CN114009177A

CN114009177A - High-rate pelleting coating material for small-particle seeds and coating method thereof

Info

Publication number: CN114009177A
Application number: CN202111281702.8A
Authority: CN
Inventors: 龙正柏; 朱德新; 黄岩; 韩庆辉
Original assignee: Beijing Baiqingyuan Animal Husbandry Technology Development Co ltd; Beijing Wanchengyuan Agricultural Technology Co ltd
Current assignee: Beijing Baiqingyuan Animal Husbandry Technology Development Co ltd; Beijing Wanchengyuan Agricultural Technology Co ltd
Priority date: 2021-11-01
Filing date: 2021-11-01
Publication date: 2022-02-08
Anticipated expiration: 2041-11-01
Also published as: CN114009177B

Abstract

The invention provides a high-rate pelleting coating material for small-particle seeds and a coating method thereof. The coating material comprises: fillers, binders, adjuvants, colorants and functional auxiliaries; the filler is a mixture obtained by mixing 100 parts by weight of 200-325-mesh vermiculite powder serving as a base material with 2-10 parts by weight of potassium carbonate, 0-15 parts by weight of bentonite and 0-20 parts by weight of diatomite by a high-speed mixer; the adhesive is a mixture which is prepared by mixing and stirring 1-3 parts by weight of high-viscosity hydroxypropyl methyl cellulose aqueous solution with the concentration of 3 wt%, 1-3 parts by weight of sodium polyacrylate aqueous solution with the concentration of 7 wt%, 3-5 parts by weight of polyvinyl alcohol aqueous solution with the concentration of 8 wt% and 10-15 parts by weight of water at the temperature of 20-40 ℃ until emulsification; the auxiliary agent comprises 200 meshes of talcum powder and a film-forming agent, and the mass ratio is 1: 1; the functional auxiliary agent comprises one or a combination of a microbial fertilizer, a trace element fertilizer and a water-retaining agent. The invention solves the problems that the large-magnification pelleting of small-particle seeds is difficult or the pelleting effect is not good and the seed bud rate is influenced.

Description

High-rate pelleting coating material for small-particle seeds and coating method thereof

Technical Field

The invention relates to the field of agricultural seedling culture, in particular to a high-rate pelleting coating material for small-particle seeds and a coating method thereof.

Background

The seed pelleting coating is a seed treatment technology commonly adopted in developed countries, and is a high and new technology for seed treatment, which is realized by a coating machine/dryer and integrates multiple disciplinary achievements into a whole, wherein seeds are taken as cores, inert materials are taken as main auxiliary materials, adhesive is taken as auxiliary materials, and meanwhile, a proper amount of beneficial components such as trace fertilizer, insecticide and antibacterial agent are added. The method changes the shape of the seeds of the crops from irregular and tiny shapes into spheres with uniform size and regular shape, so that the crops which are not suitable for mechanical sowing realize precision sowing, plant protection before sowing and disease and pest control, and provides micro-fertilizer for the early growth stage of the crops to promote the growth of the crops and improve and enhance the stress resistance of the seeds.

The application of the seed pelleting and coating technology is closely related to the development of seeding machinery, particularly precision seeding machinery, because the level of agricultural machinery in China has larger difference compared with that in developed countries, particularly the difference on the precision seeding machinery is larger, the proportion of the seed pelleting application is lower, along with the transfer of a large number of rural population in China to non-agricultural industry, the requirements of large-scale and mechanization of agriculture are more and more urgent, and the pelleting effect of pelleted seeds, particularly small-particle seeds, is increasingly enhanced.

The main problems of the prior seed pelleting sowing technology in China are as follows:

1. at present, the seed pelleting technology at home and abroad is mainly and intensively applied to cotton, beet, vegetables, flowers and grass seeds (alfalfa), the pelleting technology is also commonly applied, the pelleting processing equipment also realizes commercialization, automation, standardization and serialization, and the development is directed to intellectualization, refinement and excellence. However, there are some problems to be further solved in the small-particle seeds, such as insufficient or excessive drying during the pelleting process of the high-rate pelleted seeds, uneven moisture content after pelleting treatment, severe shortening of the shelf life of the seeds, and even influence on the germination rate of the seeds.

2. The small-particle seed pelleting degree is low: the small-particle seeds are seeds with extremely small particle size and extremely low thousand seed weight, and are common in agriculture, lettuce, mustard, amaranth, celery, tobacco leaves of vegetable seeds, alfalfa, bermuda grass and the like in pasture belong to small-particle seeds, for example, the thousand seed weight of decapsulated bermuda grass is only about 0.28 g, the thousand seed weight of celery seeds is 0.4-0.6 g, the thousand seed weight of lettuce seeds is 0.5-1.2 g, and the tobacco seeds are lower to about 0.07 g.

3. Because the small-sized seeds are small in size and poor in tolerance, the phytotoxicity is easily caused by film coating by using a bactericide or adding a fertilizer, and the phytotoxicity of the pesticide to the seeds and seedlings is blocked by the seed pelleting coating due to the shielding effect of the pill coating; in addition, chemical substances and biological substances which promote the growth of roots and seedlings can be added into the pill coating to play a role in improving the quality of the seedlings and the like, so that the research of pill coating is paid attention by people.

4. The adhesive used in the existing pelleting coating mainly comprises water-soluble adhesive such as starch, hydroxymethyl cellulose, sodium alginate, gelatin, Arabic gum and the like, the filling material mainly comprises diatomite, kaolin, talcum powder, calcium sulfate, peat soil and the like, and the pelleting coating adopts a coating method as follows: the seed is put into a coating container, a binder solution is sprayed on the surface of the seed while the container is rotated, then a powder material is put into the container to combine the seed with the powder material, and the above operations are repeated until the particle diameter of the pelletized seed reaches a desired thickness. However, the use of the adhesive and the material powder ensures that the pelleting forming time is longer, the general time is 1-2 hours, and the pelleting coating is easy to crack under the natural condition; the pelleted seeds are high in thickness and not dried sufficiently or uniformly, and after the pelleted seeds are stored for a period of time, the overall moisture content is high, and the activity of the seeds is reduced quickly; the hardness of the pelleted seeds is poor, and particularly the coating time is short; the time spent for cracking when meeting water or high humidity environment after sowing is long, thus being unfavorable for germination and emergence, and having great influence on the germination of small-particle crop seeds in particular.

5. The high multiple pelleting requirement of the small-particle seeds contradicts the subsequent quality assurance of the pelleted seeds: the weight of the small-particle seeds is required to be 20-30 times or more higher than the weight of the small-particle seeds, a binding effect is required to be achieved after a binding agent and the like are dissolved in water in the pelleting process, the shells formed in the pelleting process have high water content (the water content of the un-dried pelleting shell material is usually 30-40%), the seed storage requires that the water content of the dried pelleting seeds is required to be dried to be less than 5%, the drying temperature of the pelleting seeds cannot be higher than 50 ℃, and the uniform reduction of the water content of the pelleting shells of 20-30 times or more to be less than 5% in the temperature range is very difficult, or the long drying process influences the pelleting efficiency and greatly improves the seed pelleting cost.

Disclosure of Invention

In view of the problems in the background art, the present invention aims to provide a high-rate pelleting coating material for small-particle seeds and a coating method thereof, wherein the high-rate pelleting coating material comprises: fillers, binders, adjuvants, colorants and functional auxiliaries; the filler is a mixture obtained by mixing 100 parts by weight of 200-325-mesh vermiculite powder serving as a base material with 2-10 parts by weight of potassium carbonate, 0-15 parts by weight of bentonite and 0-20 parts by weight of diatomite by a high-speed mixer; the adhesive is a mixture prepared by mixing and stirring 1-3 parts by weight of high-viscosity hydroxypropyl methyl cellulose aqueous solution with the concentration of 3 wt%, 1-3 parts by weight of sodium polyacrylate aqueous solution with the concentration of 7 wt%, 3-5 parts by weight of polyvinyl alcohol aqueous solution with the concentration of 8 wt% and 10-15 parts by weight of water at the temperature of 20-40 ℃ until emulsification is carried out; the dosage of the adhesive is 20-25% of that of the filler; the auxiliary agent comprises 200 meshes of talcum powder and a film-forming agent, and the mass ratio is 1: 1; the colorant is an aqueous color paste which does no harm to seeds, and the color of the colorant is the same as that of the film-forming agent; the functional auxiliary agent comprises one or a combination of a microbial fertilizer, a trace element fertilizer and a water-retaining agent.

Optionally, the trace element fertilizer comprises one or a combination of a boron fertilizer, a zinc fertilizer, a manganese fertilizer, a molybdenum fertilizer, a copper fertilizer and an iron fertilizer; the water-retaining agent is super absorbent polymer resin SAP.

The invention provides a high-rate pelleting coating method for small-particle seeds, which adopts the high-rate pelleting coating material for the small-particle seeds, and comprises the following steps: the first stage is as follows: coating the seeds in the kernel forming stage to obtain kernel pelleted seeds with the radius of 'seed radius +0.2 mm'; and a second stage: coating the core pelletized seeds in order to increase the pelleting stage to obtain the increased pelleted seeds with the radius of 'target radius-0.1 mm'; and a third stage: and in the film forming and polishing stage, the increased pelleted seeds are subjected to film forming and polishing to obtain high-magnification pelleted seeds with target radiuses.

Optionally, the kernel forming stage includes the following steps: firstly, averagely dividing seeds to be pelletized into K1 parts according to the unit weight of a coating machine for single pelleting, and pelleting the kernels according to the following steps: (1) wetting: firstly, seeds are added into a coating machine, the machine is started, the seeds are thrown up and rotated in the coating machine through a rotating chassis of the coating machine to form a convoluted and overturned seed flow, an adhesive is injected through a liquid supply device, and the coating machine is continuously operated for 30 seconds to wet the seeds without adhesion; (2) and (3) wrapping: according to the calculated result of the pelleting scheme, continuously and uniformly adding the filler under the starting state of the coating machine, then adding the adhesive according to the proportion of 20-25 wt% of the filler, and after the filler and the adhesive are added, continuously operating the coating machine for 25-45 seconds to uniformly coat the filler on the seeds to obtain kernel pelleted seeds; (3) and (3) drying: starting a dryer, gradually and uniformly pouring the kernel pelletized seeds into the dryer for drying, drying by using hot air at 40-50 ℃ for 15-25min, and continuously drying at the normal temperature of not higher than 30 ℃ for 5-10min to obtain kernel pelletized seeds with the water content of not higher than 5%; the radius of the dried kernel pelletized seed is R₀(ii) a (4) Sieving: using a plane classifier to sequentially use the mesh apertures of the dried kernel pelletized seeds to be 2R respectively₀0.2-0.5 mm and 2R₀Sieving (0.2-0.5) mm sieve to remove oversize and undersize kernel pelleted seeds, and further selecting and eliminating double-seed pellets and seedless pellets to obtain uniform-particle-size distributionStandard kernel pelletized seed having a coating average thickness of 0.2 mm; when K1 is greater than 1 part, repeating the above steps (1) - (4).

Optionally, the enlarged pellet stage comprises the steps of: firstly, according to the unit weight of single pelleting by a coating machine, averagely dividing standard inner core pelleting seeds formed in the first stage into K2₁Parts, each part is subjected to pellet enlargement according to the following steps: (1) wetting: starting a coating machine, adding standard inner core pelletized seeds to form a seed flow, and adding a binder which is 2-5 wt% of the standard inner core pelletized seeds to wet the standard inner core pelletized seeds without adhesion; (2) increasing: according to the calculated result of the pelleting scheme, synchronously and uniformly adding the filler, the adhesive and the functional auxiliary agent under the starting state of the coating machine, and after the addition is finished, continuously operating the coating machine for 25-45 seconds to uniformly mix the filler, the adhesive and the functional auxiliary agent in the repeated collision process and gradually and uniformly coat the surface of the standard kernel pelleted seed to obtain the enlarged pelleted seed; the addition amount of the adhesive is 20-25 wt% of the filler, and the addition amount of the functional auxiliary agent is 0-5 wt% of the filler; (3) and (3) drying: starting a dryer, gradually and uniformly pouring the increased pelletized seeds into the dryer for drying, drying the seeds with high air flow by using hot air at the temperature of 40-50 ℃ for 20-30min, and continuously drying the seeds for 5-10min at the normal temperature of not higher than 30 ℃ to obtain the increased pelletized seeds with the water content of not higher than 5%; (4) sieving: screening the dried enlarged pelleted seeds by using a plane classifier, and removing oversize and undersize particles to obtain the enlarged pelleted seeds with uniform particle size of the equal part of particles; (5) when K2₁When the weight is more than 1 part, repeating the steps (1) to (4) to obtain all equal parts of the enlarged pills; (6) carrying out nth enlargement on the enlarged and pelletized seeds according to a pelletizing scheme design, wherein N is more than or equal to 1 and less than or equal to N; dividing the volume weight of the pill into K2 equally according to the coating machine_nRepeating the increase of one equal part for each equal part according to the steps (1) to (4); via K2_nRepeating the steps to complete the nth enlarged pill of all the seeds; after N times of enlarging the pellets, the average radius of all the seeds was increased to "target radius-0.1 mm", resulting in a standard enlarged pelletizationAnd (4) seeds.

Optionally, the film forming and polishing stage comprises the following steps: firstly, dividing standard enlarged pelleting seeds obtained in the second stage into K3 parts according to the unit weight of single pelleting by a coating machine, and performing film forming and polishing according to the following steps: (1) wetting: adding the standard enlarged pelleted seeds obtained in the second stage into a coating machine, starting the machine to form a seed flow, and adding a binder accounting for 2-5 wt% of the standard enlarged pelleted seeds to wet the seeds in the coating machine without adhesion; (2) increasing: according to the calculated result of the pelleting scheme, the filling agent, the adhesive which is equivalent to 20-25 wt% of the filling agent and the coloring agent which is equivalent to 5-8 wt% of the adhesive are gradually, synchronously and uniformly added under the starting state of the coating machine, so that the filling agent, the adhesive and the coloring agent are uniformly mixed in the repeated collision process and gradually and uniformly coated on the surface of the standard enlarged pelleted seed to obtain the pelleted seed to be polished; (3) polishing: adding talcum powder which is 1 wt% of the seed into the pelleted seed to be polished, operating for 15s, finally adding a film-forming agent which is 1 wt% of the seed, and continuously operating for 10-20s to obtain the pelleted seed after polishing; (4) and (3) drying: drying the polished pelleted seeds with high air flow by using hot air at the temperature of 40-50 ℃ for 15-25min, and then continuously drying the pelleted seeds for 5-10min at the normal temperature of not higher than 30 ℃ to obtain standard high-rate pelleted seeds with the water content of not higher than 5%; (5) when K3 is greater than 1 part, repeating the above steps (1) - (4).

Optionally, the pelleting scheme calculation comprises the steps of:

the first step is as follows: calculating the average particle size r of small-particle seeds

(1) Determining the weight of each seed: taking 1000 seeds by using a seed counting instrument, combining and weighing the seeds to obtain the weight of thousand seeds, wherein the unit is g;

(2) and (3) measuring the specific gravity of the seeds: putting 1000g of seeds into a solid proportion instrument, and measuring the specific gravity of the seeds with the unit of g/cm³；

(3) Calculate the average single seed volume: calculating the volume of 1000 seeds according to the thousand seed weight and specific gravity obtained above, wherein the unit is cm³The obtained numerical value is in mm³Then, is the average single seed volume v;

(4) calculating the average single seed radius r: the small-particle seed is spherical or nearly spherical in shape, and the average single-particle radius r is calculated by the spherical volume formula (3v/4 pi) by using the average single-particle volume v^1/3In mm;

the second step is that: calculating the maximum thickness of the pellets, the number of times N required to increase the pellets and the thickness of the pellets per increase

(1) Maximum thickness of the pellet:

the maximum pelleting thickness refers to the change value of the radius of the pelleted seeds, and the maximum pelleting thickness is the target radius R of the pelleted seeds and the average single seed radius R;

(2) increasing the theoretical number of stages of the pellet and each time increasing the thickness of the pellet:

pelleting small-particle seeds is divided into three stages: core formation, pellet enlargement and film forming polishing; wherein the thickness of the inner core of the pill in the inner core forming stage is preset to be 0.2mm, and the thickness of the film forming and polishing of the pill in the film forming and polishing stage is preset to be 0.1 mm;

maximum thickness of pelletization-target radius of pelletization-radius of seeds

The thickness of the pill increasing stage is the maximum pill thickness-the thickness of the inner core-the thickness of the film forming polishing stage is the maximum pill thickness-0.3 mm;

setting the thickness of each shot increasing stage as a reference of 0.3mm, wherein the theoretical times of the increasing shot stage is the thickness of the increasing shot stage/0.3, and the theoretical times of the shot forming times are integers according to the principle that two digits after the obtained numerical decimal point are greater than 0.17, and the two digits are less than or equal to 0.17, namely the shot forming times N of the increasing shot stage;

the thickness increased by each time of the pill is equal to the thickness/N of the pill increasing stage;

the third step: calculating the increased radius, single grain weight and total seed weight of the inner core pill and each increased pill stage, and obtaining the minimum preparation value of the filling agent

Determining the kernel pelleted seed radius R₀And the radius R after the n-th enlargement of the pellet_n: wherein R is₀Is pelletized with an inner core radius "Seed radius +0.2mm ", R_n＝R_n-1+ increasing the thickness of the pellet each time, wherein n refers to the nth increasing pellet;

single seed weight gain: respectively calculating the single-seed weight gain and the total seed weight gain of the kernel forming, the enlarging pelleting and the film forming polishing stages, and calculating the weight of the pelleted seeds in each step; wherein:

the single-grain weight gain is obtained according to the difference of the single-grain volume of the seeds before and after the formation or the increase of the kernel at this time and the specific gravity of the pellet material of 1.6, wherein:

single grain weight gain G at the core formation stage₀＝(4/3*Π*R₀ ³－4/3*Π*r³) 1.6; the unit is milligram;

single grain weight gain G after nth enlargement of pellet_n＝(4/3*Π*R_n ³－4/3*Π*R_n－1 ³) 1.6; the unit is milligram;

single particle weight gain (4/3 pi R) at the film forming and polishing stage³－4/3*Π*(R－0.1)³) 1.6, R is the target radius of the standard pelleted seed; the unit is milligram;

the weight gain of all seeds was calculated as follows:

weight gain of the inner core W₀Single grain weight gain G for kernel weight gain₀Average weight of individual seeds total weight of seeds, i.e. the amount of filler required for the formation of the inner core of the seeds; the unit is gram;

increased weight gain W for n-th pelletization_n＝G_nThe weight of single particles of the pellets to be processed at this time and the total weight of the pellets to be processed; the unit is gram;

the sum of the increased weight gains of n pelleting processes

To increase seed weight gain at the pelleting stage, i.e., the seeds increase the amount of filler required at the pelleting stage;

the weight gain of the film forming and polishing stage is equal to the weight of single grain weight gain/single grain pre-pelleted seed weight of the pre-pelleted seed total weight; the quantity of the filling agent required in the film forming and polishing stage; the unit is gram;

the sum of the weight gain of the whole seed kernel, the weight gain of the pelleting and increasing and the weight gain of the film forming and polishing stage is the total amount of the filler required by the whole pelleting process.

Optionally, the method further comprises the step of determining a seed pelleting scheme: dividing the total amount of the pills to be processed each time with the single maximum processing capacity of the maximum pelleting parameter of the coating machine, and rounding according to the principle of only adding but not adding to obtain the batch times, and calculating the added amount of the pills to be processed, the filling agent, the adhesive, the auxiliary agent, the coloring agent and the functional auxiliary agent according to the proportion to obtain the total pelleting scheme; wherein the maximum pelleting parameter of the coating machine is the maximum volume weight of the seeds after each pelleting of the coating machine; the pellets to be processed refer to the present seed or to the partially pelletised particles.

Optionally, the functional auxiliary agent is added in the stage of enlarging the pill, and the total adding amount is the filler added in the stage of enlarging the pill, namely

0-5% of (a), wherein N represents the total number of shot stages.

Optionally, an auxiliary agent and a coloring agent are added in the film-forming polishing stage, the addition proportion of the auxiliary agent talcum powder and the film-forming agent is respectively 1% of the weight of the pre-pellet seeds added in the film-forming polishing stage, and the addition amount of the coloring agent is 5-8% of the addition amount of the adhesive in the film-forming polishing stage.

The invention has the following beneficial effects:

the pill coating material and the coating method thereof solve the problems that the large-magnification pill of small-particle seeds is difficult or the pill effect is poor and the seed germination rate is influenced, and also have the functions of supplying the seeds with a microbial fertilizer, a trace element fertilizer and a high-efficiency water-retaining agent which are needed in the germination period for water retention, and the pelletized seeds can be quickly disintegrated when meeting water or in a soil humid environment to promote the germination of the seeds.

The invention relates to a large-magnification pelleting solution for small-particle seeds, which comprises three aspects of pelleting coating materials and a preparation method thereof, a formulation method of the pelleting scheme and a pelleting process flow, the technology can increase the pelleting weight of the small-particle seeds by 10-100 times or increase the particle size by 2-5 times according to the set requirement, and the pelleted seeds have uniform particles, low and consistent water content, meet the requirement of the existing sowing machinery on the particle size of the seeds, and improve the safe storage period of the pelleted seeds.

The invention divides the pill coating process into three stages of a kernel forming stage, a pill enlarging stage and a film forming and polishing stage, the materials used for pill coating in each step are accurately calculated, wherein the thickness of the kernel is uniformly set to be 0.2 mm; the thickness of the shot increasing stage is not higher than 0.35 mm; the film forming and polishing stage is uniformly set to be 0.1mm, the number of non-seed particles and double-seed particles in the obtained pelleted seeds is reduced through the processes of primary nucleation, multiple weight increment and primary film forming, functional additives such as microbial fertilizers, trace element fertilizers, water-retaining agents and the like which are in direct contact with the seeds and possibly have damage to the seeds are isolated from the surfaces of the seeds, the obtained pelleted seeds are uniformly dried, and the moisture content of different positions of the pellets is consistent.

The invention also has the following beneficial effects:

1. the invention selects the adhesive which is easy to dissolve in water and the inert filler which has high hydrophilicity and is difficult to agglomerate, after sowing, the pelletized seeds are quickly split after meeting water or in a high-humidity environment of soil, and meanwhile, water retention agents (a class of resin with extremely strong water absorption capacity) are optionally added, so that the low water content of the seeds is kept during storage, meanwhile, enough water can be absorbed after germination, and the germination time of the seeds can be shortened according to the difference of the pelletized seeds;

2. the microbial fertilizer and the rhizobium activity are properly added and maintained, the germination of seeds and the early emergence of seedlings are promoted, and the effects of aligning and strengthening the seedlings are achieved. The invention adopts a low-temperature drying process, and active substances such as microbial fertilizer, rhizobium and the like added in the seed culture medium keep activity after being dried at low temperature, have the effect of promoting the growth of germs and seedlings, and can continuously play a role in the whole seed seedling stage.

3. The added microbial fertilizer, the micro-fertilizer and the water retention agent are positioned in the middle interlayer of the pelletized seeds and do not directly contact the seeds, so that the adverse effects of phytotoxicity and the like caused by the fact that the components directly contact the seeds are avoided;

4. the technical scheme adopts the processes of multiple enlargement and multiple screening, the seed volume and size of the pelleting processing are uniform, the mechanical and accurate seed taking and precision seeding are favorably realized, simultaneously, no seed particles and double seed particles are removed after the multiple screening, the proportion of seedling leakage or seedling weight after the seeding is reduced, and the yield is favorably improved.

5. The process flow of the invention can ensure that the seeds are fully and uniformly dried and can be safely dried to the safe water content and the consistent water content, thereby ensuring the vitality of the seeds and ensuring that the shelf life of the pelleted seeds is not influenced.

Other features of the present invention and its advantages will become apparent from the following detailed description of exemplary embodiments of the invention.

Detailed Description

The present invention will be described in detail with reference to the following embodiments in order to make the aforementioned objects, features and advantages of the invention more comprehensible.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

First, a high-rate pelletization coating material for small-sized seeds according to the first aspect of the present invention will be described.

The small-particle seed high-rate pelleting coating material according to the first aspect of the invention comprises a filler, a binder, an auxiliary agent, a coloring agent and a functional auxiliary agent.

The filler is a mixture obtained by mixing 100 parts by weight of 200-325-mesh vermiculite powder serving as a base material with 2-10 parts by weight of potassium carbonate, 0-15 parts by weight of bentonite and 0-20 parts by weight of diatomite by a high-speed mixer.

The adhesive is prepared by mixing and stirring 1-3 parts by weight of high-viscosity hydroxypropyl methyl cellulose aqueous solution with the concentration of 3 wt%, 1-3 parts by weight of sodium polyacrylate aqueous solution with the concentration of 7 wt%, 3-5 parts by weight of polyvinyl alcohol aqueous solution with the concentration of 8 wt% and 10-15 parts by weight of water at the temperature of 20-40 ℃ to form an emulsified mixture. The dosage of the adhesive is 20-25% of the dosage of the filler.

The auxiliary agent is an auxiliary material which is uniformly coated on the surface of the pelleted and increased pelleted seed, is filled with different colors according to requirements and enables the pelleted shell to be hard and bright, and comprises talcum powder and a film-forming agent, the adding amount of the auxiliary agent is 2 percent of that of the pre-pelleted seed, and the mass ratio of the talcum powder to the film-forming agent is 1: 1. the talcum powder is 200 meshes of talcum powder; the film forming agent refers to a special film forming agent for seed coating sold in the market, such as L502, L088, L105 and the like sold in Yingkoai company, and the film forming agent should have a bright color for distinguishing different seeds after pelleting.

The functional auxiliary agent is substances for promoting growth in a seedling planting period, such as a microbial fertilizer, a trace element fertilizer, a water-retaining agent and the like, and is selected according to the type of the pellet seeds and the difference of planting environment after the seeds are pelletized. The microbial fertilizer is a biological fertilizer prepared by industrially culturing and fermenting one or more beneficial microorganisms; the trace element fertilizer refers to a fertilizer containing trace elements which are few in crop absorption amount and indispensable, and generally refers to boron fertilizer, zinc fertilizer, manganese fertilizer, molybdenum fertilizer, copper fertilizer, iron fertilizer and the like; the water-retaining agent is super absorbent polymer resin which has high water absorption capacity after meeting water, stores water and can absorb the stored water when seeds germinate.

The colorant is the ground color of the seed film forming agent, is various non-irritant, corrosive or other water-based color pastes with different colors and no harm to the seeds, is selected according to the required pelleting appearance color and is consistent with the color of the selected film forming agent, so that the pelleting seed after film forming has a brighter appearance.

Through test comparison, after the pelleting material formula is subjected to pelleting treatment, the specific gravity of the hard shell formed by pelleting and agglomeration after being dried is 1.6 +/-5 percent g/cm³In the range of (1), the method of pelletization according to the present embodiment is used to remove the fillerThe additional weight of material added was comparable to the loss of uncoated seed surface during pelleting and the weight of oversize pellets (double seed pellets) and undersize pellets (seedless pellets) that were screened off. Because the high-rate pelleting of the small-particle seeds aims at increasing the particle size of the seeds, and a small amount of functional auxiliary agents are added on the basis of the increased particle size of the seeds to facilitate the storage and the germination of the seeds, and the precision requirement is not very high, the use amount of the filling agent of the pelleting material pelleting coating and the use scheme of the pelleting material calculated according to the specific gravity of 1.6 are suitable for preparing different pelleting schemes of the small-particle seeds.

Next, the high-rate pelleting coating method for the small-particle seeds according to the second aspect of the invention is introduced, and the pelleting coating method comprises three stages of 1 time of kernel formation, N times of pellet enlargement and 1 time of film forming and polishing. The stages are as follows:

the first stage is as follows: in the kernel forming stage, firstly, seeds to be pelletized are formed into pellet kernels in one or more batches, one part of the seeds is weighed for internucleation, a coating material with the thickness of 0.2mm is coated on the surfaces of the seeds to obtain the pellet kernels, and the method comprises the following steps:

(1) wetting: adding seeds into a coating machine, starting the machine, throwing the seeds in the coating machine through a rotary chassis of the coating machine and rotating to form a convoluted seed flow, injecting an adhesive which is 2-5% of the amount of the seeds through a liquid supply device to wet the seeds without adhesion, and after the adhesive is injected, continuously operating the coating machine for 30 seconds to wet the seeds and make the seeds adhere downwards;

(2) and (3) wrapping: and (3) gradually and uniformly adding the filling agent according to the calculation result of the pelleting scheme in the starting state of the coating machine, adding the adhesive in proportion to ensure that the seeds, the filling agent and the adhesive are in full contact, and gradually and uniformly coating the filling agent on the surfaces of the seeds in the repeated collision process. After the filler and the adhesive are added, the coating machine continues to operate for 25-45 seconds, so that the filler can be uniformly coated on the seeds, and the granulation of the inner core is realized; the adhesive is added in a proportion of 20-25% of the filler.

(3) And (3) drying: starting the drier, pouring the internucleated seeds into the drier to dry, drying with hot air at 40-50 deg.C for 15-25min, and drying at room temperature for 5-10min, wherein the temperature of the dried kernel is not higher than 30 deg.C and the water content of the seeds is not higher than 5%.

(4) Sieving: using a flat classifier, the mesh diameters were selected to be 2R₀0.2-0.5 mm and 2R₀And (3) screening the dried pelletized core twice by using a sieve of which the diameter is (0.2-0.5) mm, and removing oversize double-seed pellets and undersize seedless pellets to obtain uniform and consistent pelletized core seeds.

The first stage is finished, the uniform spherical particles with the particle diameter of the pelleting inner core being 0.4 mm larger than the seed particle diameter (diameter) are pelletized, and when the batch of the inner core required in the stage is more than 1 time, the steps (1) to (4) are repeated.

And a second stage: and (2) a step of enlarging the pellets, namely, enlarging the pellets once or for multiple times, adding a functional auxiliary agent, and increasing the weight of the pellets to a preset target size, wherein the "pellets to be enlarged" in the following description refers to the pellets obtained in the first step or the pellets of which the pellets have been enlarged n-1 times by adopting the following steps (1) to (4), and n refers to the nth enlarged pellets:

firstly, the pellets to be enlarged are equally divided into one or more batches according to the scheme determined by the second aspect, and one of the batches is weighed to enlarge the pellets.

(1) Wetting: the machine is started, the pellets to be enlarged are added to form a stream of seeds, and a binder is added in an amount corresponding to 2% to 5% by weight of the pellets to be enlarged, to wet the seeds in the coater without sticking.

(2) Increasing: calculating to gradually, synchronously and uniformly add the filler in a starting state of the coating machine according to a pelleting scheme, adding the adhesive and the functional auxiliary in proportion to fully contact the pellets to be increased, the filler, the adhesive and the functional auxiliary, gradually and uniformly coating the filler on the surface of the seeds in a repeated collision process, and after the addition is finished, continuously operating the coating machine for 25-45 seconds to uniformly coat the filler on the seeds to realize the increased pelleting; the addition amount of the adhesive is 20-25% of the addition amount of the filler, and the addition amount of the functional auxiliary agent is 0-5% of the addition amount of the filler.

(3) And (3) drying: starting the drier, pouring the pelletized seeds into the drier to dry, drying with hot air at 40-50 deg.C for 20-30min, and drying at room temperature for 5-10min, wherein the temperature of the pelletized core after drying is not higher than 30 deg.C and the water content of the seeds is not higher than 5%.

(4) Sieving: taking out the seeds, screening by using a plane classifier, removing oversize and undersize particles, and obtaining the 'prepelleted seeds' with uniform particles to be polished and colorized.

(5) Repeating the above steps (1) to (4) N times (N is calculated by the second aspect), the pre-pelleted seed diameter is as desired and pre-pelleted seeds of uniform size are obtained.

When the enlarged batch of pellets required for this stage is more than 1 time, the above (1) to (6) are repeated.

And a third stage: polishing, brightening and coloring

(1) Wetting: averagely dividing the pre-pelleted seeds obtained in the second stage into 1 or more batches, weighing one of the pre-pelleted seeds, adding the weighed pre-pelleted seeds into a coating machine, starting the coating machine to form a seed flow, and adding an adhesive which is 2-5% of the pre-pelleted seeds to wet the seeds in the coating machine without adhesion;

(2) increasing: according to the difference of the grain diameter of the pre-pelleted seeds, the filling agent calculated according to the technical scheme, the adhesive which is equivalent to 20-25 percent of the adding amount of the filling agent and the coloring agent which is equivalent to 5-8 percent of the adhesive are gradually, synchronously and uniformly added into the coating machine, so that the seeds, the filling agent, the adhesive and the coloring agent are fully contacted, and the filling agent is gradually and uniformly coated on the surfaces of the seeds in the repeated collision process;

(3) polishing: after the filling agent is added, adding talcum powder which is about equal to 1 percent of the adding amount of the pre-pelleted seeds, operating for 15 seconds, finally adding film forming agent which is equal to 1 percent of the pre-pelleted seeds, and operating for 10-20 seconds;

(4) and (3) drying: and (3) after the pelleting is finished, taking out the seeds, drying the seeds by using hot air at the temperature of 40-50 ℃ for 15-25 minutes in a large air volume manner, and then continuously drying the seeds for 5-10 minutes at the normal temperature, wherein the temperature of the inner core of the dried pellets is not higher than 30 ℃ and the water content of the seeds is not higher than 5%.

When the film-forming polishing batch required at this stage is more than 1 time, the above (1) to (4) are repeated.

The third stage is completed and the result is an increase to the desired pelleted seed.

In the pelleting coating method, the dosage of the filler is obtained by adding the total counts of the core pellets, the enlarging pellets and the weight required by the film-forming and polishing stage required by the preparation method of the pelleting scheme, and the actually prepared filling quantity is equal to or more than the total count.

In the pellet coating method of the present invention, the binder is prepared in an amount of 20 to 25% of the preparation amount of the filler.

In the pelleting coating method, the functional auxiliary agent is selectively added in the stage of increasing the size of the pellets according to the requirement of each pelleting and the difference of the characteristics of the seeds, and the total addition amount is the filler added in the stage of increasing the size of the pellets, namely

0-5% (wherein N represents the total number of shot stages increased).

In the pelleting coating method, the auxiliary agent and the coloring agent are conventional auxiliary agents and are added in the film-forming and polishing stage without being separately prepared, the addition proportion of the auxiliary agent talcum powder and the film-forming agent is respectively 1 percent of that of the pre-pelleting seeds added in the pelleting stage, and the addition amount of the coloring agent is 5 to 8 percent of that of the adhesive in the film-forming and polishing stage.

Finally, a method of preparing a pelletization protocol of the present invention is described, comprising the steps of:

the first step is as follows: calculating the average particle size of the small-particle seeds: the small-particle seed has small particle size and large size difference, and the error of measurement and calculation by using calipers is large, the average particle size of the seeds is obtained by measuring the thousand seed weight and the seed specific gravity by the technical scheme, and the measuring method comprises the following steps:

determining the weight of the individual seed to be pelleted: taking 1000 seeds to be pelleted by a particle counting instrument, combining and weighing the seeds to be pelleted to obtain the weight of thousand seeds in grams, and taking the average number of the seeds as the weight of single seeds in milligrams;

determining the volume of a single seed to be pelleted: putting 1000g of seeds into a solid proportion instrument, and measuring the specific gravity of the seeds with the unit of g/cm³；

Calculating a single seed volume: calculating the total volume value of 1000 seeds to be pelleted according to the thousand seed weight and the specific gravity, wherein the unit is cm³The value is in mm³The time is the single particle volume of the seed to be pelleted;

calculating the average radius r of the single seed: the shape of the small-particle seed is spherical or close to spherical, and the average radius r value of the single-particle seed is calculated by using the volume obtained in the above formula: r (3/4 v/l) (1/3) in mm.

The second step is that: determining the maximum thickness of the pellets to be pelletized, the number of times to increase the pellets and the thickness of the pellets per increase

According to the technical scheme of the invention, the small-particle seed pelleting is divided into three stages, namely a kernel forming stage, a pelleting increasing stage and a film forming and polishing stage, wherein the thickness of the pellets in the kernel forming stage is uniformly set to be 0.2mm, the thickness of the pellets in the film forming and polishing stage is uniformly set to be 0.1mm, the pelleting increasing stage is that the thickness of the kernels and the film forming and polishing thickness are subtracted according to the difference value between the target particle diameter and the average particle diameter of the seeds after the pelleting and the required value after the target particle diameter is subtracted, and the pelleting thickness is increased for 1-3 times according to the thickness which is close to 0.3mm and is not more than 0.35 mm each time, so that the thickness of each weight increment is uniform, and the water content of the dried seeds is lower than 5 percent and uniform.

Calculating the maximum thickness of the pelletization: the maximum thickness of pelletization means the difference between the radius of the seed to be pelletized and the target radius of the pelletized seed, and is the maximum thickness of pelletization, and the maximum thickness of pelletization is the predetermined radius of the pelletized seed-the average radius of the seed;

calculating the pelleting times N: the pelletizing process includes three stages of pelletizing kernel, enlarging pellet and forming film and polishing, and the technological scheme has kernel thickness of 0.2mm and radius of kernel of pellet R₀，R₀Seed radius + 0.2; the film-forming polishing thickness was set to 0.1mmRice; according to empirical values, in order to ensure uniform and sufficient drying, the thickness of the pills in the increasing stage is not more than 0.35 mm, the technical scheme takes a 0.3mm reference safety value to ensure sufficient drying after the pills are granulated. The theoretical number of times of increasing the pill is (the maximum thickness of the pill-the thickness of the inner core pill-the thickness of the polishing weight gain)/0.3 is (the maximum thickness of the pill-the 0.2-0.1)/0.3 is (the maximum thickness of the pill-the 0.3-1), the number of times of the pill-the integer is taken according to the principle that "two positions after the decimal point of the obtained numerical value are more than 0.17, the two positions are less than or equal to 0.17", namely the number N of times of the pill-the value is obtained, and the thickness of the pill-the arbitrary weight gain is in the interval range of 0.25-0.35 mm.

The thickness of the pellet was calculated for each increase: the thickness increased by each time of the pill is (the maximum thickness of pill formation is-0.2-0.1)/N;

the third step: calculating the increased radius, the single-grain weight and the total weight of the seeds to be processed of the inner core pill and the pill stage of each weight gain, and obtaining the minimum preparation value of the filling agent:

n-th pelleting of the inner core radius R_nAnd increasing the radius R after the shot_n: wherein R is₀Is the radius of the inner core of the pill, namely 'seed radius + 0.2', R_n＝R_n-1+ pelletising the increased thickness each time, wherein n refers to the nth increased pellet;

single seed weight gain: respectively calculating the weight (in milligrams) of each of the pelleted kernel, each shot enlarging scheme, the single grain weight (in milligrams) in the film forming and polishing stage and the weight (in kilograms) of all the seeds to be pelleted, and calculating the weight (in kilograms) of the seeds pelleted in each step; wherein:

the single grain weight gain is obtained according to the difference of the single grain volume of the kernel pill or the seeds before and after the weight gain pill of the current time and the proportion of the pill material of 1.6, wherein:

single particle weight gain of core weight gain G₀＝(4/3*Л*R₀ ³－4/3*Л*r³)*1.6；

Increased single grain weight gain G for n-th pelletization_n＝(4/3*Л*R_n ³－4/3*Л*R_n－1 ³)*1.60；

Film forming and polishing stageParticle weight gain (4/3) target radius³-4/3 a (target radius-0.1)³)*1.6

Wherein R refers to the seed radius in millimeters (in millimeters), R₀The radius (unit millimeter) of the pelletized inner core is r +0.2, and 1.60 is the specific gravity of the dried coating material of the pelletizing tool;

the weight gain of all the seeds to be pelleted was calculated as follows:

weight gain of the inner core W₀Single grain weight gain G for kernel weight gain₀Weight of single seed and weight of seed to be processed, namely the quantity of filler required for forming the kernel of the seed to be processed;

increased weight gain W for n-th pelletization_n＝G_nWeight of single seed and weight of seed to be processed;

further: the sum of the increased weight gains of n pelleting processes

In order to increase the weight gain of the seeds to be processed in the pelleting stage, namely, the quantity of the filling agent required by the seeds to be processed in the pelleting stage is increased;

the weight gain of the film forming and polishing stage is equal to the weight of single grain weight gain/single grain weight of seeds to be processed of the film forming and polishing stage; the quantity of the filling agent required by film forming and polishing of the seeds to be processed is also obtained;

the sum of the weight gain of the inner core of all the seeds to be processed, the weight gain of the seeds to be processed in the pelleting process and the weight gain of the film-forming polishing stage is the total amount of the filler required in the whole pelleting process, namely the minimum value of the preparation amount of the filler in the first part of the technical scheme;

the fifth step: determining a seed pelleting scheme: according to the steps, according to the weight of the pelletized particles in each step and the single maximum processing capacity of the maximum pelletizing parameter (the maximum volume weight of the seeds after each pelletizing of the coating machine) of the coating machine, dividing, and rounding according to the principle of only adding, the batches are obtained, the pellets to be processed (the seeds to be pelletized or the partially pelletized particles at this time) and the filling agent are evenly distributed, other auxiliary agents are added in proportion, the processing batch number required by each step is determined, and the total pelletizing scheme of the pellets to be pelletized in each batch is obtained, and the following table is as follows:

the following will specifically describe the small-particle seed high-rate pelleting coating material and the coating method thereof according to the present invention with reference to specific examples.

The raw materials used in the following examples of the present invention, unless otherwise specified, were conventional commercially available products, and the coating machine selected from those having a maximum volume weight of 10 kg per pelletization.

Example 1: the seeds of the unshelled bermuda grass are required to be enlarged to the particle size (diameter) of 2mm, functional additives are added, and red coating is carried out. The seeds are provided by Beijing Baiqing Yuan animal husbandry scientific and technological development limited company, the seed quantity is 1000g, the purity is more than 98 percent, and the germination rate is more than 85 percent. .

1. Preparing the pelleting coating material

Preparing a filling agent: the pelleting filler consists of vermiculite, potassium carbonate, bentonite and diatomite in a mass ratio of 100: 10: 5: 20; the pill particles are prepared by mixing 22.62 kg of filler, 20 kg of 200-mesh vermiculite, 2kg of potassium carbonate, 1kg of bentonite and 4kg of diatomite for 10 minutes by using a high-speed mixer according to the principle of more than or equal to the weight of the filler, and standing for later use;

preparing an adhesive: preparing 5.5 kg of adhesive according to the proportion of about 20% of the filler, wherein the adhesive is selected from 3 wt% of hydroxypropyl methyl cellulose aqueous solution, 7 wt% of sodium polyacrylate aqueous solution, 8 wt% of polyvinyl alcohol aqueous solution and water at the temperature of 20 ℃, mixing and stirring until all components are emulsified, and standing for later use; wherein the mass ratio of each component is 1: 3: 5: 12;

preparing an auxiliary agent: 0.2kg of each of 200 mesh talc and L502 film former (red) from Yingkoai;

preparing a coloring agent: selecting a water-soluble red color paste HG111 of a colorant;

preparing a functional additive: 200g of microbial fertilizer fulvic acid potassium, 50g of trace element molybdenum fertilizer sodium molybdate, 50g of boron fertilizer boric acid, 50g of anhydrous copper sulfate and a water-retaining agent which are macromolecular resin SAP50g are taken, the total weight is 400 g, the proportion of the total weight of the filler in the pill increasing stage is 3.12%, and the components are fully mixed and then stand for later use;

2. making a pelleting scheme (coating material proportion is 1.6 g/cubic centimeter)

2.1 measuring or calculating the properties of the seeds to be pelletized and the materials to be pelletized

Item	Unit of	Numerical value	Description of the invention	Remarks for note
					Thousand seed weight	Keke (Chinese character of 'Keke')	0.28	Measured to obtain
Weight per unit	Milligrams of	0.28	Computing	Equal to thousand grain weight
					Specific gravity of	G/cc	1.223	Measured to obtain
Accumulation of thousand particles	Cubic centimeter	0.23	Computing	Thousand grain weight/specific gravity
					Volume of single grain	Cubic millimeter	0.23	Computing	Weight of one thousand grains
Radius r	Millimeter	0.38	Computing	(unit volume 3/4/3.14) ^ (1/3)

2.2 determining the maximum thickness of the pellets, the number of times required to increase the pellets and the thickness of the pellets per increase

2.3 measurement and calculation of weight gain of single seed and dosage of filler in three stages

Index (I)	Unit of	Core formation phase	Increasing the shot stage	Polishing, brightening and hyperchromic stage
					After completion the single particle radius R_n	Millimeter	0.58	0.90	1.0
Volume of single grain	Cubic millimeter	0.82	3.05	4.19
					Single grain weight gain G_n	Milligrams of	0.94	3.58	1.82
Weight Wn of all seeds to be processed	Kilogram (kilogram)	3.35	12.78	6.48
					The total weight of the finished pellets	Kilogram (kilogram)	4.35	17.13	23.62

2.4 step pelletization protocol

3. The pelleting coating process flow scheme is characterized in that the pelleting coating process is completed in three stages:

the first stage is as follows: preparing a pelleted core comprising the steps of:

(1) putting 1000g of shelled bermuda grass seeds subjected to trusting processing into a coating machine, starting the machine, throwing and rotating the seeds in the coating machine through a rotating chassis of the coating machine to form a whirling and rising seed flow, adding 30g of adhesive (namely, 3 percent of the added seed amount) through a liquid supply device, and operating for 30 seconds to moisten the seeds without adhesion;

(2) after the seeds were wetted, 670g of the total amount of 3350g of filler and binder calculated in the "preparation of pelletization protocol" of this example were added, and the binder and filler were added in small amounts stepwise and simultaneously until the addition of the filler was complete to form the pelletized core seeds. After the feeding is finished, the coating machine continuously operates for 25 seconds, so that the adhesive and the filler are uniformly and firmly attached to the surface of the seeds to form a pill core;

(3) stopping the coating machine to take seeds, gradually and uniformly adding the pelletized seed kernels into a drying machine for drying treatment at 45 ℃ for 15min, then continuously drying for 5min by using normal-temperature air (room temperature is 10-25 ℃), wherein the temperature of the dried pellet kernels is not higher than 30 ℃, and the water content of the kernels is reduced to 5%.

(4) Using a flat classifier, seed-free pellets smaller than 0.9mm and double-seed pellets larger than 1.5mm were removed with sieves having mesh diameters of 0.90 mm and 1.50 mm, respectively.

The core of the pellet obtained by the above treatment was increased in weight by 3.35 times as compared with the seed to obtain a total weight of the core of the pellet of about 4.35kg and an average particle diameter (diameter) of 1.16 mm.

And a second stage: pelletizing the inner core of the pill particles for 1 time in 2 batches to form balls, adding a functional auxiliary agent, and increasing the particle size (diameter) to 1.8mm, wherein the method comprises the following steps:

(1) accurately weighing 2.175kg of the inner cores of the pills obtained in the first stage;

(2) adding the weighed pelleted cores into a coating machine, starting the machine to form a seed flow, and adding 67.5g of an adhesive to wet the seeds in the coating machine without adhesion;

(3) 6.39kg of filler, 1.3kg of adhesive and one half of prepared functional additive are gradually and synchronously and uniformly added into a coating machine, so that the seeds, the filler, the adhesive and the functional additive are fully contacted, and the filler is gradually and uniformly coated on the surfaces of the seeds in the repeated collision process; after the feeding is finished, the coating machine continuously operates for 25 seconds, so that the filler, the adhesive and the functional auxiliary agent are uniformly and firmly attached to the surface of the seeds;

(4) stopping the coating machine for taking seeds, uniformly adding the pre-pelleted seeds into a dryer for drying treatment at 45 ℃ for 25min, then continuously drying for 10min by using normal-temperature air (room temperature is 20-25 ℃), wherein the temperature of the dried pellets is not higher than 30 ℃, and the water content of the inner core is reduced to be below 5%;

(5) taking out the seeds, screening by using a plane classifier, and removing empty particles (tiny particles) which are smaller than the round holes by 1.5mm and double particles (larger particles) which are larger than the round holes by 2.3mm to obtain pre-pelletized particles with uniform particles, wherein the particle size is 1.8 mm;

(6) the treatments of steps (1) to (5) were repeated in 2 batches, and the second stage was completed to obtain pre-pelleted seeds of about 17.5kg of uniform size and an increase in average particle size to about 1.8 mm.

And a third stage: the obtained 17.5kg of pre-pelleted seeds are subjected to film forming, polishing, brightening and color increasing in 3 batches

(1) Accurately weighing 5.71kg of the pre-pelleted seeds obtained in the second stage, adding the pre-pelleted seeds into a coating machine, starting the machine to form a seed flow, and adding 135g of an adhesive to wet the seeds in the coating machine without adhesion;

(2) 2.16kg of filling agent, 450g of adhesive and 12.5 g of coloring agent are gradually and synchronously and uniformly added into the coating machine, so that the seeds, the filling agent, the adhesive and the coloring agent are fully contacted, and the filling agent is gradually and uniformly coated on the surfaces of the seeds in the repeated collision process;

(3) and after the filler is added, adding 58.5g of talcum powder, operating for 15 seconds, finally adding 58.5g of film forming agent, operating for 15 seconds, and ending the shelling bermuda grass seed pelleting process.

Repeating the steps (1) - (3) for 3 times, and polishing and brightening the whole pre-pelleted seeds obtained in the second stage.

(4) Taking out the seeds for drying after the pelleting is finished, drying the seeds with high air volume by using hot air at 45 ℃, wherein the drying time is 20 minutes, and then continuously drying the seeds for 7 minutes at normal temperature, wherein the temperature of the pelleted kernel after drying is not higher than 30 ℃, and the water content of the seeds is not higher than 5%;

through the pelleting treatment of the three stages, 23.6kg of pelleted bermuda grass seeds are obtained, the average particle size of the seeds is 2.0mm, the particle size of the seeds is increased by 2.6 times, the actual thousand seed weight of the pelleted seeds is 6.6 g, and the actual weight gain is about 23.6 times.

Example 2: the petunia seeds are increased to the particle size of 2mm without adding any functional auxiliary agent, and are coated in blue. The seeds are 1000g of petunia seeds provided by Beijing Baiqing source animal husbandry scientific and technological development limited company, the purity is more than 98 percent, and the germination rate is more than 85 percent.

1. Preparing the pelleting coating material

Preparing a filling agent: determining that the coating materials are vermiculite, methyl carbonate and bentonite, and mixing the materials according to a mass ratio of 100: 2: 15, according to the formulation method of the pelleting scheme, 65.6 kg of the filling agent is needed for the target pelleting, 60 kg of 200-mesh vermiculite, 1.2 kg of potassium carbonate and 9kg of bentonite are taken according to the principle of being more than or equal to the target pelleting, mixed for 10 minutes by a high-speed mixer to obtain 70.2kg of the filling agent, and then kept stand for later use;

preparing an adhesive: preparing 17.5kg of adhesive according to the proportion of about 25% of the filler, selecting 3% of hydroxypropyl methyl cellulose aqueous solution, 7% of sodium polyacrylate aqueous solution, 8% of polyvinyl alcohol aqueous solution and water with the temperature of 40 ℃, mixing and stirring until all components are emulsified, and standing for later use; wherein the mass ratio of each component is 3: 3: 3: 15.

preparing an auxiliary agent: 0.5 kg of each of 200 mesh talc and L088 film-forming agent (blue) from Yingkoai Co;

preparing a coloring agent: selecting water-soluble blue color paste HG111 as a colorant;

preparing a functional auxiliary agent: no functional auxiliary agent is added.

2. Method for preparing pill-forming scheme (coating machine adopting and adding the scheme has maximum single volume weight of 10 kg)

Item	Unit of	Numerical value	Description of the invention	Remarks for note
					Thousand seed weight	Keke (Chinese character of 'Keke')	0.10	Measured to obtain
Weight per unit	Milligrams of	0.10	Computing	Equal to thousand grain weight
					Specific gravity of	G/cc	1.15	Measured to obtain
Accumulation of thousand particles	Cubic centimeter	0.09	Computing	Thousand grain weight/specific gravity
					Volume of single grain	Cubic millimeter	0.09	Computing	Weight of one thousand grains
Radius r	Millimeter	0.27	Computing	(unit volume 3/4/3.14) ^ (1/3)

2.3 inner core and enlarged pellet protocol

2.4 fractional pelletization protocol

3. The pelleting coating process flow is completed in three stages:

(1) putting 1000g of entrusted petunia seeds into a coating machine, starting the machine, throwing the seeds in the coating machine through a rotary chassis of the coating machine and rotating to form a whirling and rising seed flow, then adding 50g of adhesive (namely 5 percent of the amount of the added seeds) through a liquid supply device, and operating for 30 seconds to moisten the seeds without adhesion;

(2) after the seeds were wetted, 1445g of the total amount of 5780g of filler and binder calculated as "method of preparation of pelletization protocol" in this case were added, and the binder and filler were gradually and simultaneously added in small amounts in steps until the addition of filler was completed to form pelletized core seeds. After the feeding is finished, the coating machine continuously operates for 30 seconds, so that the adhesive and the filler are uniformly and firmly attached to the surface of the seeds to form a pill core;

(3) stopping the coating machine to take seeds, gradually and uniformly adding the pelletized seed kernels into a drying machine for drying treatment at 50 ℃ for 25min, then continuously drying for 10min by using normal-temperature air (room temperature is 10-25 ℃), wherein the temperature of the dried pellet kernels is not higher than 30 ℃, and the water content of the kernels is reduced to 5%.

(4) Using a flat classifier, seedless pellets having a diameter of less than 0.70mm and double-seeded pellets having a diameter of greater than 1.4mm were removed with screens having mesh diameters of 0.70mm and 1.4mm, respectively.

The core of the pellet is obtained through the treatment, compared with the seed, the weight of the core of the pellet is increased by 5.78 times, the total weight of the core of the pellet is about 6.78kg, and the average particle size is increased to 0.94 mm.

And a second stage: pelletizing and enlarging into balls for two times, wherein the grain diameter is increased to 1.38mm for the first time, and the grain diameter is increased to 1.8mm for the second time, and the method comprises the following steps:

the first two batches increased the particle size of the 6.78kg pellet core to 1.38 mm:

(1) 3.39kg of the cores of the pellets obtained in the first stage were added to the coating machine, the machine was started up to form a seed stream, 170g of binder was added and the run was continued for 30 seconds to wet the seeds in the coating machine without sticking.

(2) 7.295kg of filler and 1.77kg of adhesive are synchronously and uniformly added into the coating machine step by step to ensure that the seeds, the filler and the adhesive are fully contacted, and the filler is uniformly coated on the surfaces of the seeds step by step in the repeated collision process. After the feeding, the coating machine is continuously operated for 35 seconds, so that the adhesive and the filler are uniformly and firmly attached to the surface of the seeds.

(3) Stopping the machine to take seeds, uniformly adding the first prepelled seeds into a dryer to dry at 50 ℃ for 30min, then continuously drying for 8 min by using normal-temperature air (room temperature is 10-25 ℃), wherein the temperature of the dried pellets is not higher than 30 ℃, and the water content of the inner core is reduced to 5%.

(4) Taking out the seeds, and screening by using a plane classifier to remove empty particles (tiny particles) with the particle size of less than 1.0mm and double particles (larger particles) with the particle size of more than 1.8mm to obtain first-time pre-pelleting particles with uniform particles, wherein the particle size is 1.38 mm.

After 2 batches of the treatments of steps (1) - (4), the first enlargement of the second stage was completed, resulting in about 21.6kg of pre-pelleted seeds of consistent size, with an average particle size increase to about 1.38 mm. Then, the second stage of pellet weight gain is carried out in three batches, and the average particle size is increased to 1.8 mm:

(1) 7.02kg of the pellets from the first enlargement of the second stage were added to the coater, the machine was started to form a stream of seeds, and 195g of binder was added to wet the seeds in the coater without sticking.

(2) 9.03kg of filler and 2.24kg of adhesive are gradually and synchronously and uniformly added into the coating machine, so that the seeds, the filler and the adhesive are fully contacted, and the filler is gradually and uniformly coated on the surfaces of the seeds in the repeated collision process. After the feeding, the coating machine is continuously operated for 35 seconds, so that the adhesive and the filler are uniformly and firmly attached to the surface of the seeds.

(3) Stopping the machine to take seeds, uniformly adding the second pre-pelleted seeds into a dryer to dry for 30min at 45 ℃, then continuously drying for 5-10min by using normal-temperature air (room temperature is 10-25 ℃), wherein the temperature of the dried pellets is not higher than 30 ℃, and the water content of the inner core is reduced to 5%.

(4) Taking out the seeds, and screening by using a plane classifier to remove empty particles (tiny particles) which are smaller than the round holes by 1.5mm and double particles (larger particles) which are larger than the round holes by 2.2mm to obtain second-time pregranulated particles with uniform particles, wherein the average particle size is 1.8 mm.

After 3 batches of the treatments of steps (1) - (4) and the second enlargement at the second stage, about 49kg of prepelled seeds of uniform size were obtained and the average particle size increased to about 1.8 mm.

And a third stage: polishing brightening and coloring

(1) Accurately weighing 7kg of the pre-pelleted seeds obtained in the second stage, adding the pre-pelleted seeds into a coating machine, starting the machine to form a seed flow, and adding 200g of adhesive to wet the seeds in the coating machine without adhesion;

(2) 2.6kg of filling agent, 650g of adhesive and 39 g of coloring agent are gradually and synchronously and uniformly added into a coating machine, so that the seeds, the filling agent, the adhesive and the coloring agent are fully contacted, and the filling agent is gradually and uniformly coated on the surfaces of the seeds in the repeated collision process;

(3) and after the filler is added, adding 70g of talcum powder, operating for 15 seconds, finally adding 70g of film forming agent, and operating for 20 seconds to finish the pelleting process of the petunia seeds.

Repeating the steps (1) to (3) for 7 times, and polishing and brightening the whole pre-pelleted seeds obtained in the second stage.

(4) After the pelleting is finished, taking out the seeds, drying the seeds by using hot air at 50 ℃ with large air volume for 25 minutes, and then continuously drying the seeds for 10 minutes at normal temperature, wherein the temperature of the pelleted kernel after drying is not higher than 30 ℃, and the water content of the seeds is not higher than 5%;

through the pelleting treatment of the three stages, 66.6kg of the pelleted petunia seeds are obtained, the average particle size of the seeds is 2.0mm, the particle size of the seeds is increased by 3.6 times, the actual thousand seed weight of the pelleted seeds is 6.7 g, and the actual weight gain is about 66.6 times.

Example 3: the celery seeds are enlarged to the particle size of 3.2 mm. The seeds are 1500g of celery seeds provided by Beijing Baiqing source animal husbandry scientific and technological development limited company, the purity is more than 98 percent, and the germination rate is more than 85 percent.

1. Preparing the pelleting coating material

Preparing a filling agent: the filling agent is selected from vermiculite, potassium carbonate and diatomite according to a mass ratio of 100: 5: 20; according to the method for preparing the pelleting scheme, the pelleting celery seeds need about 105 kg of the filling agent, 85kg of 200-mesh vermiculite, 4.25 kg of potassium carbonate and 19 kg of kieselguhr are taken according to the principle of being more than or equal to the formula, mixed for 15 minutes by using a high-speed mixer to obtain 108.5kg of the filling agent, and the mixture is kept stand for later use;

preparing an adhesive: preparing 23.8 kg of adhesive according to the proportion of about 22% of the filler, selecting 3% of hydroxypropyl methyl cellulose aqueous solution, 7% of sodium polyacrylate aqueous solution, 8% of polyvinyl alcohol aqueous solution and water with the temperature of 40 ℃, mixing and stirring until all components are emulsified, and standing for later use; wherein the mass ratio of each component is 3: 1: 4: 10.

preparing an auxiliary agent: 1.0 kg of each of 200 mesh talc and L105 film former (green) from Yingkoai;

preparing a coloring agent: selecting a water-soluble green color paste HG601 as a colorant;

preparing a functional additive: taking 800g of microbial fertilizer fulvic acid potassium, 200g of trace element molybdenum fertilizer sodium molybdate and 200g of water-retaining agent (polymer resin SAP) for totally 1200 g, fully mixing, and standing for later use; according to the formulation of the pelletization scheme in this example, 78.5 kg of the filler is required to be added in the enlarged pelletization stage of the present process, and the addition ratio of the functional additive is 1.53%.

2. Method for preparing pelletizing scheme

Item	Unit of	Numerical value	Description of the invention	Remarks for note
					Thousand seed weight	Keke (Chinese character of 'Keke')	0.4	Measured to obtain
Weight per unit	Milligrams of	0.4	Computing	Equal to thousand grain weight
					Specific gravity of	G/cc	1.21	Measured to obtain
Accumulation of thousand particles	Cubic centimeter	0.33	Computing	Weight/specific gravity
					Volume of single grain	Cubic millimeter	0.33	Computing	Accumulation of Qian-Jing-Di-Hao
Radius r	Millimeter	0.43	Computing	(unit volume 3/4/3.14) ^ (1/3)

2.2 determination of the number of pelletization of the core pellets

2.3 inner core and enlarged pellet protocol

2.4 fractional pelletization protocol

(1) putting 1500g of entrusted celery seeds into a coating machine, starting the machine, throwing the seeds in the coating machine through a rotary chassis of the coating machine and rotating to form a convoluted and overturned seed flow, then adding 33g of an adhesive through a liquid supply device, and operating for 30 seconds to wet the seeds without adhesion;

(2) after the seeds were wetted, 945g of the total 4.27kg of filler and binder calculated in the "preparation of pelletization protocol" of this example were added, and the binder and filler were added in small amounts stepwise and simultaneously until the addition of the filler was complete to form the pelletized core seeds. After the feeding is finished, the coating machine continuously operates for 40 seconds, so that the adhesive and the filler are uniformly and firmly attached to the surface of the seeds to form a pill core;

(3) stopping the coating machine to take seeds, gradually and uniformly adding the pelletized seed cores into a drying machine for drying treatment at 40 ℃ for 20min, then continuously drying for 8 min by using normal-temperature air (room temperature is 10-25 ℃), wherein the temperature of the dried pellet cores is not higher than 30 ℃, and the water content of the cores is reduced to 5%.

(4) Using a flat classifier, seedless pellets having a diameter of less than 1.0mm and double-seeded pellets having a diameter of greater than 1.5mm were removed with screens having mesh diameters of 1.0mm and 1.5mm, respectively.

The core of the pellet is obtained through the treatment, compared with the seed, the weight of the core of the pellet is increased by 2.86 times, the total weight of the core of the pellet is about 5.8kg, and the average grain diameter is increased to 1.26 mm.

And a second stage: pelletizing for three times to increase the particle size into balls, adding a functional additive for three times, increasing the particle size for the first time to 1.84mm, increasing the particle size for the second time to 2.42mm, and increasing the particle size for the third time to 3.0mm, wherein the method comprises the following steps:

first increase:

(1) the core pellets from the first stage were enlarged in 2 batches and 2.885kg of each batch was weighed into the coater, the machine was started to form a stream of seeds, 64g of binder was added and the run continued for 30 seconds to wet the seeds in the coater without sticking.

(2) 6.635kg of filler, 1.46kg of adhesive and 101.5 g of functional additive are gradually and synchronously and uniformly added into the coating machine, so that the seeds, the filler, the adhesive and the functional additive are fully contacted, and the filler is gradually and uniformly coated on the surfaces of the seeds in the repeated collision process. After the feeding, the coating machine is continuously operated for 45 seconds, so that the adhesive and the filler are uniformly and firmly attached to the surface of the seeds.

(3) Drying the pre-pelleting: stopping the machine to take seeds, uniformly adding the first pre-pelleted seeds into a dryer for drying treatment at 40 ℃ for 20min, then continuously drying the seeds for 5min by using normal-temperature air (room temperature is 10-25 ℃), wherein the temperature of the dried pellets is not higher than 30 ℃, and the water content of the inner core is reduced to 5%.

(4) Taking out the seeds, sieving with a plane classifier to obtain 1.5 and 2.3mm mesh diameters, respectively, and removing empty particles (micro particles) with particle size less than 1.5mm and double particles (larger particles) with particle size greater than 2.3mm to obtain first pre-pelletized particles with uniform particles, wherein the average particle size is 1.84 mm.

After 2 batches of the treatments of steps (1) - (4) and the first enlargement of the second stage, approximately 19.1kg of prepelled seeds of uniform size were obtained, with an average particle size increase to approximately 1.84 mm. Then, a second stage of pellet weight gain is carried out, and the pellets are increased in 5 batches:

(1) 3.91kg of the pellets obtained in the first enlargement of the second stage were weighed into the coater, the machine was started to form a seed stream, and 85g of binder was added to wet the seeds in the coater without sticking.

(2) 4.99Kg of filler, 1.1Kg of adhesive and 76.3 g of functional additive are gradually and synchronously and uniformly added into the coating machine, so that the seeds, the filler, the adhesive and the functional additive are fully contacted, and the filler is gradually and uniformly coated on the surfaces of the seeds in the repeated collision process. After the feeding, the coating machine is continuously operated for 45 seconds, so that the adhesive and the filler are uniformly and firmly attached to the surface of the seeds.

(3) Drying the pre-pelleting: stopping the machine to take seeds, uniformly adding the second pre-pelleted seeds into a dryer to dry at 40 ℃ for 20min, then continuously drying for 5min by using normal-temperature air (room temperature is 10-25 ℃), wherein the temperature of the dried pellets is not higher than 30 ℃, and the water content of the inner core is reduced to 5%.

(4) Taking out the seeds, and sieving with a plane classifier and sieves with sieve holes of 2.0mm and 2.8mm respectively to remove empty particles (tiny particles) smaller than 2.0mm and double particles (bigger particles) larger than the round holes by 2.8mm to obtain second pre-pelletized particles with uniform particles, wherein the particle size is 2.4 mm.

After 5 batches of the treatments of steps (1) - (4) and the second enlargement at the second stage, about 44.0kg of prepelled seeds of uniform size were obtained and the average particle size increased to about 2.42 mm. Then, a second stage of third pellet weight gain is carried out, and the pellets are increased in 9 batches:

(1) 4.89kg of the pellets from the second enlargement of the second stage were added to the coater, the machine was started up to form a stream of seeds, and 110g of binder was added to wet the seeds in the coater without sticking.

(2) 4.48kg of filler, 986g of adhesive and 68.5 g of functional auxiliary agent are gradually and synchronously and uniformly added into the coating machine, so that the seeds, the filler and the functional auxiliary agent of the adhesive are fully contacted, and the filler is gradually and uniformly coated on the surfaces of the seeds in the repeated collision process. After the feeding, the coating machine is continuously operated for 45 seconds, so that the adhesive and the filler are uniformly and firmly attached to the surface of the seeds.

(3) Drying the pre-pelleting: stopping the machine to take seeds, uniformly adding the second pre-pelleted seeds into a dryer to dry at 40 ℃ for 20min, then continuously drying for 10min by using normal-temperature air (room temperature is 10-25 ℃), wherein the temperature of the dried pellets is not higher than 30 ℃, and the water content of the inner core is reduced to 5%.

(4) Taking out the seeds, screening by using a plane classifier and a screen with screen holes of 2.5mm and 3.5mm respectively, and removing empty particles (tiny particles) with the size less than 2.5mm of the round holes and larger particles with the size more than 3.5mm of the round holes to obtain third pre-pelletized particles with uniform particles, wherein the particle size is 3.0 mm.

After 9 batches of the treatments of steps (1) - (4) and the third enlargement of the second stage, about 84.3kg of prepelled seeds of uniform size were obtained, with the average particle size increasing to about 3.0 mm.

And a third stage: polishing, brightening and brightening: the pre-pellet seeds obtained in the second stage were 84.3kg film-polished in 11 batches, 7.66kg per batch:

(1) accurately weighing 7.66kg of the pre-pelleted seeds obtained in the second stage, adding the pre-pelleted seeds into a coating machine, starting the machine to form a seed flow, and adding 170g of adhesive to wet the seeds in the coating machine without adhesion;

(2) 1.65kg of filling agent, 365g of adhesive and 22 g of coloring agent are gradually and synchronously and uniformly added into a coating machine to ensure that the seeds, the filling agent, the adhesive and the coloring agent are fully contacted, and the filling agent is gradually and uniformly coated on the surfaces of the seeds in the repeated collision process;

(3) and after the filler is added, adding 77g of talcum powder, operating for 15 seconds, finally adding 77g of film forming agent, and operating for 10 seconds to finish the pelleting process of the batch of celery seeds.

Repeating the steps (1) to (3) for 11 times, and polishing and brightening the whole pre-pelleted seeds obtained in the second stage.

(4) After the pelleting is finished, taking out the seeds, drying the seeds by using hot air at 40 ℃ with large air volume for 15 minutes, and then continuously drying the seeds for 5 minutes at normal temperature, wherein the temperature of the pelleted kernel after drying is not higher than 30 ℃, and the water content of the seeds is not higher than 5%;

through the pelleting treatment of the three stages, 102.5kg of pelleted celery seeds are obtained, the average particle size of the seeds is 3.2mm, the particle size of the seeds is increased by 3.7 times, the actual thousand seed weight of the pelleted seeds is 27.3 g, and the actual weight gain is about 68.3 times.

Performance testing

The pelletized seeds prepared above were used for laboratory and field comparative tests, respectively. The experiments were performed with reference to GB/T25240-2010 and GB/T15671-2009, the entire contents of which are incorporated herein by reference. Selecting main indexes such as seed rate, single seed rate, cracking degree, single seed stress resistance, uniformity, germination rate, etc. as indexes for detecting whether the pelleted seeds are qualified (the index measuring method is performed according to GB/T25240-2010 and GB/T15671-2009). The results are as follows:

TABLE 1 laboratory comparative test results

From the laboratory comparative test results, the high-rate pelleted seeds prepared by the method have good seed rate, single seed rate, cracking degree, single seed stress resistance, uniformity and germination rate, and can solve the problems that small-particle seeds are difficult to pelletize in large rate, the pelleting effect is poor and the seed germination rate is influenced.

Although some specific embodiments of the present invention have been described in detail by way of illustration, it should be understood by those skilled in the art that the above illustration is only for the purpose of illustration and is not intended to limit the scope of the invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A high-rate pelleting coating material for small-particle seeds is characterized by comprising the following components: fillers, binders, adjuvants, colorants and functional auxiliaries;

the filler is a mixture obtained by mixing 100 parts by weight of 200-325-mesh vermiculite powder serving as a base material with 2-10 parts by weight of potassium carbonate, 0-15 parts by weight of bentonite and 0-20 parts by weight of diatomite by a high-speed mixer;

the adhesive is a mixture prepared by mixing and stirring 1-3 parts by weight of high-viscosity hydroxypropyl methyl cellulose aqueous solution with the concentration of 3 wt%, 1-3 parts by weight of sodium polyacrylate aqueous solution with the concentration of 7 wt%, 3-5 parts by weight of polyvinyl alcohol aqueous solution with the concentration of 8 wt% and 10-15 parts by weight of water at the temperature of 20-40 ℃ until emulsification is carried out; the dosage of the adhesive is 20-25% of that of the filler;

the auxiliary agent comprises 200 meshes of talcum powder and a film-forming agent, and the mass ratio is 1: 1;

the colorant is an aqueous color paste which does no harm to seeds, and the color of the colorant is the same as that of the film-forming agent;

the functional auxiliary agent comprises one or a combination of a microbial fertilizer, a trace element fertilizer and a water-retaining agent.

2. The small-particle seed high-rate pelleting coating material as claimed in claim 1, wherein the trace element fertilizer comprises one or a combination of boron fertilizer, zinc fertilizer, manganese fertilizer, molybdenum fertilizer, copper fertilizer and iron fertilizer; the water-retaining agent is super absorbent polymer resin SAP.

3. A method for high-rate pelleting coating of small-particle seeds, which adopts the high-rate pelleting coating material of the small-particle seeds as claimed in any one of claims 1-2, and comprises the following steps:

the first stage is as follows: coating the seeds in the kernel forming stage to obtain kernel pelleted seeds with the radius of 'seed radius +0.2 mm';

and a second stage: coating the core pelletized seeds in order to increase the pelleting stage to obtain the increased pelleted seeds with the radius of 'target radius-0.1 mm';

and a third stage: and in the film forming and polishing stage, the increased pelleted seeds are subjected to film forming and polishing to obtain high-magnification pelleted seeds with target radiuses.

4. The small particle seed high-rate pelleting coating method as claimed in claim 3, wherein said core forming stage comprises the following steps:

firstly, averagely dividing seeds to be pelletized into K1 parts according to the unit weight of a coating machine for single pelleting, and pelleting the kernels according to the following steps:

(1) wetting: firstly, seeds are added into a coating machine, the machine is started, the seeds are thrown up and rotated in the coating machine through a rotating chassis of the coating machine to form a convoluted and overturned seed flow, an adhesive is injected through a liquid supply device, and the coating machine is continuously operated for 30 seconds to wet the seeds without adhesion;

(2) and (3) wrapping: according to the calculated result of the pelleting scheme, continuously and uniformly adding the filler under the starting state of the coating machine, then adding the adhesive according to the proportion of 20-25 wt% of the filler, and after the filler and the adhesive are added, continuously operating the coating machine for 25-45 seconds to uniformly coat the filler on the seeds to obtain kernel pelleted seeds;

(3) and (3) drying: starting a dryer, gradually and uniformly pouring the kernel pelletized seeds into the dryer for drying, drying by using hot air at 40-50 ℃ for 15-25min, and continuously drying at the normal temperature of not higher than 30 ℃ for 5-10min to obtain kernel pelletized seeds with the water content of not higher than 5%; the radius of the dried kernel pelletized seed is R₀；

(4) Sieving: using a plane classifier to sequentially use the mesh apertures of the dried kernel pelletized seeds to be 2R respectively₀0.2-0.5 mm and 2R₀Screening by a sieve of- (0.2-0.5) mm to remove the kernel pelleted seeds with overlarge and undersize particle sizes, further selecting and eliminating double-particle seed pellets and seed-free pellets to obtain standard kernel pelleted seeds with uniform particle size distribution range, wherein the average coating thickness of the standard kernel pelleted seeds is 0.2 mm;

when K1 is greater than 1 part, repeating the above steps (1) - (4).

5. The small particle seed high-rate pelleting coating method as claimed in claim 3, wherein the increasing pelleting stage comprises the following steps:

firstly, according to the unit weight of single pelleting by a coating machine, averagely dividing standard inner core pelleting seeds formed in the first stage into K2₁Parts, each part is subjected to pellet enlargement according to the following steps:

(1) wetting: starting a coating machine, adding standard inner core pelletized seeds to form a seed flow, and adding a binder which is 2-5 wt% of the standard inner core pelletized seeds to wet the standard inner core pelletized seeds without adhesion;

(2) increasing: according to the calculated result of the pelleting scheme, synchronously and uniformly adding the filler, the adhesive and the functional auxiliary agent under the starting state of the coating machine, and after the addition is finished, continuously operating the coating machine for 25-45 seconds to uniformly mix the filler, the adhesive and the functional auxiliary agent in the repeated collision process and gradually and uniformly coat the surface of the standard kernel pelleted seed to obtain the enlarged pelleted seed; the addition amount of the adhesive is 20-25 wt% of the filler, and the addition amount of the functional auxiliary agent is 0-5 wt% of the filler;

(3) and (3) drying: starting a dryer, gradually and uniformly pouring the increased pelletized seeds into the dryer for drying, drying the seeds with high air flow by using hot air at the temperature of 40-50 ℃ for 20-30min, and continuously drying the seeds for 5-10min at the normal temperature of not higher than 30 ℃ to obtain the increased pelletized seeds with the water content of not higher than 5%;

(4) sieving: screening the dried enlarged pelleted seeds by using a plane classifier, and removing oversize and undersize particles to obtain the enlarged pelleted seeds with uniform particle size of the equal part of particles;

(5) when K2₁When the weight is more than 1 part, repeating the steps (1) to (4) to obtain all equal parts of the enlarged pills;

(6) carrying out nth enlargement on the enlarged and pelletized seeds according to a pelletizing scheme design, wherein N is more than or equal to 1 and less than or equal to N; dividing the volume weight of the pill into K2 equally according to the coating machine_nRepeating the increase of one equal part for each equal part according to the steps (1) to (4); via K2_nRepeating the steps to complete the nth enlarged pill of all the seeds;

after N times of enlargement of the pellets, the average radius of all seeds was increased to "target radius-0.1 mm", resulting in standard enlarged pelleted seeds.

6. The small particle seed high-rate pelleting coating method according to claim 3, wherein the film forming and polishing stage comprises the following steps:

firstly, dividing standard enlarged pelleting seeds obtained in the second stage into K3 parts according to the unit weight of single pelleting by a coating machine, and performing film forming and polishing according to the following steps:

(1) wetting: adding the standard enlarged pelleted seeds obtained in the second stage into a coating machine, starting the machine to form a seed flow, and adding a binder accounting for 2-5 wt% of the standard enlarged pelleted seeds to wet the seeds in the coating machine without adhesion;

(2) increasing: according to the calculated result of the pelleting scheme, the filling agent, the adhesive which is equivalent to 20-25 wt% of the filling agent and the coloring agent which is equivalent to 5-8 wt% of the adhesive are gradually, synchronously and uniformly added under the starting state of the coating machine, so that the filling agent, the adhesive and the coloring agent are uniformly mixed in the repeated collision process and gradually and uniformly coated on the surface of the standard enlarged pelleted seed to obtain the pelleted seed to be polished;

(3) polishing: adding talcum powder which is 1 wt% of the seed into the pelleted seed to be polished, operating for 15s, finally adding a film-forming agent which is 1 wt% of the seed, and continuously operating for 10-20s to obtain the pelleted seed after polishing;

(4) and (3) drying: drying the polished pelleted seeds with high air flow by using hot air at the temperature of 40-50 ℃ for 15-25min, and then continuously drying the pelleted seeds for 5-10min at the normal temperature of not higher than 30 ℃ to obtain standard high-rate pelleted seeds with the water content of not higher than 5%;

(5) when K3 is greater than 1 part, repeating the above steps (1) - (4).

7. The method for high-rate pelleting coating of small-sized seed as claimed in any one of claims 4 to 6, wherein said pelleting scheme calculation comprises the steps of:

(3) Calculate the average single seed volume: calculating the volume of 1000 seeds according to the thousand seed weight and specific gravity obtained above, wherein the unit is cm³The obtained numerical value is in mm³When the temperature of the water is higher than the set temperature,is the average single seed volume v;

(4) calculating the average single seed radius r: the small-particle seed is spherical or nearly spherical in shape, and the average single-particle radius r is calculated by the spherical volume formula (3v/4 pi) by using the average single-particle volume v¹/₃In mm;

(1) Maximum thickness of the pellet:

Determining the kernel pelleted seed radius R₀And the radius R after the n-th enlargement of the pellet_n: wherein R is₀Is in the form of pelletsRadius of chemonucleous, i.e. "seed radius +0.2 mm", R_n＝R_n-1+ increasing the thickness of the pellet each time, wherein n refers to the nth increasing pellet;

the weight gain of all seeds was calculated as follows:

the sum of the increased weight gains of n pelleting processes

8. The method for high-rate pelleting coating of small-sized seeds as claimed in claim 7, further comprising the step of determining a seed pelleting scheme: dividing the total amount of the pills to be processed each time with the single maximum processing capacity of the maximum pelleting parameter of the coating machine, and rounding according to the principle of only adding but not adding to obtain the batch times, and calculating the added amount of the pills to be processed, the filling agent, the adhesive, the auxiliary agent, the coloring agent and the functional auxiliary agent according to the proportion to obtain the total pelleting scheme; wherein the maximum pelleting parameter of the coating machine is the maximum volume weight of the seeds after each pelleting of the coating machine; the pellets to be processed refer to the present seed or to the partially pelletised particles.

9. The method for high-rate pelleting coating of small-sized seeds as claimed in claim 7, wherein the functional auxiliary is added in the stage of enlarging the pellets, and the total addition amount is the amount of the filler added in the stage of enlarging the pellets

0-5% of (a), wherein N represents the total number of shot stages.

10. The method for high-rate pelleting and coating of small-sized seeds as claimed in claim 7, wherein the auxiliary agent and the colorant are added during the film-forming and polishing stage, the addition ratio of the auxiliary agent talc powder to the film-forming agent is 1% of the weight of the pre-pelleted seeds added during the film-forming and polishing stage, and the addition amount of the colorant is 5-8% of the addition amount of the binder during the film-forming and polishing stage.