil permeability, enhances plant root growth, increases the bioavailability of selenium, prevents selenium loss from the soil, and promotes the enrichment of selenium by plants.After crushing wild pea, bulrush, and ryegrass, a base fertilizer mixture rich in nitrogen, phosphorus, potassium, magnesium, zinc, boron, various amino acids, minerals, and vitamins is obtained. This mixture undergoes enzymatic hydrolysis using a mixed microbial agent containing *Bacillus spheroidans*, *Serratia demersum*, and *Pseudomonas putida*, allowing for the full release of nutrients. During fermentation, the mixed microbial agent produces antibiotics, increases the content of available nitrogen in the soil, facilitating absorption and utilization by plant roots, and reduces pathogen damage to plant roots, thereby promoting plant growth and creating a more favorable environment for root growth and absorption. It also enriches the soil's microbial community structure, promoting interactions and synergistic effects among microorganisms. Furthermore, the mixed microbial agent can convert inorganic selenium into organic selenium, improving its bioavailability. It can also alter the distribution of selenium forms in the soil through metabolic activities, converting insoluble selenium forms, such as iron-manganese bound selenium, into soluble selenium forms. Water-soluble and exchangeable selenium promotes a more even distribution of available selenium in the soil, increasing the contact opportunities between plant roots and selenium, thereby improving the plant's absorption efficiency. A selenium-enhancing compound fertilizer, mixed with calcium selenate, selenomethionine, sodium selenite, and animal manure, provides rich nutrients for oolong tea growth, increases the content of available selenium, and synergistically promotes selenium absorption by oolong tea with a clay soil conditioner. The hydroponic nutrient solution can quickly penetrate the plant, promoting cell division and growth, improving the photosynthetic efficiency and respiration intensity of seedlings, contributing to the robust growth of oolong tea seedlings, and creating a favorable physiological basis for the absorption and utilization of non-metallic elements. Oolong tea seedlings soaked in the hydroponic nutrient solution are then planted in soil conditioned with a clay soil conditioner and containing the selenium-enhancing compound fertilizer. The resulting oolong tea is rich in selenium, has stable quality, and the planting method is simple and efficient, suitable for large-scale cultivation. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in this invention or the prior art, the following description will be provided in a clear and easy-to-understand manner in conjunction with the accompanying drawings. Obviously, the drawings described below are merely for this invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0029] Figure 1 This is a scanning electron microscope image of the internal structure of the composite nanoparticles described in this invention.

[0030] Figure 2 This is a graph showing the yield results of oolong tea as described in Experimental Example 1 of this invention;

[0031] Figure 3 This is a graph showing the selenium content of the oolong tea leaves described in Experimental Example 2 of this invention.

[0032] Figure 4This is a graph showing the effective selenium content in the soil of the oolong tea plantation described in Experimental Example 2 of this invention.

[0033] Figure 5 This is a graph showing the selenium activation rate in the soil of the oolong tea plantation described in Experimental Example 2 of this invention.

[0034] Figure 6 This is a growth diagram of oolong tea in the experimental field of Example 1 of the present invention. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0037] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; unless otherwise specified, the experimental materials and test strains used in the following examples were purchased from commercial channels.

[0038] Example 1: This example provides a method for cultivating selenium-rich oolong tea, specifically including the following steps:

[0039] Step 1: Soil conditioning before planting: Select a gentle slope of brown soil with a slope of less than 15 degrees. Use a clay soil conditioner to condition the brown soil on the gentle slope. The application rate is 70 kg / mu. After application, till the soil evenly and let it sit naturally for 8 days to obtain the conditioned soil.

[0040] Step 2, meticulous cultivation: Apply the selenium-enriching compound fertilizer to the soil prepared in Step 1 at a rate of 80 kg / mu, till it evenly, harrow and level the land, and let it remain naturally for 4 days to obtain a selenium-rich soil matrix.

[0041] Step 3: Hydroponic tea seedling cultivation: Soak 25 cm tall oolong tea seedlings in hydroponic nutrient solution and cultivate them at 28℃ for 15 days to obtain robust oolong tea seedlings.

[0042] Step 4, Tea seedling planting: Plant the robust oolong tea seedlings obtained in Step 3 into planting holes with a depth of 5 cm and a diameter of 30 cm, with a plant spacing of 40 cm and a row spacing of 1.5 m. The robust oolong tea seedlings are then planted into the selenium-rich soil substrate obtained in Step 2 to obtain the planted oolong tea seedlings.

[0043] Step 5, Water and Fertilizer Management: Water, fertilize, and spray pesticides on the oolong tea seedlings after planting in Step 4. After 3 years of planting, selenium-rich oolong tea will be obtained.

[0044] In step three, the hydroponic nutrient solution is prepared by mixing 1 part ammonium chloride, 0.8 parts sodium nitrophenolate, 0.6 parts calcium nitrate, 1.1 parts magnesium nitrate, 0.6 parts zinc chloride, 0.4 parts potassium acetate, 0.3 parts 5-aminolevulinic acid, and 400 parts ultrapure water in a 1.5 kW mixing tank at a mixing temperature of 28°C for 20 min and a mixing speed of 500 r / min.

[0045] In step five, the water and fertilizer management is as follows: During the first month of growth of the oolong tea seedlings after planting, water once a day, and then once a week thereafter. Each irrigation should bring the soil moisture content to 80%. After planting, apply a compound fertilizer that promotes selenium absorption every two months at a rate of 30 kg / mu.

[0046] In step one, the preparation method of the cohesive soil conditioner specifically includes the following steps:

[0047] S1. 10 parts by weight of sodium tert-butoxide, 13 parts by weight of polybutylene succinate, 80 parts by weight of tetrahydrofuran, and 100 parts by weight of chloroform were placed in a 2.4 kW reactor. The reaction temperature was 100℃, the reaction rate was 300 r / min, and the reaction time was 6 h. The mixture was reacted to obtain the modified polybutylene succinate.

[0048] S2. 25 parts by weight of maifanite, 18 parts by weight of calcium hydroxide, and 200 parts by weight of glycerol were placed in a 2.4 kW reactor. The reaction temperature was 75℃, the reaction rate was 300 r / min, and the reaction time was 1.5 h. The mixture was mixed and reacted to carry out the modification, and the modified maifanite was obtained.

[0049] S3. The modified maifanite prepared in S2, the modified polybutylene succinate prepared in S1, and 350 parts of dichloromethane were placed in a 1.5 kW stirring tank. The stirring temperature was 75℃, the stirring time was 1 h, and the stirring speed was 400 r / min. After stirring and mixing, the mixture was filtered with sterile gauze, washed twice with anhydrous ethanol, and then dried in a 2.2 kW oven at 60℃ for 30 min to obtain the composite.

[0050] S4. Place 15 parts by weight of *Ipomoea aquatica*, 21 parts by weight of *Senecio scandens*, and 36 parts by weight of *Vegetariana* into a 1.5 kW pulverizer. Pulverize at 23°C for 15 minutes and at a speed of 3500 r / min. After pulverization, place the pulverizer into a 1.8 kW grinder. Grind at 30°C for 15 minutes and at a speed of 18000 r / min to obtain a viscous slurry.

[0051] S5. The composite prepared in S3 was placed in a vacuum freeze-spray dryer with a power of 2.3 kW, a vacuum degree of -0.05 MPa, a freeze-spray drying temperature of -40℃, a freeze-spray drying particle size of 100 nm, and a freeze-spray drying time of 2.5 h to obtain composite nanoparticles.

[0052] S6. The composite nanoparticles prepared in S5, the viscous slurry prepared in S4, 7 parts of ferric hydroxide, and 6 parts of sodium percarbonate are placed in a mixing tank with a power of 1.5 kW. The mixing temperature is 30℃, the mixing time is 30 min, and the mixing speed is 300 r / min. The mixture is mixed evenly to obtain a viscous soil conditioner.

[0053] In step two, the preparation method of the selenium absorption-promoting compound fertilizer specifically includes the following steps:

[0054] L1. Place 26 parts by weight of wild pea, 35 parts of fodder and 31 parts of ryegrass into a 1.5 kW pulverizer, pulverize at a temperature of 23℃ for 15 min and a speed of 3500 r / min to obtain a base fertilizer mixture.

[0055] L2. 1.2 parts by weight of mixed bacterial agent were inoculated into 5% sterile glucose solution and placed in a constant temperature shaking incubator with a power of 2.2 kW. The constant temperature shaking incubation temperature was 25℃, the constant temperature shaking incubation time was 24 h, and the constant temperature shaking incubation speed was 210 r / min. After constant temperature shaking incubation, it was placed with the base fertilizer mixture prepared in L1 into an enzymatic hydrolysis tank with a power of 1.6 kW. The enzymatic hydrolysis temperature was 30℃, the enzymatic hydrolysis time was 2 d, and the enzymatic hydrolysis speed was 70 r / min. After enzymatic hydrolysis and fermentation, a composition that promotes plant absorption of selenium was obtained.

[0056] L3. The plant-enhancing selenium absorption composition prepared in L2 was mixed with 3.4 parts calcium selenate, 6.8 parts selenomethionine, 9.6 parts sodium selenite, and 18 parts pig manure in a 1.5 kW mixing tank. The mixing temperature was 33℃, the mixing time was 38 min, and the mixing speed was 400 r / min to obtain the selenium-enhancing compound fertilizer.

[0057] In L2, the mixed bacterial agent consists of *Bacillus spheroides*, *Serratia demersum*, and *Pseudomonas putida*, with a weight ratio of 1.2:0.9:1. The *Bacillus spheroides* was purchased from the China General Microbiological Culture Collection Center (CGMCC) under accession number CGMCC1.8369; the *Serratia demersum* under accession number CGMCC1.1857; and the *Pseudomonas putida* under accession number CGMCC1.8829. The inoculum size of the mixed bacterial agent in 5% sterile glucose solution is 1%.

[0058] Example 2: This example provides a method for cultivating selenium-rich oolong tea, specifically including the following steps:

[0059] Step 1: Soil conditioning before planting: Select a gentle slope of brown soil with a slope of less than 15 degrees, and use a clay soil conditioner to condition the brown soil on the gentle slope. The application rate is 80 kg / mu. After application, till the soil evenly and let it sit naturally for 11 days to obtain the conditioned soil.

[0060] Step 2, meticulous cultivation: Apply the selenium-enriching compound fertilizer to the soil prepared in Step 1 at a rate of 90 kg / mu, till it evenly, harrow and level the land, and let it remain naturally for 6 days to obtain a selenium-rich soil matrix.

[0061] Step 3: Hydroponic tea seedling cultivation: Immerse 28 cm tall oolong tea seedlings in hydroponic nutrient solution and cultivate them at 28℃ for 18 days to obtain robust oolong tea seedlings.

[0062] Step 4, Planting of tea seedlings: Plant the robust oolong tea seedlings obtained in Step 3 into planting holes with a depth of 8 cm and a diameter of 30 cm, with a plant spacing of 40 cm and a row spacing of 1.5 m. The robust oolong tea seedlings are then planted into the selenium-rich soil substrate obtained in Step 2 to obtain the planted oolong tea seedlings.

[0063] Step 5, Water and Fertilizer Management: Water, fertilize, and spray pesticides on the oolong tea seedlings after planting in Step 4. After 3 years of planting, selenium-rich oolong tea will be obtained.

[0064] In step three, the hydroponic nutrient solution is prepared by mixing 1.1 parts by weight of ammonium chloride, 0.9 parts by weight of sodium nitrophenolate, 0.7 parts by weight of calcium nitrate, 1.2 parts by weight of magnesium nitrate, 0.8 parts by weight of zinc chloride, 0.6 parts by weight of potassium acetate, 0.5 parts by weight of 5-aminolevulinic acid, and 460 parts by weight of ultrapure water in a 1.6 kW mixing tank, with a mixing temperature of 30°C, a mixing time of 23 min, and a mixing speed of 500 r / min.

[0065] In step five, the water and fertilizer management is as follows: During the first month of growth of the oolong tea seedlings after planting, water once a day, and then once a week thereafter. Each irrigation should bring the soil moisture content to 80%. After planting, apply a compound fertilizer that promotes selenium absorption every two months at a rate of 40 kg / mu.

[0066] In step one, the preparation method of the cohesive soil conditioner specifically includes the following steps:

[0067] S1. 11 parts by weight of sodium tert-butoxide, 15 parts by weight of polybutylene succinate, 90 parts by weight of tetrahydrofuran, and 105 parts by weight of chloroform were placed in a 3.2 kW reactor. The reaction temperature was 100℃, the reaction rate was 500 r / min, and the reaction time was 7h. The mixture was reacted to obtain the modified polybutylene succinate.

[0068] S2. 28 parts by weight of maifanite, 22 parts by weight of calcium hydroxide, and 260 parts by weight of glycerol were placed in a 3.2 kW reactor. The reaction temperature was 80℃, the reaction rate was 380 r / min, and the reaction time was 1.8 h. The mixture was mixed and reacted to carry out the modification, and the modified maifanite was obtained.

[0069] S3. The modified maifanite prepared in S2, the modified polybutylene succinate prepared in S1, and 380 parts of dichloromethane were placed in a 1.6 kW stirring tank. The stirring temperature was 75℃, the stirring time was 1.5 h, and the stirring speed was 500 r / min. After stirring and mixing, the mixture was filtered with sterile gauze, washed three times with anhydrous ethanol, and then dried in a 2.2 kW oven at 60℃ for 35 min to obtain the composite.

[0070] S4. Place 17 parts by weight of *Ipomoea purpurea*, 22 parts by weight of *Senecio scandens*, and 37 parts by weight of *Vegetariana* into a 1.7 kW pulverizer. Pulverize at 26°C for 18 min at a speed of 4000 r / min. After pulverization, place the pulverizer into a 2.2 kW grinder. Grind at 33°C for 20 min at a speed of 19000 r / min to obtain a viscous slurry.

[0071] S5. The composite prepared in S3 was placed in a vacuum freeze-spray dryer with a power of 2.6 kW, a vacuum degree of -0.05 MPa, a freeze-spray drying temperature of -40℃, a freeze-spray drying particle size of 100 nm, and a freeze-spray drying time of 2.8 h to obtain composite nanoparticles.

[0072] S6. The composite nanoparticles prepared in S5, the viscous slurry prepared in S4, 9 parts of ferric hydroxide, and 7 parts of sodium percarbonate are placed in a mixing tank with a power of 1.6 kW. The mixing temperature is 35℃, the mixing time is 32 min, and the mixing speed is 300 r / min. The mixture is mixed evenly to obtain a viscous soil conditioner.

[0073] In step two, the preparation method of the selenium absorption-promoting compound fertilizer specifically includes the following steps:

[0074] L1. Place 32 parts by weight of wild pea, 38 parts of fodder and 34 parts of ryegrass into a 1.5 kW pulverizer, pulverize at 23℃ for 15 min at 3500 r / min to obtain a base fertilizer mixture.

[0075] L2. 1.3 parts by weight of mixed bacterial agent were inoculated into 5% sterile glucose solution and placed in a constant temperature shaking incubator with a power of 2.2 kW. The constant temperature shaking incubation temperature was 25℃, the constant temperature shaking incubation time was 24 h, and the constant temperature shaking incubation speed was 210 r / min. After constant temperature shaking incubation, it was placed with the base fertilizer mixture prepared in L1 into an enzymatic hydrolysis tank with a power of 2.1 kW. The enzymatic hydrolysis temperature was 30℃, the enzymatic hydrolysis time was 2 d, and the enzymatic hydrolysis speed was 80 r / min. After enzymatic hydrolysis and fermentation, a composition that promotes plant absorption of selenium was obtained.

[0076] L3. The plant-absorbing selenium-promoting composition prepared in L2 was mixed with 4.3 parts calcium selenate, 7.1 parts selenomethionine, 10.4 parts sodium selenite, and 21 parts pig manure in a 1.6 kW mixing tank. The mixing temperature was 35℃, the mixing time was 42 min, and the mixing speed was 500 r / min to obtain the selenium-absorbing compound fertilizer.

[0077] In L2, the mixed bacterial agent consists of *Bacillus spheroides*, *Serratia demersum*, and *Pseudomonas putida*, with a weight ratio of 1.2:0.9:1. The *Bacillus spheroides* was purchased from the China General Microbiological Culture Collection Center (CGMCC) under accession number CGMCC1.8369; the *Serratia demersum* under accession number CGMCC1.1857; and the *Pseudomonas putida* under accession number CGMCC1.8829. The inoculum size of the mixed bacterial agent in 5% sterile glucose solution is 1%.

[0078] Example 3: This example provides a method for cultivating selenium-rich oolong tea, specifically including the following steps:

[0079] Step 1: Soil conditioning before planting: Select a gentle slope of brown soil with a slope of less than 15 degrees. Use a clay soil conditioner to condition the brown soil on the gentle slope. The application rate is 90 kg / mu. After application, till the soil evenly and let it sit naturally for 13 days to obtain the conditioned soil.

[0080] Step 2, meticulous cultivation: Apply the selenium-enriching compound fertilizer to the soil prepared in Step 1 at a rate of 100 kg / mu, till it evenly, harrow and level the land, and let it remain naturally for 7 days to obtain a selenium-rich soil matrix.

[0081] Step 3: Hydroponic tea seedling cultivation: Immerse 30 cm tall oolong tea seedlings in hydroponic nutrient solution and cultivate them at 28℃ for 20 days to obtain robust oolong tea seedlings.

[0082] Step 4, Tea seedling planting: Plant the robust oolong tea seedlings obtained in Step 3 into planting holes with a depth of 10 cm and a diameter of 30 cm, with a plant spacing of 40 cm and a row spacing of 1.5 m. The robust oolong tea seedlings are then planted into the selenium-rich soil substrate obtained in Step 2 to obtain the planted oolong tea seedlings.

[0083] Step 5, Water and Fertilizer Management: Water, fertilize, and spray pesticides on the oolong tea seedlings after planting in Step 4. After 3 years of planting, selenium-rich oolong tea will be obtained.

[0084] In step three, the hydroponic nutrient solution is prepared by mixing 1.2 parts by weight of ammonium chloride, 1.3 parts by weight of sodium nitrophenolate, 0.8 parts by weight of calcium nitrate, 1.3 parts by weight of magnesium nitrate, 0.9 parts by weight of zinc chloride, 0.8 parts by weight of potassium acetate, 0.7 parts by weight of 5-aminolevulinic acid, and 500 parts by weight of ultrapure water in a mixing tank with a power of 1.8 kW, a mixing temperature of 33°C, a mixing time of 26 min, and a mixing speed of 500 r / min.

[0085] In step five, the water and fertilizer management is as follows: During the first month of growth of the oolong tea seedlings after planting, water once a day, and then once a week thereafter. Each irrigation should bring the soil moisture content to 80%. After planting, apply a compound fertilizer that promotes selenium absorption every two months at a rate of 50 kg / mu.

[0086] In step one, the preparation method of the cohesive soil conditioner specifically includes the following steps:

[0087] S1. 12 parts by weight of sodium tert-butoxide, 17 parts by weight of polybutylene succinate, 100 parts by weight of tetrahydrofuran, and 110 parts by weight of chloroform were placed in a 3.5 kW reactor. The reaction temperature was 100℃, the reaction rate was 600 r / min, and the reaction time was 8h. The mixture was reacted to obtain the modified polybutylene succinate.

[0088] S2. 30 parts by weight of maifanite, 26 parts by weight of calcium hydroxide, and 300 parts by weight of glycerol were placed in a 3.5 kW reactor. The reaction temperature was 85℃, the reaction rate was 400 r / min, and the reaction time was 2 h. The mixture was mixed and reacted to carry out the modification, and the modified maifanite was obtained.

[0089] S3. The modified maifanite prepared in S2, the modified polybutylene succinate prepared in S1, and 400 parts of dichloromethane were placed in a stirring tank with a power of 1.8 kW. The stirring temperature was 75℃, the stirring time was 2 h, and the stirring speed was 600 r / min. After stirring and mixing, the mixture was filtered with sterile gauze, washed three times with anhydrous ethanol, and then dried in an oven with a power of 2.2 kW at a temperature of 60℃ for 40 min to obtain the composite.

[0090] S4. Place 19 parts by weight of *Ipomoea aquatica*, 23 parts by weight of *Senecio scandens*, and 38 parts by weight of *Vegetariana* into a 1.8 kW pulverizer. Pulverize at 28°C for 20 min at a speed of 4500 r / min. After pulverization, place the pulverizer into a 2.4 kW grinder. Grind at 36°C for 25 min at a speed of 20000 r / min to obtain a viscous slurry.

[0091] S5. The composite prepared in S3 was placed in a vacuum freeze-spray dryer with a power of 2.8 kW, a vacuum degree of -0.05 MPa, a freeze-spray drying temperature of -40℃, a freeze-spray drying particle size of 100 nm, and a freeze-spray drying time of 3 h to obtain composite nanoparticles.

[0092] S6. The composite nanoparticles prepared in S5, the viscous slurry prepared in S4, 11 parts of ferric hydroxide, and 9 parts of sodium percarbonate are placed in a mixing tank with a power of 1.8 kW. The mixing temperature is 36℃, the mixing time is 40 min, and the mixing speed is 400 r / min. The mixture is mixed evenly to obtain a viscous soil conditioner.

[0093] In step two, the preparation method of the selenium absorption-promoting compound fertilizer specifically includes the following steps:

[0094] L1. Place 34 parts by weight of wild pea, 42 parts of fodder and 37 parts of ryegrass into a 1.5 kW pulverizer, pulverize at 23℃ for 15 min at 3500 r / min to obtain a base fertilizer mixture.

[0095] L2. 1.4 parts by weight of mixed bacterial agent were inoculated into 5% sterile glucose solution and placed in a 2.2 kW constant temperature shaking incubator. The constant temperature shaking incubation temperature was 25℃, the constant temperature shaking incubation time was 24 h, and the constant temperature shaking incubation speed was 210 r / min. After constant temperature shaking incubation, it was placed with the base fertilizer mixture prepared in L1 into an enzymatic hydrolysis tank with a power of 2.2 kW. The enzymatic hydrolysis temperature was 30℃, the enzymatic hydrolysis time was 3 days, and the enzymatic hydrolysis speed was 90 r / min. After enzymatic hydrolysis and fermentation, a composition that promotes plant absorption of selenium was obtained.

[0096] L3. The plant-enhancing selenium absorption composition prepared in L2 was mixed with 5.3 parts calcium selenate, 7.4 parts selenomethionine, 11.8 parts sodium selenite, and 23 parts pig manure in a 1.8 kW mixing tank. The mixing temperature was 36℃, the mixing time was 46 min, and the mixing speed was 600 r / min to obtain the selenium-enhancing compound fertilizer.

[0097] In L2, the mixed bacterial agent consists of *Bacillus spheroides*, *Serratia demersum*, and *Pseudomonas putida*, with a weight ratio of 1.2:0.9:1. The *Bacillus spheroides* was purchased from the China General Microbiological Culture Collection Center (CGMCC) under accession number CGMCC1.8369; the *Serratia demersum* under accession number CGMCC1.1857; and the *Pseudomonas putida* under accession number CGMCC1.8829. The inoculum size of the mixed bacterial agent in 5% sterile glucose solution is 1%.

[0098] Comparative Example 1: This comparative example provides a method for cultivating oolong tea. The only difference from Example 1 is that the added clay soil conditioner does not contain complex nanoparticles. The other components, component contents, and method steps are the same as in Example 1.

[0099] Comparative Example 2: This comparative example provides a method for cultivating oolong tea. The only difference from Example 1 is that the added selenium-enhancing composition does not undergo fermentation with mixed microbial agents. The other components, component contents, and method steps are the same as in Example 1.

[0100] Experimental Example 1: Yield Measurement Experiment of Oolong Tea.

[0101] The method for cultivating selenium-enriched oolong tea described in Examples 1-3 of this invention includes the following experimental steps for determining the yield of the cultivated oolong tea:

[0102] (1) Six mu of brown soil experimental tea field with a slope of less than 15 degrees was opened for testing. It was divided into three 3 mu of example group, two 2 mu of comparative group and one 1 mu of control group. Oolong tea was planted according to the planting method of selenium-rich oolong tea described in Examples 1-3, the planting method of oolong tea described in Comparative Examples 1-2 and the traditional planting method of oolong tea used in the control group.

[0103] (2) Using the planting methods of selenium-rich oolong tea described in Examples 1-3, the planting methods of oolong tea described in Comparative Examples 1-2, and the planting methods of traditional oolong tea used in the control group, oolong tea was planted for 3 years. After that, the oolong tea was harvested and the yield of oolong tea in 3 mu of the Example Group, 2 mu of the Comparative Group, and 1 mu of the Control Group was weighed and recorded.

[0104] Results analysis:

[0105] Figure 1 The image shows a scanning electron microscope (SEM) image of the internal structure of the composite nanoparticles described in this invention. Figure 2 The figure shows the yield results of oolong tea described in Experiment 1 of this invention. Following the planting methods of selenium-enriched oolong tea described in Examples 1-3, the planting methods of oolong tea described in Comparative Examples 1-2, and the planting method of traditional oolong tea in the control group, oolong tea was planted for 3 years before harvesting. The oolong tea yields in the tea fields of Examples 1-3 were 113 kg / mu, 116 kg / mu, and 124 kg / mu, respectively; the oolong tea yields in the tea fields of Comparative Examples 1-2 were 103 kg / mu and 92 kg / mu, respectively; and the oolong tea yield in the control group was 61 kg / mu. This demonstrates that the planting method of selenium-enriched oolong tea described in this invention promotes rapid growth of oolong tea seedlings, has strong root absorption capacity, and is simple and efficient, making it suitable for large-scale cultivation.

[0106] Experimental Example 2: Determination of selenium content in oolong tea leaves.

[0107] The method for cultivating selenium-enriched oolong tea described in Examples 1-3 of this invention includes the following experimental steps for determining the selenium content in the cultivated oolong tea leaves:

[0108] (1) Six mu of brown soil experimental tea field with a slope of less than 15 degrees was opened for testing. It was divided into three 3 mu of example group, two 2 mu of comparative group and one 1 mu of control group. Oolong tea was planted according to the planting method of selenium-rich oolong tea described in Examples 1-3, the planting method of oolong tea described in Comparative Examples 1-2 and the traditional planting method of oolong tea used in the control group.

[0109] (2) Using the planting methods of selenium-enriched oolong tea described in Examples 1-3, the planting methods of oolong tea described in Comparative Examples 1-2, and the planting methods of traditional oolong tea used in the control group, oolong tea was planted for 3 years. After that, the oolong tea was harvested. Soil samples and oolong tea samples were collected from 3 mu of oolong tea fields in the Example group, 2 mu of comparative example group, and 1 mu of control group. The selenium content in the oolong tea leaves, the total selenium content in the soil of the oolong tea field, and the available selenium content in the soil of the oolong tea field were measured in each mu of tea field. The selenium activation rate in the soil of the oolong tea field was calculated according to the formula: soil selenium activation rate = available selenium content in soil / total selenium content in soil × 100%.

[0110] Results analysis:

[0111] Figure 6 This is a growth diagram of oolong tea in the experimental field of Example 1 of the present invention. Figure 3 The figure shows the results of selenium content in the oolong tea leaves described in Experimental Example 2 of this invention. Following the planting methods for selenium-enriched oolong tea described in Examples 1-3, the planting methods for oolong tea described in Comparative Examples 1-2, and the planting method for traditional oolong tea in the control group, oolong tea was planted for 3 years before harvesting. The selenium content of the oolong tea leaves in the tea fields of Examples 1-3 was 3.47 mg / kg, 3.66 mg / kg, and 3.87 mg / kg, respectively; the selenium content of the oolong tea leaves in the tea fields of Comparative Examples 1-2 was 1.93 mg / kg and 2.53 mg / kg, respectively; and the selenium content of the oolong tea leaves in the control group was 1.2 mg / kg. Figure 4 This is a graph showing the results of the available selenium content in the soil of the oolong tea plantation described in Experimental Example 2 of this invention. Figure 5The figure shows the results of selenium activation rate in the soil of the oolong tea field described in Experimental Example 2 of this invention. Following the planting methods for selenium-enriched oolong tea described in Examples 1-3, the planting methods for oolong tea described in Comparative Examples 1-2, and the planting method for traditional oolong tea in the control group, soil samples were collected from the oolong tea fields after 3 years of planting. The available selenium content in the soil of the oolong tea fields in Examples 1-3 was 0.062 mg / kg, 0.066 mg / kg, and 0.07 mg / kg, respectively, with selenium activation rates of 50.35%, 52.26%, and 54.44%, respectively. The available selenium content in the soil of the oolong tea fields in Comparative Examples 1-2 was 0.03 mg / kg and 0.043 mg / kg, respectively, with selenium activation rates of 37.98% and 43.02%, respectively. The available selenium content in the soil of the control group was 0.0096 mg / kg. The selenium activation rate in the soil of the control group oolong tea field was 6.44% (mg / kg), indicating that the planting method of selenium-enriched oolong tea described in this invention promotes the conversion of the selenium content in the soil in the bound and residual iron-manganese oxide state into the water-soluble and exchangeable selenium state, maintaining the activity of selenium in the soil for a long time, and the oolong tea planted is rich in selenium.

[0112] Experimental Example 3: Quality determination of selenium-enriched oolong tea.

[0113] The cultivation method for selenium-enriched oolong tea described in Examples 1-3 of this invention includes the following quality testing steps for the cultivated selenium-enriched oolong tea:

[0114] (1) Six mu of brown soil experimental tea field with a slope of less than 15 degrees was opened for testing. It was divided into three 3 mu of example group, two 2 mu of comparative group and one 1 mu of control group. Oolong tea was planted according to the planting method of selenium-rich oolong tea described in Examples 1-3, the planting method of oolong tea described in Comparative Examples 1-2 and the traditional planting method of oolong tea used in the control group.

[0115] (2) Using the planting methods of selenium-enriched oolong tea described in Examples 1-3, the planting methods of oolong tea described in Comparative Examples 1-2, and the planting methods of traditional oolong tea used in the control group, the oolong tea was planted for 3 years and then harvested. The oolong tea was dried in a dryer at a temperature of 110°C until the moisture content of each group was less than 5%. The amino acid content and selenium content were tested and sensory evaluation was performed. The results were recorded.

[0116] Table 1. Oolong Tea Quality Measurement Table

[0117]

[0118] Results analysis:

[0119] As shown in Table 1, the amino acid and selenium content of the dried oolong tea in Examples 1-3 and Comparative Example 2 was higher than that in the dried oolong tea of ​​the control group. Furthermore, the appearance, liquor color, aroma, taste, and leaf residue of Examples 1-3 and Comparative Example 1-2 were all stable and of high quality. This indicates that the tea trees planted by the selenium-enriched oolong tea planting method described in this invention are in good growth condition, the oolong tea leaves are rich in selenium, and the quality after processing can remain stable.

[0120] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0121] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention. The actual application is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A method for cultivating selenium-enriched oolong tea, characterized in that, Specifically, the steps include the following: Step 1: Soil conditioning before planting: Select a gentle slope of brown soil with a slope of less than 15 degrees. Use a clay soil conditioner to condition the brown soil on the gentle slope. The application rate is 70-90 kg / mu. After application, till the soil evenly and let it sit naturally for 8-13 days to obtain the conditioned soil. Step 2, meticulous cultivation: Apply the selenium-enriching compound fertilizer to the soil prepared in Step 1 at a rate of 80-100 kg / mu, till it evenly, harrow and level the land, and let it remain naturally for 4-7 days to obtain a selenium-rich soil matrix. Step 3: Hydroponic tea seedlings: Soak oolong tea seedlings with a height of 25-30 cm in hydroponic nutrient solution and cultivate them at a temperature of 28℃ for 15-20 days to obtain strong oolong tea seedlings. Step 4, Tea seedling planting: Plant the robust oolong tea seedlings obtained in Step 3 into planting holes with a depth of 5-10 cm and a diameter of 30 cm, with a plant spacing of 40 cm and a row spacing of 1.5 m. The robust oolong tea seedlings are then planted into the selenium-rich soil substrate obtained in Step 2 to obtain the planted oolong tea seedlings. Step 5, Water and Fertilizer Management: Water, fertilize, and spray pesticides on the oolong tea seedlings after planting in Step 4. After 3 years of planting, selenium-rich oolong tea will be obtained. In step one, the preparation method of the cohesive soil conditioner specifically includes the following steps: S1. Mix 10-12 parts by weight of sodium tert-butoxide, 13-17 parts by weight of polybutylene succinate, 80-100 parts by weight of tetrahydrofuran, and 100-110 parts by weight of chloroform to obtain modified polybutylene succinate. S2. Mix 25-30 parts by weight of maifanite with 18-26 parts by weight of calcium hydroxide and 200-300 parts by weight of glycerol, and react to modify the maifanite to obtain modified maifanite. S3. Mix the modified maifanite prepared in S2, the modified polybutylene succinate prepared in S1, and 350-400 parts of dichloromethane. Filter the mixture using sterile gauze, wash it 2-3 times with anhydrous ethanol, and then dry it to obtain the composite. S4. Take 15-19 parts by weight of woad, 21-23 parts of sesame, and 36-38 parts of vetiver, crush them, and grind them into a viscous slurry. S5. After freeze-spray drying the composite prepared in S3, mix it evenly with the viscous slurry prepared in S4, 7-11 parts of ferric hydroxide, and 6-9 parts of sodium percarbonate to obtain a viscous soil conditioner. In step two, the preparation method of the selenium absorption-promoting compound fertilizer specifically includes the following steps: L1. Crush 26-34 parts by weight of wild pea, 35-42 parts of fodder, and 31-37 parts of ryegrass to obtain a base fertilizer mixture. L2. Inoculate 1.2-1.4 parts by weight of mixed bacterial agent into 5% sterile glucose solution, and after constant temperature shaking culture, mix with the base fertilizer mixture prepared by L1, and then enzymatically hydrolyze and ferment to obtain a composition that promotes plant absorption of selenium. L3. The plant-absorbing selenium-promoting composition prepared in L2 is mixed with 3.4-5.3 parts of calcium selenate, 6.8-7.4 parts of selenomethionine, 9.6-11.8 parts of sodium selenite, and 18-23 parts of pig manure to obtain a selenium-absorbing compound fertilizer. In L2, the mixed bacterial agent consists of Bacillus spheroidans, Serratia decoloris, and Pseudomonas putida, with a weight ratio of 1.2:0.9:1, and the inoculum amount of the mixed bacterial agent in 5% sterile glucose solution is 1%.

2. The method for cultivating selenium-enriched oolong tea according to claim 1, characterized in that, In step three, the hydroponic nutrient solution is prepared by mixing 1-1.2 parts by weight of ammonium chloride, 0.8-1.3 parts by weight of sodium nitrophenolate, 0.6-0.8 parts by weight of calcium nitrate, 1.1-1.3 parts by weight of magnesium nitrate, 0.6-0.9 parts by weight of zinc chloride, 0.4-0.8 parts by weight of potassium acetate, 0.3-0.7 parts by weight of 5-aminolevulinic acid, and 400-500 parts by weight of ultrapure water.

3. The method for cultivating selenium-enriched oolong tea according to claim 2, characterized in that, In step five, the water and fertilizer management is as follows: During the first month of growth of the oolong tea seedlings after planting, water once a day, and then once a week thereafter. Each irrigation should bring the soil moisture content to 80%. After planting, apply a compound fertilizer that promotes selenium absorption every two months, with an application rate of 30-50 kg / mu.

Images