Fertilizers, bagged fertilizers, methods for improving soil, and methods for promoting plant growth

Abstract

To provide a humic acid-containing fertilizer with improved rapid action. [Solution] A fertilizer that is a mixture of humic acid material and liquid fertilizer, is granular, and has a water content of 15-30% by mass. Also, a method for improving soil by spreading this fertilizer on the soil. Also, a method for promoting plant growth by giving this fertilizer to plants.

Description

Technical Field

[0001] The present invention relates to a fertilizer, a bagged fertilizer, a soil improvement method, and a plant growth promotion method.

Background Art

[0002] Humic acid is said to have an effect of promoting plant growth. For this reason, the use of a humic acid-containing substance as a fertilizer has been proposed. Further, studies on industrial production methods of humic acid have also been conducted hitherto. Humic acid exists in soil and terrestrial water. Specifically, humic acid is contained in lignite or peat, or exists as a metabolite of bacterial flora. As humic acid, while there is natural humic acid derived from animals and plants, industrially, humic acid which is an oxidative decomposition product of low-rank coal such as lignite, or an alkali metal salt or alkaline earth metal salt of the oxidative decomposition product, and the like are known.

[0003] Patent Document 1 discloses a magnesia fertilizer characterized by consisting of granules containing humic acid or a substance containing the same and a water-soluble magnesium salt. Patent Document 2 discloses a granular humic acid material that is surface-treated with a wax and / or oils and fats. Patent Document 3 describes a humic acid extract containing humic acid having a mass average molecular weight of 800 to 1,200, having a total organic carbon concentration of 25,000 to 45,000 mg / L and a pH of 2.0 to 4.0. Patent Document 4 discloses a method for producing nitrohumic acid, characterized in that when producing nitrohumic acid by reacting nitric acid with low-rank coal such as lignite and brown coal, the moisture content of the low-rank coal is pre-adjusted to 30 to 40% for humidity conditioning, and then the low-rank coal is reacted with nitric acid.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

[0005] In its research on humic acid, this invention found that fertilizers containing granular humic acid have room for improvement in terms of their rapid-acting properties.

[0006] This invention has been made in view of these circumstances. One of the objectives of this invention is to provide a humic acid-containing fertilizer with improved rapid action. [Means for solving the problem]

[0007] The inventors have completed the invention described below and solved the above problems.

[0008] 1. A fertilizer that is a mixture of humic acid material and liquid fertilizer, is in granular form, and has a moisture content of 15-30% by mass. 2. The fertilizer described in 1. A fertilizer containing 30% or more by mass of humic acid. 3. Fertilizer as described in 1. or 2., The amount of organic matter derived from the liquid fertilizer per gram of the fertilizer is 1.0 × 10 -5 ~8.0×10 -3 Fertilizer in grams. 4. A fertilizer listed in any one of items 1-3, A fertilizer in which, after immersing 5g of the fertilizer in 200mL of water for 10 minutes at room temperature, the concentration of total organic carbon (TOC) in the water is 15ppm or higher. 5. A fertilizer listed in any one of items 1 to 4, A fertilizer that is a magnesium fertilizer. 6. The fertilizer according to any one of claims 1 to 5, wherein the fertilizer is an aggregate of particles having a diameter of 10 mm or less. 7. A bag-packed fertilizer, wherein the fertilizer according to any one of claims 1 to 6 is packed in a bag. 8. A soil improvement method, which comprises applying the fertilizer according to any one of claims 1 to 7 to soil. 9. A plant growth promotion method, which comprises applying the fertilizer according to any one of claims 1 to 7 to a plant. Effects of the Invention

[0009] According to the present invention, a humic acid-containing fertilizer with improved quick-acting property is provided. Modes for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail. In the present specification, the notation "X to Y" in the description of a numerical range means X or more and Y or less unless otherwise specified. For example, "1 to 5 mass%" means "1 mass% or more and 5 mass% or less". In the present specification, "weight" may sometimes refer to "mass".

[0011] <Fertilizer> The fertilizer of the present embodiment is a mixture of a humic acid material and a liquid fertilizer. The fertilizer of the present embodiment is granular. The fertilizer of the present embodiment is not liquid at normal temperature and can maintain its shape at normal temperature. The water content of the fertilizer of the present embodiment is 15 to 30 mass%.

[0012] As described above, fertilizers containing granular humic acid have room for improvement from the viewpoint of the quick-acting property of fertilizers. Therefore, the present inventors mixed a liquid fertilizer, which is known as a quick-acting fertilizer, with a humic acid material to produce a new granular fertilizer. Liquid fertilizers are thought to be easily dissolved from the soil and absorbed by plants precisely because they are in liquid form. Therefore, it was thought that even if liquid fertilizer was used as a raw material, if the final fertilizer applied to the soil was granular, it would not be fast-acting. However, experimental results showed data demonstrating fast-acting properties (see the examples below for details). Although the details are unclear, it is possible that even in granular form, the water content of 15-30% by mass allows the active ingredients derived from the liquid fertilizer to dissolve quickly into the soil.

[0013] Furthermore, by using the fertilizer of this embodiment, the effort required to apply fertilizer to the soil can be reduced compared to applying granular humic acid-containing fertilizer and liquid fertilizer separately to the soil.

[0014] Furthermore, some experimental results suggest that not only the liquid fertilizer used, but also the active ingredients such as humic acid in the humic acid material are likely to be released early. It is possible that the active ingredients in the humic acid material and the active ingredients in the liquid fertilizer are undergoing some kind of "synergistic effect," which is promoting the transfer of active ingredients from the fertilizer to the soil. And / or, it is possible that the active ingredients in the liquid fertilizer are "taking along" the active ingredients in the humic acid material, thereby promoting the transfer of active ingredients from the fertilizer to the soil. This will be further discussed in the examples.

[0015] The description of the fertilizer in this embodiment will continue.

[0016] (Humic acid material) In this embodiment, humic acid or a substance containing humic acid can be used as the humic acid material, which is a raw material for the fertilizer, without any particular limitations. Unless otherwise specified, "humic acid" in this specification includes humic acid itself and salts of humic acid. Examples of humic acid include naturally occurring humic acid from peat and weathered coal, and artificially produced humic acid from methods such as nitrate oxidation of lignite. Other examples include humic acid salts obtained by neutralizing natural or artificial humic acid with alkaline substances such as sodium, potassium, ammonia, calcium, and magnesium. In this embodiment, humic acid obtained by nitrate oxidation of lignite is particularly preferred. Specific examples of humic acids include humic acid, nitrohumic acid, ammonium humate, calcium humate, magnesium humate, ammonium nitrohumate, calcium nitrohumate, and magnesium nitrohumate. Other examples include fulvic acid, ammonium fulvic acid, and potassium fulvic acid. Humic acids preferably include one or both of humic acid or a salt thereof, and fulvic acid or a salt thereof. For specific examples of humic acid, refer to the description in paragraph 0020 of Japanese Patent Publication No. 2023-134372. For example, the fertilizer "Azumin" (registered trademark) sold by Denka Co., Ltd. contains 40-50% by mass of humic acid, making it a suitable material for use as a humic acid fertilizer. Other examples of humic acid fertilizers include "AG Humin" from I-Agri Co., Ltd., "Humic Charge" sold in Japan by Daiko Trading Co., Ltd., and "Canadian Humin" from PIC Bio Co., Ltd.

[0017] (Humic acid ratio) From the viewpoint of more reliably obtaining the effect of promoting plant growth, the concentration of humic acid in the fertilizer is preferably 30% by mass or more, more preferably 35% by mass or more, and most preferably 40% by mass or more. Taking production costs into consideration, the concentration of humic acid in the fertilizer is preferably 30-70% by mass, more preferably 35-60% by mass, and most preferably 40-55% by mass.

[0018] (liquid fertilizer) Any liquid fertilizer can be used as long as it can be manufactured as a granular fertilizer together with humic acid materials. Liquid fertilizers typically consist of various active ingredients dissolved or dispersed in water. These active ingredients may include one or more of the following: nitrogen, phosphorus, potassium, calcium, magnesium, iron, manganese, humic acid, fulvic acid, amino acids, and other organic substances. In this embodiment, as an example, a liquid fertilizer containing organic matter can be preferably used, and a liquid fertilizer containing fulvic acid can be more preferably used. More specifically, a liquid fertilizer containing organic components in which the proportion of fulvic acid in the total organic components is 50% by mass or more is preferred. The results from the examples described below suggest that using a liquid fertilizer containing fulvic acid makes it easier for the aforementioned "synergistic effect" to occur. Although the details are unclear, the fact that fulvic acid is soluble in both acids and alkalis may be related to this synergistic effect.

[0019] Recolte (trade name), sold by Denka Co., Ltd., is a suitable liquid fertilizer. Recolte is a liquid fertilizer containing nitrogen, potassium, and fulvic acid. In addition, liquid humic acid, such as that described in International Publication No. 2023 / 139886, can also be suitably used as a liquid fertilizer.

[0020] (Amount of organic matter derived from liquid fertilizer) As described above, in the fertilizer of this embodiment, the active ingredients in the humic acid material and the active ingredients derived from the liquid fertilizer may undergo some kind of "synergistic effect," and / or the active ingredients derived from the liquid fertilizer may "take along" the active ingredients in the humic acid material, thereby promoting the transfer of active ingredients from the fertilizer to the soil. Assuming such a mechanism, it is thought that even a small amount of liquid fertilizer can provide effects such as rapid action. To express this numerically, the amount of organic matter derived from the liquid fertilizer per gram of fertilizer in this embodiment is specifically 1.0 × 10 -5 ~8.0×10 -3 Even if it's g, more specifically 1.0 × 10 -5 ~4.0×10 -3 Even in grams, it is possible to obtain effects such as rapid action.

[0021] (moisture content) The moisture content of the fertilizer in this embodiment may be 15 to 30% by mass, but preferably 15 to 23% by mass. An appropriate moisture content can, for example, suppress deterioration and clumping of the fertilizer during storage. It may also allow for adjustment of the fertilizer's rapid-acting properties. The moisture content can be measured by the dry weight method, for example, using a halogen moisture meter from Mettler-Toledo.

[0022] (particle size) In this embodiment, it is preferable that the particle size of the fertilizer be appropriately adjusted. Appropriate particle size tends to improve the handling and ease of application of the fertilizer.

[0023] From one perspective, the fertilizer of this embodiment is preferably an aggregate of particles with a diameter of 10 mm or less. When we say that the fertilizer is "an aggregate of particles with a diameter of 10 mm or less," we mean that when the fertilizer is passed through a sieve with a mesh size of 10 mm, all of the fertilizer passes through the sieve without leaving any residue. If a sieve with a mesh size of 10 mm cannot be prepared, for example, the fertilizer can be passed through a sieve with a mesh size slightly smaller than 10 mm (for example, a sieve with a mesh size of 4.75 mm), and the equivalent circular diameter of the fertilizer particles that did not pass through the sieve can be individually measured. If all of the measured equivalent circular diameters are 10 mm or less, then the fertilizer can be said to be "an aggregate of particles with a diameter of 10 mm or less."

[0024] From another perspective, the fertilizer of this embodiment is preferably an aggregate of particles with a diameter of 0.15 mm or more. In other words, preferably, even if one attempts to pass the fertilizer of this embodiment through a sieve with a mesh size of 0.15 mm, the fertilizer will hardly or none pass through the sieve. If the fertilizer of this embodiment is an aggregate of particles with a diameter of 0.15 mm or more, the proportion of particles with a diameter of less than 0.15 mm (particles that pass through a sieve with a mesh size of 0.15 mm) in the fertilizer of this embodiment is, for example, 1% by mass or less, preferably 0.5% by mass or less, and more preferably 0.1% by mass or less.

[0025] (Degree of elution of active ingredient) As already mentioned, the fertilizer of this embodiment is fast-acting, and it is believed that the active ingredients are rapidly released from the fertilizer into the soil after it has been applied to the soil. This can be quantitatively expressed by measurement using, for example, the following procedure.

[0026] <Instructions> (1) At room temperature (e.g., 25°C), soak 5g of fertilizer in 200mL of water for 10 minutes. (2) Subsequently, measure the concentration of total organic carbon (TOC) in the water in which the fertilizer was immersed (for example, the "amount of organic matter dissolved in 200 mL of tap water" in the example). (3) Then, measure the rate of organic matter elution.

[0027] In the fertilizer of this embodiment, the concentration of total organic carbon (TOC) measured by the above procedure is preferably 15 ppm or more, more preferably 20 ppm or more. There is no particular upper limit to this value, but for example, it is 30 ppm, specifically 25 ppm.

[0028] (others) The fertilizer of this embodiment can be a magnesium fertilizer, for example. In other words, the fertilizer of this embodiment can contain magnesium. For example, if the humic acid material is produced by the decomposition of lignite with nitric acid or sulfuric acid and has a low pH, it is preferable for the fertilizer to contain magnesium components for neutralization. When the fertilizer of this embodiment is a magnesium fertilizer, the content of water-soluble magnesium in the fertilizer is, for example, 1 to 15% by mass as magnesium oxide. Of course, the fertilizer in this embodiment does not have to be a magnesium fertilizer.

[0029] (Bagged fertilizer) The fertilizer of this embodiment is typically distributed in bags and stored until immediately before use. The bags are usually made of resin film.

[0030] <Method of manufacturing fertilizer> The fertilizer of this embodiment can be manufactured, for example, by a method such as Method 1 or Method 2 described below. (Method 1) Mix granular or powdered humic acid material with liquid fertilizer. (Method 2) First, an intermediate mixture is obtained by mixing a liquid or paste-like humic acid material with liquid fertilizer. The intermediate mixture is then granulated.

[0031] In either Method 1 or Method 2, the mixing ratio of humic acid material and liquid fertilizer should be determined by considering the preferred concentration of humic acid and the appropriate amount of organic matter derived from the liquid fertilizer per gram of fertilizer, as mentioned above.

[0032] <Methods for improving soil and promoting plant growth> By applying the fertilizer of this embodiment to the soil, the soil can be improved, specifically, to a state suitable for plant growth. Similarly, plant growth can be promoted by applying the fertilizer of this embodiment to plants. Specifically, plant growth can be promoted by spreading the fertilizer of this embodiment on soil in which plants are growing or planted. Various edible plants can be used as examples of plants.

[0033] The amount to be applied to the soil is not particularly limited, but considering the balance between obtaining sufficient soil improvement or plant growth promotion effects and cost, the application amount can be, for example, 150 to 800 kg / ha. More specifically, the application amounts can be as follows, depending on the crop. Of course, the values ​​shown here are just examples, and the fertilizer of this embodiment may be used in amounts less than or more than the values ​​shown here. Paddy rice: 20-40 kg / 10a Field crops: 40~80kg / 10a Fruit trees and tea: 40-100 kg / 10a

[0034] Furthermore, from another perspective, it is preferable that the fertilizer of this embodiment be mixed with seedling growing medium (potting soil) at a concentration of about 0.5 to 1%.

[0035] Although embodiments of the present invention have been described above, these are merely examples, and various other configurations can be adopted. Furthermore, the present invention is not limited to the embodiments described above, and modifications and improvements that can achieve the objectives of the present invention are included within the scope of the present invention. [Examples]

[0036] Embodiments of the present invention will be described in detail based on examples and comparative examples. It should be noted that the present invention is not limited to these examples.

[0037] <Example I: Fertilizer production and evaluation - When "Recolte" is used as liquid fertilizer> (Manufacturing) Using a pan-type granulator "PZ-01R" manufactured by AS ONE Corporation, humic acid-containing fertilizer "Azumin" manufactured by Denka Co., Ltd. and liquid fertilizer "Recolte" manufactured by Denka Co., Ltd. were mixed at 45° and 50 rpm in the proportions shown in the table below to obtain a mixture. The resulting mixture was air-dried in the laboratory for one week. The evaluation samples were manufactured in the manner described above.

[0038] For the evaluation samples, the moisture content was measured using the dry weight method with a Mettler-Toledo halogen moisture meter. Furthermore, assuming a fulvic acid (organic matter) concentration of 15,000 ppm in "Recolte," the amount of organic matter derived from Recolte in a 5 g evaluation sample ("Amount of organic matter derived from liquid fertilizer per 5 g of Azumin used in the test" in the table) was calculated.

[0039] Furthermore, all evaluation samples were sieved to confirm that they consisted of aggregates of particles with a diameter of 10 mm or less.

[0040] (Leaching test) 5 g of the obtained evaluation sample was placed in a commercially available tea bag (non-woven fabric bag). This tea bag was then placed in a container containing 200 mL of room temperature tap water and left to stand. After 10 minutes, the concentration of total organic carbon (TOC) dissolved in the tap water was measured using a Shimadzu Corporation TOC-L total organic carbon analyzer. In this process, the following three reagents were used to create a calibration curve and to confirm its accuracy. • For creating the TC (Total Carbon) calibration curve: Potassium bitum phthalate dissolved in ultrapure water and adjusted to 100 ppm. • For creating IC (Inorganic Carbon) calibration curves: Sodium bicarbonate and sodium carbonate are dissolved in ultrapure water and adjusted to a concentration of 10 ppm. ·Standard material: TOC Standard Solution traceable to SRM from NIST 10.0mg / l TOC in H2O

[0041] The table below shows the details of the evaluation samples and the results of the dissolution test.

[0042] [Table 1]

[0043] As shown in the table above, it was confirmed that a large amount of organic matter leached out of samples AP1, AP2, and AP4 even with short-term immersion. This result can be said to indicate the rapid-acting nature of the fertilizer. In particular, although samples AP1, AP2, and AP4 differed from the comparison sample only in whether or not they contained trace amounts of organic matter derived from the liquid fertilizer (Recolte), a large amount of organic matter leached from samples AP1, AP2, and AP4 in the elution test. For example, in the case of sample AP1, if the leaching of organic matter from Recolte was simply in addition to the leaching of organic matter from Azumin, the amount of organic matter in 200 mL of tap water after the leaching test should be approximately 0.0024 g + 0.00038 g = 0.00278 g. However, in this evaluation, a leaching of 0.0040 g, significantly higher than this, was confirmed. This result strongly suggests a synergistic effect between organic matter from humic acid materials and organic matter from liquid fertilizer (probably fulvic acid). Samples AP1, AP2, and AP4 contained 45-55% by mass of humic acid. The humic acid concentration was calculated from product information.

[0044] (Cultivation experiment) The impact on plant growth was evaluated under the following conditions. Common conditions Crop: Wheat, Norin No. 61 Growing medium: Soil cultivation Application method: Place directly on the ground at the same time as sowing. Schedule: 1 week cultivation Cultivation environment (using an incubator): 23°C, 55% RH (relative humidity), lighting on for 16 hours / off for 8 hours.

[0045] • Individual conditions Under the common conditions described above, wheat was cultivated under the following three different soil and fertilizer conditions. In the following, "germinated wheat" refers to seeds that germinated the day before sowing, and which have been selected for their uniform growth (excluding those that are too large or too small). (i) Comparison We prepared several 9cm diameter black pots filled with a mixture of seedling growing medium (Takii Seed Co.), lawn topsoil (Togawa Heiwa Farm Co.), and vermiculite WSS (Asahi Kogyo Co.) in a volume ratio of 1:1:1. We then sowed 5 germinated wheat seeds in each black pot, and sprinkled 0.1g of Azumin on top. (ii) AP2 The procedure was the same as in (i) above, except that 0.1g of sample AP2 was sprinkled instead of 0.1g of Azumin. (iii) AP4 The procedure was the same as in comparison (i) above, except that 0.1g of sample AP4 was sprinkled instead of 0.1g of Azumin.

[0046] The cultivation experiment was conducted twice. In each experiment, the leaf length, root length, above-ground dry weight, and below-ground dry weight of 15 germinated and grown wheat plants (N=15) were measured, and the average was calculated for each of the above (i) to (iii). In the table below, the leaf length, root length, above-ground dry weight, and below-ground dry weight in the comparison in (i) are shown as values ​​normalized to 100. The measurement method was as follows: Leaf length: Samples were taken from the above-ground parts (non-root parts) of the crop. For leaves on fully unfolded main stems, the straight-line distance from the base of the leaf (base of the leaf sheath) to the tip of the leaf was measured, and the average leaf length per plant was calculated. Root length: Crop plants were sampled. For each plant, the length from the base to the tip of the root was measured, and the average root length per plant was calculated. Dry above-ground weight: The above-ground parts (non-root portions) of the crop were sampled. The above-ground dry weight was measured after drying at 70°C for one day. The average above-ground dry weight per plant was calculated. Dry weight of underground parts: The underground parts (root portion) of the crop were sampled. The dry weight of the underground parts was measured after drying at 70°C for one day. The average dry weight of the underground parts per plant was calculated.

[0047] [Table 2]

[0048] From the results shown in the table above, it can be understood that the fertilizer of this embodiment shows a plant growth promoting effect even in a short period of one week. In other words, the fertilizer of this embodiment is preferable in terms of its rapid effect. In particular, in (ii)AP2 and (iii)AP4, the dry weight of the underground portion was large despite the root length being shorter compared to (i) comparison, suggesting that the fertilizer of this embodiment is effective in promoting lateral root formation in the underground portion.

[0049] <Example II: Fertilizer production and evaluation: Using a different liquid fertilizer than in Example I> (Manufacturing) Using a pan-type granulator "PZ-01R" manufactured by AS ONE Corporation, a mixture was obtained by mixing Denka Corporation's humic acid-containing fertilizer "Azumin" and a 10-fold diluted solution of liquid humic acid described in Example 3 of International Publication No. 2023 / 139886 as a liquid fertilizer, in the volume ratios shown in the table below, under conditions of 45° and 50 rpm. The resulting mixture was air-dried in the laboratory for one week. The evaluation samples were manufactured in the manner described above.

[0050] For the evaluation samples, the moisture content was measured using the dry weight method with a Mettler-Toledo halogen moisture meter. Furthermore, assuming that the TOC concentration of the above-mentioned liquid humic acid (undiluted, undiluted) was 99,000 ppm for fulvic acid and humic acid combined, the amount of organic matter derived from the liquid fertilizer in 5 g of the evaluation sample ("Amount of organic matter derived from liquid fertilizer per 5 g of Azumin used in the test" in the table) was calculated.

[0051] Incidentally, all evaluation samples were confirmed to be aggregates of particles with a diameter of 10 mm or less using a sieve.

[0052] (Leaching test) The same evaluation as in the dissolution test in Example I was performed.

[0053] The table below shows the details of the evaluation samples and the results of the dissolution test.

[0054] [Table 3]

[0055] As can be seen from the table above, in Example II as well, it was confirmed that a large amount of organic matter was leached out even with short-term immersion. This result can be said to demonstrate the rapid-acting nature of the fertilizer. However, in Example II, the "synergistic effect" shown in Example I was not observed. This is presumably because the main component of the liquid fertilizer used in Example II was not fulvic acid.

[0056] (Cultivation experiment) The impact on plant growth was evaluated under the following conditions. Common conditions The procedure was the same as in Example I.

[0057] • Individual conditions Under the common conditions described above, wheat was cultivated under the following four different soil and fertilizer conditions. In the following, "germinated wheat" refers to seeds that germinated the day before sowing, and which have been selected for their uniform growth (excluding those that are too large or too small). (a) Comparison The same procedure as in (i) Comparison in Example I was followed. Specifically, several 9cm diameter black pots were prepared, each containing a mixture of seedling growing medium (Takii Seed Co.), lawn topsoil (Togawa Heiwa Farm Co.), and vermiculite wss (Asahi Kogyo Co.) in a volume ratio of 1:1:1. Five germinated wheat seeds were sown in each black pot, and 0.1g of Azumin was added. (b) AD2 The procedure was the same as in (a) above, except that 0.1g of sample AD2 was sprinkled instead of 0.1g of Azumin. (c)AD4 The procedure was the same as in comparison (a) above, except that 0.1g of sample AD4 was sprinkled instead of 0.1g of Azumin. (d)AD8 The procedure was the same as in (a) above, except that 0.1g of sample AD8 was sprinkled instead of 0.1g of Azumin.

[0058] The cultivation experiment was conducted twice. In each experiment, the leaf length, root length, above-ground dry weight, and below-ground dry weight of 15 germinated and grown wheat plants (N=15) were measured, and the average was calculated for each of the above (a) to (d). The table below shows the values ​​of leaf length, root length, above-ground dry weight, and below-ground dry weight normalized to 100 for the comparison in (a).

[0059] [Table 4]

[0060] As shown in the table above, it is understood that even when using the fertilizer of Example II, a growth-promoting effect can be observed in a short period of time of one week. Table 4 also suggests that the fertilizer of this embodiment is particularly effective in promoting lateral root formation in the underground portion of the plant. Samples AD2, AD4, and AD8 contained 45-55% by mass of humic acid. The humic acid concentration was calculated from product information.

Claims

1. A fertilizer that is a mixture of humic acid material and liquid fertilizer, is in granular form, and has a water content of 15 to 30% by mass.

2. The fertilizer according to claim 1, A fertilizer containing 30% or more by mass of humic acid.

3. A fertilizer according to claim 1 or 2, The amount of organic matter derived from the liquid fertilizer per gram of the fertilizer is 1.0 × 10 －５ ~8.0 x 10 －３ Fertilizer in grams.

4. A fertilizer according to claim 1 or 2, A fertilizer in which, after immersing 5 g of the fertilizer in 200 mL of water for 10 minutes at room temperature, the concentration of total organic carbon (TOC) in the water is 15 ppm or higher.

5. A fertilizer according to claim 1 or 2, A fertilizer that is a magnesium fertilizer.

6. A fertilizer according to claim 1 or 2, Fertilizer is an aggregate of particles with a diameter of 10 mm or less.

7. A bagged fertilizer in which the fertilizer according to claim 1 or 2 is packaged in a bag.

8. A method for improving soil, comprising applying the fertilizer described in claim 1 or 2 to the soil.

9. A method for promoting plant growth, comprising applying the fertilizer described in claim 1 or 2 to the plants.

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