Liquid fertilizers, concentrated liquid fertilizers and compositions

Abstract

To provide a liquid fertilizer having improved growth promoting effect. [Solution] A liquid fertilizer containing humic acid, including humic acid and fulvic acid, and having an X value obtained by a specified method of less than 5.5%.

Description

[Technical Field]

[0001] The present invention relates to liquid fertilizers, concentrated liquid fertilizers and compositions. [Background technology]

[0002] Humic acid is a natural polymeric organic substance found in soil and land water. It is known to have a growth-promoting effect on plants and is used as a fertilizer.

[0003] Patent Document 1 describes a liquid humic acid containing humic acid and fulvic acid, with the objective of providing a liquid humic acid having a crop growth-promoting effect. The document describes that the liquid humic acid is separated into a precipitate containing the humic acid and a soluble portion containing the fulvic acid by adding hydrochloric acid to adjust the pH of the liquid humic acid to 1, and that when the total organic carbon concentration of the precipitate is A mg / L and the total organic carbon concentration of the soluble portion is B mg / L, the value of B / A × 100 is 15 to 100. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2023 / 139886 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a liquid fertilizer with improved growth-promoting effects. [Means for solving the problem]

[0006] The present inventors have discovered that the growth-promoting effect can be improved by using a liquid fertilizer that contains humic acid, which includes humic acid and fulvic acid, and has an X value obtained by a specified method within a specified range, and have completed the present invention.

[0007] That is, according to the present invention, the following liquid fertilizer, concentrated liquid fertilizer, and composition are provided.

[0008] [1] Contains humic acids, including humic and fulvic acids, Liquid fertilizers with an X value of less than 5.5% obtained by the following method: (method) A 50 mL volumetric flask is filled with the liquid fertilizer having a mass M0 (where M0 is between 490 mg and 510 mg), and then ultrapure water is added to make up to 50 mL to prepare a diluted solution. The diluted solution in the volumetric flask is stirred, and then the diluted solution is placed in a 50 mL centrifuge tube and centrifuged for 10 minutes at a relative centrifugal acceleration of 5000 × g. After removing the supernatant after centrifugation, the centrifuge tube is heated and dried in a constant temperature dryer at 80 °C for 24 hours to obtain a solid. The mass M1 of the solid is calculated from the difference between the mass of the centrifuge tube after heating and drying and the mass of the centrifuge tube before adding the diluted solution. The X value is then calculated based on the formula: X [%] = M1 [mg] / M0 [mg] × 100. [2] The liquid fertilizer according to [1], wherein the total organic carbon concentration of the liquid fertilizer is 4,000 mg / L or more and 150,000 mg / L or less. [3] The liquid fertilizer according to [1] or [2], wherein the total organic carbon concentration of the humic acid is 2,000 mg / L or more and 148,000 mg / L or less. [4] The liquid fertilizer according to any one of [1] to [3], wherein the total organic carbon concentration of the fulvic acid is 2,000 mg / L or more and 50,000 mg / L or less. [5] The liquid fertilizer according to any one of [1] to [4], wherein the humic acid contains humic acid extracted from young charcoal having a carbon content of 83 mass % or less. [6] A liquid fertilizer according to any one of [1] to [5], which has an MI of 1.71 or more obtained by the following method. (method) 1.0 g of the liquid fertilizer and 45 mL of 0.5 mol / L sodium hydroxide aqueous solution were placed in a 50 mL centrifuge tube. After shaking at 20°C and 250 rpm for 1 hour, the tube was centrifuged at a relative centrifugal acceleration of 3000 × g for 10 minutes, and the supernatant was filtered. The absorbance of the filtrate was measured using a spectrophotometer, and the absorbance at a wavelength of 450 nm was calculated as A 450 The absorbance at a wavelength of 520 nm is A 520 Formula: MI = A 450 / A 520 Based on this, MI is calculated. [7] A liquid fertilizer according to any one of [1] to [6], wherein EΔlogK obtained by the following method is greater than 0.70. (method) 1.0 g of the liquid fertilizer and 45 mL of 0.5 mol / L sodium hydroxide aqueous solution were placed in a 50 mL centrifuge tube. After shaking at 20°C and 250 rpm for 1 hour, the tube was centrifuged at a relative centrifugal acceleration of 3000 × g for 10 minutes, and the supernatant was filtered. The absorbance of the filtrate was measured using a spectrophotometer, and the absorbance at a wavelength of 400 nm was calculated as A 400 The absorbance at a wavelength of 600 nm is A 600 Formula: EΔlogK=log(A 400 / A 600 ) and calculate EΔlogK. [8] A obtained by the following method 465 / A 665 The liquid fertilizer according to any one of [1] to [7], wherein the β-glucan group is greater than 4.78. (method) 1.0 g of the liquid fertilizer and 45 mL of 0.5 mol / L sodium hydroxide aqueous solution were placed in a 50 mL centrifuge tube. After shaking at 20°C and 250 rpm for 1 hour, the tube was centrifuged at a relative centrifugal acceleration of 3000 × g for 10 minutes, and the supernatant was filtered. The absorbance of the filtrate was measured using a spectrophotometer, and the absorbance at a wavelength of 465 nm was calculated as A 465 The absorbance at a wavelength of 665 nm is A 665 And A 465 / A 665Calculate. [9] The liquid fertilizer according to any one of [1] to [8], having a pH of 5.0 or more and 10.0 or less.

[10] A concentrated liquid fertilizer that can be diluted with water to obtain the liquid fertilizer described in any one of [1] to [9].

[11] Contains humic acids, including humic and fulvic acids, A composition having an X value of less than 5.5% obtained by the following method: (method) A mass of the composition, M0 (where M0 is 490 mg or more and 510 mg or less), is placed in a 50 mL volumetric flask, and ultrapure water is added to make up to 50 mL to prepare a diluted solution. After stirring the diluted solution in the volumetric flask, the diluted solution is placed in a 50 mL centrifuge tube and centrifuged at a relative centrifugal acceleration of 5000 × g for 10 minutes. After removing the supernatant after centrifugation, the centrifuge tube is heated and dried in a thermostatic oven at 80 °C for 24 hours to obtain a solid. The mass of the solid, M1, is calculated from the difference between the mass of the centrifuge tube after heating and drying and the mass of the centrifuge tube before adding the diluted solution. The X value is then calculated based on the formula: X [%] = M1 [mg] / M0 [mg] × 100. [Effects of the Invention]

[0009] According to the present invention, a liquid fertilizer with improved growth-promoting effect can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described. In this specification, "A to B" indicating a range of numerical values means A or more and B or less unless otherwise specified.

[0011] In this specification, "humic acid" is a general term for alkali-soluble components of humic substances, "humic acid" is a general term for alkali-soluble but acid-insoluble components of humic substances, and "fulvic acid" is a general term for alkali-soluble and acid-soluble components of humic substances. These components are fractionated by the IHSS method.

[0012] (liquid fertilizer) The composition of this embodiment is preferably a liquid fertilizer. The liquid fertilizer of this embodiment contains humic acid, which includes humic acid and fulvic acid. In the liquid fertilizer of this embodiment, the X value obtained by the following method is less than 5.5%.

[0013] (method) A 50 mL volumetric flask is filled with liquid fertilizer with a mass of M0 (where M0 is between 490 mg and 510 mg), and then ultrapure water is added to make up to 50 mL to prepare a diluted solution. After stirring the diluted solution in the volumetric flask, the diluted solution is poured into a 50 mL centrifuge tube and centrifuged for 10 minutes at a relative centrifugal acceleration of 5000 x g. After removing the supernatant after centrifugation, the centrifuge tube is heated and dried in a constant temperature dryer at 80°C for 24 hours to obtain a solid. The mass of the solid, M1, is calculated from the difference between the mass of the centrifuge tube after heating and drying and the mass of the centrifuge tube before adding the diluted solution. The X value is then calculated based on the formula: X [%] = M1 [mg] / M0 [mg] x 100.

[0014] The humic acid contained in the liquid fertilizer of this embodiment contains humic acid and fulvic acid, which can improve the growth-promoting effect of the liquid fertilizer.

[0015] In the liquid fertilizer of this embodiment, the X value is less than 5.5%, preferably 3.0% or less, more preferably 2.0% or less, even more preferably 1.0% or less, even more preferably 0.5% or less, even more preferably 0.1% or less, and even more preferably less than 0.1%. The X value is an index related to the amount of insoluble components in the liquid fertilizer, and the smaller the X value, the smaller the amount of insoluble components in the liquid fertilizer. Therefore, it is thought that the smaller the X value, the smaller the amount of undissolved humic acid in the liquid fertilizer, and therefore the more improved the growth-promoting effect of the liquid fertilizer.

[0016] In the liquid fertilizer of this embodiment, the total organic carbon concentration of humic acid is preferably 2,000 mg / L to 148,000 mg / L, more preferably 2,500 mg / L to 128,000 mg / L, and even more preferably 3,000 mg / L to 117,500 mg / L. By setting the total organic carbon concentration of humic acid within the above range, the growth-promoting effect of the liquid fertilizer can be further improved.

[0017] In the liquid fertilizer of this embodiment, the total organic carbon concentration of the fulvic acid is preferably 2,000 mg / L to 50,000 mg / L, more preferably 2,000 mg / L to 45,000 mg / L, and even more preferably 2,500 mg / L to 40,000 mg / L. By setting the total organic carbon concentration of the fulvic acid within the above range, the growth-promoting effect of the liquid fertilizer can be further improved.

[0018] In this embodiment, the total organic carbon concentration of the liquid fertilizer is preferably 4,000 mg / L to 150,000 mg / L, more preferably 5,000 mg / L to 130,000 mg / L, and even more preferably 5,000 mg / L to 120,000 mg / L. By setting the total organic carbon concentration of the liquid fertilizer within the above range, the growth-promoting effect of the liquid fertilizer can be further improved.

[0019] The liquid fertilizer of this embodiment preferably has a pH of 5.0 or more and 10.0 or less, more preferably 5.5 or more and 9.5 or less, and even more preferably 6.0 or more and 9.0 or less. By setting the pH within the above range, the growth-promoting effect of the liquid fertilizer can be further improved.

[0020] In this embodiment, MI, EΔlogK, and A 465 / A 665 get. (method) 1.0 g of liquid fertilizer and 45 mL of 0.5 mol / L sodium hydroxide solution are placed in a 50 mL centrifuge tube. After shaking at 20°C and 250 rpm for 1 hour, the tube is centrifuged at a relative centrifugal acceleration of 3000 × g for 10 minutes, and the supernatant is filtered. The absorbance of the filtrate is measured using a spectrophotometer. The absorbance at a wavelength of 450 nm is expressed as A 450 The absorbance at a wavelength of 520 nm is A 520 Formula: MI = A 450 / A 520 The MI is calculated based on the absorbance at a wavelength of 400 nm. 400 The absorbance at a wavelength of 600 nm is A 600 Formula: EΔlogK=log(A 400 / A 600 ) and calculate EΔlogK. 465 The absorbance at a wavelength of 665 nm is A 665 And A 465 / A 665 Calculate.

[0021] In the liquid fertilizer of this embodiment, the MI is preferably 1.71 or greater, more preferably greater than 1.71, even more preferably 1.8 to 5.0, and even more preferably 2.0 to 4.5. MI is an index used to classify humic acids and can be adjusted by increasing or decreasing the amount of acid in the oxidation reaction step when preparing humic acid. Specifically, reducing the amount of acid in the oxidation reaction step tends to decrease the MI. Therefore, from the perspective of adjusting the amount of acid in the oxidation reaction step to an appropriate amount and reducing the production cost of humic acid, it is preferable to set the MI to not more than the above upper limit. Furthermore, a large MI is considered to indicate that the amount of undissolved humic acid in the liquid fertilizer is small. Therefore, by setting the MI above or equal to the above lower limit, the growth-promoting effect of the liquid fertilizer can be further improved.

[0022] In the liquid fertilizer of this embodiment, EΔlogK is preferably greater than 0.70, more preferably greater than 0.70 but less than 1.33, even more preferably 0.75 to 1.25, and even more preferably 0.80 to 1.20. EΔlogK is an index used to classify humic acids and indicates the degree of humification. The higher the EΔlogK, the lower the degree of humification and the greater the content of aromatic compounds in the liquid fertilizer. Because aromatic compounds are easily decomposed and are thought to be highly active against plants, the higher the EΔlogK, the more the growth-promoting effect of the liquid fertilizer can be improved. On the other hand, an appropriate level of EΔlogK indicates that the content of fulvic acid in the liquid fertilizer is appropriate, and the root-promoting effect of humic acid (e.g., humic acid) can be maintained.

[0023] In the liquid fertilizer of this embodiment, A 465 / A 665 is preferably greater than 4.78, more preferably 5.00 or greater and 14.00 or less, and even more preferably 5.50 or greater and 13.00 or less. 465 / A 665 is an index related to the molecular weight of humic acid. 465 / A 665 The higher the value, the greater the content of humic acid in the liquid fertilizer, which has a relatively small molecular weight and is highly active against plants. This can further improve the growth-promoting effect of the liquid fertilizer. 465 / A 665 An appropriate level of fulvic acid indicates that the liquid fertilizer contains an appropriate amount of fulvic acid, which can maintain the rooting effect of humic acid (e.g., humic acid).

[0024] (Liquid fertilizer manufacturing method) The liquid fertilizer of this embodiment can be produced, for example, as follows.

[0025] First, young coal is reacted with acid (oxidation reaction step). Young coal is coal with a relatively low carbon content, and is defined as coal with a carbon content of 83% by mass or less. In other words, the humic acid may include humic acid extracted from young coal with a carbon content of 83% by mass or less. The acid reacted with young coal in the oxidation reaction step may be nitric acid. The oxidation reaction step may be carried out under conditions of 70°C or higher and 95°C or lower for 1 hour to 6 hours.

[0026] Next, a base is added to the product obtained in the oxidation reaction step to adjust the pH, and extraction is performed (extraction step). The base added to the product may include potassium hydroxide. The pH in the extraction step may be 0.5 or more and 7.5 or less. The extraction step may be performed under conditions of 40°C or more and 95°C or less for 0.5 hours or less and 24 hours or less.

[0027] The obtained extract is subjected to solid-liquid separation to obtain the liquid fertilizer of the present embodiment as a liquid (solid-liquid separation step). The method of solid-liquid separation may be centrifugation.

[0028] That is, the method for producing liquid fertilizer of this embodiment includes, for example, an oxidation reaction process in which young charcoal is reacted with an acid, an extraction process in which a base is added to the product obtained by the oxidation reaction process to obtain an extract, and a solid-liquid separation process in which the extract is subjected to solid-liquid separation to obtain liquid fertilizer.

[0029] (Concentrated liquid fertilizer) The concentrated liquid fertilizer of this embodiment is a concentrated version of the liquid fertilizer of this embodiment. In other words, the liquid fertilizer of this embodiment can be obtained by diluting the concentrated liquid fertilizer of this embodiment with water.

[0030] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. [Example]

[0031] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the descriptions in these examples.

[0032] (1) Preparation of liquid fertilizer Example 1 27.3 g of lignite (from Berezovsk, Russia) with a carbon content of 68% by mass was placed in a 500 mL beaker, and 65.0 g of 48% by mass nitric acid was added. The oxidation reaction was carried out in a water bath at 80 °C for 5 hours (oxidation reaction step). Next, a 30% by mass potassium hydroxide aqueous solution was added to adjust the pH to 7.1, and extraction was carried out at 80 °C for 1 hour (extraction step). The obtained extract was centrifuged at a relative centrifugal acceleration of 5000 × g for 10 minutes using a centrifuge (Eppendorf "Centrifuge 5430R"), and the resulting supernatant was used as liquid fertilizer (centrifugation step).

[0033] (Comparative Example 1) Except for changing the pH to 2.4 in the extraction step, a liquid fertilizer was obtained in the same manner as in Example 1. The liquid fertilizer of Comparative Example 1 did not contain humic acid.

[0034] (Comparative Examples 2 and 3) A liquid fertilizer was prepared by extracting leonardite.

[0035] (2) Measurement of total organic carbon concentration (TOC) The total organic carbon concentration of the liquid fertilizer was measured using a total organic carbon meter (Shimadzu Corporation's "TOC-L", combustion catalytic oxidation method).

[0036] Hydrochloric acid was added to the liquid fertilizer to adjust the pH to 1.0, and the mixture was centrifuged for 10 minutes at a relative centrifugal acceleration of 5000 × g using a centrifuge (Eppendorf Centrifuge 5430R). The total organic carbon concentration of the supernatant was measured using a total organic carbon analyzer (Shimadzu TOC-L, combustion catalytic oxidation method), and this was used as the total organic carbon concentration of fulvic acid. The total organic carbon concentration of humic acid was calculated using the formula: (total organic carbon concentration of humic acid) = (total organic carbon concentration of liquid fertilizer) - (total organic carbon concentration of fulvic acid). The measurement results are shown in Table 1.

[0037] (3) Absorbance measurement 1.0 g of liquid fertilizer and 45 mL of 0.5 mol / L sodium hydroxide solution were placed in a 50 mL centrifuge tube. After shaking at 20°C and 250 rpm for 1 hour, the tube was centrifuged for 10 minutes at a relative centrifugal acceleration of 3000 × g using a centrifuge (Eppendorf Centrifuge 5430R). The supernatant was filtered using Advantec's Quantitative Filter Paper No. 5C. The absorbance of the filtrate was measured using a spectrophotometer. Formula: MI = A 450 / A 520 MI was calculated based on the formula: EΔlogK=log(A 400 / A 600 ) was used to calculate EΔlogK. 465 / A 665 was calculated. Here, A λ The absorbance at wavelength λ nm is shown in Table 1.

[0038] (4) Measurement of sediment volume A 50 mL volumetric flask was filled with liquid fertilizer with a mass of M0 (M0 = 490 mg to 510 mg), and then ultrapure water was added to the volume of 50 mL to prepare a diluted solution. The diluted solution in the volumetric flask was stirred, then transferred to a 50 mL centrifuge tube and centrifuged for 10 minutes at a relative centrifugal acceleration of 5000 × g using a centrifuge (Eppendorf Centrifuge 5430R). After removing the supernatant, the centrifuge tube was heated and dried in a thermostatic oven at 80 °C for 24 hours to obtain a solid. The mass of the solid, M1, was calculated from the difference between the mass of the centrifuge tube after heating and the mass of the centrifuge tube before adding the diluted solution. The X value was then calculated using the formula: X [%] = M1 [mg] / M0 [mg] × 100. The measurement results are shown in Table 1.

[0039] (5) Cultivation test (5-1) Cultivation test of frill lettuce A cultivation test was conducted on frill lettuce ("Frill Ice" manufactured by Snow Brand Seed Co., Ltd.). Seedlings at the three-leaf stage germinated and raised on urethane foam were transplanted onto polystyrene foam panels. Using a hydroponic cultivation system ("Neo Planta Mini" manufactured by Sanshin Metal Industries Co., Ltd.), hydroponic cultivation was performed for 38 days under conditions of a 12-hour photoperiod (LED lighting) and 22°C (room temperature). The liquid fertilizers from each example and comparative example were diluted with water to the same concentration and used as the culture solution. A control group was used in which water was used instead of the culture solution. The dry mass of the aboveground and underground parts of seven randomly selected individuals from each cultivation group was measured, and the average was calculated. The test results are shown in Table 1. The dry mass is expressed as a relative value, with the value for the control group set at 100.

[0040] (5-2) Komatsuna cultivation test A cultivation test of komatsuna (Takii Seed Co., Ltd., "Rakuten") was conducted. 265 g of Takii seedling soil was placed in 12 cm black pots as a culture medium. Komatsuna seeds were sown in each culture medium (n=10). The same amount of water was sprayed on each cultivation area every day. Furthermore, 2 and 3 weeks after sowing, a culture solution was sprayed on each cultivation area. The culture solution was prepared by diluting the liquid fertilizer of each Example and Comparative Example with water to the same concentration. A cultivation area using water instead of a culture solution served as a control area. Four weeks after sowing, the dry mass of the aboveground and underground parts of seven randomly selected individuals in each cultivation area was measured, and the average value was calculated. The test results are shown in Table 1. The dry mass is shown as a relative value, with the value of the control area set at 100.

[0041] (5-3) Tomato cultivation test Uniformly grown tomato seedlings (Takii Seed Co., Ltd. "CF Momotaro Fight", two weeks after sowing) were prepared. Liquid fertilizer was diluted with water to prepare diluted liquid fertilizer so that the total organic carbon concentration was 10 mg / L. 200 mL of diluted liquid fertilizer was applied to each pot of tomato seedlings daily. A cultivation area that received water instead of diluted liquid fertilizer served as a control area. Two weeks after the start of the test, the number of flowers was counted for six random individuals in each cultivation area, and the average value was calculated. The test results are shown in Table 1. The number of flowers is shown relative to the value for the control area, which is set at 100.

[0042]

Table 1

Claims

1. Contains humic acids, including humic and fulvic acids, The X value obtained by the following method is less than 5.5%, A liquid fertilizer having an EΔlogK obtained by the following method of greater than 0.

70. (method) In a 50 mL volumetric flask, add mass M ０ (However, M ０ After adding 490 mg to 510 mg of the liquid fertilizer, add ultrapure water to make up to 50 mL to prepare a diluted solution. After stirring the diluted solution in the volumetric flask, place the diluted solution in a 50 mL centrifuge tube and centrifuge it at a relative centrifugal acceleration of 5,000 × g for 10 minutes. After removing the supernatant after centrifugation, the centrifuge tube is heated and dried in a thermostatic oven at 80°C for 24 hours to obtain a solid. The mass of the solid, M １ Then, the formula: X [%] = M １ [mg] / M ０ The X value is calculated based on [mg] x 100. (method) 1.0 g of the liquid fertilizer and 45 mL of 0.5 mol / L sodium hydroxide aqueous solution were placed in a 50 mL centrifuge tube. After shaking at 20°C and 250 rpm for 1 hour, the tube was centrifuged at a relative centrifugal acceleration of 3000 x g for 10 minutes, and the supernatant was filtered. The absorbance of the filtrate was measured using a spectrophotometer, and the absorbance at a wavelength of 400 nm was defined as A400, and the absorbance at a wavelength of 600 nm was defined as A600. EΔlogK was calculated based on the formula: EΔlogK = log(A400 / A600).

2. A obtained by the following method ４６５ / A ６６５ The liquid fertilizer of claim 1, wherein the ρ is greater than 4.

78. (method) 1.0 g of the liquid fertilizer and 45 mL of 0.5 mol / L aqueous sodium hydroxide solution were placed in a 50 mL centrifuge tube. After shaking at 20°C and 250 rpm for 1 hour, the tube was centrifuged at a relative centrifugal acceleration of 3000 × g for 10 minutes, and the supernatant was filtered. The absorbance of the filtrate was measured using a spectrophotometer, and the absorbance at a wavelength of 465 nm was calculated as A. ４６５ The absorbance at a wavelength of 665 nm is A ６６５ And A ４６５ / A ６６５ Calculate.

3. Contains humic acids, including humic and fulvic acids, The X value obtained by the following method is less than 5.5%, A liquid fertilizer having an A 465 / A 665 of greater than 4.78 obtained by the following method. (method) In a 50 mL volumetric flask, add mass M ０ (However, M ０ After adding 490 mg to 510 mg of the liquid fertilizer, add ultrapure water to make up to 50 mL to prepare a diluted solution. After stirring the diluted solution in the volumetric flask, place the diluted solution in a 50 mL centrifuge tube and centrifuge it at a relative centrifugal acceleration of 5,000 × g for 10 minutes. After removing the supernatant after centrifugation, the centrifuge tube is heated and dried in a thermostatic oven at 80°C for 24 hours to obtain a solid. The mass of the solid, M １ Then, the formula: X [%] = M １ [mg] / M ０ The X value is calculated based on [mg] x 100. (method) 1.0 g of the liquid fertilizer and 45 mL of 0.5 mol / L sodium hydroxide aqueous solution were placed in a 50 mL centrifuge tube. After shaking at 20°C and 250 rpm for 1 hour, the tube was centrifuged at a relative centrifugal acceleration of 3000 x g for 10 minutes, and the supernatant was filtered. The absorbance of the filtrate was measured using a spectrophotometer, and the absorbance at a wavelength of 465 nm was defined as A465, and the absorbance at a wavelength of 665 nm was defined as A665, to calculate A465 / A665.

4. The liquid fertilizer according to any one of claims 1 to 3, wherein the total organic carbon concentration of the liquid fertilizer is 4,000 mg / L or more and 150,000 mg / L or less.

5. The liquid fertilizer according to any one of claims 1 to 3, wherein the total organic carbon concentration of the humic acid is 2,000 mg / L or more and 148,000 mg / L or less.

6. The liquid fertilizer according to any one of claims 1 to 3, wherein the total organic carbon concentration of the fulvic acid is 2,000 mg / L or more and 50,000 mg / L or less.

7. The liquid fertilizer according to any one of claims 1 to 3, wherein the humic acid contains humic acid extracted from young charcoal having a carbon content of 83% by mass or less.

8. The liquid fertilizer according to any one of claims 1 to 3, wherein the MI obtained by the following method is 1.71 or more. (method) 1.0 g of the liquid fertilizer and 45 mL of 0.5 mol / L aqueous sodium hydroxide solution were placed in a 50 mL centrifuge tube. After shaking at 20°C and 250 rpm for 1 hour, the tube was centrifuged at a relative centrifugal acceleration of 3000 × g for 10 minutes, and the supernatant was filtered. The absorbance of the filtrate was measured using a spectrophotometer, and the absorbance at a wavelength of 450 nm was calculated as A. ４５０ The absorbance at a wavelength of 520 nm is A ５２０ Formula: MI = A ４５０ / A ５２０ Based on this, MI is calculated.

9. The liquid fertilizer according to any one of claims 1 to 3, having a pH of 5.0 or more and 10.0 or less.

10. A concentrated liquid fertilizer that can be obtained by diluting with water to obtain the liquid fertilizer described in any one of claims 1 to 3.

11. Contains humic acids, including humic and fulvic acids, The X value obtained by the following method is less than 5.5%, A composition having an EΔlogK obtained by the following method of greater than 0.

70. (method) In a 50 mL volumetric flask, add mass M ０ (However, M ０ After adding 490 mg or more and 510 mg or less of the composition, ultrapure water is added to the volumetric flask to make up to 50 mL, to prepare a diluted solution. After stirring the diluted solution in the volumetric flask, the diluted solution is placed in a 50 mL centrifuge tube and centrifuged at a relative centrifugal acceleration of 5,000 × g for 10 minutes. After removing the supernatant after centrifugation, the centrifuge tube is heated and dried in a thermostatic oven at 80°C for 24 hours to obtain a solid. The mass of the solid, M １ Then, the formula: X [%] = M １ [mg] / M ０ The X value is calculated based on [mg] x 100. (method) 1.0 g of the composition and 45 mL of 0.5 mol / L aqueous sodium hydroxide solution were placed in a 50 mL centrifuge tube. After shaking at 20°C and 250 rpm for 1 hour, the tube was centrifuged at a relative centrifugal acceleration of 3000 x g for 10 minutes, and the supernatant was filtered. The absorbance of the filtrate was measured using a spectrophotometer, and the absorbance at a wavelength of 400 nm was defined as A400, and the absorbance at a wavelength of 600 nm was defined as A600. EΔlogK was calculated based on the formula: EΔlogK = log(A400 / A600).

12. Contains humic acids, including humic and fulvic acids, The X value obtained by the following method is less than 5.5%, A composition having an A 465 / A 665 greater than 4.78 obtained by the following method. (method) In a 50 mL volumetric flask, add mass M ０ (However, M ０ After adding 490 mg or more and 510 mg or less of the composition, ultrapure water is added to the volumetric flask to make up to 50 mL, to prepare a diluted solution. After stirring the diluted solution in the volumetric flask, the diluted solution is placed in a 50 mL centrifuge tube and centrifuged at a relative centrifugal acceleration of 5,000 × g for 10 minutes. After removing the supernatant after centrifugation, the centrifuge tube is heated and dried in a thermostatic oven at 80°C for 24 hours to obtain a solid. The mass of the solid, M １ Then, the formula: X [%] = M １ [mg] / M ０ The X value is calculated based on [mg] x 100. (method) 1.0 g of the composition and 45 mL of 0.5 mol / L aqueous sodium hydroxide solution are placed in a 50 mL centrifuge tube. After shaking at 20°C and 250 rpm for 1 hour, the tube is centrifuged at a relative centrifugal acceleration of 3000 x g for 10 minutes, and the supernatant is filtered. The absorbance of the filtrate is measured using a spectrophotometer, and the absorbance at a wavelength of 465 nm is defined as A465, and the absorbance at a wavelength of 665 nm is defined as A665, to calculate A465 / A665.

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