KR101031365B1 - Biodegradable compositions for liquid mulching, a method for preparing the same and a method for mulching using the same - Google Patents

Abstract

PURPOSE: A biodegradable composition for liquid mulching is provided to prevent the contamination caused by vinyl waste due to excellent biodegradability of a mulching film and to form a firm film without the loss caused by strong wind or heavy rain. CONSTITUTION: A biodegradable composition for liquid mulching comprises 0.1-10 weight% of water soluble polymer, 0.1-10 weight% of carbon-based material, 0.01-2 weight% of humic acid, and 80-99 weight% of water. The water soluble polymer is a biodegradable composition for liquid mulching which is polyethylene oxide alone or a mixture with at least one kind selected form polyethylene oxide, polyvinyl alcohol and polyethylene glycol.

Description

Biodegradable compositions for liquid mulching, a method for preparing the same and a method for mulching using the same}

The present invention relates to the manufacture and application of agricultural mulching agents, and more particularly, to a biodegradable liquid mulching composition containing a water-soluble polymer, a carbon-based material and humic acid, a preparation method thereof and a mulching method using the same.

Crop cultivation technology using vinyl mulching membranes in agriculture is one of the ten modern agricultural technologies. Covering the mulching membrane with the soil surface can satisfy the requirements of keeping the crops warm, maintaining moisture, preventing cold damage, suppressing weed growth, preventing pests and reducing pesticide use, and maintaining soil fertility. Since its inception in Japan in the early 50s for the first time, mulching membranes have been used at an enormous rate of increase every year. The application of crop cultivation technology using mulching membranes has greatly improved the yield of crops and promoted the development of agriculture in the world, so the use of vinyl mulching membranes is sometimes called the "white revolution" of agriculture.

However, the use of vinyl mulching membranes causes serious environmental pollution. Since vinyl mulching membranes are hydrocarbon hydrocarbons made of polyethylene mixed with antioxidants and anti-UV modifiers, they have high molecular weight and stable characteristics, making them difficult to decompose under natural conditions. 400 years. Currently, very thin mulching films (0.003 ~ 0.006mm) of less than 0.012mm are used. These mulching membranes have low strength, are easy to tear to smaller sizes, and cannot be recovered and recycled, and if left untreated or lost in nature and incorporated into the soil, they cause serious environmental pollution to the soil and the environment for many years. Indeed, the abundant harvest now is a form of predatory production, based on the sacrifice of soil potential.

In addition, the vinyl mulching membrane is poorly breathable and permeable, and when it remains in the soil, it destroys the monolithic structure in the soil, hinders the penetration of capillary water and natural water, and affects the moisture absorption of the soil, impairing water movement. To slow down the flow of moisture. In addition, the gap between the soil is bad, the path of the roots are blocked, and the growth is prevented, and the air permeability is lowered, which makes the air circulation and exchange worse. It results in local excess or under water, leading to excessively high carbon dioxide content in the soil. Thus, it affects the activity of soil microorganisms and the formation of the normal structure of the soil, which also lowers the fertility of the soil and eventually leads to the reduction of crops. Residual mulching membranes adversely affect the physical properties of the soil, causing the crops to grow short and steadily, and reducing the performance of water and fertilizers, leading to subtraction of crops. In addition, it is scattered everywhere by the wind from the cultivated land, and hangs on crops, tree branches around the cultivated land, and buildings, and floats on waterways, rivers, and lakes, thereby damaging the natural scenery. Submersion in water affects the quality and quantity of irrigation and water supply, and can lead to contamination, which can have a significant impact on aquatic ecosystems. Residual flakes, if mixed with crop stalks or fodder, may damage the gastrointestinal function of livestock, adversely affect fattening and, in severe cases, death. Incineration of residual mulching membranes generates harmful gases such as dioxins, which pollute the atmosphere and cause secondary pollution. In addition, the plasticizer (o-Phthalaldehyde: OPA compound) in the mulching membrane component is low water-soluble and high fat-soluble, and has a significant bioaccumulation, which causes harm to the human body through soil, crops, and livestock. It is called white pollution.

As one of the methods for solving the white pollution, a decomposable mulching film has been developed and used. Examples of biodegradable mulching membranes include degradable vinyl mulching membranes in which biodegradable natural substances such as starch are mixed with polyethylene, and solid-phase mulching membranes made by mixing biodegradable natural substances such as starch in water-soluble resins, fibers or paper mulching membranes.

However, the conventional mulching film is processed in the form of a film or sheet in most cases, it requires a separate process for laying, maintaining and dismantling it is disadvantageous in terms of economics, even in the case of containing a functional material due to poor adhesion to soil. There is a problem that the effect of the functional material is insignificant, difficult to adhere to the soil surface and is lost by strong winds and heavy rain.

As an alternative to solve this problem, the development of a liquid mulching agent has been made, and the liquid mulching agent forms a mulching film on the soil surface by spraying a polymer resin emulsion. For example, Japanese Unexamined Patent Publication No. 2001-45879 discloses a liquid mulching method characterized by spraying a resin emulsion in which plant fibers are dispersed. Japanese Unexamined Patent Publication No. 2001-145428 discloses a biodegradable polymer and a carbon-based material. And liquid mulching agents containing colloidal silica are known.

However, the mulching membrane formed by the conventional liquid mulching agent is not good adhesion to the soil, the water resistance is low, the mulching membrane is easily lost by moisture, or when the water resistance of the film is high, the moisture permeability of the soil, such as rotting the roots of the crop to control the moisture of the soil, etc. There has been a problem with functionality. In addition, even in the method of preparing a liquid mulching agent, since other substances are mixed in the resin emulsion, it is difficult to uniformly mix the mixed constituents, and there is a problem that the uniformity of the mulching film formed may be reduced because it is sprayed onto the soil in such a state. .

The present invention is excellent in the biodegradability of the mulching membrane formed by drying when spraying on the soil to prevent contamination due to waste vinyl in advance, the strength and compactness is improved and the soil adhesion is improved to form a strong membrane without being lost in strong wind or heavy rain It is an object of the present invention to provide a biodegradable liquid mulching composition, which can be effective in improving the crop growth by the function of the components contained in the mulching membrane effectively.

In addition, the present invention has an object to provide a method for producing a liquid mulching composition that can not only properly control the moisture of the soil by having an appropriate moisture permeability and water content properties, but also easy mulching operation.

In addition, the present invention has another object to provide an agricultural mulching method using a liquid mulching composition according to the present invention.

As a result of intensive studies to solve the above problems, the present inventors dissolve a water-soluble polymer, especially polyethylene oxide (PEO) in water, and then add a carbon-based material and humic acid to form a liquid mulching composition. When manufacturing, and spraying it on the soil surface to form a mulching membrane, it has been found that to form a solid membrane having appropriate moisture retention and moisture permeability, improved soil adsorption capacity, excellent water resistance and completed the present invention.

The humic acid contained in the liquid mulching composition according to the present invention is a material prepared from organic waste liquids such as brewing waste, seaweed waste, molasses waste, in addition to promoting nutrition by supplying nutrients to the soil, Surprisingly, it has been found to facilitate the formation of mulching membranes formed after spraying and drying, to improve the soil adsorption power of the mulching membranes, and to improve the moisture content of the mulching membranes, thereby improving the function of controlling the soil moisture to the extent necessary for plant growth. It was. In addition to the above components, it is possible to further form a mulching membrane by cross-linking by adding a vegetable natural polymer and to improve soil adhesion, and to further improve biodegradability by adding a water-soluble polymer-degradable microorganism or a mixture thereof. It was found that the addition of thixotropic agent to prevent the flow, and to add a functional additive such as silicon fertilizer, chitosan to prepare a multifunctional liquid mulching composition, by mixing the silicon fertilizer with humic acid It was found that the film formation performance was significantly improved when used.

Accordingly, the present invention provides a liquid mulching composition containing a water-soluble polymer, a carbon-based material and humic acid, the composition according to the present invention is a vegetable natural polymer, water-soluble polymer degradable microorganisms or mixtures thereof, thixotropic agents, chitosan, magnesium fertilizer, It may further contain one or more selected from silicon fertilizers, insecticides, fungicides and herbicides. The liquid mulching composition according to the present invention is stored and transported in a concentrated state packed in a plastic container, so the volume and weight are very small, which can reduce the storage cost or the transportation cost, and the thickness or characteristics of the mulching membrane formed by spraying and drying It has the advantage of being uniformly adjusted.

The present invention also provides a method for producing a liquid mulching composition for mixing a carbon-based material and humic acid in a water-soluble polymer dispersion. The production method according to the invention can be prepared in a liquid composition by dispersing in water. In addition, the mulching method according to the present invention by spraying the liquid mulching composition in the aqueous dispersion state on the surface of the soil provides a mulching film is formed while drying on the soil surface.

Hereinafter, the present invention will be described in more detail.

At this time, if there is no other definition in the technical terms and scientific terms used, it has a meaning commonly understood by those of ordinary skill in the art. Repeated descriptions of the same technical constitution and operation as those of the conventional art will be omitted.

The liquid mulching composition according to the present invention may be in a solid state, an emulsion state or a suspension state, and the constituents include a water-soluble polymer, a carbon-based material and a humic acid, and additionally, a vegetable natural polymer, It may further contain one or more selected from a water-soluble polymer-degradable microorganism or a mixture thereof, thixotropic agent, chitosan, magnesium fertilizer, silicon fertilizer, insecticide, fungicide and herbicide.

The water-soluble polymer is preferably a mixture of one or more selected from polyethylene oxide, polyvinyl alcohol or polyethylene glycol and polyethylene oxide, and the polyethylene oxide preferably has an average molecular weight of 100,000 to 8,500,000. More preferably, 300,000 to 6,500,000 are good in terms of film forming performance and water solubility. When the molecular weight of polyethylene oxide is less than 100,000, film-forming performance falls and when the molecular weight exceeds 8,500,000, water solubility falls and it is disadvantageous. Said average molecular weight is relative mass and is an atomic mass unit (amu), and says dimensionless.

The water-soluble polymer may be used in a solid or emulsion state, the content of the water-soluble polymer is preferably used in 0.1 to 10% by weight of the liquid mulching composition. More preferably, 0.5 to 5% by weight of the water-soluble polymer is appropriate for film formation and moisture permeability of the mulching film. When the content of the water-soluble polymer is less than 0.1% by weight may lower the film forming function and durability of the film, when the content is more than 10% by weight is impossible due to the high viscosity and biodegradation efficiency is lowered more than one year It is not desirable to decompose and remain on the soil surface.

Liquid mulching composition according to the present invention can suppress the weed generation by the light-shielding effect by the mulching film and absorb the sunlight by containing a carbon-based material to increase or adjust the geothermal heat. Activated carbon, carbon black, graphite, or a mixture thereof may be used as the carbon-based material, and it is more preferable to use active carbon, carbon black, or a mixture thereof in terms of effects and economics. The content of the carbonaceous material is preferably used in 0.1 to 10% by weight of the liquid mulching composition. If the content of the carbon-based material is less than 0.1% by weight, the light shielding effect and the geothermal thermal insulation effect are insignificant, and if the content is more than 10% by weight, the film formation and water dispersibility of the liquid mulching composition may be inhibited. Not.

Humic acid contained in the liquid mulching composition according to the present invention generally refers to residues in which plants have been corroded for a long time in the ground. The humic acid may be a commercially available product or may be manufactured and used directly, and the manufacturing method may include, for example, fermenting and drying the brewing waste, seaweed waste, molasses waste, and other high-concentration organic waste liquid using a conventional composting process. Rough

Humic acid content according to the present invention is preferably used in 0.01 to 2% by weight of the liquid mulching composition. When the amount of humic acid is less than 0.01% by weight, the effect on the water content of the mulching film, soil adsorption capacity and the film formation of the mulching film may be insignificant, and when the content is more than 2% by weight, dispersibility and workability of the mulching composition. This can be weakened, which is undesirable.

The liquid mulching composition according to the present invention is more excellent in plant growth because it further contains a vegetable natural polymer improves the water dispersibility of the composition, cross-linking performance and soil adhesion of the mulching membrane and has an appropriate moisture permeability. . The vegetable natural polymers may include polysaccharides such as starch and derivatives thereof, cellulose derivatives such as cellulose, methyl cellulose, Carboxy Methyl Cellulose, and hydroxymethyl cellulose, or mixtures thereof. It is preferred that it is 0.1 to 2% by weight in the composition. When the content of the vegetable natural polymer is less than 0.1% by weight, the effect of improving the crosslinking performance of the mulching membrane or the effect of soil adhesion is insignificant, and when the content is more than 2% by weight, the durability of the mulching membrane may be lowered.

The liquid mulching composition according to the present invention exhibits a very good effect of preventing soil acidification, maintaining soil quality, and increasing plant growth rate when it further contains a water-soluble polymer-decomposing microorganism or a mixture thereof.

The microorganism refers to the screening of water-soluble polymer-degrading microorganisms with a solution in which the humus collected from the arable land (field) is well dispersed in water and the solids are filtered out.

The content of the water-soluble polymer-decomposable microorganism or a mixture thereof is used in proportion to the content of the water-soluble polymer, and the content of the water-soluble polymer-decomposable microorganism or a mixture thereof is preferably used in the range of 0.0001 to 0.01% by weight in the liquid mulching composition. If the content is less than 0.0001% by weight, the effect of improving the rate of decomposition of the water-soluble polymer is insignificant, and if it exceeds 0.01% by weight, the rate of decomposition of the water-soluble polymer is too fast, which is not appropriate. In general, the biodegradable mulching film is preferably completely decomposed within a period of about 1 year, preferably from 3 months to 6 months. Therefore, it is not preferable that the decomposition period is less than 3 months or more than 6 months when the usage range is out of range.

The liquid mulching composition according to the present invention exhibits the effect of preventing the flow down when spraying when the thixotropic agent is further contained. Sodium alginate may be used as the thixotropic agent. The content of the thixotropic agent is preferably used in the range of 0.01 to 1% by weight in the liquid mulching composition. If it is less than the above range, the effect of suppressing downflow is insignificant, and if it exceeds the above range, sprayability is inferior.

In addition, the liquid mulching composition according to the present invention may further add a fertilizer, an insecticide, a fungicide, a herbicide, and the like, as a functional additive, chitosan, magnesium fertilizer, and silicon fertilizer. In the present invention, when the functional additive is added, the additives in the membrane are coagulated together by forming a film, and then slowly dissolved by water and continuously supplied to the root of the crop. Among the functional additives, chitosan is a product obtained by easily processing chitin contained in crustaceans in plants, and specifically refers to a material obtained by deacetylating chitin in crabs, crayfish, and shrimp shells. By adding chitosan, the cells of the crops are activated to enhance immunity, prevent disease, and control the natural healing ability to reduce the amount of pesticides used, and also release heavy metals and pollutants that the crops have already absorbed. Indicates the effect of the function. Moreover, when further containing a silicon fertilizer among the said functional additives, the film-forming performance improves. The content of the functional additive may be added in an amount of 0.01 to 1% by weight in the liquid mulching composition. If it is added below the content, the expression of the effect may be insignificant, and if it exceeds the content, the fertilization content in the soil may be too high, which is not preferable.

Hereinafter, the manufacturing method of the liquid mulching composition which concerns on this invention is demonstrated.

The liquid mulching composition according to the present invention may be in a solid state, an emulsion state or a suspension state, and is prepared by a manufacturing method including the following preparation step.

a) mixing the water-soluble polymer and water to prepare a mixed solution;

b) preparing a mixed solution by adding a carbonaceous material and a humic acid to the mixed solution of step a);

c) To the mixed solution of step b), one or more mixtures selected from vegetable natural polymers, water-soluble polymer-decomposing microorganisms or mixtures thereof, thixotropic agents, chitosan, magnesium fertilizers, silicon fertilizers, fungicides, insecticides and herbicides are further added. Mixing by mixing;

It includes.

In step a), the water-soluble polymer is prepared by a method for producing a biodegradable liquid mulching composition, which is one or more mixtures selected from polyethylene oxide having an average molecular weight of 100,000 to 8,500,000, or polyethylene oxide, polyvinyl alcohol, and polyethylene glycol.

In addition, one or two or more mixtures selected from vegetable natural polymers, water-soluble polymer-degrading microorganisms or mixtures thereof, thixotropic agents, chitosan, magnesium fertilizers, silicon fertilizers, fungicides, insecticides and herbicides are further added to the mixed solution of step b). To prepare a mixed solution.

In the step a), the mixed solution may be heated to completely dissolve the water-soluble polymer, and the heating temperature is preferably in the range of 40 to 80 ° C. in view of effectiveness and economics.

In another aspect, the present invention provides a mulching method using a liquid mulching composition of the aqueous dispersion prepared by the above production method. The mulching method according to the present invention is to spray the liquid mulching composition in the aqueous dispersion state on the surface of the soil so that the mulch film is formed while drying on the soil surface, the spraying method may be made using a conventional spreader or sprayer. The mulching membrane formed by the mulching method according to the present invention is biodegradable within one year, preferably 3 months to 6 months, environmentally friendly, it is unnecessary to recover the mulching film can reduce labor costs.

The liquid mulching composition according to the present invention uses humic acid obtained from a high concentration of biological waste and is biodegradable, which is environmentally friendly, and improves the water content of the mulching membrane formed from the liquid mulching composition according to the present invention, thereby improving the moisture content of the soil. It is excellent in the function to control the extent necessary for the growth of the plant, the soil adsorption power of the mulching membrane is improved, as well as having the moisture and moisture permeability suitable for the growth of the crop, and has the effect of promoting the growth of the crop.

In addition, the mulching method using the liquid mulching composition according to the present invention is easier to install than conventional vinyl mulching membrane because it is prepared by spraying the composition for mulching in the aqueous dispersion state, is hardly affected by the unevenness of the terrain, it is also installed on the slope It is easy and there is no need to collect the residual mulching film, and labor cost is saved. In addition, fertilizer application, insecticides, fungicides and herbicides can be applied together, which is economically advantageous.

The present invention will be described in more detail with reference to the following examples. However, the following examples are merely examples of the present invention, and the claims of the present invention are not limited thereto.

≪ Example 1 >

To prepare a liquid mulching composition consisting of the materials described below.

1. Polyethylene oxide (PEO, average molecular weight (Mw): 1,600,000, manufacturer: Japan, Meisei Chemical, product name: ALKOX): 10 g

2. Powdered activated carbon (manufacturer: Kaya activated carbon industry, type: D-1-10-30): 10 g

3. Water-soluble humic acid (manufacturer: Daishin Corporation, product name: Multi-Humic Soluble, Granule): 2 g

4. Starch: 2 g

5.Carbon Methyl Cellulose (CMC, manufacturer: Hercules Chemicals Company Ltd., China, Product Name: Sodium Carboxymethyl Cellulose): 10g

6. Water: 1000mL containing the above substance

10 g of polyethylene oxide (PEO) was added to 800 mL of water and completely dissolved by heating and stirring at 60 ° C., followed by starch, activated carbon, humic acid, and CMC powder, followed by stirring at room temperature for 4 hours, mixing, and then adding water to solid content. 1 L of a liquid mulching composition having a content of 3.4 wt% was prepared.

<Example 2>

A liquid mulching composition was prepared in the same manner as in Example 1, except that 0.005 g of soil microorganism having PEO degradability was further added to the liquid mulching composition of Example 1.

The soil microorganisms having PEO degradability were obtained by screening water-soluble polymer-decomposing microorganisms with a solution obtained by dispersing the humus collected in a farmland (field) using a liquid mulching agent in water and filtering the solids.

&Lt; Example 3 >

To the liquid mulching composition of Example 2, 1 g of siliceous fertilizer (manufacturer: Saturn Biotech Co., Ltd., big hand silicic acid grains) and 1 g of sodium alginate (manufacturer: Qingdao Bright Moon Seaweed Group Co. Ltd.) are further added. Except that was prepared in the same manner as in Example 2 liquid mulching compositions.

<Comparative Example 1>

A conventional black mulching film (manufacturer: Ilshin Chemical, product name: agricultural black HDPE Film) was used as Comparative Example 1.

Using the liquid mulching composition prepared in Examples 1 to 3 and Comparative Example 1 to form a mulching film as described below, the physical properties were measured.

After arranging the agricultural test packaging (area: 700cmX445cm) three times in the arable land with the ingot mass method, it is boned and sowing soybean (golden bean) (planting distance: 60cm × 15cm), and then no mulching agent is applied under the same climatic conditions. The unused bare paper was used as a control and compared with the results of forming the mulching film with the compositions of Examples 1 to 3 and Comparative Example 1.

Growth conditions under the same conditions for four months, growth conditions, weed development inhibitory effect is shown in Table 1 below. The growth status was determined based on the height of crops and the yield of fruit. If it is more than 15% of the control group, it is good. If it is more than 30%, it is very good. It was made normal. In addition, the inhibition of weed generation was determined as the growth condition on the basis of the number of weed generation, and the biodegradability was very good if more than 90% was removed after 6 months, and 70 to 90% was good, and 40 to 70% was normal. If less than 50%, it was determined as bad. The film formation performance was relatively evaluated by the strength of the soil surface until it was broken by finger pressing. The formation of a very hard and tough film is very good, and it is good to be sure that a hard film is formed. The back side was judged as defective.

TABLE 1

As shown in Table 1, the growth state showed excellent results compared to Comparative Example 1 in the case of Examples 1 to 3 progressed by the mulching method according to the present invention, in comparison with the use of black raw mulching film in terms of weed generation suppression effect The effect was equivalent to one. In terms of biodegradability, Examples 1 to 3 were all degraded within 6 months, and in particular, Examples 2 and 3 containing water-soluble polymer-degradable microorganisms were degraded within 4 months compared to Example 1, which did not contain it. Results are shown. In terms of film forming performance, all of Examples 1 to 3 showed good film forming performance, and in Example 3 using siliceous fertilizer, the strength of the formed film was slightly improved due to the action of siliceous and thixotropic agents.

Claims (12)

Biodegradable liquid mulching composition comprising 0.1 to 10% by weight of water-soluble polymer containing polyethylene oxide, 0.1 to 10% by weight of carbonaceous material, 0.01 to 2% by weight of humic acid and 80 to 99% by weight of water. delete The method of claim 1,
The water-soluble polymer is a composition for biodegradable liquid mulching is polyethylene oxide alone or a mixture of polyethylene oxide and one or more selected from polyvinyl alcohol and polyethylene glycol. The method of claim 3, wherein
The polyethylene oxide is a biodegradable liquid mulching composition having an average molecular weight of 100,000 to 8,500,000. The method of claim 1,
The carbonaceous material is a biodegradable liquid mulching composition selected from activated carbon, carbon black, graphite or a mixture thereof. delete The method of claim 1,
The liquid mulching composition is a biodegradable liquid mulching composition further comprises 0.1 to 2% by weight of a vegetable natural polymer selected from starch, cellulose, methyl cellulose, Carboxy Methyl Cellulose, hydroxymethyl cellulose or a mixture thereof. The method of claim 1,
The liquid mulching composition is a biodegradable liquid mulching composition further comprises a water-soluble polymer degradable microorganism or a mixture thereof in 0.0001 to 0.01% by weight. The method of claim 1,
The liquid mulching composition is a biodegradable liquid mulching composition further comprises 0.01 to 1% by weight of sodium alginate as a thixotropic agent. The method according to any one of claims 1, 3 to 5 and 7 to 8,
The liquid mulching composition is a biodegradable liquid mulching composition further comprises one or more functional additives selected from chitosan, magnesium fertilizers, silicon fertilizers, fungicides, insecticides and herbicides. a) mixing a water-soluble polymer containing polyethylene oxide and water to prepare a mixed solution;
b) preparing a mixed solution by adding a carbonaceous material and a humic acid to the mixed solution of step a);
c) To the mixed solution of step b), one or more mixtures selected from vegetable natural polymers, water-soluble polymer-decomposing microorganisms or mixtures thereof, thixotropic agents, chitosan, magnesium fertilizers, silicon fertilizers, fungicides, insecticides and herbicides are further added. Comprising; mixing;
A method for producing a biodegradable liquid mulching composition comprising 0.1 to 10% by weight of a water-soluble polymer containing polyethylene oxide, 0.1 to 10% by weight of carbonaceous material, 0.01 to 2% by weight of humic acid and 80 to 99% by weight of water. The method of claim 11,
The water-soluble polymer is a method for producing a biodegradable liquid mulching composition is a polyethylene oxide alone having an average molecular weight of 100,000 to 8,500,000 or a mixture of polyethylene oxide and one or more selected from polyvinyl alcohol and polyethylene glycol.