Inhibitor of damage caused by agricultural materials

Abstract

To provide an inhibitor against crop injury due to agricultural material.SOLUTION: The present invention relates to an inhibitor against crop injury due to agricultural material, the inhibitor containing humic acid as an active ingredient.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an inhibitor of phytotoxicity caused by agricultural materials. [Background technology]

[0002] Agricultural materials such as metal salts are sometimes used to protect plants from pathogenic bacteria and viruses. For example, Patent Document 1 discloses a plant pathogen control agent that contains a metal chelate or salt as an active ingredient. For example, Patent Document 2 discloses a plant viral disease control agent that contains at least one of zinc gluconate and copper gluconate as an active ingredient. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-132552 [Patent Document 2] Patent No. 6634325 Summary of the Invention [Problem to be solved by the invention]

[0004] Agricultural materials such as metal salts may cause phytotoxicity when applied to crops. The present invention has been made in view of such circumstances, and an object of the present invention is to provide an agent for suppressing phytotoxicity caused by agricultural materials. [Means for solving the problem]

[0005] The present invention relates to the following inventions. [1] An inhibitor of damage caused by agricultural materials, containing humic acid as the active ingredient. [2] An inhibitor of phytotoxicity caused by agricultural materials according to [1], having a melanic index of 2.0 or more. [3] The inhibitor of phytotoxicity caused by agricultural materials according to [1] or [2], wherein the mass average molecular weight of the humic acid is 100 to 6,000. [4] The inhibitor of phytotoxicity caused by agricultural materials according to any one of [1] to [3], wherein the active ingredient is a humic acid extract, and the humic acid extract has a total organic carbon concentration of 15,000 mg / L or more. [5] The inhibitor of phytotoxicity caused by agricultural materials according to [4], wherein the mass average molecular weight of the humic acid is 100 to 1,200, and the total organic carbon concentration of the humic acid extract is 15,000 to 25,000 mg / L. [6] An inhibitor of phytotoxicity caused by agricultural materials according to any one of [1] to [5], which is derived from lignite. [7] The inhibitor of phytotoxicity caused by agricultural materials according to any one of [1] to [6], wherein the agricultural material is a pesticide. [8] The inhibitor of phytotoxicity caused by agricultural materials according to [7], wherein the pesticide is a metal salt. [9] The inhibitor of phytotoxicity caused by agricultural materials according to [7] or [8], wherein the pesticide is at least one metal salt selected from the group consisting of copper salts, zinc salts, and iron salts.

[10] A method for suppressing chemical damage to a crop caused by an agricultural material, the method comprising applying humic acid to the crop. [Effects of the Invention]

[0006] According to the present invention, an agent for suppressing phytotoxicity caused by agricultural materials can be provided. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a graph showing the calculation results of the disease incidence of tomatoes inoculated with pathogenic bacteria. [Figure 2] 1 is a graph showing the results of calculating the disease severity of Chinese cabbage inoculated with a pathogen. [Figure 3] 1 shows photographs showing the results of observation of phytotoxicity of Chinese cabbage inoculated with a pathogen. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes in detail the embodiments of the present invention, but the present invention is not limited to the following embodiments.

[0009] [Inhibitor of phytotoxicity caused by agricultural materials] The inhibitor of phytotoxicity caused by agricultural materials according to this embodiment contains humic acid as an active ingredient. The inhibitor of phytotoxicity caused by agricultural materials according to this embodiment can suppress the occurrence of phytotoxicity caused by agricultural materials compared to when the inhibitor is not used.

[0010] <Agricultural materials> The agricultural material may be, for example, a pesticide. A pesticide is an agricultural chemical, and any chemical that falls under the category of "pesticide" under the Agricultural Chemicals Control Act of Japan (Act No. 82 of 1948, last revised: enforced December 1, 2020) can be used. Specifically, the pesticide may be a fungicide, insecticide, herbicide, or other chemical used to control bacteria, nematodes, mites, insects, rodents, grasses, other plants and animals, or viruses (collectively referred to as "diseases and insect pests") that harm agricultural crops (including trees and agricultural and forestry products; hereinafter referred to as "agricultural crops, etc."), or a growth promoter, germination inhibitor, or other chemical (excluding fertilizers as defined in Article 2, Paragraph 1 of the Act on Assurance of Fertilizer Quality, etc. (Act No. 127 of 1950)) used to promote or suppress the physiological functions of agricultural crops, etc.

[0011] The pesticide may be, for example, a metal salt. Examples of metals in the metal salt include copper, zinc, and iron. The salt in the metal salt may be an organic acid salt or an inorganic acid salt. The salt in the metal salt may be a sulfate or an acetate. The metal salt may be at least one selected from the group consisting of copper salts, zinc salts, and iron salts, and is preferably at least one selected from the group consisting of copper sulfate, copper acetate, zinc sulfate, and zinc acetate. The metal salt may be an anhydride or a hydrate.

[0012] <Crop body> Crops that can be targeted by inhibitors of phytotoxicity caused by agricultural materials include vegetables, such as leafy vegetables like Chinese cabbage, komatsuna, spinach, and lettuce, as well as solanaceae fruit vegetables like tomatoes, eggplants, bell peppers, and chili peppers.

[0013] <Drug-related harm> "Phytotoxicity caused by agricultural materials" refers to damage to the appearance, function, quality, etc. of crops caused by agricultural materials. Phytotoxicity caused by agricultural materials includes, for example, growth inhibition, partial or total whitening of plant tissues, white or brown spots on plant tissues, and symptoms that appear on stems and leaves, such as chlorosis (yellowing), necrosis (death of tissues, cells, etc.), leaf fall, and deformed leaves.

[0014] <Humic acid> As used herein, "humic acid" includes humic acid and fulvic acid. Humic acid includes one or more species selected from the group consisting of humic acid and humate salts. Humic acid has agricultural advantages such as promoting crop growth and reducing susceptibility to environmental stress (e.g., the effects of global warming). Therefore, the inhibitor of phytotoxicity caused by agricultural materials according to this embodiment can achieve effects such as promoting crop growth and reducing susceptibility to environmental stress (e.g., the effects of global warming) while suppressing phytotoxicity caused by agricultural materials.

[0015] Humic acids include natural humic acids produced in nature such as peat and weathered coal, artificial humic acids produced artificially by nitric acid oxidation of lignite, and humates obtained by neutralizing natural or artificial humic acids with alkaline substances such as sodium, potassium, ammonia, calcium, and magnesium. Humic acids include fulvic acid, humic acid, nitrohumic acid, ammonium humate, calcium humate, magnesium humate, ammonium nitrohumate, calcium and magnesium nitrohumate, potassium humate, and potassium nitrohumate.

[0016] The active ingredient may be a humic acid extract, which is an extract obtained by extracting nitric acid oxide from young charcoal with an extraction solvent containing water and, if necessary, an alkali.

[0017] Young coal is coal with a lower carbon content than bituminous coal and is defined as having a carbon content of 83% by mass or less. Examples of young coal include peat, lignite, brown coal, and subbituminous coal. Young coal may be used alone or in combination of two or more types. Humic acid may be derived from brown coal in view of the effect of suppressing phytotoxicity caused by agricultural materials.

[0018] Nitric acid oxides of young coal are obtained by oxidatively decomposing young coal with nitric acid. Concentrated nitric acid is preferred as the nitric acid. From the viewpoint of safety and reactivity, it is preferable to use nitric acid with a concentration of 40 to 60 mass%. The amount of nitric acid (HNO3) used during oxidative decomposition may be 10 parts by mass or more, or 20 parts by mass or more, relative to 20 parts by mass of young coal, and may be 300 parts by mass or less, 250 parts by mass or less, 200 parts by mass or less, 150 parts by mass or less, 100 parts by mass or less, 50 parts by mass or less, 36 parts by mass or less, or 20 parts by mass or less. The amount of nitric acid (HNO3) used may be 10 to 20 parts by mass or 20 to 36 parts by mass relative to 20 parts by mass of young coal. Here, the amount of nitric acid used is a value converted to 100% nitric acid (100% HNO3).

[0019] The temperature during oxidative decomposition may be, for example, 70 to 95° C. Heating to 70 to 95° C. in a hot water bath or the like as a starter for the oxidation reaction tends to facilitate rapid progress of the oxidation reaction. The reaction time may be, for example, 20 minutes or more, 0.5 hours or more, or 1 hour or more, or 6 hours or less, 4 hours or less, or 1 hour or less.

[0020] Humic acid extract can be obtained as a liquid by, for example, stirring nitric acid oxide of young coal (hereinafter referred to as crude humic acid) with an extraction solvent containing water and alkali, followed by a solid-liquid separation process.

[0021] Examples of alkalis include hydroxides and ammonia. Examples of hydroxides include alkali metal hydroxides and ammonium hydroxide. Preferred hydroxides are alkali metal hydroxides. Examples of alkali metal hydroxides include potassium hydroxide and sodium hydroxide. Preferred hydroxides are one or more of potassium hydroxide, sodium oxide, and ammonium hydroxide (aqueous ammonia). The pH of the extraction solvent may be 0.5 to 7.0, 0.5 to 4.0, or 1.0 to 3.0.

[0022] The temperature (extraction temperature) when extracting the humic acid crude product with the extraction solvent may be, for example, 40 to 90° C., from the viewpoint of further suppressing freezing and deterioration of the extract. The time (extraction time) for extracting the humic acid crude product with the extraction solvent may be, for example, 0.5 hours or more, 24 hours or less, or 1 hour or less.

[0023] The amount of extraction solvent relative to the amount of raw young coal used to prepare the humic acid crude product is defined as the solid-liquid ratio. For example, if 100 g (100 mL) of extraction solvent (water) is added to humic acid crude product prepared from 20 g of young coal, the solid-liquid ratio (extraction solvent / young coal) will be 5. The solid-liquid ratio may be 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, or 10 or more, and may be 15 or less, 13 or less, 11 or less, 9 or less, 7 or less, or 6 or less. The solid-liquid ratio can be adjusted by adding water. The solid-liquid ratio may be adjusted to the desired solid-liquid ratio after adjusting the pH. The solid-liquid separation method may be centrifugation, filter press, etc.

[0024] The total organic carbon concentration (TOC) of the humic acid extract may be 15,000 mg / L or more, 15,300 mg / L or more, 15,500 mg / L or more, 16,000 mg / L or more, 16,500 mg / L or more, 17,000 mg / L or more, 17,500 mg / L or more, 18,000 mg / L or more, 18,500 mg / L or more, 19,000 mg / L or more, 19,500 mg / L or more, 20,000 mg / L or more, or 20,500 mg / L or more. The TOC of the humic acid extract may be 75,000 mg / L or less, 70,000 mg / L or less, 65,000 mg / L or less, 60,000 mg / L or less, 55,000 mg / L or less, 50,000 mg / L or less, 45,000 mg / L or less, 40,000 mg / L or less, 35,000 mg / L or less, 30,000 mg / L or less, 25,000 mg / L or less, 24,000 mg / L or less, 23,000 mg / L or less, or 22,000 mg / L or less.

[0025] The TOC measurement method for humic acid extracts is defined as follows: The supernatant liquid obtained by centrifuging the humic acid extract at 3,000 x g is measured using a total organic carbon analyzer (Shimadzu TOC-L) with a combustion catalytic oxidation method. If the extract contains non-humic substances such as urea, a fertilizer component, the extract is fractionated in accordance with the International Humic Substances Society method (Fujitake, Humic Substances Research Vol. 3, p. 1-9) and the fractions (humic acid fraction and fulvic acid fraction) are quantified using the above method, and the TOC of the humic acid extract is then measured.

[0026] The melanic index (MI) of the humic acid may be, for example, 1.5 or more, 2.0 or more, 2.2 or more, 2.5 or more, 3.0 or more, or 3.5 or more. The MI of the humic acid may be 6.5 or less, 6.0 or less, 5.5 or less, 5.0 or less, 4.5 or less, 4.0 or less, 3.5 or less, or 3.0 or less.

[0027] MI is an index used to classify humic acid, and is the ratio of absorbance at wavelengths of 450 nm and 520 nm (A450 / A520) in the absorption spectrum of a sodium hydroxide extract (Kyoichi Kumada, Chemistry of Soil Organic Matter, 2nd Edition, Academic Press Center (1981), Japanese Journal of Soil Science and Plant Nutrition, Vol. 71, No. 1, pp. 82-85 (2000)).

[0028] More specifically, MI is calculated using the following method: A sample is crushed into a 250 μm sieve using a mortar and a 250 μm sieve. Approximately 10 g of the crushed material is weighed accurately into a weighing bottle with a known mass. The weighing bottle is then left in a dryer maintained at 105°C for approximately 12 hours, then returned to room temperature in a desiccator and re-weighed. The resulting mass loss is considered to be moisture, and the moisture content of the sample is calculated. Next, 0.10 g of the 250 μm sieve (equivalent to the dry mass) and 45 ml of 0.5 mol / L sodium hydroxide solution are placed in a 50 ml centrifuge tube. The tube is shaken at 250 rpm for approximately 1 hour at room temperature (20°C), then centrifuged at 3,000 × g for approximately 10 minutes. The supernatant is then filtered through Advantec No. 5C filter paper. The absorbance of the filtrate at 450 nm and 520 nm is measured using distilled water as a blank. If the absorbance at 450 nm is 1.0 or higher, add 0.1 mol / L sodium hydroxide solution to adjust the absorbance to 0.8 or higher but less than 1.0, and then measure the absorbance at 520 nm. The ratio (absorbance at 450 nm / absorbance at 520 nm) is calculated and used as the MI.

[0029] The mass average molecular weight of the humic acid may be 100 to 6,000. The lower limit of the mass average molecular weight of the humic acid may be, for example, 200 or more, 300 or more, 400 or more, 500 or more, 600 or more, 700 or more, 800 or more, 900 or more, or 1,000 or more. The upper limit of the mass average molecular weight of the humic acid may be, for example, 5,500 or less, 5,000 or less, 4,500 or less, 4,000 or less, 3,500 or less, 3,000 or less, 2,500 or less, 2,000 or less, 1,500 or less, 1,2000 or less, or 1,000 or less.

[0030] The mass average molecular weight of humic acid is measured by HPSEC (GPC) using a Waters Alliance HPLC System. The column is a Showa Denko SB-803HQ, the standard sample is sodium polystyrene sulfonate, and the detection wavelength is 260 nm. The mobile phase is 10 mmol / L sodium phosphate buffer containing 25% acetonitrile by mass, the flow rate is 0.8 ml / min, and the column temperature is 40 °C (column oven setting).

[0031] The dosage form of the inhibitor of phytotoxicity caused by agricultural materials may be, for example, a liquid or a powder. A powder can be obtained as a resolubilizable powder, for example, by drying up the liquid inhibitor of phytotoxicity caused by agricultural materials by freeze-drying or the like.

[0032] The inhibitor of phytotoxicity caused by agricultural materials can be used in combination with agricultural materials. For example, when a pesticide is used as the agricultural material, by applying a chemical agent containing the pesticide and humic acid to the target, it is possible to obtain the pest control effect of the pesticide while suppressing the occurrence of phytotoxicity caused by the pesticide.

[0033] The method for suppressing phytotoxicity of a crop plant caused by an agricultural material according to this embodiment includes applying humic acid to the crop plant.

[0034] Methods for applying humic acid to crop plants include spraying or painting the crop plants, soil drenching, soil incorporation, and the like.

[0035] The application amount and period of humic acid are not particularly limited, and in the case of soil application, it can be applied 1 to 12 times a month at a total organic carbon concentration of 0.1 to 5000 mg / L, in the case of hydroponic cultivation, it can be applied 1 to 12 times a month at a total organic carbon concentration of 0.1 to 5000 mg / L, and in the case of foliar application, it can be applied 1 to 12 times a month at a total organic carbon concentration of 0.1 to 5000 mg / L.

[0036] The part of the crop to which humic acid is applied may be the whole or a part of the crop, and can be appropriately selected depending on the type of crop, the type of agricultural material, etc. For example, the part of the crop to which humic acid is applied may be the leaves of the crop.

[0037] The timing of applying humic acid is not particularly limited and can be appropriately selected depending on the type of crop, the type of agricultural material to be applied, etc. For example, humic acid may be applied to crops to which an agricultural material has been applied, to crops before the agricultural material is applied, or to crops simultaneously with the application of the agricultural material. [Example]

[0038] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0039] [Preparation of Humic Acid Extract A] In a draft chamber, 500 g of lignite with a carbon content of 77% by mass was placed in a 1,000 ml beaker, and 1,562.5 g of 48% nitric acid (150 parts by mass of 100% nitric acid per 100 parts by mass of young coal) was added. The oxidation reaction was carried out in an 80 °C water bath for 3 hours. The crude product containing humic acid obtained by this operation was subjected to the following extraction operation. Approximately 450 mL of 0.5 mol / L potassium hydroxide aqueous solution was added to 100 g of this crude product, and while monitoring with a pH meter, 1.0 mol / L potassium hydroxide aqueous solution was added appropriately to adjust the pH to 2.0. Water was added to achieve a solid-liquid ratio (extraction solvent / young coal) of 5:1, and extraction was carried out at 80°C for 1 hour. This extract was centrifuged at 3,000 × g, and the resulting supernatant was diluted appropriately, and the mass-average molecular weight, total organic carbon concentration (TOC), and melanic index (MI) were measured.

[0040] The MI of the humic acid in humic acid extract A was 4.8. The total organic carbon concentration (TOC) of humic acid extract A was 22,000 mg / L. The mass average molecular weight of the humic acid in humic acid extract A was 530.

[0041] [Mass average molecular weight] The mass average molecular weight of humic acid was measured by HPSEC (GPC) using a Waters Alliance HPLC System. The column was a Showa Denko SB-803HQ, the standard sample was sodium polystyrene sulfonate, and the detection wavelength was 260 nm. The mobile phase was a 10 mmol / L sodium phosphate buffer solution containing 25% acetonitrile by mass, the flow rate was 0.8 ml / min, and the column temperature was 40 °C (column oven setting).

[0042] [Total organic carbon concentration (TOC)] The TOC of humic acid extract A was measured using a total organic carbon meter (Shimadzu TOC-L) by the combustion catalytic oxidation method.

[0043] [Melanic Index (MI)] The sample was crushed to a 250 μm sieve using a mortar and a 250 μm sieve. Approximately 10 g of the crushed material was weighed into a weighing bottle with a known mass. The weighing bottle was then placed in a dryer maintained at 105°C for approximately 12 hours, then returned to room temperature in a desiccator and re-weighed. The mass loss was considered to be the moisture content of the sample. Next, 0.10 g of the 250 μm sieve (equivalent to the dry mass) and 45 ml of 0.5 mol / L sodium hydroxide solution were placed in a 50 ml centrifuge tube and shaken at 250 rpm for approximately 1 hour at room temperature (20°C). The tube was then centrifuged at 3,000 × g for approximately 10 minutes, and the supernatant was filtered through Advantec No. 5C filter paper. The absorbance of the filtrate at 450 nm and 520 nm was measured using distilled water as a blank. In this case, if the absorbance at 450 nm was 1.0 or higher, 0.1 mol / L aqueous sodium hydroxide was added to adjust the absorbance to 0.8 or higher but less than 1.0, and then the absorbance at 520 nm was measured. The ratio (absorbance at 450 nm / absorbance at 520 nm) was calculated and used as the MI.

[0044] [Test Example 1: Pathogen inoculation test on tomatoes 1] The following methods were used to prepare the control, test area 1 (humic acid extract A 40 ppm), test area 2 (0.4 mM CuSO4·5H2O), and test area 3 (humic acid extract A (40 ppm) + 0.4 mM CuSO4·5H2O).

[0045] Tomato plants (cv. Regina) (2 plants / pot, 19 days old after sowing, 2.5 true leaves) were sprayed with each agent and placed in a culture chamber (24°C, 16 hours (light) / 8 hours (dark) light / dark cycle, 50% humidity). Three days after treatment, the tomato bacterial spot pathogen Pseudomonas syringae (5 × 10 6 The plants were then inoculated by spraying with 10 ...

[0046] The severity of disease was calculated using the following method, and the results are shown in Figure 1. The severity of the disease is expressed by the following formula: Incidence = {(1n1 + 2n2 + 3n3 + 4n4 + 5n5) / (5 x number of surveys)} x 100 The disease survey was conducted by dividing the severity of the disease into the following five categories. 0: No symptoms, 1: Minor spots, 2: Lesions observed on less than 25% of the leaf area, 3: Lesions observed on 25% to less than 50% of the leaf area, 4: Lesions observed on 50% or more of the leaf area, 5: Leaf fall or withering n1 to n5 indicate the number of individuals.

[0047] When copper sulfate was sprayed alone on tomatoes, slight chlorosis occurred at the leaf tips after inoculation. When humic acid extract A and copper sulfate were sprayed together, the phytotoxicity was reduced.

[0048] [Test Example 2: Pathogen inoculation test on Chinese cabbage] Each agent was sprayed onto Chinese cabbage seedlings (Kogokoro 85) (3 plants / pot, 14 days old, 2 expanded leaves and 2 unexpanded leaves). The treated plants were left at 24°C under a 16-hour (light) / 8-hour (dark) light / dark condition. Two days after treatment, the plants were infected with Pseudomonas cannabina pv. alisalensis (5×10 6 The plants were inoculated by spraying with 1000 mg of 10 ...

[0049] FIG. 3 is a set of photographs showing the observation results of Chinese cabbage seedlings treated with each agent 5 days after inoculation with the pathogen. When Chinese cabbage was used, the same results as with tomatoes were obtained: reduced phytotoxicity. Chinese cabbage is susceptible to phytotoxicity, so when copper sulfate was used alone, phytotoxicity (white spots, brown spots, etc.) occurred to a degree that could not be tested. On the other hand, when humic acid extract A was used in combination with copper sulfate, phytotoxicity was suppressed.

Claims

1. Contains humic acid as an active ingredient, An inhibitor of chemical damage caused by agricultural materials, when the crop to be applied is leafy vegetables or solanaceous fruit vegetables.

2. 2. The inhibitor of phytotoxicity caused by agricultural materials according to claim 1, which has a melanic index of 2.0 or more.

3. 3. The inhibitor of phytotoxicity caused by agricultural materials according to claim 1, wherein the mass average molecular weight of the humic acid is 100 to 6,000.

4. The active ingredient is a humic acid extract, The inhibitor of phytotoxicity caused by agricultural materials according to any one of claims 1 to 3, wherein the humic acid extract has a total organic carbon concentration of 15,000 mg / L or more.

5. The mass average molecular weight of the humic acid is 100 to 1,200, 5. The inhibitor of phytotoxicity caused by agricultural materials according to claim 4, wherein the humic acid extract has a total organic carbon concentration of 15,000 to 25,000 mg / L.

6. The inhibitor of phytotoxicity caused by the agricultural material according to any one of claims 1 to 5, which is derived from lignite.

7. The inhibitor of phytotoxicity caused by agricultural materials according to any one of claims 1 to 6, wherein the agricultural materials are pesticides.

8. The inhibitor of phytotoxicity caused by agricultural materials according to claim 7, wherein the pesticide is a metal salt.

9. 9. The inhibitor of phytotoxicity caused by agricultural materials according to claim 7 or 8, wherein the pesticide is at least one metal salt selected from the group consisting of copper salts, zinc salts, and iron salts.

10. A method for suppressing phytotoxicity of a crop body caused by an agricultural material, comprising: applying humic acid to the crop plant; The method, wherein the crop plant is a leafy vegetable or a solanaceous fruit vegetable.

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