CN111837510A

CN111837510A - Litchi seed coating method

Info

Publication number: CN111837510A
Application number: CN202010763280.7A
Authority: CN
Inventors: 刘泽洋
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-08-01
Filing date: 2020-08-01
Publication date: 2020-10-30

Abstract

The invention discloses a litchi seed coating method, and belongs to the technical field of seed processing. Mixing and kneading the litchi seeds and coarse sand to roughen the surfaces of the seeds, adding hydrophobic powder particles and a penetrating agent into a conventional seed coating agent containing pesticide, and coating by a conventional method. The beneficial seed coating agent is attached to the surface of seeds, the seed coating success rate is improved, the coating falling rate is reduced, and the coating pesticide can effectively prevent and control the damage of soil-borne diseases and insects to the seeds and does not generate obvious phytotoxicity to roots and seedlings. The method is easy to operate and has obvious effect.

Description

Litchi seed coating method

Technical Field

The invention belongs to the technical field of seed processing, and particularly relates to a method for treating seeds and applying a seed coating agent related to litchi seed coating.

Background

1. Seed coating and pesticide amount

The seed coating is that the seeds and the seed coating agent are stirred and mixed according to a certain proportion, the seed coating agent is evenly coated on the surface of the seeds, and a firm medicine film is formed after the seed coating agent is dried. The seed coating agent product is widely applied to crops such as rice, wheat, corn, soybean, cotton and the like at present, and has good use effect on crops such as vegetables, watermelon, sorghum, cabbage and the like (seed coating agent development summary in China, peasant consummate, 2017 (24): 48) in the time of prince), so that the coating mainly takes medium and small-grain seeds as objects.

At present, seeds are coated with pesticides most commonly, and after the coated seeds are sown, pesticides attached to the surfaces of the seeds and released to the periphery of soil form a protection area or a protection belt to prevent the seeds from being invaded by soil diseases and pests. Secondly, when the pesticide is diffused from the surface of the seeds and sinks to the root system part of the plant along with rainfall or irrigation water, the root system is protected. Active ingredients slowly released by the coating film can enter the seedling body through the absorption of a root system and can also enter the seedling body through the absorption of a seed embryo, and are conducted to the ground part without application of the pesticide through the plant system, so that the effects of preventing diseases, controlling insects, promoting growth, strengthening seedlings and the like are exerted.

The pesticide adheres to the surface of the coated seeds and is gradually released into the soil, with the result that the damage that the pesticide may cause to the seeds must be strictly controlled "because the pesticide is concentrated around the seeds and in addition the germination of the seeds is a growth period that is quite sensitive to the pesticide. Similarly, the pesticide content of the pesticide film is too high, the pesticide film can cause direct damage to the root system after being released into soil and subside, and the seedling can be damaged by upward conduction after being absorbed by the root. Therefore, the determination of the concentration of the seed coating agent pesticide and the seed coating seed ratio (the ratio of the dosage of the seed coating agent to the quantity of the seeds) has the general principle of effectively preventing and treating the diseases and insect pests of the seeds, the root systems and the seedlings without generating obvious phytotoxicity on the seeds, the root systems and the seedlings.

2. Invasion of litchi seed by pests

Lichee (lichee)Litchi chinensis) Is a sapindaceae fruit tree, adopts 'seedling grafting' to breed litchi, usually uses a seeding seedling as a stock, and also needs seeding and seedling emergence in cross breeding. The litchi seeds (seed pits) are relatively large, brown, nearly ellipsoidal, about 2cm long and about 1.2cm wide at the maximum, and have the characteristics of large surface area and smooth surface leather with wax.

The litchi seed hilum has a large area, the diameter is 0.6-0.7 cm, the fruit seeds with aril removed are still rich in nutrients (adhesive substances in hilum cells can also be the components) and are good culture media for microorganisms. Therefore, in practical observation, it is found that white mildew-like substances appear on the surface of seed coats after 2-3 days under the environment with high humidity, which is undoubtedly caused by the invasion and proliferation of microorganisms. The umbilicus portion is also affected and turns into black brown, and the embryo shows brown water stain and further necrosis. "(Lumeiying, etc. litchi seed structure scanning electron microscope observation, Guangxi agricultural bioscience, 18(4): 291-" 293). When the seeds are sowed in soil, the seeds are often infected by pathogenic bacteria and invaded by pests, diseases damaging litchi seedlings comprise litchi downy mildew, anthracnose and the like, and pests comprise litchi leaf gall midge, a wok and the like.

3. The coating technology of litchi seeds is difficult.

Because the surfaces of litchi seeds are smooth and provided with wax, a low-energy surface is formed, the seed coating agent takes water as a solvent, the surface energy is large, the surface tension is higher than the critical surface tension of the wax, the seed coating agent is not easy to spread and adhere on the surfaces of the seeds and flows under the action of gravity, the seed coating agent is unevenly distributed on the surfaces of the seeds after film formation, the thickness of seed coating films is different, the litchi seeds are large-grain seeds, the seed coating agent is possibly not adhered to some parts of the surfaces of the seeds, the coating rate (the ratio of the covering area of the pesticide film to the total surface area of the seeds) is reduced, and the coating films are easy to fall off due to vibration in the transportation and sowing processes, so that the purpose.

For the pesticide type seed coating agent, the surface area of large-grain seeds is large under the conventional coating thickness, the using amount of the seed coating agent required by each seed is also large, the seed coating agent adopts the conventional pesticide concentration, although the seed coating agent has no damage to the seeds, because the absolute amount of the pesticide carried by each seed is large, the pesticide amount dissolved and released from the coating and settled to the roots of the plants is large during irrigation and rainfall after the coated seeds are sowed, the direct phytotoxicity to the roots is easy to cause, and the roots absorb the excessive pesticide and conduct to the overground stems and leaves, so the phytotoxicity to the stems and leaves can also be caused. If the pesticide concentration of the coated seed pesticide film is lower than that of the conventional pesticide film, although the root and seedling phytotoxicity can be reduced, for the seed, the damage of soil diseases and pests to the seed cannot be effectively prevented, and the seed cannot be protected ideally.

4. Effect of penetrant on seed coat wax

Generally, a surfactant with an HLB value of 7-9 is used as a wetting agent, and the wetting agent in the pesticide mainly reduces the solid-liquid interfacial tension and increases the wetting and contact of a liquid medicine on the surface of a treated object (pests, plants and the like). The penetrant can increase the penetration of the liquid medicine on the surface of the treated object and promote the absorption of the liquid medicine (Zhang Zong, application and research progress of pesticide adjuvant, pesticide science and management, 2009, 30 (1): 42-47), and the penetrant has good wetting effect, but only a few kinds of wetting agents have good penetration effect (Zhonghong, Mangan, wetting and penetration, Jiangsu silk, 1995, (2) 20-51, Weining, et al, discussion of pesticide wetting penetrant, surfactant industry, 1994(1):19-24, 14), such as nekal powder and penetrant JFC. Therefore, when the liquid is mixed with the seeds with the wax, the wetting agent and the penetrating agent can enable the liquid to be in full contact with the wax layer of the seeds and be easy to wet and attach to the surfaces of the seeds, and the penetrating agent can promote active ingredients of the liquid to penetrate into the wax layer and the seed coats to be absorbed and utilized by the seeds under the action of capillary tubes and the like.

Disclosure of Invention

The invention mainly aims to provide a litchi seed coating method which comprises the steps of increasing the roughness of the surface of a seed, improving the adhesion capacity of a seed coating agent on the surface of the seed, preventing excessive pesticide released by the seed coating agent from damaging the root system, and promoting the active ingredients of the seed coating agent to permeate into the seed so as to solve the problems in the background technology.

A method for coating the seeds of litchi includes such steps as washing fresh litchi seeds, kneading with coarse sand, and grinding to remove wax from the surface of litchi seeds to make the surface of litchi seeds rough. The hydrophobic powdery particles are added into the conventional seed coating agent, the seeds are mixed with the seed coating agent during coating, the particles are filled into the gaps and the pits, and when one part of a single particle is filled into the pits and one part of the single particle protrudes out of the surface of the litchi seed skin, the surface roughness of the seeds is increased, the flowing speed of the seed coating agent on the surface of the seeds can be hindered, and the beneficial seed coating agent is uniformly distributed on the surface of the seeds.

The seed coating agent is also added with a penetrating agent, so that the surface tension of the seed coating agent is reduced, the seed coating agent is easier to be soaked and attached in wax on the surface of the seed, the seed coating agent is uniformly distributed, and the penetrating agent is also beneficial to the active ingredients of the seed coating agent to penetrate a wax layer and seed coats and enter seed embryos to play a role.

The seed coating agent with the conventional pesticide concentration is doped with the hydrophobic powdery particles, namely the seed coating agent contains liquid and solid parts, and is coated according to the conventional pesticide ratio. In the aspect of the seed coating liquid part, regardless of the size of the seeds, the pesticide concentration is in a normal range, so that the damage of soil diseases and pests to the litchi seeds can be effectively resisted after the coated seeds are sowed. When large seeds are coated, under the condition that the pesticide seed ratio is unchanged, although the absolute amount (sum of solid amount and liquid amount) of the seed coating agent used by each seed is larger, the absolute amount of the pesticide contained by each seed is reduced because the hydrophobic powder particles occupy a certain volume in the seed coating agent and the liquid amount of the seed coating agent is correspondingly reduced, the pesticide amount released after sowing and deposited to the root along with water flow is small, and thus, the direct pesticide damage to the root or the indirect damage to seedlings are not easily caused.

The technical scheme of the invention is as follows:

a litchi seed coating method comprises mixing litchi seed with coarse sand, kneading for 8-20 min to form rough surface on the seed surface. Adding hydrophobic powder particles and penetrant into the conventional seed coating agent, and coating by a conventional method.

The volume of the coarse sand is the same as the volume of the seed.

The hydrophobic powder particles are powdery or fine particles, do not react with the seed coating agent, have specific gravity larger than that of the seed coating agent, and do not obviously improve the viscosity of the seed coating agent, and limestone powder (main component calcium carbonate) and fine sand (main component silicon dioxide) are mixed in equal volume, and the volume ratio of the hydrophobic powder particles to the seed coating agent is 1: 1-4.

The penetrant added in the seed coating agent is stable in hard water and is one of dioctyl sodium sulfosuccinate (OT) and polyoxyethylene lauryl ether, or the diisooctyl sodium sulfosuccinate and the polyoxyethylene lauryl ether are mixed according to the volume ratio of 2-8:1, the concentration of the penetrant in the seed coating agent is 0.03-0.3% (the volume of the seed coating agent refers to the volume of a liquid part, and the volume of hydrophobic powder particles is not counted in the volume of the seed coating agent),

the invention has the beneficial effects that: the pretreatment of seeds causes the surface groove and hole of the seeds, the seed coating agent is added with hydrophobic powder particles, the roughness of the surface of the seeds can be increased during coating, and the penetrant added into the seed coating agent is beneficial to the adhesion of the seed coating agent on the surface of the seeds and is uniformly distributed, so that the seed coating success rate is improved, and the film falling rate is reduced. The penetrating agent is also beneficial to the active ingredients of the seed coating agent to penetrate the wax layer and the seed coat and enter the seed embryo to play a role. The added hydrophobic powder particles in the seed coating agent are also beneficial to the pesticide of the coating film, so that the damage of soil-borne diseases and insects to seeds is effectively prevented and controlled, and obvious phytotoxicity to root systems and seedlings is not generated. The method has the advantages of low cost, easy operation, obvious effect and suitable popularization.

Detailed Description

Example one

Method (A)

1. Cleaning fresh litchi seeds, rubbing with coarse sand with the same volume and a small amount of water for 10 minutes to roughen the surfaces of the fresh litchi seeds, and airing. The conventional seed coating agent contains 8% of systemic fungicide carbendazim and 15% of insecticide thiamethoxam, and inactive ingredients (pesticide auxiliary agents, thickening agents, film forming agents, pigments, antifreeze agents and water) are used in conventional dosage.

The litchi seeds are divided into four groups, namely, the seeds are not coated. ② coating with conventional seed coating agent containing pesticide, namely, the conventional purpose of preventing and controlling diseases and pests. Thirdly, seed coating agent dilution, wherein the volume ratio of the inactive ingredients of the seed coating agent to the conventional seed coating agent is 1:2, namely, the pesticide is diluted and coated. And fourthly, coating by the method, adding penetrant diisooctyl succinate sodium sulfonate and lauryl alcohol polyoxyethylene ether (volume ratio is 4: 1) into the seed coating agent, mixing limestone powder and fine sand in equal volume when the concentration of the seed coating agent is 0.08%, adding the seed coating agent into the mixture, and quickly stirring the mixture and the seed coating agent in a volume ratio of 1: 2.

During coating, 40ml of seed coating agent (the fourth group contains the volume of hydrophobic powder particles) is added into each kilogram of seeds, the seeds are stirred continuously in a roller and dried in the air, and the seed coating agent is solidified into a film within 20 minutes.

2. The coating success rate is determined by the percentage of the number of the seeds and the total number of the coated seeds which are successfully coated. The seeds which are successfully coated are shaken for 30 min on a shaking table of 250 r/min and then weighed, and the percentage of the dropping amount of the seed coating agent to the total weight of the coated seeds is the dropping rate. And (4) taking the coated seeds which do not obviously fall off through the oscillation coating film for soil sowing, and observing the conditions of budding, seedling growth and pest infection.

3. The germination standard is that the length of the protruded seed coat of the radicle is half of the length of the seed, and the germination vigor is counted on the 6 th day.

(II) results

1. The quality of the seed coating is shown in Table 1

TABLE 1 pesticide content and coating quality of coated seeds

The success rate of the coating is 94%, compared with the conventional seed coating and seed coating agent dilution, the coating falling rate is obviously improved, and the falling rate of the coating is 0.6%, compared with other two groups, the coating falling rate is obviously reduced, namely, the method enables the coating to be completely and uniformly covered on the surface of the seed and not to fall off easily.

TABLE 2 germination, growth and infestation of coated seeds

2. The difference of the germination rates of four groups of seeds is not large, the germination potential of the conventional coated seeds is 47 percent, and the germination potential is obviously lower than that of other three groups, namely, the emergence is slow, so that the absolute amount of pesticide in each seed is large, and the table 2 shows.

3. Disease and pest infestation was observed on day 50 after sowing, see table 2. Compared with the conventional sowing method, the film coating pesticide concentration and the absolute amount of the pesticide of each seed of the conventional coating method can effectively reduce the pest and disease infection rate of the seeds, the stems and the leaves.

Although the absolute amount of the pesticide in each coated seed is lower than that in the conventional coated seed, the concentration is unchanged (equivalent to that in the coating group II), the damage of soil-borne diseases and pests to the seeds can be effectively prevented, and the protection effect on the seeds is equivalent to that in the coating group II. The absolute amount of the pesticide of each coated seed is lower than that of the conventional coated seed, and is equivalent to that of the conventional coated seed, but the penetrant is favorable for the seeds to absorb the coating pesticide, and the pesticide is conducted in vivo, so that the effect of protecting the stems and leaves is obviously better than that of the first group and the third group, and is equivalent to that of the conventional coated seed.

The seed coating agent dilution (c) is the same as the absolute amount of the pesticide in each coated seed (c), but the pesticide concentration is lower, and no penetrating agent promotes the embryo to absorb the pesticide, so the protection effect on the seeds, stems and leaves is much poorer.

4. Growth was observed on day 50 after sowing, see table 2. After conventional coating, the root length and the fresh weight of the roots are obviously reduced compared with other three groups. The absolute amount of the pesticide in each coated seed is less than that in the conventional coating, and the root growth index is not obviously influenced, which is equivalent to that of the conventional seed and the seed coating dilution.

(III) conclusion

1. The method of the invention ensures that the coating film covers the surface of the seed completely and firmly, improves the coating success rate and is not easy to fall off.

2. The dosage of the conventional coated seed coating agent pesticide has ideal effect on inhibiting the diseases and the pests from infecting the seeds, the stems and the leaves, but seriously influences the growth of root systems and delays the germination and emergence time of the seeds. If the concentration of the seed coating pesticide is reduced, the seed coating pesticide cannot effectively prevent and control the diseases and insect pests in the seedling stage although the seed coating pesticide has no adverse effect on the germination time and the root growth.

Therefore, for the large-grain seeds such as litchi, the method can effectively infect the seeds, stems and leaves by pests without causing adverse effects on the root growth and the seedling emergence speed, and is an ideal coating method.

Claims

1. A litchi seed coating method is characterized in that: mixing litchi seeds with coarse sand, kneading for 8-20 min to roughen the seed surface, adding hydrophobic powder particles and penetrant into conventional seed coating agent containing pesticide, and coating by conventional method;

the coarse sand has the same volume with the seeds;

the specific gravity of the hydrophobic powder particles is greater than that of the seed coating agent, limestone powder and fine sand are mixed in equal volume, and the volume ratio of the hydrophobic powder particles to the seed coating agent is 1: 1-4;

the penetrant is stable in hard water, one of diisooctyl succinate sodium sulfonate and polyoxyethylene lauryl ether is selected, or the diisooctyl succinate sodium sulfonate and the polyoxyethylene lauryl ether are mixed according to the volume ratio of 2-8:1, and the concentration of the penetrant in the seed coating agent is 0.03-0.3%.