Liquid fertilizer composition comprising microbial metabolites and method for preparing same

Abstract

The present invention relates to a liquid fertilizer composition comprising microbial metabolites and a method for manufacturing the same. By using the metabolites of waste microorganisms as raw materials for the liquid fertilizer, nutrients such as macronutrients and micronutrients necessary for crop growth can be utilized. In addition, the present invention relates to an eco-friendly liquid fertilizer composition and a method for manufacturing the same, which includes metabolic products of waste microorganisms and can improve salt accumulation, inhibit denitrification, solubilize insoluble nutrients in the soil, increase nutrient utilization rate, inhibit greenhouse gas generation, and exhibit bactericidal and insecticidal effects, and improves yield by rapidly supplying nutrients to the roots of fruit trees or crops by supplying various nutrients to plants.

Description

Technology Field

[0001] The present invention relates to a liquid fertilizer composition containing microbial metabolites and a method for preparing the same. Background Technology

[0002] Recently, as environmental issues have attracted global attention due to their direct link to human survival, particularly food security, the development of modern agricultural technology has increased agricultural productivity and significantly contributed to the stable supply of food, but it has also given rise to a new problem: environmental pollution.

[0003] Pollution in rural areas is intensifying due to soil contamination (fertilizer accumulation, etc.), water pollution (fertilizer leaching, etc.), and air pollution (fertilizer denitrification, etc.) caused by the excessive use and input of artificial chemical fertilizers. Such agricultural pollution not only directly and indirectly threatens the health of farmers but also damages natural landscapes and is a cause of reduced crop safety.

[0004] Specifically, most of the farmland currently being cultivated has experienced a significant decline in soil fertility due to the excessive application of chemical fertilizers and pesticides used for the quantitative production of grains and plants cultivated over the past 30 to 40 years. As the soil has become acidified, crops not only fail to grow well but are also susceptible to pests and diseases, resulting in a significant decrease in crop yields.

[0005] In addition, crops grown in soil with declining fertility are deficient in essential trace minerals such as calcium, magnesium, and iron. Therefore, if humans consume such crops, it may cause serious nutritional imbalances, potentially delaying human development or weakening resistance to disease.

[0006] Meanwhile, microbial metabolites are generally classified as waste, incurring water treatment costs. In particular, since microbial metabolites are collected and treated directly by licensed treatment companies, the procedures are complicated and enormous costs are incurred for treatment.

[0007] There is a need to develop an eco-friendly functional liquid that utilizes the aforementioned microbial metabolites to not only solve the problems of the conventional fertilizer compositions described earlier but also actively utilize nutrients, such as macronutrients and micronutrients, necessary for crop growth. Prior art literature

[0008] (Patent Document 1) KR 10-2430858 B1 The problem to be solved

[0009] The object of the present invention is to provide a liquid fertilizer composition comprising microbial metabolites and a method for preparing the same.

[0010] Another objective of the present invention is to provide an eco-friendly liquid fertilizer composition that utilizes the metabolic products of waste microorganisms as raw materials for liquid fertilizer, thereby enabling the utilization of nutrients, such as trace elements, necessary for crop growth.

[0011] Another objective of the present invention is to provide an eco-friendly liquid fertilizer composition that includes metabolic products of waste microorganisms, which can improve salt accumulation, inhibit denitrification, solubilize insoluble nutrients in the soil, increase nutrient utilization rate, inhibit greenhouse gas generation, and exhibit sterilization and insecticidal effects, and improve yield by rapidly supplying nutrients to the roots of fruit trees or crops by supplying various nutrients to plants. means of solving the problem

[0012] To achieve the above objective, the present invention relates to a liquid fertilizer composition comprising a microbial metabolite, wherein the composition comprises a microbial metabolite and a trace element, and the microbial metabolite may be a byproduct obtained by culturing and isolating lactic acid bacteria.

[0013] The above lactic acid bacteria are Lactobacillus bulgaricus, Lactobacillus acidophilus, Lactobacillus delbrueckii, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus delbrueckii subsp. lactis (Lactobacillus lactis), Lactobacillus reuteri, Lactobacillus brevis, Lactobacillus salivarius, Lactobacillus casei, Lactobacillus curvatus, It may be selected from the group consisting of Lactobacillus crispatus, Lactobacillus paracasei, Lactobacillus fermentum, Lactobacillus perolens, Lactobacillus helveticus, and mixtures thereof.

[0014] The above trace elements may be selected from the group consisting of iron sulfate hydrate, zinc sulfate hydrate, manganese sulfate hydrate, copper sulfate hydrate, boric acid, sodium molybdate, potassium iodate, cobalt sulfate, sodium selenite, and mixtures thereof.

[0015] The above liquid fertilizer composition may additionally include an organic acid.

[0016] The above organic acid may be selected from the group consisting of sodium citrate, ascorbic acid, citric acid, succinic acid, maleic acid, malic acid, tartaric acid, oxalic acid, malonic acid, and mixtures thereof.

[0017] The above liquid fertilizer composition may have a pH of 2.5 to 4.

[0018] The above liquid fertilizer composition may contain 0.1 to 60 parts by weight of trace elements per 100 parts by weight of microbial metabolites.

[0019] The above microbial metabolites may include lactic acid, which is an organic acid.

[0020] The above lactic acid and trace elements can be combined by a chelation reaction.

[0021] A method for preparing a liquid fertilizer composition containing a microbial metabolite according to another embodiment of the present invention includes the step of mixing a trace element with the microbial metabolite and chelating it, wherein the microbial metabolite may be obtained by inoculating lactic acid bacteria into a culture medium, culturing the lactic acid bacteria in large quantities in a culture medium, and centrifuging the culture solution of the lactic acid bacteria in a centrifuge.

[0022] The above-mentioned recovered metabolite can adjust the pH to 2.5 to 4.

[0023] For every 100 parts by weight of the above microbial metabolite, trace elements may be included in an amount of 0.1 to 60 parts by weight. Effects of the invention

[0024] The present invention utilizes the metabolic products of waste microorganisms as raw materials for liquid fertilizer, thereby enabling the utilization of nutrients such as trace elements necessary for crop growth.

[0025] In addition, by including the metabolic products of waste microorganisms, it can improve salt accumulation, inhibit denitrification, solubilize insoluble nutrients in the soil, increase nutrient utilization rate, suppress greenhouse gas generation, and exhibit bactericidal and insecticidal effects, and by supplying various nutrients to plants, it can rapidly supply nutrients to the roots of fruit trees or crops, thereby improving yield. Brief explanation of the drawing

[0026] FIG. 1 relates to a test of fertilizer efficacy on cabbage treated with a liquid fertilizer composition according to one embodiment of the present invention. FIG. 2 relates to a comparative test of crops treated with a liquid fertilizer composition according to one embodiment of the present invention. Figure 3 relates to the results of a comparative test of bok choy treated with a liquid fertilizer composition according to one embodiment of the present invention. Figure 4 relates to the comparative test results of kale treated with a liquid fertilizer composition according to one embodiment of the present invention. Figure 5 relates to the comparative test results of red mustard treated with a liquid fertilizer composition according to one embodiment of the present invention. Figure 6 relates to the comparative test results of chicory treated with a liquid fertilizer composition according to one embodiment of the present invention. Figure 7 relates to the results of a comparative test on lettuce treated with a liquid fertilizer composition according to one embodiment of the present invention. Specific details for implementing the invention

[0027] Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0028] The "microbial metabolite" of the present invention refers to a byproduct remaining after culturing a useful microorganism, and includes all culture media in which the microorganism can grow. In the present invention, the term "microorganism" refers to a useful microorganism, including both Gram-positive and Gram-negative bacteria, and preferably may be lactic acid bacteria. In the present invention, "lactic acid bacteria" refers to Lactobacillus bulgaricus, Lactobacillus acidophilus, Lactobacillus delbrueckii, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus delbrueckii subsp. lactis (Lactobacillus lactis), Lactobacillus reuteri, Lactobacillus brevis, Lactobacillus salivarius, Lactobacillus casei, Lactobacillus curvatus, A bacterium selected from the group consisting of Lactobacillus crispatus, Lactobacillus paracasei, Lactobacillus fermentum, Lactobacillus perolens, Lactobacillus helveticus, and mixtures thereof, which breaks down sugars to produce lactic acid, but is not limited to the above examples.

[0029] Today, rapid industrial development is accelerating urbanization and shifting the workforce from rural areas to urban and industrial sites. This is leading to changes in the economic positions of cities and rural communities, resulting in a rapid relative decline in the rural population.

[0030] The decline in the rural population inevitably led to the mechanization of agricultural technology, and to meet the food demand resulting from population growth, the problem of having to significantly increase production or harvest yield per unit area of ​​cultivated land became a reality.

[0031] The solutions to these problems involve the use of pesticides to prevent pests and diseases and chemical fertilizers to increase yields. Chemical fertilizers are primarily used to supply nitrogen, which is deficient in the soil, and are also used to supply phosphorus and potassium.

[0032] However, it is reported that the excessive use of chemical fertilizers contributes to soil acidification, and when soil becomes acidified, it hinders the proliferation of microorganisms in the soil, which in turn reduces the decomposition of organic matter by microorganisms and consequently limits plant growth. In this regard, it is concluded that using chemical fertilizers over a long period of time may actually harm crop growth.

[0033] Accordingly, there was a need to develop an eco-friendly fertilizer that can replace chemical fertilizers, and the present invention relates to an eco-friendly liquid fertilizer composition.

[0034] The eco-friendly liquid fertilizer composition of the present invention is characterized by directly providing the nutritional components necessary for the substantial growth of crops, as well as enabling the availability of insoluble nutrients present in the soil.

[0035] In addition, the present invention is characterized by utilizing microbial metabolites that were previously discarded, thereby providing a liquid fertilizer composition that is highly eco-friendly in terms of recycling discarded resources.

[0036] Specifically, a liquid fertilizer composition comprising a microbial metabolite according to one embodiment of the present invention comprises a microbial metabolite and a trace element, wherein the microbial metabolite may be a byproduct obtained by culturing and isolating lactic acid bacteria.

[0037] As explained above, the "microbial metabolite" of the present invention refers to a byproduct remaining after culturing a useful microorganism, and may be a culture medium in which the microorganism can grow, but specifically, the microorganism may be a lactic acid bacterium.

[0038] The above lactic acid bacteria are Lactobacillus bulgaricus, Lactobacillus acidophilus, Lactobacillus delbrueckii, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus delbrueckii subsp. lactis (Lactobacillus lactis), Lactobacillus reuteri, Lactobacillus brevis, Lactobacillus salivarius, Lactobacillus casei, Lactobacillus curvatus, It may be selected from the group consisting of Lactobacillus crispatus, Lactobacillus paracasei, Lactobacillus fermentum, Lactobacillus perolens, Lactobacillus helveticus, and mixtures thereof, but is not limited to the above examples.

[0039] The above-mentioned microbial metabolite is a culture medium in which lactic acid bacteria are cultured, specifically a waste culture medium recovered after centrifuging lactic acid bacteria. Since it contains a large amount of culture components capable of enabling the growth of microorganisms such as lactic acid bacteria, it can exhibit various beneficial effects when used as a fertilizer composition.

[0040] The above microbial metabolites include metabolites generated during the fermentation culture process of lactic acid bacteria, such as lactic acid, organic acid, and bacteriocin. By including these metabolites, when used as a fertilizer composition, various effects of lactic acid bacteria can be provided.

[0041] Specifically, during the process of cultivating crops, mycelium is formed on the roots to protect them, and by assisting in the absorption of nutrients by the crops, continuous differentiation and growth of the roots are promoted, and it is possible to facilitate the rooting of plants even in hot and humid soil.

[0042] In addition, it can provide effects such as promoting crop growth, standardizing fruit size, improving crop freshness, increasing yield, increasing fruit size, and enhancing root vitality. Furthermore, by suppressing soil acidity, it promotes the growth of beneficial microorganisms and provides growth inhibitory effects against various putrefactive and pathogenic microorganisms. It also produces antibiotic substances (bacteriocins) while simultaneously promoting seed germination and root development, and produces organic acids that chelate with cations of insoluble phosphate compounds to make phosphate available.

[0043] The above trace elements may be one or more selected from metal sulfate hydrates, boric acid, sodium molybdate, potassium iodate, and sodium selenite. Here, the metal sulfate may be one or more selected from iron sulfate (FeSO4), zinc sulfate (ZnSO4), manganese sulfate (MnSO4), copper sulfate (CuSO4), and cobalt sulfate (CoSO4), and the metal sulfate hydrate may be one selected from metal sulfate hydrates 1 through 7. For example, the trace elements may consist of iron sulfate hydrate, zinc sulfate hydrate, manganese sulfate hydrate, copper sulfate hydrate, boric acid, sodium molybdate, potassium iodate, and sodium selenite, and the zinc sulfate hydrate may be zinc sulfate monohydrate (ZnSO4H2O).

[0044] According to an embodiment of the present invention, the trace element, iron sulfate (FeSO4), is a sulfate of iron and serves as a source of the trace elements sulfur and iron; zinc sulfate (ZnSO4) is a sulfate of zinc and serves as a source of the trace elements sulfur and zinc; it is a colorless powder and water-soluble; manganese sulfate (MnSO4) is a colorless solid sulfate of manganese and serves as a source of the trace elements sulfur and manganese; furthermore, copper sulfate (CuSO4) serves as a source of sulfur and copper, is related to the production of chlorophyll, and plays a role in binding to chlorophyll to stabilize and protect it; boric acid (H3BO3) serves as a source of boron, assists in the translocation of sugars photosynthesized in plant leaves to fruits, branches, and roots, and helps increase the fruit set rate by promoting pollen germination and pollen tube elongation during flowering and fertilization; and sodium molybdate (Na2MoO4) is an oxyacid of molybdenum, of molybdenum Calcium iodate (KIO3) serves as a source of iodine and plays a role in nitrogen absorption within the plant; cobalt sulfate (CoSO4) is a source of cobalt and a key element for root development; and sodium selenite (Na2SeO3) is a source of selenium and an essential element for maintaining the immune system.

[0045] The above-mentioned trace elements serve as a source of essential trace elements that perform the function of regulating plant rooting and growth by supplying trace metals that may be contained within the plant body. Although they are absolutely necessary for the growth of crops, only very small amounts are required, and if included in excess, they may actually hinder the growth of crops. In the present invention, by appropriately mixing these trace elements to form a trace element fertilizer, it is possible to help promote the growth of crops.

[0046] Specifically, the above trace elements, namely, inorganic minerals such as iron sulfate hydrate, zinc sulfate hydrate, manganese sulfate hydrate, copper sulfate hydrate, boric acid, sodium molybdate, potassium iodate, cobalt sulfate, and sodium selenite, can increase the absorption rate of crops through chelation reactions with organic acids as described below, thereby exhibiting significant effects compared to conventional chemical fertilizers, such as promoting crop growth, nitrogen fixation, phosphate solubilization, root development, strengthening disease resistance, and relieving salt accumulation.

[0047] In addition, existing amino acid-bound mineral products have low value as fertilizers because plants cannot absorb them due to their large molecular weight and insoluble nature; however, lactic acid contained in the metabolic products of lactic acid bacteria has a relatively low molecular weight and is highly soluble in water, which can maximize nutrient utilization efficiency.

[0048] In addition, by including trace elements in appropriate amounts that can continuously promote plant growth, various nutrients can be evenly supplied to plants, and soil salt accumulation can be prevented and reduced.

[0049] Specifically, for every 100 parts by weight of the microbial metabolite, trace elements may be included in an amount of 0.1 to 60 parts by weight. By including trace elements within the above range, they are provided in an amount essential for the growth of crops, thereby enabling the function of regulating plant rooting and growth.

[0050] More specifically, based on 100 parts by weight of the microbial metabolite, it may include 0.2 to 10 parts by weight of iron sulfate hydrate in inorganic form, 0.2 to 10 parts by weight of zinc sulfate hydrate, 0.2 to 10 parts by weight of manganese sulfate hydrate, 0.1 to 5 parts by weight of copper sulfate hydrate, 0.1 to 5 parts by weight of boric acid, 0.001 to 0.1 parts by weight of sodium molybdate, 0.1 to 5 parts by weight of potassium iodate, 0.1 to 5 parts by weight of cobalt sulfate, and 0.1 to 5 parts by weight of sodium selenite. When mixed and used within the above range, it can provide an appropriate amount of trace elements essential for crop growth.

[0051] The above liquid fertilizer composition may additionally include an organic acid. As described below, the organic acid may be included to adjust the pH of the microbial metabolites before mixing the microbial metabolites with trace elements.

[0052] The above organic acid may be selected from the group consisting of sodium citrate, ascorbic acid, citric acid, succinic acid, maleic acid, malic acid, tartaric acid, oxalic acid, malonic acid, and mixtures thereof, and preferably selected from the group consisting of sodium citrate, ascorbic acid, and mixtures thereof, but is not limited to the above examples; any organic acid capable of adjusting the pH of microbial metabolites and capable of chelating with trace elements as described below may be used without limitation.

[0053] The above liquid fertilizer composition may have a pH of 2.5 to 4. Within the above pH range, organic acids and trace elements may be combined by a chelation reaction. As the trace elements are combined by the chelation reaction with organic acids as described above, the crops can easily absorb the trace elements.

[0054] The above microbial metabolites may include lactic acid, an organic acid, and the lactic acid may be combined with trace elements through a chelation reaction. As previously explained, lactic acid is an organic acid that combines with trace elements through a chelation reaction, enabling crops to easily absorb the trace elements.

[0055] In addition, the soil improvement properties of lactic acid, a metabolic product of lactic acid bacteria, can be utilized. Specifically, the lactic acid can chelate with insoluble components in the soil, and due to its relatively low molecular weight and high solubility in water, it can solubilize insoluble components, thereby exhibiting excellent soil improvement properties.

[0056] Specifically, chelation refers to the bonding of a mineral substance to a ligand as if it were being held by a claw. Chelate chemical bonding refers to a state in which a chelating agent, an organic molecule with special properties, surrounds a metal element and forms a heterocyclic structural bond from both sides, as if it were being held tightly by pliers.

[0057] The metabolites of lactic acid bacteria contain various organic acids, such as lactic acid, that act as chelating agents. When these organic acids chelate with inorganic trace elements, they are converted into organic trace elements, which can drastically increase the crop's absorption rate due to the binding action of surface ligands. This not only increases the crop's nutrient utilization rate but also reduces insoluble nutrients remaining in the soil, thereby preventing and mitigating salt accumulation even with continuous use.

[0058] As previously explained, organic acids such as lactic acid included in metabolites and organic acids included to adjust the pH of metabolites can undergo a chelation reaction with trace elements, and through such chelation reaction, chemical bonding occurs, which can rapidly increase the absorption rate of trace elements by crops.

[0059] In addition, organic acids can chelate insoluble nutrients remaining in the soil to enable crop absorption, thereby exhibiting the effect of a slow-release fertilizer.

[0060] In other words, slow-release fertilizers generally involve the continuous release of components, such as trace elements, over a long period of time, and exhibit a continuous fertilizer delivery effect through methods such as coating the fertilizer composition. On the other hand, the liquid fertilizer composition of the present invention does not continuously supply components within the fertilizer composition, but rather enables crops to absorb nutrients in an insoluble form within the soil, thereby serving as a slow-release fertilizer.

[0061] A method for preparing a liquid fertilizer composition containing a microbial metabolite according to another embodiment of the present invention includes the step of mixing a trace element with the microbial metabolite and chelating it, wherein the microbial metabolite may be obtained by inoculating lactic acid bacteria into a culture medium, culturing the lactic acid bacteria in large quantities in a culture medium, and centrifuging the culture solution of the lactic acid bacteria in a centrifuge.

[0062] Specifically, the microbial metabolite may be obtained by culturing lactic acid bacteria as described below and isolating and recovering the lactic acid bacteria from the culture medium; the process may be carried out as a continuous process for manufacturing a liquid fertilizer composition, or the microbial metabolite discarded after manufacturing lactic acid bacteria may be recovered and manufactured into a liquid fertilizer composition.

[0063] In other words, beneficial bacteria such as lactic acid bacteria can be cultured, the waste culture solution that is discarded can be recovered, the pH adjusted, and mixed with trace elements to produce a liquid fertilizer composition.

[0064] Specifically, the microbial metabolite is produced by inoculating a culture medium with lactic acid bacteria, culturing it in large quantities in a culture vessel, centrifuging the culture medium in the vessel to separate it into lactic acid bacteria and metabolites, and then recovering the metabolites.

[0065] The above metabolites include organic acids such as lactic acid and metabolites generated during the fermentation culture process of lactic acid bacteria such as bacteriocins, and the liquid fertilizer composition containing the above metabolites can directly supply beneficial components such as organic acids and bacteriocins to crops.

[0066] Next, in the present invention, the trace element fertilizer can be prepared by chelating the recovered metabolite with trace elements and organic acids.

[0067] The above trace elements are as previously explained, so a detailed explanation will be omitted.

[0068] The above microbial metabolites can adjust the pH. Specifically, 5 to 30 parts by weight of an organic acid can be added to 100 parts by weight of the metabolites so that the pH of the metabolites is adjusted to 2.5 to 4.0. Under conditions of pH 4 or lower, a binding reaction between the organic acid, such as lactic acid, and the inorganic trace element mineral, such as a metal sulfate compound, may occur.

[0069] Adding organic acid as described above is intended to adjust the pH and to facilitate a more stabilized chelation reaction.

[0070] Next, a mixture is prepared by adding a mineral in the form of an inorganic substance to the above pH-adjusted metabolite. Here, the mineral in the form of an inorganic substance may be a metal sulfate hydrate, boric acid, sodium molybdate, potassium iodate, and sodium selenite, and the metal sulfate hydrate may be one or more selected from iron sulfate hydrate, zinc sulfate hydrate, manganese sulfate hydrate, copper sulfate hydrate, and cobalt sulfate. Preferably, the mixture may be composed by adding 0.2 to 10 parts by weight of iron sulfate hydrate in inorganic form, 0.2 to 10 parts by weight of zinc sulfate hydrate, 0.2 to 10 parts by weight of manganese sulfate hydrate, 0.1 to 5 parts by weight of copper sulfate hydrate, 0.1 to 5 parts by weight of boric acid, 0.001 to 0.1 parts by weight of sodium molybdate, 0.1 to 5 parts by weight of potassium iodate, 0.1 to 5 parts by weight of cobalt sulfate, and 0.1 to 5 parts by weight of sodium selenite to 100 parts by weight of the metabolite with a pH adjusted to 2.5 to 4.0.

[0071] Next, the above mixture can be chelated at 40 to 60°C for 80 to 100 minutes.

[0072] Meanwhile, in the present invention, as the medium for inoculating and fermenting the lactic acid bacteria, an MRS broth medium suitable for culturing lactic acid bacteria may be used, or a medium containing a carbon source, a nitrogen source, vitamins, and minerals may be used. In addition, to promote the proliferation of lactic acid bacteria, one or more of a mineral concentrate derived from seawater, an aqueous dispersion of sulfur, and an aqueous dispersion of illite may be added to the fermentation medium. Furthermore, the lactic acid bacteria may be cultured under appropriate culture conditions to enable smooth proliferation, and the culture conditions are not limited to the scope of the present invention. For example, the culture conditions of the lactic acid bacteria may be a temperature of 20 to 40°C, an air injection amount of 0.2 to 0.4 vvm, and a rotation speed of 50 to 200 rpm for 2 to 4 days.

[0073] The liquid fertilizer composition produced by the above manufacturing process may contain a trace element fertilizer in an amount of 3 to 15 weight percent relative to the total weight of the liquid fertilizer composition. If the trace element is contained in an amount of less than 3 weight percent, a deficiency of the trace element may occur.

[0074] According to the fertilizer standards established by the Rural Development Administration pursuant to Article 4 of the Fertilizer Management Act, it is stipulated that at least two of the following must be contained in water-soluble form in amounts exceeding the specified minimum amount among boron (B2O3), iron (Fe), copper (Cu), manganese (Mn), molybdenum (Mo), and zinc (Zn) as the main components of complex trace element fertilizers, and the maximum allowable amount of harmful substances such as arsenic (As), nickel (Ni), chromium (Cr), titanium (Ti), nitrite (NO2), sulfur dioxide (SO3), and cadmium (Cd) is specified.

[0075] However, conventional complex trace element fertilizers are chemical fertilizers manufactured using sulfates, which cause soil nutrient insolubilization and make it difficult to supply various minerals other than guaranteed components; consequently, these chemical fertilizers are becoming the main culprits causing salt accumulation in the soil.

[0076] In contrast, the metabolite liquid fertilizer according to the present invention can provide various nutrients evenly to plants by including an appropriate amount of trace elements that can continuously promote plant growth, and can be provided as an eco-friendly liquid fertilizer composition that can prevent and reduce salt accumulation in the soil.

[0078] Preparation Example

[0079] Preparation of liquid fertilizer composition

[0080] Lactobacillus plantarum was inoculated into a culture medium and cultured in an incubator at 30°C, an air injection rate of 0.3 vvm, and a rotation speed of 100 rpm for 3 days. Subsequently, the culture medium from the incubator was centrifuged to separate the lactic acid bacteria and metabolites. 15 parts by weight of sodium citrate were added to 100 parts by weight of the metabolites to adjust the pH to 3. Then, to 100 parts by weight of the metabolites, 9 parts by weight of iron monohydrate (FeSO4H2O), 8 parts by weight of zinc monohydrate (ZnSO4H2O), 10 parts by weight of manganese sulfate (MnSO4H2O), 2 parts by weight of copper monohydrate (CuSO4H2O), 3 parts by weight of boric acid (H3BO3), and 0.1 parts by weight of sodium molybdate (Na2MoO4) were added to prepare a mixture. A liquid fertilizer composition was prepared by chelating the above mixture at 50°C for 90 minutes.

[0082] Experimental Example 1

[0083] Crop fertilizer efficacy test results

[0084] To confirm the effect of increasing the biomass of crops by the liquid fertilizer composition of the present invention, a crop fertilization test was conducted.

[0085] The target crop was cabbage, the variety was Buram Plus, and it was cultivated for 64 days.

[0086] The overview of the warning is as follows:

[0087] Experiment scale: Area 5m, transplanted at 20x10cm intervals in the cultivation site

[0088] Experimental design: Randomized block design, 3 replications (experimenting by dividing the region into 4 sections)

[0089] Cultivation site management

[0090] - Vinyl covering: Black PE covering

[0091] - Irrigation: Spray agricultural water for 30 minutes every morning

[0092] - Weeding: Hand weeding

[0093] Other: Follow conventional cultivation practices, such as foliar spraying at 15-day intervals.

[0094] Treatment area and treatment method

[0095] Treatment area Fertilization treatment volume Processing method Untreated group agricultural water 500ml of the test substance was applied as foliar spray to each plot a total of three times on days 15, 30, and 45 after transplanting, respectively. * 01. Foliar treatment: 21.12.07 * 02. Foliar treatment: 21.12.22 * 03. Foliar treatment: 22.01.06 Contrast After preparing a sample identical to the guaranteed components of the prototype, process it in the same way as the treatment group. Standard 1,000-fold diluted solution of the prototype using agricultural water [standard fertilizer application amount provided by the client] Bae Yang Gu 500x diluted solution of prototype using agricultural water

[0096] A progress photo of cabbage cultivation is shown in Figure 1.

[0097] The results of the investigation into Napa cabbage vinegar sauce are as shown in Table 2 below:

[0098] division Average initial length by test group Average initial length by treatment group Compared to the untreated group Compared to the control group (cm) (cm) (%) (%) Untreated group 01 25 23±2d 100 91 02 25 03 20 04 23 05 24 06 23 07 20 08 21 09 20 10 25 Control group 01 30 25±3c 110 100 02 26 03 25 04 25 05 21 06 26 07 22 08 24 09 27 10 20 Publicly disclosed substance standards 01 27 28±4b 124 113 02 30 03 26 04 32 05 31 06 21 07 26 08 30 09 26 10 29 Publicly disclosed substance drainage 01 29 30±3a 131 119 02 32 03 33 04 33 05 30 06 25 07 34 08 28 09 29 10 31

[0099] (48 individuals surveyed per treatment group, 12 x 4 replicates, excluding the highest and lowest weights / excluding some pests and damaged subjects) The results of the fresh weight survey of Napa cabbage are as shown in Table 3 below:

[0100] division Average weight per test group Average weight by treatment group Compared to the untreated group Compared to the control group (g) (g) (%) (%) Untreated group 01 2,146 1,651±433d 100 84 02 2,441 03 1,244 04 1,671 05 1,785 06 1,889 07 1,412 08 1,229 09 1,154 10 1,798 Control group 01 1,946 1,970±306c 119 100 02 1,451 03 1,847 04 2,114 05 1,790 06 2,164 07 1,785 08 2,456 09 2,211 10 1,896 Publicly disclosed substance standards 01 2,132 2,035±355b 123 103 02 1,819 03 1,901 04 2,314 05 2,714 06 1,750 07 2,258 08 1,667 09 2,234 10 1,879 Publicly disclosed substance drainage 01 2,115 2,151±295a 130 109 02 2,344 03 2,490 04 2,215 05 2,494 06 1,957 07 2,104 08 1,829 09 1,994 10 2,714

[0101] (48 specimens surveyed per treatment, 12 x 4 replicates, excluding highest and lowest weights / excluding some pests and damaged targets)

[0102] According to the experimental results above, the results of the plant height test of cabbage grown using the liquid fertilizer composition of the present invention showed that the average height of the untreated group was 23 cm, the control group was 25 cm, the standard group for the test substance was 28 cm, and the doubled group for the test substance was 30 cm. The results of the comparison of plant height by treatment group showed that the standard group and the doubled group improved by 24% and 31%, respectively, compared to the untreated group, and by 13% and 19%, respectively, compared to the control group. Based on the experimental results above, it can be said that treating with the liquid fertilizer composition of the present invention has an effect of increasing the plant height of cabbage.

[0103] In addition, the results of the fresh weight test on Chinese cabbage showed that the average weight of the untreated group was 1,651g, the control group was 1,970g, the standard group for the test substance was 2,035g, and the doubled group for the test substance was 2,151g. The results of the fresh weight comparison by treatment group showed that the standard group and the doubled group for the test substance improved by 23% and 30%, respectively, compared to the untreated group, and the standard group and the doubled group for the test substance improved by 3% and 9%, respectively, compared to the control group. Based on the above experimental results, it can be said that treatment with the liquid fertilizer composition of the present invention has an effect of increasing the fresh weight of Chinese cabbage.

[0104] Experimental Example 2

[0105] Crop comparison test results

[0106] A comparative test on crops was conducted using the liquid fertilizer composition of the present invention.

[0107] The exam overview is as follows:

[0108] Exam Period: 2022.01.10 - 2022.01.20. (10 days)

[0109] Test crops: Bok choy, kale, red mustard, chicory, and romaine lettuce

[0110] Pot Preparation: A total of 45 pots with 3 replications per treatment group and per crop

[0111] Potting soil preparation: “Hanareum” horticultural potting soil 50% + sandy loam 50%

[0112] Seedling Transplanting: Bok choy (Singsing Hagye), kale (Matjjang Kale), red mustard (Asian red mustard), chicory (Endive Cuor), and leaf lettuce (Seonpung Plus)

[0113] Cultivation Management: Water 3 times a day using a pressure sprayer / Maintain temperature at 20℃ in small greenhouse

[0114] Treatment area and treatment method

[0115] Treatment area Fertilization treatment volume Processing method Standard 1,000-fold diluted solution of the prototype using agricultural water [standard fertilizer application amount provided by the client] Foliar treatment of 500ml of the test substance per test plot three times on days 1, 5, and 10 after transplanting 01. Foliar treatment: 22.01.10 0 2. Foliar treatment: 22.01.15 0 3. Foliar treatment: 22.01.20 Bae Yang Gu 500x diluted solution of prototype using agricultural water

[0116] The test results are as shown in Figure 2.

[0117] The results of the comparative test of the prototype were reviewed according to the following investigation methods and judgment criteria.

[0118] Survey Method: Visual inspection on days 1, 5, and 10 after initial foliar treatment

[0119] Test Results: No abnormal symptoms were detected in any of the treatment plots after foliar application of the test substance, so it was evaluated as having no adverse effects.

[0120] The comparison criteria are as shown in Table 5 below:

[0121] degree of comparison Judgment criteria 0 Visually, there is no impact on growth and no visible damage. 1 Visually, there is an appearance of minor spots or leaf discoloration. 2 Symptoms such as minor spots, leaf discoloration, and leaf burn are visible to the naked eye; some (about 5-10%) growth inhibition or some (about 5-10%) germination (poor seedling emergence) 3 Visually, symptoms such as spots, leaf discoloration, and leaf burn are present in a significant portion (approx. 50%). Significant growth inhibition (approx. 10-20%) or significant poor germination (seedling emergence) (10-20%). 4 It is suffering significant damage, but there are still sound parts remaining. 5 It suffered severe damage and is in a withered state.

[0122] The comparative investigation for bok choy is as shown in Table 6 and Figure 3 below:

[0123] Treatment area Processing level Compared to (0-5) Comparison symptoms Day 1 of processing Day 5 of processing Day 10 of processing Standard 1,000 times dilution 0 0 0 No comparison Bae Yang Gu 500x dilution 0 0 0 No comparison

[0124] The comparative investigation for kale is as shown in Table 7 and Figure 4 below:

[0125] Treatment area Processing level Compared to (0-5) Comparison symptoms Day 1 of processing Day 5 of processing Day 10 of processing Standard 1,000 times dilution 0 0 0 No comparison Bae Yang Gu 500x dilution 0 0 0 No comparison

[0126] The comparative investigation regarding red mustard is as shown in Table 8 and Figure 5 below:

[0127] Treatment area Processing level Compared to (0-5) Comparison symptoms Day 1 of processing Day 5 of processing Day 10 of processing Standard 1,000 times dilution 0 0 0 No comparison Bae Yang Gu 500x dilution 0 0 0 No comparison

[0128] The comparative investigation for chicory is as shown in Table 9 and Figure 6 below:

[0129] Treatment area Processing level Compared to (0-5) Comparison symptoms Day 1 of processing Day 5 of processing Day 10 of processing Standard 1,000 times dilution 0 0 0 No comparison Bae Yang Gu 500x dilution 0 0 0 No comparison

[0130] The comparative investigation for flower lettuce is as shown in Table 10 and Figure 7 below:

[0131] Treatment area Processing level Compared to (0-5) Comparison symptoms Day 1 of processing Day 5 of processing Day 10 of processing Standard 1,000 times dilution 0 0 0 No comparison Bae Yang Gu 500x dilution 0 0 0 No comparison

[0132] According to the experimental results above, when the liquid fertilizer composition of the present invention was applied, no abnormal symptoms (spots, discoloration, leaf burn, etc.) were observed in both the standard and double dose groups of bok choy, kale, red mustard, chicory, and lettuce, confirming that there was no damage.

[0133] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

Claims

Claim 1 A liquid fertilizer composition comprising microbial metabolites; and trace elements, additionally comprising organic acids, having a pH of 2.5 to 4, wherein the microbial metabolites are waste culture liquid recovered by inoculating lactic acid bacteria into a culture medium, culturing the lactic acid bacteria in large quantities in an incubator, and centrifuging the culture liquid of the cultured lactic acid bacteria in a centrifuge. Claim 2 In claim 1, the lactic acid bacteria are Lactobacillus bulgaricus, Lactobacillus acidophilus, Lactobacillus delbrueckii, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus delbrueckii subsp. lactis (Lactobacillus lactis), Lactobacillus reuteri, Lactobacillus brevis, Lactobacillus salivarius, Lactobacillus casei, Lactobacillus curvatus, A liquid fertilizer composition comprising a microbial metabolite selected from the group consisting of Lactobacillus crispatus, Lactobacillus paracasei, Lactobacillus fermentum, Lactobacillus perolens, Lactobacillus helveticus, and mixtures thereof. Claim 3 A liquid fertilizer composition according to claim 1, wherein the trace element comprises a microbial metabolite selected from the group consisting of iron sulfate hydrate, zinc sulfate hydrate, manganese sulfate hydrate, copper sulfate hydrate, boric acid, sodium molybdate, potassium iodate, cobalt sulfate, sodium selenite, and mixtures thereof. Claim 4 delete Claim 5 A liquid fertilizer composition according to claim 1, wherein the organic acid comprises a microbial metabolite selected from the group consisting of sodium citrate, ascorbic acid, citric acid, succinic acid, maleic acid, malic acid, tartaric acid, oxalic acid, malonic acid, and mixtures thereof. Claim 6 delete Claim 7 In claim 1, the liquid fertilizer composition comprises a microbial metabolite containing 0.1 to 60 parts by weight of a trace element per 100 parts by weight of the microbial metabolite. Claim 8 A liquid fertilizer composition comprising, in claim 1, a microbial metabolite including lactic acid, which is an organic acid. Claim 9 In claim 8, a liquid fertilizer composition comprising a microbial metabolite in which the lactic acid and trace elements are combined by a chelation reaction. Claim 10 A liquid fertilizer composition comprising the step of mixing trace elements with a microbial metabolite and chelating them, wherein the microbial metabolite is a waste culture solution recovered by inoculating lactic acid bacteria into a culture medium, culturing the lactic acid bacteria in large quantities in a culture vessel, and centrifuging the culture solution of the lactic acid bacteria in a centrifuge; wherein an organic acid is additionally mixed with the microbial metabolite, and the liquid fertilizer composition comprises a microbial metabolite having a pH of 2.5 to 4. Claim 11 delete Claim 12 A method for preparing a liquid fertilizer composition comprising a microbial metabolite, wherein, in addition to 100 parts by weight of the microbial metabolite, a trace element is included in an amount of 0.1 to 60 parts by weight.

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