CN111096335A - Soil fumigant and application thereof - Google Patents

Abstract

The invention relates to a soil fumigant, wherein the effective component of the soil fumigant is cyanamide, the mass fraction of the cyanamide in the soil fumigant is 20-50%, and the balance is auxiliary components which are allowed to be used and can be accepted in pesticides. The pesticide composition is suitable for preventing and controlling vegetables, flowers, strawberries, orchards, vineyards, Chinese herbal medicines and other crops, and can effectively kill nematodes, soil-borne pathogenic fungi, underground pests and the like in soil. The fumigant can be processed into preparations such as water aqua, suspending agent, aqueous emulsion, wettable powder, water dispersible granules and the like, and can be applied in fields by methods such as mechanical injection, drip irrigation, spraying, furrow application and the like.

Description

Soil fumigant and application thereof

The invention relates to the technical field of agriculture, in particular to a soil fumigant and application thereof.

Background

Soil-borne diseases are a class of plant diseases caused by infection with pathogens that survive in the soil. Mainly comprises nematode diseases, fungal and bacterial diseases and soil pests. Once enough pathogenic bacteria are accumulated, the root and the stem of the crop can be infected, destructive influence is caused to the crop, and serious damage is caused to melons, fruits, vegetables, ornamental plants and medicinal materials, particularly to the crop in a greenhouse. Generally, after 3-5 years of greenhouse cultivation, the yield and quality of crops are seriously affected, and the yield is generally reduced by 20% -40%, and the serious yield is reduced by more than 60% or even no harvest.

The traditional method for preventing and treating soil-borne diseases comprises disease-resistant breeding, soil disinfection, crop rotation, deep grafting, chemical pesticide application and the like. The soil fumigation is the most common and effective method, can control soil-borne pathogenic bacteria, soil nematodes and underground pests, reduce the death rate of plants and improve the growth vigor and yield of crops, and is an essential important measure for plant disease and insect pest management.

Common fumigants include methyl bromide, metham, chloropicrin and dazomet, all of which are biocidal fumigants. The methyl bromide soil disinfection can well kill nematodes, fungi, pests, weeds and the like in the soil, the crop yield is remarkably increased, the methyl bromide soil disinfection is deeply welcomed by farmers in production, and the application is wide at home and abroad. However, because methyl bromide is unsafe to the environment and human beings, the use of methyl bromide is prohibited in 2015 by the environmental planning agency (UNEP) which lists the limiting substance as a limiting substance in the united nations. The other fumigants have high toxicity to a drug applicator and have long residual period in soil. Therefore, research and search of alternative technologies of soil fumigation and disinfection such as methyl bromide and the like as soon as possible becomes a significant work in environmental protection and agricultural production, and the research is developed under the background.

Cyanamide, CAS: 420-04-2, also known as cyanamide, known by the scientific name aminonitrile. White orthorhombic crystals were colorless, moist, with a melting point of 42 ℃, a boiling point of 83 ℃ (50.66kPa), and a vapor pressure (20 ℃) of 500 mPa. Cyanamide has high solubility in water and weak acidity, is completely miscible with water at 43 ℃, and has a solubility (20 ℃): 4.59kg/L of water can be volatilized together with the water vapor. The crystal cyanamide is very unstable and has high polarity, and because the molecular structure of the cyanamide contains cyano and amino, both of which are active groups, the cyanamide has multiple reaction performances of the functional groups, and is easy to generate reactions such as addition, substitution, condensation and the like. Cyanamide is photostable, and is decomposed in the presence of alkali to produce dicyandiamide and polymer, and in the presence of acid to produce urea.

The cyanamide can be used as a plant growth regulator in agriculture, has insecticidal, bactericidal and herbicidal effects, can be directly sprayed on crops, can effectively inhibit the activity of catalase in plants, and accelerate the oxidative pentose phosphate (PPP) circulation in plants, thereby accelerating the generation of basic substances in plants and playing a role in regulating growth. The field efficacy test shows that the growth of cherries and grapes can be regulated, the yield of the grapes can be increased, the grapes are uniformly sprayed on branches 15-20 days before sprouting, the buds can sprout for 7-10 days in advance, and the early flowering phase, the full flowering phase, the coloring phase, the maturation phase and the like are all advanced. Meanwhile, the pesticide is a good dormancy terminator in the production of the kiwi fruits, the large cherries and the grapes, and is uniformly sprayed in the dormancy stage of the kiwi fruits, the large cherries and the grapes, so that the buds and eyes are uniformly sprayed, the dormancy stage can be broken, the germination and the flowering are advanced, the fruits are ripe and come into the market early, and the pesticide has the effects of obviously improving the yield, changing the meat quality of the fruits and improving the variety quality. In addition, the cyanamide also has a certain nitrogen fertilizer effect.

The liquid cyanamide is used for industrial raw materials, medicines, pesticide intermediates, agricultural fertilizers, plant regulators, food additives and the like.

Tests show that the cyanamide has good control effect on pathogenic bacteria in soil, soil nematodes and soil insects. The cyanamide is widely used in modern agricultural production, the production input cost is relatively low, and the cyanamide can be degraded into a nitrogen-containing substance after being used for soil fumigation, so that a nitrogen-containing fertilizer is provided for crops, the yield and the quality of the crops can be improved, the harvest period is not prolonged, the effect is stable, the cyanamide can be used for a long time, and no new environmental protection problem exists.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide the soil fumigant and the application thereof, and the soil fumigant has the advantages of good control effect, high efficiency, no toxicity, environmental protection and low medication cost.

In order to realize the purpose of the invention, the technical scheme of the invention is as follows:

the soil fumigant contains cyanamide as effective component in 0.1-99.5 wt%.

The mass fraction of the cyanamide in the soil fumigant is between 1 and 50 percent. Preferably between 10 and 40 percent, and the balance of auxiliary components which are allowed to be used and accepted in the pesticide.

The soil fumigant can be prepared into any agriculturally acceptable dosage form by being supplemented with auxiliary components in the processing of pesticide preparations. Preferably, the solid cyanamide technical material and any one of aqueous solution, suspending agent, aqueous emulsion, wettable powder, soluble liquid, microcapsule granules, tablets, microcapsule suspending agent, dispersible oil suspending agent, powder, granules, microemulsion, missible oil, water dispersible granules, emulsifiable powder, water dispersible oil suspending agent, emulsifiable granules, seed treatment agent and sustained release granules containing effective components. More preferably solid cyanamide technical and any one of aqueous solution, suspending agent, aqueous emulsion, soluble solution, microcapsule granules, microcapsule suspending agent, microemulsion and missible oil containing active ingredients. Most preferably solid cyanamide technical material and any one of aqueous solution and aqueous emulsion containing effective components.

The soil fumigant is used for soil fumigation. Is used for melon, vegetable, flower, strawberry, orchard, vineyard, nursery garden, medicinal material, tobacco and other economic crops in the agricultural field.

The soil fumigant is applied to preparing an agricultural fumigant for preventing and treating soil-borne pathogenic bacteria, soil nematodes and underground pests.

The application mode of the soil fumigant can adopt methods such as mechanical injection, spraying, drip irrigation, root irrigation, seed soaking, throwing application, broadcasting application, furrow application, hole application and the like.

The auxiliary components are selected from one or more than one of liquid carrier (solvent) or solid carrier, emulsifier, dispersant, wetting agent, thickener, adhesive, antifreeze, preservative, stabilizer, synergist and defoamer, and the like, and are mixed in any proportion. In each case, a homogeneous distribution of the active ingredient according to the invention should be ensured.

The soil fumigants of the present invention may be formulated using (liquid or solid) carriers and various adjuvants well known to those skilled in the art. Examples include, but are not limited to, the following classes of materials.

Suitable liquid carriers, solvents or co-solvents may be one or more of water, various aromatic hydrocarbons, aliphatic hydrocarbons, ketones, ethers, etc., such as toluene, xylene, fatty acid methyl esters, pine-base oil, soybean oil, biodiesel, cyclohexane, isopropanol, ethylene glycol, sorbitol, S-150, trimethylbenzene, acetone, cyclohexanone, acetonitrile, motor oil, methylated soybean oil, epoxidized tributyl phosphate, ethyl acetate, methanol, ethyldimethylformamide, dimethyl sulfoxide, N-methyl-pyrrolidone, diesel oil, white oil, alcohols, butanol, methylnaphthalene, methyl oleate, sec-butyl acetate, dimethyl carbonate, decalin, mineral spirit S-200, methyl isobutyl ketone, tetramethylbenzene, soybean oil, or methyl cellosolve, etc.

Suitable solid carriers include natural or synthetic clays and silicates, and suitable solid carriers for powders include naturally occurring rock powders, chalk, quartz, white carbon, clays, montmorillonite, silica, diatomaceous earth, pumice, gypsum, talc, bentonite, kaolin, attapulgite, precipitated calcium carbonate, china clay and synthetic ground minerals (e.g. microdispersed silicic acid or alumina). Suitable particulate carriers include crushed and fractionated natural rocks such as calcite, marble, pumice, sepiolite and dolomite and synthetic particles made from powders of organic and inorganic substances.

Suitable emulsifiers can be ammonium styrene polyoxyethylene ether sulfate, magnesium salts of alkyl diphenyl ether disulfonates, triethanolamine salts, phenethylphenol polyoxypropylene ether, Nongru No. 600 (phenylphenol polyoxyethylene ether), Nongru No. 700 (alkylphenol formaldehyde resin polyoxyethylene ether), NP-10 phosphate, OP-10 phosphate, Nongru No. 500 (calcium alkylbenzene sulfonate), Nongru series 0P phosphate (nonylphenol polyoxyethylene ether phosphate), Nongru No. 600 phosphate (phenylphenol polyoxyethylene ether phosphate), Nongru No. 400 (benzyldimethylphenol polyoxyethylene ether), Nongru No. 36 (phenethylphenol formaldehyde resin polyoxyethylene ether), Nongru No. 1600 (phenethylphenol polyoxyethylene polyoxypropylene ether), ethylene oxide-propylene oxide block copolymers, Nongru No. 0P (nonylphenol polyoxyethylene ether), By series (castor oil polyoxyethylene ether), Nongru No. 33 (alkylaryl polyoxypropylene polyoxyethylene ether), Agricultural emulsifier 34# (alkylaryl polyoxyethylene polyoxypropylene ether), span series (sorbitan monostearate), tween series (sorbitan fatty acid ester polyoxyethylene ether), AEO series (fatty alcohol polyoxyethylene ether), calcium dodecylbenzene sulfonate, fatty acid polyoxyethylene ether, alkylphenol polyoxyethylene ether sulfosuccinate, styrylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, polyoxyethylene fatty alcohol ether, polyoxyethylene (n20) phenethyl phenol-based oleate, alkylaryl formaldehyde resin polyoxyethylene ether, tristyrylphenol (n20) ether phosphated triethanolamine salt, alkyl vinyl arylphenyl ether (YUS-SC3), diphenylphenol polyoxyethylene (n18) ether formaldehyde condensate, calcium isostearate oleate, ethoxylated castor oil and the like.

Suitable dispersants may be sodium lignosulfonate, calcium lignosulfonate, sodium salt of a polycondensate of alkylnaphthalenesulfonic acids, detergents LS, alkylnaphthalenesulfonates, formaldehyde condensates of bis (alkyl) naphthalenesulfonates, salts of arylphenolpolyoxyethylene succinates, polyoxyethylene octylphenol ether sulfates, polycarboxylates, sulfates of alkylphenol polyoxyethylene ether formaldehyde condensates, calcium salts of alkylbenzenesulfonic acids, sodium salts of naphthalenesulfonic acid formaldehyde condensates, alkylphenol ethoxylates, fatty acid polyoxyethylene ethers, fatty acid polyoxyethylene esters, glycerol fatty acid ester polyoxyethylene ethers, methylnaphthalenesulfonic acid formaldehyde condensates, sodium alkyl-diethylene glycol ether-sulfonates, sodium N-methyl-oleoyl-taurates, sodium methylenenaphthalenesulfonate, sodium methylaminoethylsulfonate oleate, epoxy polyethers, p-tert-butyl ether, piperonyl ether, alkylamidotaurates, sodium salts of alkyl naphthalenesulfonic acids, sodium salts of alkyl-naphthalenesulfonic acids, sodium salts of alkylnaphthalenesulfonic acids, sodium salts of alkylbenzenesulfonic, One or more of dibutyl naphthalene sulfonic acid formaldehyde condensate, alkylphenol polyoxyethylene ether formaldehyde condensate sulfate, alkylphenol polyoxyethylene phosphate, etc.

Suitable wetting agents may be one or more of sodium sulfate, sodium alkyl alcohol polyoxyethylene ether sulfate, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, alkylphenol polyoxyethylene ether formaldehyde condensate sulfate, sodium lauryl sulfate, sodium methylene naphthalene sulfonate, Morwet EFW, sodium isopropyl naphthalene sulfonate, wetting agent Igepal BC/10, wetting agent GEROPONL-WET/P, wetting agent Rhodasurf860/P, calcium dodecylbenzene sulfonate, wetting agent SP-SC 3266, wetting agent YUS-LXC, sodium alkyl naphthalene sulfonate fatty alcohol polyoxyethylene ether, wetting agent YUS-204, and the like.

Suitable thickeners may be one or more of xanthan gum, carboxymethyl cellulose, gelatin, gum arabic, polyvinylpyrrolidone carboxyethyl cellulose, methyl cellulose, magnesium aluminum silicate, polyvinyl alcohol, and the like.

Suitable defoaming agents are one or more of natural killer, SAG1522, silicone oil, silicones, C8-10 fatty alcohol, phosphates, C10-20 saturated fatty acids (such as capric acid), amides and the like.

Suitable binders may be one or more of polyvinyl alcohol, white dextrin, polyvinyl acetate, xanthan gum, gelatin, carboxymethyl cellulose, sodium alginate and the like.

The anti-freeze agent may be selected from: ethylene glycol, glycerol, propylene glycol, polyethylene glycol, sorbitol or urea.

Preservatives can generally be selected from: one or more of sodium benzoate, carbazone (2-methyl-4-isothiazolin-3-one and (B) 5-chloro-2-methyl-4-isothiazolin-3-one), potassium sorbate, sodium dehydroacetate, calcium propionate, sodium diacetate, sodium lactate, propyl p-hydroxybenzoate, etc.

The wall material comprises one or more of natural polymer material, semisynthetic polymer material and fully synthetic polymer material;

natural polymer material selected from one or more of gelatin, acacia, agar, alginate, chitosan, fibrin, zein, etc.;

semi-synthetic polymer material selected from one or more of methyl (ethyl) cellulose, cellulose acetate and its esters, carboxymethyl cellulose (sodium) or others;

the fully synthetic high molecular material can be one or more of polyacrylic resin, urea resin, polyamide, polyester, polymethyl methacrylate, polyurea, polyurethane, diphenylmethane diisocyanate, ethylenediamine, diethylaminopropylamine or the like.

The synergist is selected from: one or more of an organosilicon pesticide synergist, an organosilicon pesticide penetrant extender, an agricultural organosilicon pesticide synergist, azone and the like.

The stabilizer is selected from: 1, 2-butanediol, isopropyl phosphate, wgwin D902, bentonite, sodium benzoate, linseed oil, benzenediol, borax and oleic acid triethanolamine.

The soil fumigant can be diluted by a user or directly mixed with water for spraying before use, and can also be directly used.

According to the action target and the application mode of the soil fumigant, the soil fumigant is endowed with the optimal use effect by adding the auxiliary agent matched with the effective components, the soil fumigant containing the cyanamide is developed, and the purpose of improving the diffusion, penetration, attachment, fumigation and decomposition of the effective components in the soil is achieved, so that the biological activity of the pesticide is improved, the use dosage is reduced, and the harm of the pesticide to human bodies and the pollution to the environment are reduced.

Wherein, when the preparation formulation is prepared, different auxiliary agents are matched according to the original medicine and the characteristics of the formulation, and the auxiliary agent system and the original medicine interact with each other to improve the pesticide effect. However, there is no mention in the prior art of processing of cyanamide into a commercial soil fumigant. And at present, no report is provided for the study of the cyanamide soil fumigant.

Compared with the prior art, the invention has the following advantages:

(1) the soil fumigant disclosed by the invention is prepared from cyanamide which can volatilize together with water vapor, has good activity of preventing and treating soil-borne pathogenic bacteria, soil nematodes and underground pests, is low in toxicity, less in residue in crops, and low in harm to people and livestock, well solves the problems that the existing fumigant is high in toxicity, large in harm to the environment and more in residue in crops, and improves the safety of agricultural production.

(2) The soil fumigant disclosed by the invention has no problems of good interactive resistance performance, prevention and treatment of existing soil-borne diseases and the like with the existing fumigant, and can well solve the problem after methyl bromide is forbidden.

(3) The soil fumigant of the invention has simple application method, can be used for soil treatment in the plant seedling stage or before seedling transplantation, can also be used in other growth stages of crops, can be used for mechanical injection, spraying, drip irrigation, root irrigation, seed soaking, throwing application, broadcasting application, furrow application, hole application and the like, has diversified application methods, improves the cultivation efficiency and reduces the workload.

(4) The soil fumigant is fumigant and hydrolyzed into urea, and further hydrolyzed into ammonium carbonate or ammonium cyanogen carbonate, and the urea becomes nitrogen nutrition which can be absorbed by plants, so that the soil fumigant is pollution-free, safe and sanitary, has no residue, and does not pollute the environment.

(5) The soil fumigant disclosed by the invention is strong in adhesive force and penetrability, high in biological activity, small in dosage and more environment-friendly.

Detailed Description

The following specific examples are intended to illustrate the invention in further detail, but the invention is by no means limited to these examples, and methods known to those skilled in the art are included within the scope of the invention. The percentage and the parts in the formula are all by weight, and all the raw materials are all commercially available products.

EXAMPLE 1 preparation of 30% Cyanuramine emulsifiable concentrate

Respectively adding 30 parts of cyanamide, 4 parts of phenethyl phenol polyoxyethylene polypropylene ether, 5 parts of fatty acid polyoxyethylene ether, 0.5 part of silicone oil, 0.1 part of 1, 2-butanediol, 2 parts of castor oil polyoxyethylene ether, 7 parts of methanol and solvent oil S-150 to 100 percent, stirring and mixing uniformly, and heating and dissolving by using a hot water bath if necessary to obtain 30 percent cyanamide missible oil.

Example 2 preparation of 35% aqueous emulsion of cyanamide

Respectively adding 35 parts of cyanamide, 4 parts of alkyl aryl formaldehyde resin polyoxyethylene ether, 8 parts of phenyl phenol polyoxyethylene ether phosphate, 5 parts of grease, calcium dodecyl benzene sulfonate, 0.1 part of isopropyl phosphate, 10 parts of methyl isobutyl ketone, 0.2 part of SAG1522 and 5 parts of solvent oil S-150 into a mixing kettle, stirring and mixing to dissolve the mixture into a uniform oil phase, and adding the balance of water (which is up to 100%) into the oil phase under high-speed stirring to obtain the 35% cyanamide aqueous emulsion with good dispersibility.

Example 3, 20% Cyanocyanamide dispersible oil suspension

20 parts of cyanamide, 2 parts of sodium methylene naphthalene sulfonate, 4 parts of nonylphenol polyoxyethylene ether phosphoric acid, 4 parts of naphthalenesulfonic acid formaldehyde condensate sodium salt, 0.1 part of xanthan gum, 0.1 part of oleic acid triethanolamine, 0.2 part of SAG1522, 0.5 part of white carbon black and 5 parts of ethylene glycol are complemented to 100% by water, sequentially added into a mixing tank for mixing, subjected to high shear for coarse crushing and homogenization, pumped into a sand mill for fine grinding, the particle size of the sand-ground material is detected by a particle size distribution instrument, and filtered when the particle size reaches the standard requirement, the 20% cyanamide dispersible oil suspending agent is obtained.

Example 4, 50% Cyanuramine microemulsion

Adding 50 parts of cyanamide, 8 parts of diphenyl phenol polyoxyethylene (n18) ether formaldehyde condensate, 5 parts of alkylphenol formaldehyde resin polyoxyethylene ether, 3 parts of phenethyl phenol polyoxyethylene polypropylene ether, 6 parts of solvent oil S-200, 0.2 part of SAG1522, 0.1 part of oleic acid triethanolamine and 6 parts of acetonitrile together to dissolve into a uniform oil phase, complementing the balance to 100% by water, adding the water phase into the oil phase or adding the oil phase into the water phase under high-speed stirring to form the 50% cyanamide microemulsion with good dispersibility.

Example 5, 45% Cyanuramine Solvabe solution

45 parts of cyanamide, 8 parts of castor oil polyoxyethylene ether, 2 parts of phenethyl phenol polyoxyethylene polypropylene ether, 5 parts of calcium dodecyl benzene sulfonate, 2 parts of alkylphenol formaldehyde resin polyoxyethylene ether, 10 parts of cyclohexanone, 5 parts of acetonitrile, 20 parts of solvent oil S-200, 0.1 part of oleic acid triethanolamine, 0.2 part of silicone oil and methyl-soluble fiber are complemented to 100 percent and mixed uniformly, and the mixture is heated and dissolved by a hot water bath if necessary to prepare the 45 percent cyanamide soluble solution.

Example 6, formulation of 40% Monocyanamide microcapsule suspension

Uniformly stirring 40 parts of cyanamide, 4 parts of styrene polyoxyethylene ether ammonium sulfate, 5 parts of styrene phenol polyoxyethylene ether, 2 parts of sorbitan monostearate, 10 parts of methylcellulose and 3 parts of diphenylmethane diisocyanate to prepare an oil phase, adding the oil phase into a water phase consisting of 5 parts of diethylaminopropylamine, 5 parts of glycerol, 3 parts of polyurethane, 0.2 part of SAG1522, 0.1 part of oleic acid triethanolamine and the balance of water, and stirring at a high speed, curing and preserving heat to prepare the 40% cyanamide microcapsule suspending agent.

Example 7 preparation of 33% aqueous cyanamide solution

Respectively adding 33 parts of cyanamide, 4 parts of phenethyl phenol polyoxyethylene polypropylene ether, 5 parts of fatty acid polyoxyethylene ether, 0.5 part of silicone oil, 0.1 part of 1, 2-butanediol and water to 100 percent, adding into a mixing kettle, and stirring and mixing uniformly to obtain the 33 percent cyanamide aqueous solution.

Examples of biological Activity test

Example 1 prevention and treatment of watermelon wilt with 33% aqueous solution of cyanamide

The test method comprises the following steps: ploughing and preparing soil before transplanting the watermelon, tightly covering with a plastic film, diluting 33% cyanamide water agent with 7500 kg/hectare of clear water, and irrigating. The treatment time is 7 days, the film is required to be uncovered and the air is released for more than 1 day before transplanting, the area of each cell is 30 square meters, 4 cells are arranged for each treatment, and the cells treated by clear water are used as blank reference. And (5) investigating the number of the plants suffered by each cell according to the blank control morbidity condition, and calculating the control effect.

TABLE 1 field test of 33% cyanamide aqueous solution for watermelon fusarium wilt

The field test result shows that the medicament in the application embodiment has good control effect on watermelon fusarium wilt.

Example 2 prevention and control of Notoginseng radix root rot by 30% cyanamide emulsifiable concentrate

Diluting 30% cyanamide emulsifiable concentrate with water, spraying the diluted solution on soil, covering a mulching film with the thickness of 0.05 mm after plowing and land preparation, wherein the treatment time is 7 days, the mulching film needs to be uncovered and deflated for more than 1 day before transplanting, the area of each cell is 30 square meters, and each treatment is repeated for 4 cells. And (5) investigating the number of the plants suffered by each cell according to the blank control morbidity condition, and calculating the control effect.

TABLE 2 field test of 30% Cyanuric cyanamide emulsifiable concentrate for treating root rot of Panax notoginseng

The results of field experiments show that the medicament in the application examples has good control effect on the root rot of panax notoginseng.

Example 3 control of Meloidogyne incognita Micyocochl suspension with 40% Monocyanamide

Diluting a 40% cyanamide microcapsule suspending agent by adding water, spraying the diluted agent on soil, covering a mulching film with the thickness of 0.05 mm after ploughing and land preparation, wherein the treatment time is 7 days, the film is required to be uncovered and deflated for more than 1 day before transplanting, the area of each cell is 30 square meters, and each treatment is repeated for 4 cells. The embodiment is applied to control of meloidogyne incognita in cucumbers, the control effect of each treatment is investigated in the adult plant stage, the nematode condition of each treatment is counted in a uprooting grading manner, and the control effect is calculated.

The grading standards adopted by root-knot nematodes are:

0, the root has no root knot;

1, a small number of small root knots are arranged on the fibrous roots, and the number of the root knots is less than 5;

3, most root systems are clean, obvious visible root knots are formed on fibrous roots, and the number of the root knots is less than 10;

5, a few of main roots are infected, the number of root knots is less than 5, and the number of root knots on fibrous roots is more than 10;

7, a large number of root knots are arranged on the main root, and all fibrous roots are provided with root knots;

9, all the root systems have root knots, and the overground parts of the plants wilted.

The calculation method comprises the following steps:

TABLE 3 field test of 40% Monocyanamide microcapsule suspension on Meloidogyne incognita

The results of field experiments show that the medicament in the application example has good control effect on the meloidogyne incognita of cucumbers.

Example 4 control of tobacco damping-off by 45% Cyanuramine Solvabe solution

Diluting 45% cyanamide soluble agent with water, filling into uniform holes in field soil, covering with soil, and covering with mulching film. The treatment time is 7 days, the tobacco is transplanted into the treated holes, and the growth vigor of the tobacco is observed 30 days after the treatment. A clear water treated blank control was set. And (5) investigating the number of the plants suffered by each cell according to the blank control morbidity condition, and calculating the control effect.

TABLE 4 field test of 45% cyanamide solubles on tobacco damping-off

The field test result shows that the medicament in the application embodiment has good control effect on the tobacco damping-off.

In conclusion, the soil fumigant can effectively prevent and control soil-borne pathogenic bacteria, soil nematodes and soil insects, is simple in application method, and is a fumigant which is pollution-free, safe, sanitary, residue-free and pollution-free to the environment.

The above embodiments are merely illustrative of the inventive concept and are not intended to limit the scope of the claims, and any insubstantial modifications of the inventive concept using the above embodiments are intended to fall within the scope of the claims.

Claims (9)

1. A soil fumigant is characterized in that: the soil fumigant comprises the effective component of cyanamide, the mass fraction of the cyanamide in the soil fumigant is 20-50%, and the balance is auxiliary components which are allowed to be used and can be accepted in pesticides.

2. A soil fumigant according to claim 1, characterised in that: the mass fraction of the cyanamide in the soil fumigant is 20-40%, and the balance is auxiliary components which are allowed to be used and can be accepted in pesticides.

3. A soil fumigant according to claim 1, characterised in that: the mass fraction of the cyanamide in the soil fumigant is 35%, and the balance is auxiliary components which are allowed to be used and can be accepted in pesticides.

4. A soil fumigant according to any one of claims 1 to 3, characterised in that: the soil fumigant comprises solid cyanamide raw pesticide and any one of aqueous solution, suspending agent, aqueous emulsion, wettable powder, soluble solution, microcapsule granules, tablets, microcapsule suspending agent, dispersible oil suspending agent, powder, granules, microemulsion, missible oil, water dispersible granules, emulsifiable powder, water dispersible oil suspending agent, emulsifiable granules, seed treatment agent and sustained release granules containing effective components.

5. A soil fumigant according to any one of claims 1 to 3, characterised in that: the soil fumigant comprises solid cyanamide raw pesticide and any one of aqueous solution, suspending agent, aqueous emulsion, soluble solution, microcapsule granules, microcapsule suspending agent, microemulsion and missible oil containing active ingredients.

6. A soil fumigant according to any one of claims 1 to 3, characterised in that: the soil fumigant comprises solid cyanamide technical material and any one of aqueous solution and aqueous emulsion containing effective components.

7. A soil fumigant according to any one of claims 1 to 3, characterised in that: the soil fumigant is used for soil fumigation.

8. A soil fumigant according to any one of claims 1 to 3, characterised in that: the soil fumigant is used for soil fumigation of melons, vegetables, flowers, strawberries, orchards, vineyards, nurseries, medicinal materials, tobaccos and other economic crops.

9. A soil fumigant according to any one of claims 1 to 13, characterised in that: the soil fumigant is used for preventing and controlling soil-borne pathogenic bacteria, soil nematodes and underground pests.