Disclosure of Invention
In order to solve the technical problems, the invention provides a device for preventing and controlling the fruit shrink of 'short-branch' winter jujube and a use method thereof, which improve the disease resistance of jujube trees, and enable potassium and calcium to be absorbed and act by the jujube trees at the same time, thereby improving the fruit shrink prevention and control efficiency.
In order to achieve the above object, the present invention provides the following solutions:
the invention provides a device for preventing and controlling fruit shrinkage of winter jujubes, which comprises a container body and a connecting piece; the upper end of the container body is provided with a liquid injection port, and the lower end of the container body is provided with a liquid outlet; the connecting piece is including set up in the nail of container body bottom and jujube tree contact position, and set up in two dead levers of container body side and bottom and connect respectively on two dead levers and be used for fixing the dead lever in two bandages on the jujube tree branch.
Further, the included angle between the two fixing rods at the side surface and the bottom of the container body is 80-95 degrees, the included angle is 80-95 degrees, the two fixing rods are bound with the branches of the jujube tree through the binding band, the two branches of the jujube tree are propped open, the included angle is 80-95 degrees, and the backflow of photosynthetic products to the main rod and the root can be reduced as the same as the branch pulling effect.
Further, the number of nails is 6 or 9, the nails penetrate into the xylem of the jujube tree branch, phloem healing can be prevented, the effect is the same as nail opening, backflow of photosynthetic products to the main rod and the root can be reduced, and nutrition is guaranteed preferentially to grow and develop fruits.
The invention also provides a composition for preventing and controlling the fruit shrinkage of the winter jujube with short branches, which consists of a mixed matrix and Pythium oligandrum with the mass ratio of 100:0.2, wherein the mixed matrix comprises the following components in percentage by mass: 1:1:0.5:1.5:4, potato blocks, green beans, chicken bone powder or eggshells, brown sugar, soil and water.
Further, the particle size of the chicken bone powder or the eggshell and the soil is smaller than 60 meshes.
Further, the soil is taken from a soil layer of 20cm on the surface of the winter jujube plantation with 'short branches'.
The invention also provides a preparation method of the composition for preventing and controlling the shrinkage of the winter jujube with short branches, which comprises the following steps:
cutting potatoes into potato blocks with the length and width of less than 0.5cm, mixing potato blocks, green beans, chicken bone powder or eggshells, brown sugar, soil and water according to the mass ratio, adding saccharomycetes for sealing fermentation to obtain a mixed matrix, and then adding Pythium oligandrum for continuous fermentation to obtain the composition for preventing and treating the winter jujube fruit shrink of short branches.
Further, the adding amount of the saccharomycetes is 0.4-1% of the total mass of the chicken bone powder or the eggshells, the green beans and the potato blocks, the number of days of fermentation after adding the saccharomycetes is 45-50 days, and the number of days of fermentation after adding the Pythium oligandrum is 3-5 days.
Further, the potato blocks are blocks with length, width and length smaller than 0.5cm after peeling off the surface layer of the potato by 0.3 cm.
The invention also provides a method for preventing and controlling the shrinkage of the winter jujube with the short branches, which comprises the steps of removing the bark on the upper side (the joint part of the side branches and the trunk) of the winter jujube with the short branches in the middle ten days or the late ten days of 6 months to form a pit, smearing the composition for preventing and controlling the shrinkage of the winter jujube with the short branches on the pit, fixing the device on the pit coated with the composition, and then injecting the Pythium oligandrum solution into a liquid injection port of the device.
Further, the recess is 0.5-2 cm wide, 2-4 cm long and 0.2-0.5 cm deep.
Further, the bark is cut 0.1 to 0.2cm deep into the xylem.
Further, the smearing thickness of the composition for preventing and controlling the shrinkage of the winter jujube with short branches is 1-2 cm.
Further, the Pythium oligandrum solution is prepared by mixing Pythium oligandrum and water according to a mass ratio of 0.1:100.
Further, 2-5 mL of the Pythium oligandrum solution flows out of the liquid outlet of the device every 3-5 days and is injected into the pit of the jujube tree, and the injection is continuously carried out for 4-6 times.
Furthermore, the composition for preventing and controlling the shrinkage of the winter jujube with short branches can be properly added with water or soil before being smeared to be modulated into a state that the composition can be held by hands to form clusters.
Further, the composition for preventing and controlling the fruit shrinkage of the winter jujube with short branches is matched with potassium and calcium fertilizers.
The fruit shrinkage of the winter jujubes with short branches is caused by nutrition imbalance and is caused by the deficiency of elements such as potassium, calcium and the like of the tree body, and the number of microbial communities on the tree body, particularly on the branches and leaves of new growth is unbalanced, namely, the number of beneficial microorganisms is reduced and harmful microorganisms are increased.
The absorption of potassium ions by winter jujube root cells is an active transport, requiring both the assistance of carrier proteins and the supply of ATP. Aerobic respiration releases energy so that root cells only take up more potassium ions under conditions where the oxygen supply is sufficient. The ability of potassium ions to rob channels is much greater than calcium, so simultaneous administration of potassium and calcium will disable calcium due to antagonism.
The Pythium oligandrum is parasitic fungus with strong aggressivity, can be planted in the root soil of various crops, can not only generate pathogenic effect on the crops, but also inhibit or kill other pathogenic bacteria and soil-borne pathogenic bacteria, induce plants to generate defending reaction, and reduce invasion of the pathogenic bacteria; meanwhile, secretion and various enzymes generated by the Pythium oligandrum are good growth promoting active agents for plants, and can promote the root system development of crops and improve nutrient absorption. Pythium oligandrum can produce a pseudo-elicitor which is related to induced resistance and is called oligomeric androstatin, the induced plant generates resistance, the invasion of pathogenic bacteria is resisted, and the occurrence rate of diseases is obviously reduced.
The invention discloses the following technical effects:
(1) The device of the invention uses the fixing rod and the binding belt to open the jujube tree branch to a certain angle, and has the same action as the branch pulling, thereby realizing the suppression of top advantages and reducing the backflow of photosynthetic products to the main rod and the root; meanwhile, nails in the device penetrate into the xylem of the jujube tree, the phloem can be prevented from healing, the effect is the same as that of opening the nails, and backflow of photosynthetic products to the main rod and the root can be reduced, so that nutrition is guaranteed to grow and develop preferentially; the device container body is also provided with a liquid injection port and a liquid outlet, so that the Pythium oligandrum solution is continuously supplied to the jujube tree, and the purpose of continuously supplementing nutrients is achieved.
(2) According to the invention, the Pythium oliganum is colonized by a mixed matrix formed by potato blocks, green beans, chicken bone powder or eggshells, brown sugar, soil and water, so that the Pythium oliganum can be exerted in a mode of penetrating into the xylem of the winter jujube branch to prevent pathogen invasion, and the disease resistance of the jujube tree is improved. The secretion of the oligandrum pythium herb to obtain oligandrum proteins and the like can induce the crops to generate systemic resistance, so that the disease resistance of the crops is effectively improved.
(3) The composition for preventing and controlling the fruit shrink of the winter jujube with short branches has low manufacturing cost, simple device using method and high fruit shrink prevention efficiency by combining the two.
Detailed Description
Various exemplary embodiments of the invention will now be described in detail, which should not be considered as limiting the invention, but rather as more detailed descriptions of certain aspects, features and embodiments of the invention.
It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In addition, for numerical ranges in this disclosure, it is understood that each intermediate value between the upper and lower limits of the ranges is also specifically disclosed. Every smaller range between any stated value or stated range, and any other stated value or intermediate value within the stated range, is also encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.
It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the invention described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from consideration of the specification of the present invention. The specification and examples of the present invention are exemplary only.
As used herein, the terms "comprising," "including," "having," "containing," and the like are intended to be inclusive and mean an inclusion, but not limited to.
The device for preventing and controlling the fruit shrinkage of the winter jujubes with short branches, which is used in the following embodiments of the invention, comprises a container body and a connecting piece; the upper end of the container body is provided with a liquid injection port, and the lower end of the container body is provided with a liquid outlet; the connecting piece is including set up in the nail of container body bottom and jujube tree contact position, and set up in the dead lever of device side and bottom and connect respectively on two dead levers and be used for fixing the dead lever in two bandage on the jujube tree branch. The liquid outlet is provided with a plurality of small holes, and the number of the small holes can be set according to the required liquid outlet speed. The effect of the liquid outlet is to make the liquid medicine slowly and evenly penetrate into the action part downwards, so the aperture of the small holes is not too large, and the diameter of the small holes is 0.2mm and the number of the small holes is 5 in the embodiment of the invention. The diameter of the liquid injection port is not too large, otherwise, the volatilization of the liquid medicine is accelerated or impurities or rainwater enter, the drug effect is affected, as long as the liquid medicine can be injected, and the embodiment of the invention preferably has the liquid injection port aperture of 3mm. The included angle between the two fixing rods at the side surface and the bottom of the container body is 80-95 degrees, the included angle is 80-95 degrees, and the included angle between the two fixing rods is 80-95 degrees by combining the binding belt with the jujube tree branches. The number of nails is 6 or 9, the nails penetrate into the xylem of the jujube tree branch, and the number of nails in the embodiment of the invention is 6.
The shape of container body and medicine position adaptation, so that the container body can hug closely the branch, thereby make the nail can with the container body is closely fixed in on the branch, bandage and dead lever length, the width of bandage can be adjusted according to the specific condition of jujube tree branch thickness.
The invention also provides a composition for preventing and controlling the fruit shrinkage of the winter jujube with short branches, which consists of a mixed matrix and Pythium oligandrum with the mass ratio of 100:0.2, wherein the mixed matrix comprises the following components in percentage by mass: 1:1:0.5:1.5:4, potato blocks, green beans, chicken bone powder or eggshells, brown sugar, soil and water.
The invention also provides a preparation method of the composition for preventing and controlling the shrinkage of the winter jujube with short branches, which comprises the following steps:
cutting potatoes into potato blocks with the length and width of less than 0.5cm, mixing potato blocks, green beans, chicken bone powder or eggshells, brown sugar, soil and water according to the mass ratio, adding saccharomycetes for sealing fermentation to obtain a mixed matrix, and then adding Pythium oligandrum for continuous fermentation to obtain the composition for preventing and treating the winter jujube fruit shrink of short branches.
Further, the addition amount of the saccharomycetes is 0.4-1% of the total mass of the potato blocks, the chicken bone powder or the eggshells and the green beans.
Further, the number of days of post fermentation after adding saccharomycetes is 45-50 days, and the number of days of fermentation after adding Pythium oligandrum is 3-5 days.
The invention also provides a method for preventing and controlling the shrinkage of the short-branch winter jujube, which comprises the steps of removing the bark on the upper side (the joint part of the side branch and the trunk) of the branch of the short-branch winter jujube in the middle ten days or the late ten days of 6 months to form a pit, fixing the device on the pit coated with the composition, and then injecting the Pythium oligandrum solution into a liquid injection port of the device.
Further, the recess is 0.5-2 cm wide, 2-4 cm long and 0.2-0.5 cm deep.
Further, the bark is cut 0.1 to 0.2cm deep into the xylem.
Further, the smearing thickness of the composition for preventing and controlling the shrinkage of the winter jujube with short branches is 1-2 cm.
Further, the Pythium oligandrum solution is prepared by mixing Pythium oligandrum and water according to a mass ratio of 0.1:100.
Further, 2-5 mL of the Pythium oligandrum solution flows out of the liquid outlet of the device every 3-5 days and is injected into the pit of the jujube tree, and the injection is continuously carried out for 4-6 times.
Further, the specific preparation steps of the Pythium oligandrum solution are as follows: and (3) taking Pythium oligandrum and water according to the mass ratio, pouring the Pythium oligandrum into a container, adding water, fully stirring, standing for 45-60 minutes to form a uniform suspension of the liquid medicine, and filtering by a 200-mesh filter screen to prepare the Pythium oligandrum solution.
Furthermore, the composition for preventing and controlling the shrinkage of the winter jujube with short branches can be properly added with water or soil before being smeared to be modulated into a state that the composition can be held by hands to form clusters.
Further, the composition for preventing and controlling the fruit shrinkage of the winter jujube with short branches is matched with potassium and calcium fertilizers.
The length and width of the potato blocks used in the embodiment of the invention are smaller than 0.5cm, the grain size of the used chicken bone powder or egg shell and the soil is smaller than 60 meshes, the potato blocks are blocks with the length and width not larger than 0.5cm after the surface layer of the potato is peeled off, the soil is taken from a soil layer with the length and width of 20cm on the surface of a winter jujube plantation, and the Pythium oligandrum solution is prepared by mixing Pythium oligandrum and water according to the mass ratio of 0.1:100.
The Pythium oligandrum used in the examples of the present invention was purchased from Chlamydia czech biologies, inc., and the yeast was purchased from Angel Yeast, inc.
The potassium fertilizer used in the embodiment of the invention is monopotassium phosphate produced by China center group limited company, the calcium fertilizer used is sugar alcohol calcium produced by Shandong sea Dai oasis biological engineering limited company, the main component fertilizer components are sugar alcohol chelating agent and calcium, and the phosphate fertilizer used is monoammonium phosphate produced by Hubei manufacturer Wuhan Ji chemical industry limited company. The application of the fertilizer is implemented according to the nutrient diagnosis and recommended fertilization technical specification of DB65/T3799-2016 jujube.
The examples and comparative examples of the present invention were carried out in Gu Yingcun winter jujube orchard in the depression of contaminated area of coastal state of Shandong province, and the incidence of shrinkage of winter jujubes in 2018 'short branch' in this jujube orchard was counted to be 32.4%.
All treatments of the jujube tree in the inventive and comparative examples were started on the same day and harvested on the same day.
The technical scheme of the invention is further described by the following examples.
Example 1
(1) The cross section of the device for preventing and controlling the shrinkage of the winter jujubes with short branches is shown in figure 1, wherein 1-binding band, 1' -binding band, 2-liquid outlet, 3-liquid injection port, 4-nail, 11-side fixing rod and 12-bottom fixing rod are arranged. The left side view of the device is shown in fig. 2, wherein the 1-strap, 5-container body. The top view of the device is shown in fig. 3, wherein the 1-strap, 3-port is shown. The device comprises a container body 5 and a connecting piece; the upper end of the container body 5 is provided with a liquid injection port 3, and the lower end is provided with a liquid outlet 2; the connecting piece comprises nails 4 arranged at the contact part of the bottom of the container body 5 and the jujube tree, fixing rods 11 and 12 arranged at the side surface and the bottom of the device, and two binding bands 1 and 1' respectively connected with the two fixing rods 11 and 12 and used for fixing the fixing rods on the branches of the jujube tree. The included angle between the two fixing rods at the side surface and the bottom of the container body is 90 degrees, and the included angle between the two fixing rods is 90 degrees by combining the binding belt with the jujube tree branches. The number of nails is 6, and the nails penetrate into the xylem of the jujube tree branch.
(2) Preparation of a composition for preventing and controlling fruit shrinkage of 'short-branch' winter jujube: at the beginning of 5 months in 2018, cutting potatoes into potato blocks with the length and width of less than 0.5cm, wherein the mass ratio is 2:1:1:0.5:1.5: weighing potato blocks, green beans, chicken bone powder, brown sugar, soil and water, mixing, adding saccharomycetes (0.6% of the sum of the mass of the potato blocks, the chicken bone powder and the green beans), sealing and fermenting for 48 days to obtain a mixed matrix, adding Pythium oligandrum (0.2% of the mass of the mixed matrix) in the ten days of 6 months, and continuously fermenting for 4 days to obtain the composition for preventing and treating winter jujube fruit shrink of 'short branches'.
(3) In the middle of 6 months, 10 'short-branch' winter jujube trees in a jujube garden are randomly selected in a depression Zhenxi Gu Yingcun winter jujube garden under a contaminated area of coastal city of Shandong province, 3 branches are respectively selected in 4 directions of east and west of each 'short-branch' winter jujube tree, bark on the upper side of a crotch (a joint part of a side branch and a trunk) is cut to be 0.2cm deep into a xylem to form a pit with the width of 2cm and the length of 4cm and the depth of 0.2cm (see fig. 4, wherein 6-xylem, 7-pit and 8-phloem), and then the composition for preventing and controlling the shrinkage of 'short-branch' winter jujube is smeared on the pit with the thickness of 2cm (see fig. 5, wherein 9-composition); and applying potash fertilizer, calcium fertilizer and phosphate fertilizer.
(4) The device was mounted on a composition-coated well (see fig. 6, where 9-composition, 10-device) and 4mL of Pythium oligandrum solution (mixed with water at a mass ratio of 0.1:100) was injected into the well every 4 days, followed by 4 consecutive injections.
(5) In the middle 10 th 2018, the incidence rate of jujube fruits on the selected branches is counted to be 3.6%.
(6) In 2019, the same batch of short-branch winter jujube trees is continuously processed according to the steps (1) - (4), and the incidence rate of jujube fruits on the selected branches is counted to be 2.8% in 10 middle ten days of 2019.
Example 2
(1) The structure of the device for preventing and controlling the fruit shrinkage of the winter jujubes with short branches is the same as that of the embodiment 1;
(2) Preparation of a composition for preventing and controlling fruit shrinkage of 'short-branch' winter jujube: at the beginning of 5 months in 2018, cutting potatoes into potato blocks with the length and width of less than 0.5cm, wherein the mass ratio is 2:1:1:0.5:1.5: weighing potato blocks, green beans, egg shells, brown sugar, soil and water, mixing, adding saccharomycetes (1% of the mass sum of the potato blocks, the egg shells and the green beans), sealing and fermenting for 45 days to obtain a mixed matrix, adding Pythium oligandrum (0.2% of the mass of the mixed matrix) in the ten days of 6 months, and continuously fermenting for 5 days to obtain the composition for preventing and treating winter jujube fruit shrink of 'short branches'.
(3) Randomly selecting 10 short-branch winter jujube trees in a depression area Gu Yingcun winter jujube garden under a contaminated area of coastal city of Shandong province, selecting 3 branches from each short-branch winter jujube tree in the north-south 4 directions, removing bark on the upper side of a crotch (the joint part of a side branch and a trunk) from the bark deep into xylem by 0.1cm to form a pit with the width of 0.5cm, the length of 2cm and the depth of 0.5cm, and then smearing the composition for preventing and treating the shrinkage of the short-branch winter jujube on the pit with the smearing thickness of 1cm; and applying potash fertilizer, calcium fertilizer and phosphate fertilizer.
(4) The device was inserted into a recess coated with the composition and 5mL of Pythium oligandrum solution (mixed by Pythium oligandrum and water in a mass ratio of 0.1:100) was injected into the recess every 3 days, followed by 5 consecutive injections.
(5) And in 10 middle 10 days 2018, counting the incidence rate of the jujube fruits on the selected branches to be 3.7%.
(6) In 2019, the same batch of short-branch winter jujube trees is continuously processed according to the steps (1) - (4), and the incidence rate of jujube fruits on the selected branches is counted to be 3.2% in 10 middle ten days of 2019.
Example 3
(1) The structure of the device for preventing and controlling the fruit shrinkage of the winter jujubes with short branches is the same as that of the embodiment 1;
(2) Preparation of a composition for preventing and controlling fruit shrinkage of 'short-branch' winter jujube: at the beginning of 5 months in 2018, cutting potatoes into potato blocks with the length and width of less than 0.5cm, wherein the mass ratio is 2:1:1:0.5:1.5: weighing potato blocks, green beans, egg shells, brown sugar, soil and water, mixing, adding saccharomycetes (0.4% of the mass of the potato blocks, the egg shells and the green beans), sealing and fermenting for 50 days to obtain a mixed matrix, adding Pythium oligandrum (0.2% of the mass of the mixed matrix) in ten days of 6 months, and continuously fermenting for 3 days to obtain the composition for preventing and treating winter jujube fruit shrink of 'short branches'.
(3) In the middle ten days of 6 months, 10 'short-branch' winter jujube trees in a jujube garden are randomly selected in a depression Zhenxi Gu Yingcun winter jujube garden under a contaminated area of coastal city of Shandong province, 3 branches are respectively selected in 4 directions of east and west of each 'short-branch' winter jujube tree, bark on the upper side of a crotch (the joint part of a side branch and a trunk) is cut off and goes deep into a xylem by 0.2cm to form a pit with the width of 1cm, the length of 3cm and the depth of 0.2cm, and then the composition for preventing and controlling the shrinkage of the 'short-branch' winter jujube is smeared on the pit with the smearing thickness of 1cm; and applying potash fertilizer, calcium fertilizer and phosphate fertilizer.
(4) The device was inserted into a recess coated with the composition and 2mL of Pythium oligandrum solution (mixed by Pythium oligandrum and water in a mass ratio of 0.1:100) was injected into the recess every 5 days, followed by 6 consecutive injections.
(5) The incidence rate of jujube fruits on the selected branches is counted to be 4.0% in 10 ten days of 2018.
(6) In 2019, the same batch of short-branch winter jujube trees is continuously processed according to the steps (1) - (4), and in 10 middle ten days of 2019, the incidence rate of jujube fruits on the selected branches is counted to be 3.3%.
Comparative example 1
The blank control, namely 10 jujube trees are randomly selected, no treatment is carried out, 3 branches are respectively selected from the north and south directions of the east and west of each selected 'short branch' winter jujube tree in 10 days in 2018, the incidence rate of the jujubes is counted to be 32.4%, the operation of 2018 is repeated in 2019, and the incidence rate is counted to be 35.1%.
Comparative example 2
10 jujube trees are randomly selected from a winter jujube garden of a depression town and a western Gu Yingcun winter jujube garden in a contaminated area of coastal city of Shandong province, kasugamycin produced by Shandong Bainong Si da biotechnology limited company is sprayed in the middle 6 th 2018, and the medicine is taken for the 2 nd time after 7-10 days by spraying 500-600 times of 2% aqueous solution. The incidence rate of jujube fruits is 12.4% in 10 middle ten days, the practice of 2018 is repeated in 2019, and the incidence rate is 14.7%.
Comparative example 3
10 jujube trees are randomly selected from a winter jujube garden of Zhenxi Gu Yingcun in a contaminated area of coastal city of Shandong province, and each jujube tree is applied with a soil-applied calcium fertilizer, so that the incidence rate of jujube fruits in 2018 is 23.5%, and the incidence rate in 2019 is 26.4%.
Comparative example 4
10 jujube trees are randomly selected from a winter jujube garden of a depression Zhenxi Gu Yingcun winter jujube garden in a contaminated area of coastal city of Shandong province, phosphate fertilizer is applied to the root of each jujube tree in 6 months of 2018, and the fertilizer consumption is referred to DB65/T3799-2016 jujube nutrition diagnosis and recommended fertilization technical rules. In the middle 10 th month, 3 branches are selected from 4 directions of east, west, south and north of each selected 'short branch' winter jujube tree, the incidence rate of the jujube fruits is counted to be 34.2%, the method of 2018 is repeated in 2019, and the incidence rate is counted to be 33.8%.
Comparative example 5
10 jujube trees are randomly selected from a winter jujube garden of Zhenxi Gu Yingcun in a contaminated area of coastal city of Shandong province, potash fertilizer is applied to the root of each jujube tree, and the fertilizer consumption is referred to DB 65/d/T3799-2016 jujube nutrition diagnosis and recommended fertilization technical rules. The incidence rate of the statistical jujube fruits on 3 branches is 21.8% respectively from 4 directions of the east, the south and the north of each selected 'short branch' winter jujube tree in 10 middle of 2018, and the repeated practice in 2018 in 2019 and the statistical incidence rate are 28.3%.
Comparative example 6
10 jujube trees are randomly selected from a winter jujube garden of a depression Zhenxi Gu Yingcun winter jujube garden in a contaminated area of coastal city of Shandong province, potash fertilizer and calcium fertilizer are applied to the root of each jujube tree in 6 months of 2018, and the fertilizer consumption is referred to DB65/T3799-2016 jujube nutrition diagnosis and recommended fertilization technical rules. The incidence rate of the statistical jujube fruits on 3 branches selected from 4 directions of the east, the south and the north of each 'short branch' winter jujube tree in 10 middle of 2018 is 22.6%, and the repeated practice in 2018 in 2019 and the statistical incidence rate are 21.2%.
The above embodiments are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the claims of the present invention without departing from the design spirit of the present invention.