Planting method of selenium-rich oolong tea

Abstract

The invention belongs to the field of oolong tea planting, and particularly relates to a planting method of selenium-enriched oolong tea. Sodium tert-butoxide and degradable poly (butylene succinate) are mixed for reaction, the modified poly (butylene succinate) and calcium hydroxide modified medical stone are subjected to hydrogen bond interaction, freeze spray drying and mixing of viscous slurry, iron oxide hydroxide and sodium percarbonate are performed, and the obtained viscous soil conditioner efficiently and continuously adjusts the pH value of soil. A base fertilizer mixture is subjected to sufficient enzymolysis through a mixed microbial agent and mixed with calcium selenate, selenomethionine, sodium selenite and pig manure, and the obtained selenium absorption promoting compound fertilizer promotes selenium absorption of oolong tea; the oolong strong seedlings soaked in the hydroponic nutrient solution are planted in the soil which is conditioned by the viscous soil conditioner and contains the selenium absorption promoting compound fertilizer, the planted oolong is rich in selenium element and stable in quality, the planting method is simple and efficient, and large-scale popularization and planting can be achieved.

Description

Technical Field

[0001] The invention belongs to the field of oolong tea planting, and specifically relates to a planting method for selenium-enriched oolong tea. Background Art

[0002] Oolong tea, also known as green tea or semi-fermented tea, is a unique tea category among the major tea categories in China. It is made from new shoots of Camellia sinensis tea trees of suitable maturity, and is processed through reasonable main processing techniques such as withering, shaking and cooling, killing, shaping, and drying to produce suitable drinking tea. Oolong tea has many health benefits, such as decomposing fat, reducing weight and keeping fit, refreshing the mind, and anti-oxidation. Long-term drinking of oolong tea can improve physical health and prevent many diseases.

[0003] The cultivation of oolong tea refers to the cultivation and management of tea trees through scientific cultivation techniques under specific ecological environment and soil conditions to obtain high-quality fresh tea leaves, and then produce high-quality oolong tea. The cultivation process of oolong tea includes multiple links such as site selection, selection of tea tree varieties, planting, tea garden management, and picking. Oolong tea is usually planted in mountainous or semi-mountainous areas with rich vegetation. Through scientific tea garden management, the soil can be protected, soil erosion can be prevented, and ecological balance can be maintained. The improvement of the ecological environment of tea gardens provides habitats for a variety of organisms and promotes the development of biodiversity. Oolong tea cultivation is the main source of income for farmers in many tea-growing areas. Through scientific planting and management, the yield and quality of oolong tea can be improved, which can significantly increase farmers' income.

[0004] At present, the existing oolong tea planting methods have the following problems: First, the planting of selenium-rich oolong tea has clear requirements on the selenium content of the soil, which makes the planting area of ​​selenium-rich oolong tea subject to great restrictions and difficult to promote on a large scale; Second, the existing planting technology cannot increase the selenium content in tea leaves, and may also cause selenium pollution in the soil, affecting the growth of tea trees and the quality of tea leaves, and even having adverse effects on the surrounding environment; Third, the existing planting operation of selenium-rich oolong tea is complicated. Improper operation in any link may lead to poor growth of tea trees and unstable quality of the selenium-rich oolong tea grown. Summary of the invention

[0005] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a method for planting selenium-rich oolong tea. In order to solve the problems that the existing oolong tea planting method is difficult to promote on a large scale, cannot increase the selenium content in tea leaves, and the quality of the selenium-rich oolong tea grown is unstable, the present invention uses hydroponic nutrient solution to treat oolong tea seedlings, sticky soil conditioner to condition the soil, and selenium-absorbing compound fertilizer to apply. The selenium-rich oolong tea planting method adopted is simple to operate, can be planted on a large scale, effectively improves the selenium content in oolong tea, and the quality of the selenium-rich oolong tea grown is stable.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows: the present invention proposes a method for growing selenium-enriched oolong tea, which specifically comprises the following steps: Step 1: Soil conditioning before planting: Select brown soil on a gentle slope 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 amount is 70-90 kg / mu. After application, till the soil evenly and keep it naturally for 8-13 days to obtain the conditioned soil. Step 2: intensive cultivation: apply the selenium absorption-promoting compound fertilizer to the conditioned soil prepared in step 1 at an application rate of 80-100 kg / mu, till the soil evenly, harrow and level the land, and maintain the soil naturally for 4-7 days to obtain a selenium-rich soil matrix; Step 3, hydroponic tea seedlings: immerse oolong tea seedlings with a plant height of 25-30 cm in a hydroponic nutrient solution, cultivate them at a temperature of 28°C for 15-20 days, and obtain strong oolong tea seedlings; Step 4, planting tea seedlings: dig planting holes with a depth of 5-10 cm and a diameter of 30 cm for the oolong tea seedlings obtained in step 3 according to the specifications of 40 cm spacing between plants and 1.5 m spacing between rows, and implant the oolong tea seedlings into the selenium-rich soil matrix obtained in step 2 to obtain planted oolong tea seedlings; Step 5. Water and fertilizer management: water, fertilize, spray and manage the oolong tea seedlings after planting in step 4. After 3 years of planting, you can get selenium-rich oolong tea.

[0007] 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 of sodium nitrophenolate, 0.6-0.8 parts of calcium nitrate, 1.1-1.3 parts of magnesium nitrate, 0.6-0.9 parts of zinc chloride, 0.4-0.8 parts of potassium acetate, 0.3-0.7 parts of 5-aminolevulinic acid, and 400-500 parts of ultrapure water in a stirring tank with a power of 1.5-1.8 kW, at a stirring temperature of 28-33° C., a stirring time of 20-26 min, and a stirring speed of 500 r / min, and stirring and mixing.

[0008] Preferably, in step five, the water and fertilizer management: water the oolong tea seedlings once a day within the first month of growth after transplanting, and then water them once a week. The amount of irrigation each time should make the soil moisture content reach 80%. After transplanting, apply compound fertilizer that promotes selenium absorption every 2 months, and the application amount is 30-50 kg / mu.

[0009] Preferably, in step 1, the method for preparing the clay soil conditioner specifically comprises the following steps: S1, putting 10-12 parts by weight of sodium tert-butoxide, 13-17 parts of polybutylene succinate, 80-100 parts of tetrahydrofuran, and 100-110 parts of chloroform into a reactor with a power of 2.4-3.5 kW, the reaction temperature is 100° C., the reaction speed is 300-600 r / min, the reaction time is 6-8 h, and the mixture is reacted to obtain modified polybutylene succinate; S2, 25-30 parts by weight of medical stone, 18-26 parts of calcium hydroxide, and 200-300 parts of glycerol are placed in a reactor with a power of 2.4-3.5 kW, the reaction temperature is 75-85°C, the reaction speed is 300-400 r / min, the reaction time is 1.5-2 h, mixed reaction is carried out, and modified to obtain modified medical stone; S3, putting the modified medical stone prepared by S2, the modified polybutylene succinate prepared by S1, and 350-400 parts of dichloromethane into a stirring tank with a power of 1.5-1.8 kW, stirring at a temperature of 75°C, stirring for 1-2 h, stirring at a speed of 400-600 r / min, stirring and mixing, filtering with sterile gauze, washing with anhydrous ethanol 2-3 times, and drying in an oven with a power of 2.2 kW at a temperature of 60°C for 30-40 min to obtain a composite; S4, putting 15-19 parts of scutellaria baicalensis, 21-23 parts of sesbania odorifera and 36-38 parts of vetiver grass into a 1.5-1.8 kW grinder at a grinding temperature of 23-28°C, a grinding time of 15-20 min, and a grinding speed of 3500-4500 r / min, and then putting them into a 1.8-2.4 kW refiner at a grinding temperature of 30-36°C, a grinding time of 15-25 min, and a grinding speed of 18000-20000 r / min to obtain a viscous slurry; S5, placing the composite prepared in S3 into a vacuum freeze-nano spray dryer with a power of 2.3-2.8 kW, a vacuum degree of -0.05 MPa, a freeze-nano spray drying temperature of -40°C, a freeze-nano spray drying particle size of 100 nm, and a freeze-nano spray drying time of 2.5-3 h, and performing freeze-spray drying to obtain composite nanoparticles; S6. Put the composite nanoparticles prepared by S5, the viscous slurry prepared by S4, 7-11 parts of ferric hydroxide, and 6-9 parts of sodium percarbonate into a stirring tank with a power of 1.5-1.8 kW, stir at a temperature of 30-36°C, stir for 30-40 min, and stir at a speed of 300-400 r / min, mix well, and obtain a viscous soil conditioner.

[0010] Preferably, in step 2, the method for preparing the compound fertilizer promoting selenium absorption specifically comprises the following steps: L1, put 26-34 parts by weight of vetch, 35-42 parts of hair grass, and 31-37 parts of ryegrass into a 1.5 kW grinder, the grinding temperature is 23° C., the grinding time is 15 min, the grinding speed is 3500 r / min, and the basal fertilizer mixture is obtained; L2, inoculate 1.2-1.4 parts by weight of the mixed bacterial agent into a 5% sterile glucose solution, put it into a constant temperature shaking incubator with a power of 2.2 kW, the constant temperature shaking culture temperature is 25°C, the constant temperature shaking culture time is 24 h, the constant temperature shaking culture speed is 210 r / min, after the constant temperature shaking culture, put it into an enzymolysis tank with a power of 1.6-2.2 kW, the enzymolysis temperature is 30°C, the enzymolysis time is 2-3 d, the enzymolysis speed is 70-90 r / min, and after enzymolysis and fermentation, obtain a composition for promoting plant absorption of selenium; L3. Put the composition for promoting plant absorption of selenium prepared in L2 into a stirring tank with a power of 1.5-1.8 kW, with a stirring temperature of 33-36°C, a stirring time of 38-46 min, and a stirring speed of 400-600 r / min, and mix them to obtain a compound fertilizer for promoting selenium absorption.

[0011] Further, in L2, the mixed bacterial agent is composed of spherical lysine Bacillus, discolored Serratia, and Pseudomonas putida, with a weight ratio of 1.2:0.9:1. The spherical lysine Bacillus was purchased from the China General Microbiological Culture Collection Administration Center with a preservation number of CGMCC1.8369, the discolored Serratia was purchased from the China General Microbiological Culture Collection Administration Center with a preservation number of CGMCC1.1857, and the Pseudomonas putida was purchased from the China General Microbiological Culture Collection Administration Center with a preservation number of CGMCC1.8829. The inoculation amount of the mixed bacterial agent in a 5% sterile glucose solution is 1%.

[0012] The beneficial effects achieved by the present invention are as follows: The invention adopts sodium tert-butoxide and degradable polybutylene succinate to react with each other. Sodium tert-butoxide introduces tert-butoxy groups on the surface of polybutylene succinate, which can be chemically bonded with acidic groups in acidic compounds in soil to form stable chemical bonds. The modified polybutylene succinate has a higher specific surface area and more pore structures, forms adsorption, neutralizes soil acidity, and increases soil pH. A higher pH is conducive to the dissolution and movement of selenium, increases the biological effectiveness of selenium, and enables plants to more effectively absorb selenium in the soil. Calcium hydroxide reacts with medical stone. The modified medical stone has a larger specific surface area and provides more adsorption space for the adsorbed compounds. After being applied to the soil, it can provide a rich calcium source, increase the content of effective calcium in the soil, and combine with heavy metal ions in the soil to form insoluble calcium metal compounds, avoid competitive absorption of heavy metals and selenium, and improve the air permeability and water permeability of the soil. The blue cabbage, sesbania and vetiver are crushed and pulverized to obtain a viscous slurry and the soil The clay minerals have a large specific surface area and rich surface active sites, which can adsorb selenium in the soil and increase the concentration of selenium in the soil. Ferric hydroxide forms a stable complex with selenium in the soil to fix selenium and prevent its loss. Sodium percarbonate decomposes in water to produce hydrogen peroxide and sodium carbonate, which can oxidize the sparingly soluble selenium in the soil into soluble selenium, thereby improving the solubility and bioavailability of selenium. The modified medical stone and the modified polybutylene succinate interact through hydrogen bonds to form stable chemical bonds. After freeze spray drying, the obtained composite nanoparticles are mixed with viscous slurry, ferric hydroxide and sodium percarbonate. The prepared viscous soil conditioner can efficiently and continuously adjust the soil pH value, improve soil permeability, enhance plant root growth, improve the bioavailability of selenium, prevent the loss of selenium in the soil, and promote the enrichment of selenium by plants.After crushing the large-flowered wild pea, hair grass and ryegrass, a base fertilizer mixture rich in nitrogen, phosphorus, potassium, magnesium, zinc, boron, various amino acids, minerals and vitamins is obtained. After being enzymatically hydrolyzed by a mixed bacterial agent containing spherical lysine Bacillus, discolored Serratia and Pseudomonas putida, the nutrients are fully released. During the fermentation process, the mixed bacterial agent can produce antibiotics, increase the content of fast-acting nitrogen in the soil, facilitate the absorption and utilization by plant roots, reduce the damage of pathogens to plant roots, thereby promoting plant growth, creating a more favorable environment for the growth and absorption of plant roots, enriching the microbial community structure in the soil, and promoting the interaction and synergistic effect between microorganisms. The mixed bacterial agent can also convert inorganic selenium into organic selenium, improve the biological effectiveness of selenium, and can also change the form distribution of selenium in the soil through metabolic activities, and convert insoluble selenium forms, such as iron-manganese bound selenium, into soluble selenium forms, such as Water-soluble selenium and exchangeable selenium make the distribution of effective selenium in the soil more uniform, increase the contact opportunities between plant roots and selenium, and thus improve the absorption efficiency of selenium by plants. The selenium-promoting plant absorption composition is mixed with calcium selenate, selenomethionine, sodium selenite, and animal feces. The obtained selenium-promoting compound fertilizer provides rich nutrition for the growth of oolong tea, increases the content of effective selenium, and cooperates with the sticky soil conditioner to promote the absorption of selenium by oolong tea. The hydroponic nutrient solution can quickly penetrate the plant body, promote cell division and growth, improve the photosynthetic efficiency and respiratory intensity of the seedlings, and help the healthy growth of oolong tea seedlings, thereby creating a good physiological basis for the absorption and utilization of non-metallic elements. The oolong tea seedlings soaked in the hydroponic nutrient solution are planted in the soil conditioned by the sticky soil conditioner and containing the selenium-promoting compound fertilizer. The planted oolong tea is rich in selenium and has stable quality. The planting method is simple and efficient, and can be promoted on a large scale. ; BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the present invention or the technical solutions in the prior art, the following will be described in a clear and understandable manner in conjunction with the accompanying drawings. Obviously, the drawings described below are only for the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 This is a scanning electron microscope image of the internal structure of the composite nanoparticles of the present invention; Figure 2 This is a graph showing the yield of oolong tea described in Experimental Example 1 of the present invention; Figure 3 This is a graph showing the selenium content of oolong tea leaves described in Experimental Example 2 of the present invention; Figure 4 This is a result diagram of the effective selenium content in the soil of the oolong tea field described in Experimental Example 2 of the present invention; Figure 5This is a result diagram of selenium activation rate in the soil of the oolong tea field described in Experimental Example 2 of the present invention; Figure 6 This is a growth diagram of oolong tea in the experimental field of Example 1 of the present invention. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments; based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0016] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein may be applied to the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only and are not intended to limit the content of this application.

[0017] The experimental methods in the following examples are conventional methods unless otherwise specified; the experimental materials and test strains used in the following examples are purchased from commercial channels unless otherwise specified.

[0018] Embodiment 1: This embodiment provides a method for growing selenium-enriched oolong tea, which specifically comprises the following steps: Step 1: Soil conditioning before planting: Select brown soil on a gentle slope 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 amount is 70 kg / mu. After application, plow the soil evenly and keep it naturally for 8 days to obtain the conditioned soil. Step 2: Intensive cultivation: Apply the selenium absorption-promoting compound fertilizer to the conditioned soil prepared in step 1 at an application rate of 80 kg / mu, till the soil evenly, harrow and level the land, and maintain the soil naturally for 4 days to obtain a selenium-rich soil matrix; Step 3, hydroponic tea seedlings: immerse oolong tea seedlings with a plant height of 25 cm in a hydroponic nutrient solution, cultivate them at a temperature of 28°C for 15 days, and obtain strong oolong tea seedlings; Step 4, planting tea seedlings: dig planting holes with a depth of 5 cm and a diameter of 30 cm for the oolong tea seedlings obtained in step 3 according to the specifications of 40 cm plant spacing and 1.5 m row spacing, and implant the oolong tea seedlings into the selenium-rich soil matrix obtained in step 2 to obtain planted oolong tea seedlings; Step 5. Water and fertilizer management: After planting in step 4, water the oolong tea seedlings, fertilize, spray pesticides, manage and plant them. After planting for 3 years, you can get selenium-rich oolong tea.

[0019] In step three, the hydroponic nutrient solution is prepared by mixing 1 part by weight of ammonium chloride, 0.8 part by weight of sodium nitrophenolate, 0.6 part by weight of calcium nitrate, 1.1 part by weight of magnesium nitrate, 0.6 part by weight of zinc chloride, 0.4 part by weight of potassium acetate, 0.3 part by weight of 5-aminolevulinic acid, and 400 parts by weight of ultrapure water in a stirring tank with a power of 1.5 kW, a stirring temperature of 28° C., a stirring time of 20 min, and a stirring speed of 500 r / min, and stirring and mixing.

[0020] In step five, the water and fertilizer management: water the oolong tea seedlings once a day in the first month after planting, and then water them once a week. The amount of irrigation each time should make the soil moisture content reach 80%. After planting, apply compound fertilizer that promotes selenium absorption every 2 months, and the application amount is 30 kg / mu.

[0021] In step 1, the method for preparing the clay soil conditioner specifically comprises the following steps: S1, putting 10 parts by weight of sodium tert-butoxide, 13 parts of polybutylene succinate, 80 parts of tetrahydrofuran, and 100 parts of chloroform into a reactor with a power of 2.4 kW, the reaction temperature is 100° C., the reaction speed is 300 r / min, the reaction time is 6 hours, and mixing reaction is performed to obtain modified polybutylene succinate; S2, 25 parts by weight of medical stone, 18 parts of calcium hydroxide and 200 parts of glycerol were placed in a reactor with a power of 2.4 kW, the reaction temperature was 75°C, the reaction speed was 300 r / min, the reaction time was 1.5 h, mixed reaction was carried out, and modified to obtain modified medical stone; S3, put the modified medical stone prepared by S2, the modified polybutylene succinate prepared by S1, and 350 parts of dichloromethane into a stirring tank with a power of 1.5 kW, the stirring temperature is 75°C, the stirring time is 1 h, the stirring speed is 400 r / min, stir and mix, filter with sterile gauze, wash twice with anhydrous ethanol, and dry in an oven with a power of 2.2 kW at a temperature of 60°C for 30 min to obtain a composite; S4, putting 15 parts of blue cabbage, 21 parts of sesbania, and 36 parts of vetiver into a 1.5 kW grinder at a grinding temperature of 23°C, a grinding time of 15 min, and a grinding speed of 3500 r / min, and then putting them into a 1.8 kW refiner at a grinding temperature of 30°C, a grinding time of 15 min, and a grinding speed of 18000 r / min to obtain a viscous slurry; S5, placing the composite prepared in S3 into a vacuum freeze-nano spray dryer with a power of 2.3 kW, a vacuum degree of -0.05 MPa, a freeze-nano spray drying temperature of -40°C, a freeze-nano spray drying particle size of 100 nm, and a freeze-nano spray drying time of 2.5 h, and performing freeze-spray drying to obtain composite nanoparticles; S6. Put the composite nanoparticles prepared in S5, the viscous slurry prepared in S4, 7 parts of ferric hydroxide, and 6 parts of sodium percarbonate into a stirring tank with a power of 1.5 kW. The stirring temperature is 30°C, the stirring time is 30 min, the stirring speed is 300 r / min, and mix them evenly to obtain a viscous soil conditioner.

[0022] In step 2, the preparation method of the compound fertilizer promoting selenium absorption specifically comprises the following steps: L1, put 26 parts by weight of Vetch oleracea, 35 parts of Rhizoma Coptidis, and 31 parts of Lolium into a 1.5 kW grinder, the grinding temperature is 23° C., the grinding time is 15 min, the grinding speed is 3500 r / min, and the basal fertilizer mixture is obtained; L2, inoculate 1.2 parts by weight of the mixed bacterial agent into a 5% sterile glucose solution, put it into a constant temperature shaking incubator with a power of 2.2 kW, the constant temperature shaking culture temperature is 25°C, the constant temperature shaking culture time is 24 h, the constant temperature shaking culture speed is 210 r / min, after the constant temperature shaking culture, put it into an enzymolysis tank with a power of 1.6 kW, the enzymolysis temperature is 30°C, the enzymolysis time is 2 d, the enzymolysis speed is 70 r / min, and after enzymolysis and fermentation, a composition for promoting plant absorption of selenium is obtained; L3. Put the composition for promoting plant absorption of selenium prepared in L2 into a stirring tank with a power of 1.5 kW, 3.4 parts of calcium selenate, 6.8 parts of selenomethionine, 9.6 parts of sodium selenite and 18 parts of pig manure, stir at a temperature of 33°C, stir for 38 min and stir at a speed of 400 r / min to obtain a compound fertilizer for promoting selenium absorption.

[0023] In L2, the mixed bacterial agent consists of spherical lysine Bacillus, discolored Serratia, and Pseudomonas putida, with a weight ratio of 1.2:0.9:1. The spherical lysine Bacillus was purchased from the China General Microbiological Culture Collection Center with a preservation number of CGMCC1.8369, the discolored Serratia was purchased from the China General Microbiological Culture Collection Center with a preservation number of CGMCC1.1857, and the Pseudomonas putida was purchased from the China General Microbiological Culture Collection Center with a preservation number of CGMCC1.8829. The inoculation amount of the mixed bacterial agent in a 5% sterile glucose solution is 1%.

[0024] Embodiment 2: This embodiment provides a method for growing selenium-enriched oolong tea, which specifically comprises the following steps: Step 1: Soil conditioning before planting: Select brown soil on a gentle slope 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 amount is 80 kg / mu. After application, plow the soil evenly and keep it naturally for 11 days to obtain the conditioned soil. Step 2: intensive cultivation: apply the selenium absorption-promoting compound fertilizer to the conditioned soil prepared in step 1 at an application rate of 90 kg / mu, till the soil evenly, harrow and level the land, and maintain the soil naturally for 6 days to obtain a selenium-rich soil matrix; Step 3, hydroponic tea seedlings: immerse oolong tea seedlings with a plant height of 28 cm in a hydroponic nutrient solution, cultivate them at a temperature of 28°C for 18 days, and obtain strong oolong tea seedlings; Step 4, planting tea seedlings: dig planting holes with a depth of 8 cm and a diameter of 30 cm for the oolong tea seedlings obtained in step 3 according to the specifications of 40 cm plant spacing and 1.5 m row spacing, and implant the oolong tea seedlings into the selenium-rich soil matrix obtained in step 2 to obtain planted oolong tea seedlings; Step 5. Water and fertilizer management: After planting in step 4, water the oolong tea seedlings, fertilize, spray pesticides, manage and plant them. After planting for 3 years, you can get selenium-rich oolong tea.

[0025] In step three, the hydroponic nutrient solution is composed of 1.1 parts by weight of ammonium chloride, 0.9 parts of sodium nitrophenolate, 0.7 parts of calcium nitrate, 1.2 parts of magnesium nitrate, 0.8 parts of zinc chloride, 0.6 parts of potassium acetate, 0.5 parts of 5-aminolevulinic acid, and 460 parts of ultrapure water, which are placed in a stirring tank with a power of 1.6 kW, the stirring temperature is 30°C, the stirring time is 23 min, the stirring speed is 500 r / min, and the mixture is stirred and mixed.

[0026] In step five, the water and fertilizer management is as follows: water the oolong tea seedlings once a day within the first month of growth after planting, and then water them once a week. The amount of irrigation each time should make the soil moisture content reach 80%. After planting, apply compound fertilizer that promotes selenium absorption every 2 months, and the application amount is 40 kg / mu.

[0027] In step 1, the method for preparing the clay soil conditioner specifically comprises the following steps: S1, putting 11 parts by weight of sodium tert-butoxide, 15 parts of polybutylene succinate, 90 parts of tetrahydrofuran, and 105 parts of chloroform into a reactor with a power of 3.2 kW, the reaction temperature is 100° C., the reaction speed is 500 r / min, the reaction time is 7 hours, and mixing reaction is performed to obtain modified polybutylene succinate; S2, put 28 parts by weight of medical stone, 22 parts of calcium hydroxide and 260 parts of glycerol into a reactor with a power of 3.2 kW, the reaction temperature is 80°C, the reaction speed is 380 r / min, the reaction time is 1.8 h, mixed reaction is carried out, and modified to obtain modified medical stone; S3, put the modified medical stone prepared by S2, the modified polybutylene succinate prepared by S1, and 380 parts of dichloromethane into a stirring tank with a power of 1.6 kW, the stirring temperature is 75°C, the stirring time is 1.5 h, the stirring speed is 500 r / min, stir and mix, filter with sterile gauze, wash with anhydrous ethanol for 3 times, and dry in an oven with a power of 2.2 kW at a temperature of 60°C for 35 min to obtain a composite; S4, putting 17 parts by weight of scutellaria baicalensis, 22 parts by weight of sesbania odorifera, and 37 parts by weight of vetiver into a 1.7 kW grinder at a grinding temperature of 26°C, a grinding time of 18 min, and a grinding speed of 4000 r / min, and then putting the grinders into a 2.2 kW refiner at a grinding temperature of 33°C, a grinding time of 20 min, and a grinding speed of 19000 r / min to obtain a viscous slurry; S5, placing the composite prepared in S3 into a vacuum freeze-nano spray dryer with a power of 2.6 kW, a vacuum degree of -0.05 MPa, a freeze-nano spray drying temperature of -40°C, a freeze-nano spray drying particle size of 100 nm, and a freeze-nano spray drying time of 2.8 h, and performing freeze-spray drying to obtain composite nanoparticles; S6. Put the composite nanoparticles prepared by S5, the viscous slurry prepared by S4, 9 parts of ferric hydroxide, and 7 parts of sodium percarbonate into a stirring tank with a power of 1.6 kW, stir at a temperature of 35°C, stir for 32 min, and stir at a speed of 300 r / min. Mix them evenly to obtain a viscous soil conditioner.

[0028] In step 2, the preparation method of the compound fertilizer promoting selenium absorption specifically comprises the following steps: L1, put 32 parts by weight of Vetch oleracea, 38 parts of Rhizoma Coptidis, and 34 parts of Lolium into a 1.5 kW grinder, the grinding temperature is 23° C., the grinding time is 15 min, the grinding speed is 3500 r / min, and the basal fertilizer mixture is obtained; L2, inoculate 1.3 parts by weight of the mixed bacterial agent into a 5% sterile glucose solution, put it into a constant temperature shaking incubator with a power of 2.2 kW, the constant temperature shaking culture temperature is 25°C, the constant temperature shaking culture time is 24 h, the constant temperature shaking culture speed is 210 r / min, after the constant temperature shaking culture, put it into an enzymolysis tank with a power of 2.1 kW, the enzymolysis temperature is 30°C, the enzymolysis time is 2 d, the enzymolysis speed is 80 r / min, and after enzymolysis and fermentation, a composition for promoting plant absorption of selenium is obtained; L3. Put the composition for promoting plant absorption of selenium prepared in L2 into a stirring tank with a power of 1.6 kW, 4.3 parts of calcium selenate, 7.1 parts of selenomethionine, 10.4 parts of sodium selenite and 21 parts of pig manure, stir at a temperature of 35°C, stir for 42 min, and stir at a speed of 500 r / min to obtain a compound fertilizer for promoting selenium absorption.

[0029] In L2, the mixed bacterial agent consists of spherical lysine Bacillus, discolored Serratia, and Pseudomonas putida, with a weight ratio of 1.2:0.9:1. The spherical lysine Bacillus was purchased from the China General Microbiological Culture Collection Center with a preservation number of CGMCC1.8369, the discolored Serratia was purchased from the China General Microbiological Culture Collection Center with a preservation number of CGMCC1.1857, and the Pseudomonas putida was purchased from the China General Microbiological Culture Collection Center with a preservation number of CGMCC1.8829. The inoculation amount of the mixed bacterial agent in a 5% sterile glucose solution is 1%.

[0030] Embodiment 3: This embodiment provides a method for growing selenium-enriched oolong tea, which specifically comprises the following steps: Step 1: Soil conditioning before planting: Select brown soil on a gentle slope 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 amount is 90 kg / mu. After application, till the soil evenly and keep it naturally for 13 days to obtain the conditioned soil. Step 2: intensive cultivation: apply the selenium absorption-promoting compound fertilizer to the conditioned soil prepared in step 1 at an application rate of 100 kg / mu, till the soil evenly, harrow and level the land, and maintain the soil naturally for 7 days to obtain a selenium-rich soil matrix; Step 3, hydroponic tea seedlings: immerse oolong tea seedlings with a plant height of 30 cm in a hydroponic nutrient solution, cultivate them at a temperature of 28°C for 20 days, and obtain strong oolong tea seedlings; Step 4, planting tea seedlings: dig planting holes with a depth of 10 cm and a diameter of 30 cm for the oolong tea seedlings obtained in step 3 according to the specifications of 40 cm plant spacing and 1.5 m row spacing, and implant the oolong tea seedlings into the selenium-rich soil matrix obtained in step 2 to obtain planted oolong tea seedlings; Step 5. Water and fertilizer management: After planting in step 4, water the oolong tea seedlings, fertilize, spray pesticides, manage and plant them. After planting for 3 years, you can get selenium-rich oolong tea.

[0031] In step three, the hydroponic nutrient solution is composed of 1.2 parts by weight of ammonium chloride, 1.3 parts of sodium nitrophenolate, 0.8 parts of calcium nitrate, 1.3 parts of magnesium nitrate, 0.9 parts of zinc chloride, 0.8 parts of potassium acetate, 0.7 parts of 5-aminolevulinic acid, and 500 parts of ultrapure water, which are placed in a stirring tank with a power of 1.8 kW, the stirring temperature is 33° C., the stirring time is 26 min, the stirring speed is 500 r / min, and the mixture is stirred and mixed.

[0032] In step five, the water and fertilizer management: water the oolong tea seedlings once a day in the first month after planting, and then water them once a week. The amount of irrigation each time should make the soil moisture content reach 80%. After planting, apply compound fertilizer that promotes selenium absorption every 2 months, and the application amount is 50 kg / mu.

[0033] In step 1, the method for preparing the clay soil conditioner specifically comprises the following steps: S1, putting 12 parts by weight of sodium tert-butoxide, 17 parts of polybutylene succinate, 100 parts of tetrahydrofuran, and 110 parts of chloroform into a reactor with a power of 3.5 kW, the reaction temperature is 100° C., the reaction speed is 600 r / min, the reaction time is 8 hours, and mixing reaction is performed to obtain modified polybutylene succinate; S2, 30 parts by weight of medical stone, 26 parts of calcium hydroxide and 300 parts of glycerol were placed in a reactor with a power of 3.5 kW, the reaction temperature was 85°C, the reaction speed was 400 r / min, the reaction time was 2 h, mixed reaction was carried out, and modified to obtain modified medical stone; S3, putting the modified medical stone prepared by S2, the modified polybutylene succinate prepared by S1, and 400 parts of dichloromethane into a stirring tank with a power of 1.8 kW, stirring at a temperature of 75°C, stirring for 2 h, stirring at a speed of 600 r / min, stirring and mixing, filtering with sterile gauze, washing with anhydrous ethanol for 3 times, and drying in an oven with a power of 2.2 kW at a temperature of 60°C and a drying time of 40 min to obtain a composite; S4, putting 19 parts of scutellaria baicalensis, 23 parts of sesbania odorifera and 38 parts of vetiver grass into a 1.8 kW grinder at a grinding temperature of 28°C, a grinding time of 20 min and a grinding speed of 4500 r / min, and then putting the grinders into a 2.4 kW refiner at a grinding temperature of 36°C, a grinding time of 25 min and a grinding speed of 20000 r / min to obtain a viscous slurry; S5, placing the composite prepared in S3 into a vacuum freeze-nano spray dryer with a power of 2.8 kW, a vacuum degree of -0.05 MPa, a freeze-nano spray drying temperature of -40°C, a freeze-nano spray drying particle size of 100 nm, and a freeze-nano spray drying time of 3 h, and performing freeze-spray drying to obtain composite nanoparticles; S6. Put the composite nanoparticles prepared in S5, the viscous slurry prepared in S4, 11 parts of ferric hydroxide, and 9 parts of sodium percarbonate into a stirring tank with a power of 1.8 kW, stir at a temperature of 36°C, stir for 40 min, and stir at a speed of 400 r / min. Mix them evenly to obtain a viscous soil conditioner.

[0034] In step 2, the preparation method of the compound fertilizer promoting selenium absorption specifically comprises the following steps: L1, put 34 parts by weight of Vetch oleracea, 42 parts of Rhizoma Coptidis, and 37 parts of Lolium into a 1.5 kW grinder, the grinding temperature is 23° C., the grinding time is 15 min, the grinding speed is 3500 r / min, and the basal fertilizer mixture is obtained; L2, inoculate 1.4 parts by weight of the mixed bacterial agent into a 5% sterile glucose solution, put it into a constant temperature shaking incubator with a power of 2.2 kW, the constant temperature shaking culture temperature is 25°C, the constant temperature shaking culture time is 24 h, the constant temperature shaking culture speed is 210 r / min, after the constant temperature shaking culture, put it into an enzymolysis tank with a power of 2.2 kW, the enzymolysis temperature is 30°C, the enzymolysis time is 3 d, the enzymolysis speed is 90 r / min, and after enzymolysis and fermentation, a composition for promoting plant absorption of selenium is obtained; L3. Put the plant absorption promoting selenium composition prepared in L2, 5.3 parts of calcium selenate, 7.4 parts of selenomethionine, 11.8 parts of sodium selenite, and 23 parts of pig manure into a stirring tank with a power of 1.8 kW, and stir at a temperature of 36°C, for 46 min, at a stirring speed of 600 r / min to obtain a compound fertilizer that promotes selenium absorption.

[0035] In L2, the mixed bacterial agent consists of spherical lysine Bacillus, discolored Serratia, and Pseudomonas putida, with a weight ratio of 1.2:0.9:1. The spherical lysine Bacillus was purchased from the China General Microbiological Culture Collection Center with a preservation number of CGMCC1.8369, the discolored Serratia was purchased from the China General Microbiological Culture Collection Center with a preservation number of CGMCC1.1857, and the Pseudomonas putida was purchased from the China General Microbiological Culture Collection Center with a preservation number of CGMCC1.8829. The inoculation amount of the mixed bacterial agent in a 5% sterile glucose solution is 1%.

[0036] Comparative Example 1: This comparative example provides an oolong tea planting method, which is different from Example 1 only in that the added clay soil conditioner does not contain composite nanoparticles, and the remaining components, component contents, and method steps are the same as those in Example 1.

[0037] Comparative Example 2: This comparative example provides an oolong tea planting method, which is different from Example 1 only in that the added plant absorption promoting selenium composition is not fermented with mixed bacterial agents, and the remaining components, component contents, and method steps are the same as those in Example 1.

[0038] Experimental Example 1: Oolong tea yield determination test.

[0039] The steps of the test for determining the yield of the grown oolong tea according to the method for growing selenium-enriched oolong tea described in Examples 1-3 of the present invention are as follows: (1) A 6-mu brown soil experimental tea field with a slope of less than 15 degrees was opened for testing, and the field was divided into a 3-mu embodiment group, a 2-mu comparative group, and a 1-mu control group. Oolong tea was planted according to the planting method of selenium-enriched oolong tea described in Examples 1-3, the planting method of oolong tea described in Comparative Examples 1-2, and the control group adopted a traditional oolong tea planting method; (2) Using the selenium-enriched oolong tea planting method described in Examples 1-3, the oolong tea planting method described in Comparative Examples 1-2, and the traditional oolong tea planting method for the control group, oolong tea was picked after being planted for 3 years. The oolong tea yields of 3 mu of tea fields in the example group, 2 mu of tea fields in the comparative group, and 1 mu of tea fields in the control group were weighed and recorded.

[0040] Result analysis: Figure 1 This is a scanning electron microscope image of the internal structure of the composite nanoparticles of the present invention. Figure 2 This is a graph showing the yield of oolong tea described in Experimental Example 1 of the present invention. As shown in the figure, after planting oolong tea for 3 years according to the planting method of selenium-enriched oolong tea described in Examples 1-3, the planting method of oolong tea described in Comparative Examples 1-2, and the planting method of traditional oolong tea in the control group, the oolong tea was picked. The yields of oolong tea in the tea fields of Examples 1-3 were 113 kg / mu, 116 kg / mu, and 124 kg / mu, respectively; the yields of oolong tea in the tea fields of Comparative Examples 1-2 were 103 kg / mu and 92 kg / mu, respectively; and the yield of oolong tea in the tea fields of the control group was 61 kg / mu, indicating that the planting method of selenium-enriched oolong tea of ​​the present invention promotes the rapid growth of oolong tea seedlings, has a strong absorption capacity of the root system, is simple and efficient, and can be promoted for large-scale planting.

[0041] Experimental Example 2: Test for determining the selenium-rich content in oolong tea leaves.

[0042] In the method for growing selenium-rich oolong tea described in Examples 1-3 of the present invention, the test steps for determining the selenium-rich content in the grown oolong tea leaves are as follows: (1) A 6-mu brown soil experimental tea field with a slope of less than 15 degrees was opened for testing, and the field was divided into a 3-mu embodiment group, a 2-mu comparative group, and a 1-mu control group. Oolong tea was planted according to the planting method of selenium-enriched oolong tea described in Examples 1-3, the planting method of oolong tea described in Comparative Examples 1-2, and the control group adopted a traditional oolong tea planting method; (2) Using the planting method of selenium-enriched 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 in the control group, oolong tea was planted for 3 years, and then oolong tea was picked. Soil samples and oolong tea samples from 3 mu of oolong tea fields in the embodiment group, 2 mu of the comparative group, and 1 mu of the control group were collected, and the selenium content in the oolong tea leaves per mu of tea field, the total selenium content in the soil of the oolong tea field, and the effective selenium content in the soil of the oolong tea field were measured, and the selenium activation rate in the soil of the oolong tea field was calculated according to the formula: soil selenium activation rate = effective selenium content in soil / total selenium content in soil × 100%.

[0043] Result analysis: Figure 6 This is a growth diagram of oolong tea in the experimental field of Example 1 of the present invention. Figure 3 This is a result diagram of the selenium content of oolong tea leaves described in Experimental Example 2 of the present invention. As shown in the figure, according to the planting method of selenium-enriched oolong tea described in Examples 1-3, the planting method 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 and then picked. The selenium contents of oolong tea leaves in the tea fields of Groups 1-3 of Examples were 3.47 mg / kg, 3.66 mg / kg, and 3.87 mg / kg, respectively; the selenium contents of oolong tea leaves in the tea fields of Groups 1-2 of Comparative Examples were 1.93 mg / kg and 2.53 mg / kg, respectively; the selenium content of oolong tea leaves in the tea fields of Groups 1-2 of Comparative Examples was 1.2 mg / kg, Figure 4 This is the result diagram of the effective selenium content in the soil of the oolong tea field described in Experimental Example 2 of the present invention. Figure 5The selenium activation rate result diagram of the oolong tea field soil described in Experimental Example 2 of the present invention is shown in the figure. 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 planting method of traditional oolong tea in the control group, oolong tea was planted for 3 years, and soil samples were collected from the oolong tea field. The effective selenium contents in the soil of the oolong tea fields of Examples 1-3 were 0.062 mg / kg, 0.066 mg / kg, and 0.07 mg / kg, respectively. The selenium activation rates of the soil of the oolong tea fields of Examples 1-3 were 50.35%, 52.26%, and 54.44%, respectively. The effective selenium contents in the soil of the oolong tea fields of Comparative Examples 1-2 were 0.03 mg / kg and 0.043 mg / kg, respectively. The selenium activation rates of the soil of the oolong tea fields of Comparative Examples 1-2 were 37.98% and 43.02%, respectively. The effective selenium content in the soil of the oolong tea fields of the control group was 0.0096 mg / kg, and the selenium activation rate of the soil in the oolong tea field of the control group was 6.44%, indicating that the planting method of selenium-enriched oolong tea of ​​the present invention promotes the conversion of the selenium content in the soil bound to iron-manganese oxides and residual states into the selenium content in the water-soluble and exchangeable states, maintains the activity of selenium in the soil for a long time, and the planted oolong tea is rich in selenium.

[0044] Experimental Example 3: Quality determination of selenium-enriched oolong tea.

[0045] The method for growing selenium-rich oolong tea described in Examples 1-3 of the present invention includes the following steps for testing the quality of the grown selenium-rich oolong tea: (1) A 6-mu brown soil experimental tea field with a slope of less than 15 degrees was opened for testing, and the field was divided into a 3-mu embodiment group, a 2-mu comparative group, and a 1-mu control group. Oolong tea was planted according to the planting method of selenium-enriched oolong tea described in Examples 1-3, the planting method of oolong tea described in Comparative Examples 1-2, and the control group adopted a traditional oolong tea planting method; (2) Using the selenium-enriched oolong tea planting method described in Example 1-3, the oolong tea planting method described in Comparative Example 1-2, and the traditional oolong tea planting method for the control group, oolong tea was planted for 3 years, and then the oolong tea was picked. The oolong tea of ​​each group was dried in a dryer at a drying temperature of 110°C until the moisture content was less than 5%. The amino acid content and selenium content therein were tested, and a sensory evaluation was conducted and the results were recorded.

[0046] Table 1. Oolong tea quality test table

[0047] Result analysis: As shown in Table 1, the amino acid and selenium contents in the dried oolong tea of ​​Examples 1-3 and Comparative Example 2 were higher than those in the dried oolong tea of ​​the control group, and the appearance, soup color, aroma, taste and leaf bottom of Examples 1-3 and Comparative Example 1-2 were stable and of high quality, indicating that the tea trees grown by the planting method of selenium-enriched oolong tea of ​​the present invention are in good growth condition, the oolong tea leaves are rich in selenium, and the quality after processing can be kept stable.

[0048] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0049] The present invention and its implementation methods are described above, which is not restrictive. The drawings are only one of the implementation methods of the present invention, and the actual application is not limited thereto. In short, if ordinary technicians in the field are inspired by it and design methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A method for growing selenium-enriched oolong tea, characterized in that: The specific steps include: Step 1: Soil conditioning before planting: Select brown soil on a gentle slope 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 amount is 70-90 kg / mu. After application, plow the soil evenly and keep it naturally for 8-13 days to obtain the conditioned soil. Step 2: intensive cultivation: apply the selenium absorption-promoting compound fertilizer to the conditioned soil prepared in step 1 at an application rate of 80-100 kg / mu, till the soil evenly, harrow and level the land, and keep it naturally for 4-7 days to obtain a selenium-rich soil matrix; Step 3, hydroponic tea seedlings: immerse oolong tea seedlings with a plant height of 25-30 cm in a hydroponic nutrient solution, cultivate them at a temperature of 28°C for 15-20 days, and obtain strong oolong tea seedlings; Step 4, planting tea seedlings: dig planting holes with a depth of 5-10 cm and a diameter of 30 cm for the oolong tea seedlings obtained in step 3 according to the specifications of 40 cm spacing between plants and 1.5 m spacing between rows, and implant the oolong tea seedlings into the selenium-rich soil matrix obtained in step 2 to obtain planted oolong tea seedlings; Step 5. Water and fertilizer management: After planting in step 4, water the oolong tea seedlings, fertilize, spray pesticides, manage and plant them. After planting for 3 years, you can get selenium-rich oolong tea.

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

3. The method for growing selenium-enriched oolong tea according to claim 2, characterized in that: In step five, the water and fertilizer management is as follows: water the oolong tea seedlings once a day in the first month after planting, and then water them once a week. The amount of irrigation each time should make the soil moisture content reach 80%. After planting, apply compound fertilizer that promotes selenium absorption every 2 months, and the application amount is 30-50kg / mu.

4. The method for growing selenium-enriched oolong tea according to claim 3, characterized in that: In step 1, the method for preparing the clay soil conditioner specifically comprises the following steps: S1, mixing 10-12 parts by weight of sodium tert-butoxide, 13-17 parts of polybutylene succinate, 80-100 parts of tetrahydrofuran, and 100-110 parts of chloroform to obtain modified polybutylene succinate; S2, mixing 25-30 parts by weight of medical stone with 18-26 parts of calcium hydroxide and 200-300 parts of glycerol for reaction, and modifying the mixture to obtain modified medical stone; S3, the modified medical stone prepared in S2, the modified polybutylene succinate prepared in S1, and 350-400 parts of dichloromethane are stirred and mixed, filtered through sterile gauze, washed with anhydrous ethanol 2-3 times, and then dried to obtain a composite; S4, crushing 15-19 parts by weight of spatholobi, 21-23 parts by weight of sesbania, and 36-38 parts by weight of vetiver, and then grinding to obtain a viscous slurry; S5. The composite prepared in S3 is freeze-spray dried, and then mixed 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.

5. The method for growing selenium-enriched oolong tea according to claim 4, characterized in that: In step 2, the preparation method of the compound fertilizer promoting selenium absorption specifically comprises the following steps: L1, crushing 26-34 parts by weight of Vicia oleracea, 35-42 parts by weight of Rhizoma Cibotii, and 31-37 parts by weight of Lolium to obtain a base fertilizer mixture; L2, inoculating 1.2-1.4 parts by weight of the mixed bacterial agent into a 5% sterile glucose solution, culturing at a constant temperature with shaking, and then mixing with the base fertilizer prepared in L1, and performing enzymatic hydrolysis and fermentation to obtain a composition for promoting plant absorption of selenium; L3. Mix the composition for promoting plant absorption of selenium prepared in L2 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 compound fertilizer for promoting selenium absorption.

6. The method for growing selenium-enriched oolong tea according to claim 5, characterized in that: In L2, the mixed bacterial agent consists of spherical lysine Bacillus, discolored Serratia, and Pseudomonas putida, and the mixing ratio by weight is 1.2:0.9:

1. The inoculation amount of the mixed bacterial agent in 5% sterile glucose solution is 1%.

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