JPS6230726B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to vegetation soil that can retain sufficient moisture for a long period of time for the germination and growth of plants, and that allows plants to take root on the land surface as quickly as possible. Traditionally, land that requires vegetation, such as road slopes, mountain slopes with exposed bedrock, and residential development sites,
Moreover, its main component is mountain sand, which has extremely poor water retention.
If the soil is sandy such as river sand, sand, or white sand, or gravelly soil with a low soil content, or if the soil is very dry with little rainfall, some germination will occur when sown on the land. However, the composition as described above,
In the case of land with special characteristics, water supply tends to be insufficient for plant growth, and plants often die due to lack of water. As countermeasures against this problem, in the old days people tried to prevent the land from drying out by laying down the ground, and recently, the ground surface was improved by adding soil. In the latter method, the water retention effect differs depending on the thickness of the soil layer, for example.
A thin layer of soil less than 30 mm has a small water retention effect, and is usually
It is necessary to use a layer of soil with a thickness of about 30 to 100 mm. Therefore, if a thick layer of soil is constructed on a slope, the layer of soil will collapse due to its own weight, and it will slide off due to rainwater. It is difficult to maintain it permanently over a long period of time, and it is also subject to restrictions in terms of maintenance and management. In particular, greening of bedrock surfaces, crushed rock, etc. was considered impossible in ancient times, and recently, the above-mentioned soil replacement method has been used as a temporary method.
There are limits to the construction of additional soil on sloped land. For this reason, a method of increasing water retention has been applied by mixing perlite, vermiculite, etc. into the thin layer of soil to retain water, but these admixtures worsen the compaction of the soil. Moreover, since it cannot hold more water than its own volume, there is a limit to the amount of water that can be mixed. In addition, if there is a device that periodically sprinkles water from above the soil, it would be possible to grow vegetation using a thin layer of soil, but this is not practical as it would require a large amount of equipment cost. The present invention was devised in view of the above points,
First, in order to maintain sufficient water-holding capacity even in a thin layer of soil, we searched for substances with extremely high water-holding properties in the admixture. We focused on the use of powder of crosslinked acrylic acid polymers (hereinafter referred to as water retention agents). This powder has a high water absorption rate and has the property of not turning liquid into a jelly and flowing out, and its water-retaining properties have been used in sanitary napkins, diapers for infants, etc.; This has never been seen before as an application as one of the main compositions, and the present invention also achieves effective use of such a water retention agent. The soil for vegetation according to the present invention has a composition of a soil powder dried to a low moisture content of 10% or less, and a low weight ratio, specifically 0.1 to 3% by weight, of the soil powder. It consists of a water-retaining agent that swells into a jelly-like form when it absorbs water, such as grafted starch and cross-linked acrylic acid polymer. First, the soil powder adopted in the present invention is an activated compost powder that is easier to obtain than simple soil powder, has relatively stable quality, and is easy to process such as drying and mixing, such as Sumitomo The product name ``Lipe S'' manufactured by Forest Industry Co., Ltd., or the humus soil, such as the product name ``Porus No. 1'' manufactured by Nippon Peat Kaihatsu Co., Ltd., has a high organic matter content and is suitable for plant growth other than water retention. It is suitable as it contains many necessary ingredients. In addition, as the water retention agent adopted in the present invention, graft starch, for example, "Polymer 35-A-100" (trade name, manufactured by Grain Processing Co., Ltd., USA) is used.
Alternatively, a crosslinked acrylic acid polymer, for example, the product name "Aqua Keep" manufactured by Seitetsu Kagaku Kogyo Co., Ltd.
etc. are suitable because they swell to about 100 to 1000 times their own weight due to water content, become jelly-like, and do not flow down. This water retention agent powder can be mixed in advance with the above-mentioned soil powder that has been dried to a water content of 10% or less, and can be used for vegetation by mixing 1% by weight of the soil powder. When used as soil, black soil (fine grain size of 20 mesh), sand (river sand of 35 mesh), vermiculite (trade name, permiculite No. 2,
It exhibits remarkable water retention performance compared to each of perlite (specific gravity 0.1), perlite (specific gravity 0.2), and humus (one of the main compositions of the present invention) alone, and especially compared to the own weight of simple humus soil. It was demonstrated that the water retention performance is 5 times or more. The experimental method at this time was to put a certain amount of sample 3 into each funnel 2 with filter paper 1 inside, as shown in FIG. The water content at saturation of each sample 3 was compared in weight %.

[Table] In addition, 100g of each of the above samples was taken out with its saturated water content (wt%), left outdoors under the same conditions, and the drying conditions were tested for a certain period of time. As shown in Fig. 3, it was demonstrated that the soil according to the present invention (reference number F) can withstand drying for a long period of time compared to other samples. In addition, if the water content of the soil starch powder exceeds 10%, it is not preferable because the water retention agent absorbs the moisture of the soil starch powder and tends to become joint powder. In addition, if the mixing ratio of the water retention agent to the soil powder is less than 0.1% by weight, the water content of general soil is the same as the average of 50%.
Similarly, if the weight ratio is more than 3%, the swelling upon addition of water will be too large, making mixing difficult. Therefore, the mixing ratio of water retention agent to soil powder is 0.1 to 3% by weight.
It was found that a range of 1 to 2% is appropriate, and within that range, 1 to 2% is the optimum value. Next, in order to manufacture and apply the soil for vegetation according to the present invention, first, humus powder (replacement soil powder) is dried to a water content of about 7%, and the dried humus powder is added to the Fine particles of a crosslinked acrylic acid polymer (water retention agent) having a ratio of 1% are mixed. After adding three times the weight of water to the soil with this composition and kneading it in a mixer to ensure an appropriate viscosity for spraying,
A mortar pressure sprayer is used to spray the mortar onto the river sand slope with an average layer thickness of 3 mm. At the same time, the top soil was constructed using humus soil, which is a general soil, of the same thickness, and the top soil was placed in the shape of a sandwich between pieces of topsoil stabilizing net (20 x 20 cm), and the soil was placed outside to avoid the effects of rain. As a result of measuring changes in water content due to natural rainfall over a period of approximately one month, it was found that the soil for vegetation according to the present invention had no humus content, as shown in the table of Figure 3. It was demonstrated that water can be retained permanently for a long period of time compared to the case of soil. As mentioned above, the vegetation soil according to the present invention exhibits various properties as shown below. As shown in the table above, while normal earth and sand has a water content of about 1.5 times its own weight, the soil of the present invention has a water content of more than 10 times that of this earth and sand, and more than 5 times its own weight. . Incidentally, vermiculite, perlite, etc. used as soil admixtures also exhibit a water content nearly five times their own weight, but since their specific gravity is about 0.1, the volume is nearly ten times that of the soil of the present invention, which is not preferable. When the ground is covered with the soil of the present invention in a layer thickness of about 1 cm, it will not completely dry for at least about two weeks. Therefore, judging from the actual annual rainfall in our country, if there is rainfall in between, water retention will be maintained permanently for a long period of time. Furthermore, if the topsoil of the present invention is covered with a topsoil stabilizing net, the outflow and drying of the topsoil will be effectively suppressed, and the topsoil effect will be dramatically improved. By adding viscosity to the soil of the present invention with an appropriate amount of water, it can be easily sprayed onto the desired ground using a pressure-feed mortar spraying machine. In this way, even if the soil for vegetation according to the present invention is a thin layer of soil, even if it is presumed from the actual annual rainfall in Japan that there will be no rainfall for a long period of time, it will not cause germination of plants.
It can permanently retain and supply the moisture necessary for growth over a long period of time, and has various innovative effects as a supplementary soil for vegetation.

[Brief explanation of the drawing]

Figure 1 is a sample water retention test device, Figure 2 is a table showing the drying status of the sample, and Figure 3 is a table showing changes in water content due to natural rainfall.

Claims (1)

[Claims] 1. By water absorption of soil powder dried to a low moisture content of 10% or less, grafted starch at a low weight ratio of 1 to 2% to the soil powder, crosslinked acrylic acid polymer, etc. A water retention agent that swells is mixed with water retention agent, water is added to this, the mixture is kneaded using a mixer, and the mixture is sprayed onto the land surface using a mortar pressure blower to form a thin layer of top soil. A method of constructing soil for vegetation by covering it with netting.