JPH0551250B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an artificial culture medium made of mineral fiber aggregates for plant cultivation in which harmful algae do not grow on the surface of the culture medium. [Prior Art] The use of mineral fiber aggregates such as rock wool, slag wool, and glass wool as hydroponic cultivation beds for plants, particularly vegetables, has already been widely practiced. Mineral fiber aggregates are produced by melting mineral inorganic raw materials such as rocks and slag, blowing them away using centrifugal force or steam to form fibers, stacking them together with a spray adhesive on a net conveyor, and drying and hardening them. By manufacturing mats into mats and cutting them into appropriate dimensions, artificial cultivation beds in the form of sheets or blocks are made. Furthermore, this artificial cultivation bed is treated to make it hydrophilic,
Modification treatments such as improving water absorption and adding fertilizer components are also being carried out. In hydroponic cultivation using an artificial cultivation bed, it is desirable to always maintain an appropriate amount of the nutrient solution on the cultivation bed, but in this way, the surface of the bed remains moist with the nutrient solution, which prevents the development and growth of green algae. They grow and grow thickly in a relatively short period of time, covering the entire floor surface, and then wither and rot, forming a surface layer that reduces ventilation and water permeability, and causing disease and insect damage. There was a problem with the decline. Conventionally, in order to prevent the occurrence and growth of algae, attempts have been made to cover the surface of the cultivation bed with a light-shielding film or to add an algaecide to the nutrient solution. [Problems to be Solved by the Invention] However, with the method of covering with a light-shielding film, it is difficult to completely block light, and there are problems in that the effect is insufficient and the aesthetic appearance is lacking. In addition, algaecides lack practicality because they have a negative effect on the growth of the cultivated plants themselves, and the algaecides remain on the cultivated plants themselves. The present inventor has already developed an algae-proof mineral fiber cultivation bed in which copper hydroxide is attached to the upper layer of the mineral fiber aggregate (Japanese Patent Application Laid-Open No.
63-52827), but the present invention is even more excellent in surface uniformity distribution and algicidal effect. [Means for Solving the Problems] The above problems are solved by the algae-proof mineral fiber cultivation bed according to the present invention, which is characterized in that flux fibers carrying a silver compound are distributed and adhered to at least the upper surface layer. . Even if a silver compound is simply attached to the surface layer of a mineral fiber cultivation bed, algae-proofing properties can be obtained, but as watering etc. are repeated, it will flow out and its effectiveness will rapidly decrease. Further, when it is kneaded with an adhesive and adhered to the surface layer of a mineral fiber cultivation bed, the silver compound contained in the adhesive becomes difficult to dissolve into water, and a sufficient effect cannot be obtained. If the amount of adhesive is small, the elution of the silver compound into water will increase, but the adhesive will easily flow out, making it impossible to obtain a lasting effect. The present inventor has obtained an algae-proofing mineral fiber cultivation bed which has a long-lasting effect by supporting silver on flux fibers and allowing it to be distributed and adhered to the surface layer of the mineral fiber cultivation bed. It is necessary for the silver compound used in the present invention to elute silver ions into the nutrient solution, and sparingly soluble compounds such as silver chloride are not preferred, but soluble compounds such as silver nitrate are preferred. In particular, silver compounds such as silver sulfa diazine, which combine with chlorine and the like contained in the solution and are less likely to become insolubilized, are preferable because stable effects can be obtained. Flux fibers are produced by the flux method and have the chemical formula K ₂ Ti ₆ O ₁₃ .
The basic structural unit is _TiO6 octahedral coordination, and its geometric bonding mode forms a tunnel structure, which is a bundled fiber with a typical fiber length of 0.1 to 10 mm. The method for distributing and adhering flux fibers carrying silver compounds to the surface layer of a mineral fiber cultivation bed is to add silver compounds, flux fibers, and auxiliary agents and additives as necessary to water, and stir to disperse them uniformly. It is common to spray the aqueous solution with a spray gun. Examples of the auxiliary agent include a dispersant, and examples of the additive include an adhesive. In particular, when a small amount of adhesive is used together, the adhesive adheres dotted or partially due to migration during drying, so flux fibers or flux fibers and mineral fibers are fixed to each other without interfering with silver elution. preferable. Subsequently, the mineral fiber cultivation bed sprayed with the aqueous solution is dried, and the silver compound is fixed to the surface layer of the mineral fiber cultivation bed together with the flux fibers. [Function] While the flux fibers are stirred in the aqueous solution and uniformly dispersed, the silver compound enters the tunnels, cracks, and gaps of the flux fibers and is dried.
The flux fibers sprayed on the surface layer of the mineral fiber cultivation bed penetrate between the mineral fibers on the surface layer of the mineral fiber cultivation bed. Therefore, even when watered or fertilized, the flux fibers are blocked by the mineral fibers and do not easily flow out, and an appropriate amount of silver continues to be eluted from the supported silver compound. . [Example] Example 1 Eight rectangular parallelepiped blocks each 10 cm on a side obtained by cutting rock wool (bulk specific gravity 80 Kg/m ³ ) were prepared.
AgSD and AgNO ₃ are respectively 0 and 0.01mg in terms of Ag.
0.05mg, 0.1mg was attached. The method of attachment is 0.8 g of flux fiber, 2 ml of water, and 0.1 ml of ethyl alcohol.
After adding 0.01 g of vinyl acetate adhesive and stirring, it was applied to the upper surface of the block in a layer of about 0 to 3 mm using an air spray gun, and then dried to obtain 8 test bed blocks. . Add each block to the culture medium (nitrogen 100ppm, phosphorus 30ppm, potassium 30ppm)
After immersing the block in the liquid, the bottom part was immersed in a culture solution vat with a depth of 20 mm and placed on the block, and the shredded green algae was placed on the surface of the block.
0.05g (fresh weight) was sprayed and cultured for 20 days in a greenhouse with a culture solution temperature of 25±3°C, and the results shown in Table 1 were obtained. Comparative Example 1 The same procedure as Example 1 was carried out except that no silver compound was added, and the results shown in Table 1 were obtained. Example 2 0.05 g (fresh weight) of shredded green algae was sprinkled on the surface of a test bed block obtained in the same manner as in Example 1, ^and approximately 1 ml of culture solution (nitrogen
100ppm, phosphorus 30ppm, potassium 30ppm) at 9am.
The cells were sprayed twice a day at 4:00 p.m. and 4:00 p.m. and cultured for 20 days in a greenhouse at 25±3° C., and the results shown in Table 1 were obtained. Comparative Example 2 The results shown in Table 1 were obtained in the same manner as in Example 2, except that 0.8 g of clay was used instead of 0.8 g of flux fiber. [Effects of the Invention] As is clear from the above culture test results, the cultivation bed of the present invention having a surface layer of silver ions has an excellent effect of preventing and suppressing the growth of green grass, and especially when AgSD is used, it is almost completely green. A remarkable effect can be obtained that can inhibit the growth of grass. Furthermore, even when the cultivation bed of the present invention is irrigated from above, the silver compound will not flow out and the effect will not deteriorate rapidly, and it has an excellent long-lasting effect. 【table】

Claims (1)

[Scope of Claims] 1. An algae-proof mineral fiber cultivation bed characterized by having flux fibers carrying a silver compound distributed and attached to at least the upper surface layer. 2 The silver compound is silver sulfadiazine (AgSD)
The algae-proof mineral fiber cultivation bed according to claim 1, which is characterized in that: