Spraying materials and spraying layer formation method

Abstract

To provide a spraying material that can obtain a sprayed layer with high water retention when constructed for the purpose of greening the soil or rock surface.SOLUTION: The spraying material of the present invention comprises a vegetation base material and a water retention material. The water retention material contains at least one of silicate clay mineral and biochar, and the water retention material has a black soil content of 5% or less in 100% of the total volume of the vegetation base material and the water retention material. Since the sprayed layer formed by the spraying material is difficult to dry, it is easy for plants to grow. By using the spraying material, it is possible to carry out greening work even in the dry season.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a spraying material and a method for forming a sprayed layer. [Background technology]

[0002] Traditionally, vegetation substrate spraying has been known as a method for greening soil and bedrock surfaces. In vegetation substrate spraying, seeds are impregnated with vegetation substrate and sprayed onto the target surface to cause the seeds to germinate. However, if the vegetation substrate is exposed to sunlight and wind for a long time after spraying, water evaporates from the surface, causing it to dry out, which can lead to failure of the seeds to germinate. Therefore, it is desirable to refrain from greening work during periods of low rainfall, when the risk is high, but it is sometimes unavoidable to carry out work in conjunction with other processes. As a result, there have been cases where rework was required due to failure to green the soil.

[0003] The causes of drying include the low water retention of bark compost, which is widely used as a vegetation substrate, and the fact that it becomes water repellent when it dries, making it difficult to absorb water. Therefore, spray materials containing surfactants have been proposed to suppress water repellency (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4048800 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even if water penetrates into soil with suppressed water repellency, if the soil has insufficient water retention, the water evaporates quickly and plants have difficulty surviving. The present invention aims to provide a spraying material that can obtain a spraying layer with high water retention when applied to green soil or rock surfaces. Another aim is to provide a method for forming a spraying layer using this spraying material. [Means for solving the problem]

[0006] The present invention provides a spray material comprising a vegetative substrate and a water-retentive material, the water-retentive material containing at least one of a silicate clay mineral and biochar, and a black soil content of the water-retentive material being 5% or less of the total volume (100%) of the vegetative substrate and the water-retentive material.

[0007] This spraying material contains a water-retentive material, so the sprayed layer obtained by spraying this spraying material has high water-retentiveness, is less likely to dry out, and is favorable for plant growth. Furthermore, by using this spraying material, greening work can be carried out even during dry seasons.

[0008] This spray material may further contain a penetrating agent. When the spray material contains a penetrating agent, the sprayed layer obtained by spraying this spray material is more likely to absorb water. In other words, water repellency is suppressed. In addition, the water-retentive material may contain biochar, and the content of biochar may be 1% to 60% of the total volume of the vegetation substrate and the water-retentive material, which is 100%.

[0009] In this spraying material, the water-retentive material contains silicate clay minerals and biochar, and the content of biochar is preferably greater by volume than the content of silicate clay minerals. In addition, this spraying material may further contain fertilizer and may contain an adhesive. The adhesive acts to bond between particles of the spraying material, so that when this spraying material is sprayed on a slope, the sprayed layer can be prevented from sliding down.

[0010] The present invention also provides a method for forming a sprayed layer by spraying the above-mentioned spraying material onto a target surface, wherein the target surface may be a slope. Effect of the Invention

[0011] According to the present invention, it is possible to provide a spraying material that can obtain a spraying layer with high water retention when applied to soil or bedrock surfaces for the purpose of greening, and a method for forming a spraying layer using the spraying material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] A preferred embodiment of the present invention will be described in detail below. The spraying material of this embodiment is sprayed onto horizontal surfaces or slopes to form a sprayed layer that serves as a base for vegetation, for the purpose of greening the surface of soil or bedrock, or concrete, etc. The spraying material of this embodiment contains seeds, so that the seeds germinate from the sprayed layer and the plants grow, greening the target surface.

[0013] The spray material of this embodiment includes a vegetative substrate, a water-retentive material, an adhesive, and seeds. The spray material may further include a fertilizer. The spray material may also include a penetrating agent to increase the permeability of water.

[0014] The vegetation substrate is preferably one that has the water retention required for plant growth and is preferably an organic material. Examples of the vegetation substrate include bark compost and a mixture of bark compost and at least one of leaf mold, peat moss, coconut fiber, etc. The dry specific gravity of the vegetation substrate is 0.05 to 0.45 g / cm. 3 and preferably 0.15 to 0.3 g / cm 3 It is more preferable that:

[0015] The water-retentive material is a material having higher water-retentiveness than the vegetation substrate. The water-retentive material may be an inorganic material or an organic material, and examples thereof include silicate clay minerals, biochar, palm fiber, peat moss, wood fiber, inorganic porous materials, and ceramic materials. Among these, the water-retentive material includes either silicate clay minerals or biochar. It is also preferable to include both silicate clay minerals and biochar. Since silicate clay minerals are rich in silicic acid, it is expected that the strength and disease resistance of the plant body will be improved in plants with high silicic acid requirements, such as grasses.

[0016] Examples of silicate clay minerals include zeolite, kaolinite, and smectite. Among these, bentonite, which is mainly composed of montmorillonite, a type of smectite, is preferred. Bentonite strongly adsorbs water, thereby suppressing water evaporation and delaying the drying of the spray material. Bentonite that has a small degree of swelling due to water absorption is preferred, and from this viewpoint, calcium-type bentonite is preferred. In particular, when the spray material is applied to a slope, it is preferred that the degree of swelling due to water absorption is small.

[0017] The content of silicate clay minerals is preferably 0.01% to 50% of the total volume of the vegetation substrate and the water-retaining material (100%), more preferably 0.1% to 25%, and even more preferably 0.5% to 15%.

[0018] Biochar (vegetable charcoal) is a carbonized organic matter. Biochar is generally porous, so by retaining water in its fine pores, evaporation can be suppressed and water can be provided to plants. The pores also provide space for plant roots to breathe, and can also be used by microorganisms, so that an increase in useful microorganisms can be expected. Examples of biochar include rice husk charcoal, coconut shell charcoal, wood charcoal, and bamboo charcoal. Since biochar is not easily decomposed in soil, when it is used as a constituent material of the spraying material of this embodiment, it is expected to have the effect of storing carbon dioxide absorbed by plants from the atmosphere in the soil.

[0019] The content of biochar in the spraying material is preferably 1% to 60% of the total volume of the vegetation substrate and the water-retentive material (100%), more preferably 5% to 50%, and even more preferably 10% to 40%. In particular, when using rice husk charcoal as biochar, since rice husk charcoal is an alkaline material with a pH of 8 to 9, it is preferable that the content does not exceed these upper limits. In addition, in soil with a high pH, ​​there is a risk that invasive species such as Solidago altissima (designated as a invasive species requiring caution under the Invasive Alien Species Act) are more likely to invade than native species.

[0020] As for the relative ratio of the content of silicate clay mineral to that of biochar, from the viewpoint of suppressing water repellency (enhancing water permeability), the content of biochar may be 1 to 40 times, 1.5 to 20 times, or 2 to 10 times the volume of the silicate clay mineral.

[0021] The water-retentive material may contain black soil, but in the spray material of this embodiment, the content of black soil is 5% or less of the total volume of the vegetation substrate and the water-retentive material (100%). If the content exceeds 5%, the water-retentive property tends to decrease.

[0022] Any type of fertilizer can be used as long as it is a fertilizer that is normally used for plants. The amount of fertilizer to be mixed is, for example, 50 g / m2 based on the area of ​​the sprayed layer when the sprayed material is sprayed to form a sprayed layer. 2 ~150g / m 2 When the total weight of the vegetation base material and the water-retentive material is taken as 100%, it is preferable to mix in an amount of 1% to 5% by weight.

[0023] The adhesive bonds the particles in the spray material together so that the spray layer does not slide off when the spray material is applied to a slope to form a spray layer. The adhesive is preferably an organic polymer, and is particularly preferably polyvinyl acetate, vinyl acetate-ethylene copolymer, or polyvinyl alcohol. The content of the adhesive may be 0.05% to 2%, or may be 0.1% to 1%, when the total volume of the vegetation base material and the water-retentive material is taken as 100%.

[0024] The penetrating agent is intended to increase the water permeability of the sprayed layer (suppress water repellency). If the sprayed layer has high water permeability, rainwater can easily penetrate during rainfall, and water retention is likely to be exhibited. The penetrating agent is preferably a surfactant, and any of anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants can be used. The penetrating agent is preferably a liquid from the viewpoint of mixability, and the blending amount may be 0.01 mL / L to 2.5 mL / L, or may be 0.03 mL / L to 0.25 mL / L based on the total volume of the vegetation substrate and the water-retentive material.

[0025] The degree of water repellency can be determined by a water repellency test. For example, it can be determined by recording the time it takes for a 0.5 mL water droplet to penetrate according to the WDPT method (Bisdom et al., 1993). In the WDPT method, the target material is spread on a petri dish, and the dryness of the target material is set to the value that indicates the highest water repellency (e.g., volumetric water content of 20%). Then, the water droplet penetration time (unit: seconds) is used to evaluate the water repellency into one of five levels (WR0 to WR4). Less than 5 seconds: WR0 (no water repellency) 5 to 60 seconds: WR1 (slightly water repellent) 60 seconds to less than 600 seconds: WR2 (strong water repellency) 600s to 3600s: WR3 (highly water repellent) Over 3600 seconds: WR4 (extreme water repellency)

[0026] Examples of seeds include seeds of grasses of the family Poaceae, legumes, and woody plants of the family Betulaceae and Rosaceae. The amount of seeds to be used is determined taking into consideration the greening target, region, construction period, etc.

[0027] The procedure for spraying the spraying materials is to first mix various materials. For example, a vegetation base material, a water-retentive material, an adhesive, a penetrating agent, fertilizer, and seeds are put into a tank of a spraying machine such as mortar and mixed. This prepares the spraying materials. The materials to be mixed may be added in any order, and the addition of any material may be delayed. For example, the seeds may be added after the materials other than the seeds have been thoroughly mixed.

[0028] The target surface to which the material is sprayed may be a horizontal surface or a slope. If the surface is a slope, the gradient may be up to 1:0.6. An anti-slip material such as a lath net is provided on the target surface, and the spraying material is pumped and discharged from a nozzle onto the anti-slip material. The spraying thickness is determined in the range of 3cm to 10cm depending on the construction conditions such as the rock type of the substrate, the soil gradient, and the type of plant used. In this way, a sprayed layer can be formed on the target surface.

[0029] A vegetative substrate spraying technique has been known for the purpose of greening soil and bedrock surfaces, but if the vegetative substrate is exposed to sunlight and wind for a long time after spraying, water evaporates from the surface, causing it to dry out, which can lead to seeds failing to germinate. Therefore, it is desirable to refrain from greening work during periods of low rainfall, as this risk is high, but it has sometimes been necessary to carry out the work in conjunction with other processes. As a result, there have been cases where rework was required due to failure to green the work.

[0030] If the water retention of the sprayed layer is insufficient, water evaporates quickly, making it difficult for plants to grow. In particular, if the water retention is insufficient on a slope, water is likely to run off even if it rains. In this regard, since the sprayed material of this embodiment contains a water retention material, the sprayed layer obtained by spraying this sprayed material has high water retention. Therefore, with this sprayed layer, the water retention under dry conditions is higher than with conventional vegetation substrates, and the survival period of plants can be extended. In addition, since the sprayed layer is difficult to dry out, greening work can be carried out even in dry seasons by using the sprayed material of this embodiment. Therefore, the construction period can be set freely regardless of the season.

[0031] Since the spray material of this embodiment contains a penetrating agent, the spray layer is easily absorbent and can efficiently absorb water even with a small amount of rainfall. In addition, since the spray material of this embodiment contains an adhesive, the particles of the spray layer are bonded together, so it can be applied to slopes where there is a risk of the spray layer sliding off.

[0032] The preferred embodiments of the present invention have been described above. The present invention is not limited to the above embodiments. For example, in the above embodiments, the spray material contains seeds, but it may not contain seeds, and seeds may be sown after the spray layer is formed, or a greening sheet or the like with seeds attached thereto may be laid. Also, seedlings may be planted in the spray layer instead of sowing seeds. The surface to be sprayed may be concrete or mortar in addition to soil or bedrock. EXAMPLES

[0033] The water retention and water repellency of the spray material of the present invention were evaluated in the following experimental examples, but the present invention is not limited to the following experimental examples.

[0034] <Water retention study> A 1.125-liter container (150 mm x 150 mm x 50 mm) was prepared. The vegetation substrate and water-retentive material shown below were mixed in the volume ratios shown in Table 1 (Experimental Examples 1 to 24), and an adhesive was added in an amount that would make up 0.2% of the total volume of the mixture, assuming that the total volume was 100%, to prepare modified vegetation substrates. In each experiment, the container was filled with 1.5 times the volume of the modified vegetation substrate. 150 seeds were sown per experiment.

[0035] (Materials used) [1] Vegetation substrate (mainly bark compost: product name "Fujimi Soil", manufactured by Fujimi Kogyo Co., Ltd., dry bulk density 0.18 g / cm 3 ) [2] Water-retaining materials Bentonite (calcium bentonite: product name "Bentonite Granules", manufactured by AgriCreate Co., Ltd.) Black soil (product name "Black soil", manufactured by Togawa Heiwa Farm) Rice husk charcoal (product name "Green Power Biocharcoal", manufactured by Kansai Sangyo Co., Ltd.) Coconut shell charcoal (product name "HiPro C", manufactured by King Coal) Palm fiber (product name "Cocoyuki", manufactured by DIA) Peat moss (product name "Peat Moss", manufactured by Togawa Heiwa Farm Co., Ltd.) Wood fiber (product name "DW Fiber", manufactured by Daiken Corporation) [3] Adhesive (vinyl acetate-ethylene copolymer: product name "Lunasol Powder S", manufactured by Japan Coating Resin Co., Ltd.) [4] Seeds (annual ryegrass seeds)

[0036] Each container with the seeds sown was placed in an artificial climate chamber at 25°C and 55% humidity, with a 12-hour light / dark cycle and water absorption cycle for growth. Watering was stopped 14 days after sowing, or when germination of 45% or more (half ±5%) was confirmed. The number of days it took for more than half of the test grass to wilt was then recorded as the number of days the grass survived under dry conditions. The results are shown in Table 1.

[0037] According to the results shown in Table 1, when bentonite or biochar (rice husk charcoal, coconut shell charcoal) was mixed as a water-retentive material (Experimental Examples 2-5, 13-18), the plant survival days were longer than when only the vegetation substrate was used (Experimental Example 1). In addition, when coco peat, peat moss, and wood fiber were used as water-retentive materials (Experimental Examples 19-24), the effect of extending the plant survival days was not as high as when bentonite or biochar was used. In addition, when black soil was mixed at 5% as a water-retentive material (Experimental Example 6), the plant survival days were longer than when only the vegetation substrate was used (Experimental Example 1), but when it was mixed at more than 5% (Experimental Examples 7-12), the plant survival days decreased. This is thought to be due to the decrease in voids in the modified vegetation substrate, which reduced the water retention capacity.

[0038] <Study of water retention and water repellency> In addition to the water retention improvement effect, the presence or absence of a water repellency suppression effect was also examined. The same vegetation substrate and water-retentive materials (bentonite, rice husk charcoal) used in the above water retention study were mixed in the volume ratios shown in Table 2, and an adhesive was mixed in an amount that would make the volume 0.2% when the volume of these was taken as 100%, and a penetrating agent (non-ionic surfactant: product name "Good Touch", manufactured by Maruwa Biochemical Co., Ltd.) was mixed in an amount that would make the total volume of the vegetation substrate and water-retentive materials 0.063 mL / L based on the total volume of the vegetation substrate and water-retentive materials to prepare a modified vegetation substrate. The modified vegetation substrate was filled in the same container as used in the above water retention study, and seeds were sown.

[0039] Each container containing the seeds was placed in an artificial climate chamber at 25°C and 55% humidity, with a 12-hour light-dark cycle for growth. Watering was stopped 14 days after sowing, or when germination of 45% or more (half ±5%) was confirmed. The number of days it took for more than half of the test grass to wilt was then recorded as the number of days the grass survived under dry conditions. The results are shown in Table 2.

[0040] Additionally, each modified vegetation substrate was placed in a separate petri dish (7 cm in diameter) and the water droplet penetration time was measured. The water repellency test was conducted according to the WDPT method by recording the time required for a 0.5 mL water droplet to penetrate. The drying conditions were a volumetric water content of 20%, at which point the unmodified vegetation substrate showed the highest water repellency in preliminary tests. The results are shown in Table 2. In Table 2, the "water droplet penetration time" is expressed as an integer value rounded off to the first decimal place.

[0041] According to the results shown in Table 2, when bentonite and rice husk charcoal were mixed as water-retentive materials (Experimental Examples 26-34), the number of days plants survived was longer than when only the vegetation substrate was used (Experimental Example 25). It was also found that increasing the mixing ratio of rice husk charcoal (Experimental Examples 26-28, 29-31, 32-34) increased water permeability (increased degree of suppression of water repellency). It was found that when the amount of bentonite was greater than the amount of rice husk charcoal (Experimental Examples 29 and 32), water repellency increased. In Experimental Example 32, the specified germination rate was not reached even after a certain period of time had passed (germination rate 40.8%). This is thought to be due to the increase in water repellency due to the increase in the amount of bentonite, and the formation of water-blocking areas due to the local concentration of bentonite, which inhibited the seeds from absorbing water.

[0042] [Table 1]

[0043] [Table 2] [Industrial Applicability]

[0044] The present invention can be used, for example, as a slope revegetation work.

Claims

1. A vegetative substrate and a water-retentive material are included, The water-retentive material includes silicate clay minerals and biochar; The content of the biochar is equal to or greater than the content of the silicate clay mineral by volume ratio; The water-retentive material is a spray material having a black soil content of 5% or less out of a total volume of 100% of the vegetation base material and the water-retentive material.

2. The spray material of claim 1 further comprising a penetrating agent.

3. A spray material as described in claim 1 or 2, wherein the biochar content is an amount that occupies 1% to 60% of the total volume of 100% of the vegetation substrate and the water-retaining material.

4. A spray material described in any one of claims 1 to 3, wherein the biochar content is greater by volume than the silicate clay mineral content.

5. The spraying material according to any one of claims 1 to 4, further comprising a fertilizer.

6. The spray material according to any one of claims 1 to 5, further comprising an adhesive.

7. A method for forming a sprayed layer, comprising spraying the spray material according to any one of claims 1 to 6 onto a target surface to form a sprayed layer.

8. The method for forming a sprayed layer according to claim 7, wherein the target surface is a slope.

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