Fertilizer composition for promoting the growth of seaweed

Abstract

According to one aspect of the present invention, there is provided a fertilizer composition for promoting the growth of seaweed, which contains iron and steel by-products containing an Fe component and a chelating agent. According to the present invention, Fe can be recycled from iron and steel by-products as a raw material, soluble Fe can be chelated in seawater and supplied, and the fertilizer can be manufactured into a solid fertilizer such as a pellet type or block type, and can be supplied as fertilizer for the sea for a long period of time.

Description

Technical Field

[0001] The present invention relates to a fertilizer composition for promoting the growth of seaweeds, which can be smoothly supplied to seaweeds growing in seawater by chelating steel by-products containing Fe components such as slag.

Background Art

[0002] Excessive coastal development, an increase in herbivorous animals, and climate change have had many impacts on coastal ecosystems, and particularly, the phenomenon of coastal rocky shore burning where seaweeds disappear has become very serious. According to the investigation of the actual situation of rocky shore burning in the coastal areas of the Korean Peninsula provided by the Korea Fisheries Resources Agency (FIRA), the damaged area of rocky shore burning along the whole country's coast is reported to reach 19,100 ha, which is 44 times the area of Yeouido based on 2020. One of the causes of rocky shore burning is understood to be due to the interruption of inorganic nutrients necessary for the growth of seaweeds flowing into rivers by landfill and reclamation.

[0003] In Japan, since the mid to late 2000s, fertilizers using Fe have been produced mainly by steel manufacturers and research institutions, and demonstration tests for the growth test effect of seaweeds and the restoration of rocky shore burning areas have been carried out. As a result, it has been revealed that the treatment with Fe is effective for the growth of Laminaria japonica gametophytes and the growth of fronds (Kato et al., 2015; Miki et al 2016). On the other hand, in Korea, an invention using iron sulfate and leaf mold as a growth promoter for seaweeds has been reported (Growth promoter for seaweeds and its mixing device: registration number 10-206330). Thus, the development of fertilizers using Fe and the purpose of their supply are to eliminate the lack of Fe among the nutrients appearing in the coastal waters where rocky shore burning occurs and supply Fe that is essential for the photosynthesis of seaweeds and the growth of fronds.

[0004] Generally, seawater exhibits a slightly alkaline pH of around 8.0 to 8.4. Inorganic nutrients containing iron (Fe) are solubilized to varying degrees depending on the pH conditions, requiring either maintaining an appropriate pH or supplying inorganic nutrients in a form suitable for the pH conditions. In particular, in slightly alkaline seawater, the degree of Fe solubilization differs significantly depending on the salt form. Generally, when Fe fertilizer salts (divalent iron) used for crops are applied to seawater, they are rapidly oxidized by dissolved oxygen in the seawater, converted to the insoluble form of trivalent iron, and become unusable for seaweed (Kato et al., 2015). As a result, previous papers and patents have introduced methods to facilitate the movement of iron in solution by adding humic acid to chelate it. However, applying iron salts as fertilizer along with humic acid to seawater requires additional steps, such as installing nets or equipment to prevent leakage.

[0005] Therefore, there is a need to develop fertilizer production methods for the effective and sustainable supply of soluble iron in seawater. [Overview of the project] [Problems that the invention aims to solve]

[0006] The present invention aims to provide a fertilizer composition for promoting the growth of seaweed. [Means for solving the problem]

[0007] According to one aspect of the present invention, a fertilizer composition for promoting the growth of seaweed is provided, comprising a steel by-product containing an iron component and a chelating agent. [Effects of the Invention]

[0008] According to the present invention, iron by-products can be recycled as a raw material for Fe, soluble Fe can be chelated in seawater and supplied, and the soluble Fe can be manufactured into solid fertilizer such as pellets or blocks, which can then be supplied as marine fertilizer for a long period of time. [Brief explanation of the drawing]

[0009] [Figure 1] This shows the results of comparing the amount of Fe leached out in seawater in different forms according to Example 1 of the present invention. [Figure 2] This shows the Fe elution concentration in the fertilizer composition based on the weight percentage ratio of DTPA to the total Fe weight, according to Example 2 of the present invention. [Figure 3] This image shows a solid fertilizer produced according to Example 3 of the present invention. [Figure 4] This shows the weight change of kelp grown after being treated with the fertilizer composition of the present invention according to Example 4 of the present invention. [Figure 5] This shows the change in length of kelp grown in a sea area after being treated with the fertilizer composition of the present invention in accordance with Example 5 of the present invention. [Modes for carrying out the invention]

[0010] Preferred embodiments of the present invention will be described below. However, embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.

[0011] This invention relates to a fertilizer composition for promoting the growth of seaweed.

[0012] Examples of seaweed to which the present invention can be applied include green laver, wakame seaweed, kelp, kelp, and hijiki seaweed, but it is not limited to these, and for example, it can be applied to kelp or kelp.

[0013] Specifically, according to one aspect of the present invention, a fertilizer composition for promoting the growth of seaweed is provided, comprising a steel by-product containing an Fe component and a chelating agent.

[0014] In the present invention, the steel by-product containing the above Fe component can be slag or the like. Any by-product generated in the steelmaking process that contains 10 to 30% by weight of Fe, for example about 20% by weight, can be used without limitation. For example, steelmaking slag, preferably unaged steelmaking slag, can be used. For example, steelmaking slag can be dried at 100 to 150°C, for example 105°C, for 1 to 48 hours, for example 24 hours, and then pulverized to 500 μm or less to produce it in powder form.

[0015] Fe is an inorganic nutrient that can exist in the form of divalent or trivalent Fe under the pH conditions of seawater, which is slightly alkaline with a pH of 8.0 to 8.4. Fe used as fertilizer can be in the form of divalent Fe, which can be converted to insoluble trivalent Fe by dissolved oxygen in seawater.

[0016] As a result, the chelating agent prevents Fe from being oxidized to an insoluble form in seawater, and allows iron salts to be converted into fertilizer in a way that facilitates the movement of Fe in solution.

[0017] As the chelating agent mentioned above, crop chelating agents can be used, such as EDTA (Ethylenediamine tetra-acetic acid) and DTPA (Diethylenetriamine penta-acetic acid), with DTPA being preferred.

[0018] The iron by-products containing the above Fe component and the chelating agent may be in a weight ratio of 20:1 to 1:10, preferably 10:1 to 1:10, and more preferably 13:1 to 2:1.

[0019] Furthermore, the fertilizer composition for promoting the growth of seaweed according to the present invention may further include a binder, a base, or a mixture thereof.

[0020] Specifically, the binder can be used without limitation as long as it can be used to produce a solid fertilizer formulation. For example, at least one selected from the group consisting of lignin, molasses, and waste molasses can be used, and preferably molasses can be used.

[0021] On the other hand, when the fertilizer composition for promoting the growth of seaweeds of the present invention contains a mixture of a binder and a base, they may be mixed in a ratio of 2:1 to 20:1 by weight.

[0022] The above base can be used without limitation as long as it is a base commonly used in fertilizer compositions. For example, rare earth minerals such as monazite and zeolite can be used.

[0023] In the present invention, when containing a binder, a base or a mixture thereof, the fertilizer composition can contain 80 to 98% by weight of a steel by-product containing an Fe component and a chelating agent; and 2 to 20% by weight of other components containing a binder, a base, or a mixture thereof. When mixed within the above weight range, the best physical properties can be obtained when manufacturing a solid formulation.

[0024] On the other hand, the fertilizer composition for promoting the growth of seaweeds of the present invention may be in the form of powder, block or pellet, and preferably may be in the form of pellet.

[0025] When the fertilizer composition is in the form of block or pellet, the strength is preferably 10 to 50 kgf. When having the strength within the above range, considering the transportation, storage and use of the fertilizer, handling and fertilization by the flow of seawater can be the easiest.

Examples

[0026] Hereinafter, the present invention will be described more specifically through specific examples. The following examples are only illustrative for helping to understand the present invention, and the scope of the present invention is not limited thereto.

[0027] Examples Example 1: Measurement of Fe elution concentration in salt form To compare the Fe elution performance of different salt forms under seawater conditions of pH 8.2, tests were conducted by treating seawater with 1 mM of FeCl3, Fe-EDTA, and Fe-DTPA.

[0028] The soluble Fe elution test proceeded as follows: Sterilized seawater collected at Odo-ri Beach in Pohang was filtered through a membrane filter. FeCl3, Fe-EDTA, and Fe-DTPA were then added at a concentration of 1 mM each, and the mixture was stirred at room temperature for 7 days. Subsequently, the supernatant liquid filtered through the membrane was quantitatively analyzed using ICP-Mass, and the results are shown in Figure 1. The control group used seawater only. As a result, the FeCl3 and Fe-EDTA groups eluted Fe ions at concentrations of 0.025 to 0.028 ppm. On the other hand, the Fe-DTPA experimental group eluted at a concentration level of 0.08 ppm, confirming that it eluted at the highest concentration. Therefore, it was confirmed that Fe salts elute most effectively when chelated with DTPA under seawater conditions.

[0029] Example 2: Measurement of the weight percentage ratio of DTPA to Fe Dissolution tests were conducted while varying the weight percentage ratio of DTPA to Fe from 5% to 1,000%, and the results are shown in Figure 2. As a result, it was confirmed that the dissolution concentration of Fe increased as the weight percentage ratio of DTPA increased.

[0030] Example 3: Production of solid fertilizer Solid fertilizer was manufactured using steelmaking slag (Kwangyang Steelworks), DTPA (Shijiazhuang Jackchem Co.), molasses (EverMiracle Co.), and agricultural water. First, unaged steelmaking slag (Kwangyang Steelworks) was purchased from HYOSEOK Co., Ltd., dried at 105°C for 24 hours, and crushed into a powder with a diameter of 500 μm or less. Then, steelmaking slag, DTPA, and molasses were mixed in a weight ratio of 158:27:15 to produce pelletized solid fertilizer. The strength of the solid fertilizer produced was 13.2 kgf. The total Fe content in the steelmaking slag was approximately 20%, and the weight ratio of Fe to DTPA was measured to be approximately 1:0.85.

[0031] Example 4: Growth test of seaweed We used kelp (Laminaria japonica), purchased from Uripoza in Wando County, South Jeolla Province. The kelp was used in its apo-form stage, attached to a skein. This was then cut into uniform sizes and grown in a constant temperature and humidity growing chamber at 15°C and a light intensity of 40 μmol / cm². 2 Harvesting was performed after maintaining light and dark photoperiod conditions for 12 hours each. The control group used only sterilized seawater. The fertilizer produced in Example 3 was stirred with sterilized seawater for 48 hours and filtered through a membrane filter, and the eluate was used as the treatment group. The sterilized seawater and eluate were exchanged at 7-day intervals, and a 3-week growth test was conducted. After 3 weeks, the results of the kelp apophyte growth test for the control and treatment groups are shown in Figure 4. The weight per unit length of the control group was measured at 9.5 mg / cm, and the weight per unit length of the treatment group was measured at 13.7 mg / cm. In other words, the weight of the treatment group increased by 43.8% compared to the control group.

[0032] Example 5: Sea Test A field test was conducted on an artificial reef off the coast of Namyang-ri, Ulleungdo (latitude 37.28, longitude 130.49) using the fertilizer produced in Example 3. After applying the fertilizer, the growth changes of Ecklonia cava, the dominant seaweed species attached to the reef, were compared over a period of 5 months (January to June 2021). Figure 5 shows the change in length between the control group and the treated group. Before fertilization (i.e., before the treatment group and before the control group), there was no difference in the length of Ecklonia cava between the control group and the treated group. However, after 5 months, the length of the treated group (i.e., after the treatment group and after the control group) increased by 28% compared to before treatment, while the change in length growth over 5 months was not significant in the control group. Between the treated group and the control group, the length increased by 19% in the treated group.

[0033] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be obvious to those with ordinary skill in the art that various modifications and variations are possible without departing from the technical idea of ​​the present invention as described in the claims.

Claims

1. Contains iron by-products containing Fe and chelating agents, The chelating agent is DTPA (diethylenetriaminepentaacetic acid), A fertilizer composition for promoting the growth of seaweed, wherein the weight ratio of the Fe component to the chelating agent is 2:1 to 1:

5.

2. The fertilizer composition for promoting the growth of seaweed according to claim 1, further comprising a binder, a base, or a mixture thereof.

3. 80-98% by weight of steel by-products and chelating agents containing Fe; and A fertilizer composition for promoting the growth of seaweed according to claim 2, comprising 2 to 20% by weight of other components including a binder, base, or mixture thereof.

4. The fertilizer composition for promoting the growth of seaweed according to claim 2, wherein the binder is at least one selected from the group consisting of lignin, molasses, and waste molasses.

5. The fertilizer composition for promoting the growth of seaweed according to claim 1, wherein the fertilizer composition for promoting the growth of seaweed is in block or pellet form.

6. The block or pellet form of the fertilizer composition for promoting the growth of seaweed according to claim 5 has a strength of 10 to 50 kgf.

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