TWI489945B - Explosive agents for aquatic plants - Google Patents

Description

Germination inhibitor for aquatic plants

The present invention relates to a germination preventing agent for aquatic plants rooted in the sediment of freshwater water, such as emergent plants, floating leaf plants and submerged plants, and a method for preventing germination of aquatic plants.

It is known that in freshwater waters such as rivers and lakes, aquatic plants are rich in nutrients such as phosphorus and nitrogen from water or sediment, and have the effect of suppressing the occurrence of water bloom.

However, when aquatic plants grow abnormally, there will be foul odors (adverse effects on life), ship navigation obstacles, fishery obstacles (deterioration of fishery environment), deterioration of lake bottom environment (mud, lack of oxidation), etc. It is a variety of problems that have an adverse effect.

A method of removing aquatic plants that grow in freshwater waters has a method of cutting aquatic plants. However, this method requires a great labor force and there is a problem that it is necessary to deal with the sected aquatic plants.

Patent Document 1 describes a method of preventing the weeds on the ground from being propagated, and is a method of hardening the ground. The method for hardening the ground described in Patent Document 1 is to supply a weed propagation preventing material containing magnesium oxide on the ground, and to mix and mix the weed propagation preventing material with the soil, and then water the soil to mix with the soil. A method in which magnesium oxide reacts with water to harden.

[Previous Technical Document]

[Patent Document]

[Patent Document 1] JP-A-2003-47388

The method of hardening the ground described in the aforementioned Patent Document 1 is extremely effective for preventing weed propagation on the ground, but since the sediment of the freshwater water is inhabited by many kinds of organisms, the sediment of the freshwater waters is hardened, and the freshwater waters may be feared. The ecosystem has an adverse effect.

Accordingly, an object of the present invention is to provide a method for preventing the germination of aquatic plants without hardening the sediment of fresh water, and a germination preventing agent suitable for preventing aquatic plants from germination of the aquatic plants.

The team of the present invention has found that magnesium oxide powder having a particle diameter of 1 mm or less is dispersed on the bottom mud of fresh water, so that the sediment can be hardened and the aquatic plants can be prevented from germinating.

Therefore, the present invention is a germination preventing agent for root plants rooted in the sediment of freshwater water, which contains magnesium oxide powder having a particle diameter of 1 mm or less.

Embodiments of the germination inhibitor suitable for aquatic plants of the present invention are as follows.

(1) The magnesium oxide powder contains 80% by mass or more of particles having a particle diameter of 1 mm or less.

(2) The magnesium oxide powder contains 80% by mass or more of particles having a particle diameter of 0.75 mm or less.

(3) The magnesium oxide powder showed an apparent density of 2.10 g/cm ³ or more.

(4) Magnesium oxide powder is burnt hard magnesium oxide powder or fused magnesium oxide powder.

(5) Plants of the family Hydrocaryaceae family (also known as Trapaceae family).

Further, the present invention is a method for dispersing the above-mentioned germination preventing agent for aquatic plants of the present invention on the sediment of fresh water, and preventing the germination of aquatic plants rooted in the sediment of freshwater water, such as water-producing plants, floating-leaf plants and submerged plants.

By displacing the germination inhibitor of the aquatic plant of the present invention on the sediment of the freshwater water, it is possible to efficiently prevent germination particularly in the plant.

[Best form of implementing the invention]

The germination preventing agent of the present invention contains finely divided magnesium oxide powder having a particle diameter of 1 mm or less. The average particle diameter of the magnesium oxide powder is preferably 0.75 mm or less, more preferably in the range of 0.03 to 0.5 mm. The apparent density (or bulk density) of the magnesium oxide powder is preferably 2.10 g/cm ³ or more, more preferably 3.10 to 3.56 g/cm ³ , and preferably 3.10 to 3.50 g/cm ³ , and 3.15 to 3.30 g. The range of /cm ³ is particularly good. The apparent density of the magnesium oxide powder can be determined by a gas phase substitution method based on the principle of Archimedes.

The magnesium oxide powder used in the germination preventing agent of the present invention may contain coarse particles having a larger particle diameter of 1 mm. However, the magnesium oxide powder is preferably fine particles having a particle diameter of 1 mm or less of 80% by mass or more, and particularly preferably 90% by mass or more. Further, the magnesium oxide powder is preferably a particle having a particle diameter of 80% by mass or more and 0.75 mm or less, and particularly preferably 90% by mass or more. In addition, it is preferable that the particles having a particle diameter of 80% by mass or more are larger than 0.005 mm, and more preferably 90% by mass or more.

The magnesium oxide powder used in the germination preventing agent of the present invention is preferably a calcined magnesia powder or an fused magnesia powder.

In the present invention, the burnt hard magnesium oxide powder can be obtained by firing a magnesium compound such as magnesium hydroxide or magnesium carbonate at a temperature of 900 ° C or higher, more preferably 1600 ° C or higher, and particularly preferably at a temperature of 1700 to 2100 ° C. The obtained magnesium oxide fired product is used as it is, or it is subjected to crushing treatment, and then it is produced by a method of adjusting the particle size by a general classification method such as a sieve.

In the present invention, the fused magnesia powder may be directly used or crushed by a magnesium oxide compound such as magnesium oxide, magnesium hydroxide or magnesium carbonate, and then subjected to crushing, and then sieved. It is manufactured by a method of adjusting the particle size by a general classification method.

The magnesium hydroxide which is a raw material for the production of the hard magnesium oxide powder and the fused magnesium oxide powder can be dried, for example, by adding slaked lime to seawater or a salt of a magnesium salt and brine, and drying the precipitated magnesium hydroxide. The magnesium hydroxide powder was obtained. The magnesium carbonate may, for example, be natural magnesite. Examples of the magnesium oxide used as a raw material for producing the fused magnesium oxide powder include calcined light magnesium oxide powder, burnt hard magnesium oxide powder, and sintered magnesium oxide.

The bulk density of the magnesium oxide calcined product and the magnesia molten solidified product is preferably 2.10 g/cm ³ or more, more preferably 3.10 to 3.50 g/cm ³ , and particularly preferably 3.10 to 3.30 g/cm ³ . Further, the bulk density of the magnesium oxide fired product and the magnesia molten solidified product can be measured by using the medium as kerosene and using the Archimedes method.

By dispersing the germination preventing agent of the present invention on the sediment of the freshwater water, it is possible to prevent the emergent plants (for example, reed, cattail, lotus, white bamboo shoots, scallions, puppies), and floating leaf plants (for example, water chestnut, big king lotus) , water lily, eye dish), and submerged plants (such as water blue, water grass, polyalga, algae, Chara) and other roots rooted in the freshwater waters of the aquatic plants sprouted.

The amount of the germination preventing agent to be dispersed is preferably in the range of 0.1 to 10 kg, and particularly preferably in the range of 0.5 to 5 kg, with respect to the sediment having an area of 1 m ² . The spreading period of the germination inhibitor is preferably from 1 week to 3 months before the germination period of the aquatic plant begins.

The method of dispersing the germinating agent is not particularly limited. For example, the germination preventing agent may be dispersed in the water state of the fresh water area in a powder state, or the germination preventing agent may be dispersed in the water and then injected into the fresh water water in the state of the dispersion.

The germination inhibitor dispersed in the freshwater water will settle to the freshwater waters and quickly reach the surface of the sediment. Since the germination preventing agent (magnesium oxide powder) reaching the surface of the sediment is a minute powder, it is rapidly dissolved in water to deteriorate the surrounding sediment to be weakly alkaline, and the dissolved magnesium ions react with the phosphide around the sediment. Forms poorly soluble magnesium phosphate. The germination of aquatic plants can be effectively suppressed by degrading the bottom mud to be weakly alkaline and further fixing the phosphide around the sediment into magnesium phosphate which is poorly soluble in water.

[Examples]

[Example 1]

Take the sediment and lake water that grows in the lake's water chestnut, so that the transparent plastic box (length 18 cm × width 30 cm × height 23 cm), the depth of the sediment is about 3 cm, and the depth of the lake is about 9 cm. Next, 54 g (1 kg per 1 m ² of the amount of the bottom mud) of the calcined magnesium oxide powder (particle size: 0.75 mm or less, apparent density: 3.23 g/cm ³ ) was uniformly deposited on the entire sediment. Spread and stand still. Figure 1 shows a photograph taken from above the transparent plastic box after 3 weeks. As shown in Fig. 1, there was no water chestnut growth even after 3 weeks. In addition, the sediment was passed through the glass rod after 3 weeks, and no cracking of the sediment was observed.

[Comparative Example 1]

Except that the magnesium oxide powder was not dispersed, the same experiment as in Example 1 was carried out, and the sediment and the lake water were placed in a transparent plastic box and allowed to stand. Figure 2 shows photographs taken from above the transparent plastic box after 3 weeks. As shown in Figure 2, after 3 weeks, the water chestnut grows lush.

[Fig. 1] Photographs taken from above the transparent plastic case of Example 1.

Fig. 2 is a photograph taken from above the transparent plastic case of Comparative Example 1.

Claims (7)

A germination preventing agent for an aquatic plant rooted in a sediment of a freshwater water, which comprises a magnesium oxide powder having a particle diameter of 1 mm or less and an apparent density of 3.10 to 3.56 g/cm ³ . The germination preventing agent for aquatic plants according to the first aspect of the invention, wherein the magnesium oxide powder contains 80% by mass or more of particles having a particle diameter of 1 mm or less. The germination preventing agent for aquatic plants according to the first aspect of the invention, wherein the magnesium oxide powder contains 80% by mass or more of particles having a particle diameter of 0.75 mm or less. The germination preventing agent for aquatic plants according to the first aspect of the invention, wherein the magnesium oxide powder is a burnt hard magnesium oxide powder or an fused magnesium oxide powder. The germination preventing agent for aquatic plants according to the first aspect of the patent application, wherein the aquatic plant is a plant of the family Lingaceae. A method for preventing germination of an aquatic plant rooted in a sediment of a freshwater water, which is a germination preventing agent for an aquatic plant according to any one of claims 1 to 5, which is applied to a sediment of a freshwater water. For example, in the method of preventing the germination of aquatic plants according to Item 6 of the patent application, the amount of the germination inhibitor of the aquatic plants is in the range of 0.1 to 10 kg with respect to the sediment having an area of 1 m ² .