AU2012321759B2

AU2012321759B2 - Vegetation bed, and method for cultivating plants

Info

Publication number: AU2012321759B2
Application number: AU2012321759A
Authority: AU
Inventors: Hiroshi Kajiyama; Shigeto Matsumoto; Takamune SHIRAI
Original assignee: Toray Industries Inc; Mitsukawa and Co Ltd
Current assignee: Toray Industries Inc; Mitsukawa and Co Ltd
Priority date: 2011-10-13
Filing date: 2012-10-11
Publication date: 2016-08-25
Anticipated expiration: 2032-10-11
Also published as: CN103929943A; WO2013054859A1; CN103929943B; ZA201402818B; JPWO2013054859A1; AU2012321759A1

Abstract

The present invention provides a vegetation bed comprising knit multifilament fibers made from aliphatic polyester, the vegetation bed having excellent transportability and excellent properties with respect to ultraviolet degradation. The present invention pertains to a vegetation bed composed of cylinders of knit fabric composed of a multifilament fiber comprising aliphatic polyester, and filled with a culture, the fabric being placed contiguously side by side, or to a vegetation bed characterized in being composed of two cylinders of knit fabric that are placed contiguously side by side, having a concave portion occurring at their top in which a culture is placed.

Description

DESCRIPTION

Title of the Invention:

VEGETATION BED, AND METHOD FOR CULTIVATING PLANTS

Technical Field [0001]

The present invention relates to a method for cultivating a plant and a vegetation bed used therein. Further, the present invention relates to a vegetation bed that can be suitably used in a method for greening wasteland where a plant is difficult to grow, is excellent in ultraviolet deterioration resistance characteristics, is also excellent in that it can be moved or transported according to a request even after vegetation has been formed, and can cultivate a plant with improvement and modification of soil, and a method for cultivating a plant using the same.

Background Art [0002]

In recent years, as a method for greening wasteland where a plant is difficult to grow, generally, there is a method of directly planting seedlings or young trees of specific plants that are easy to grow on that land. There is also a method of planting seedlings or seeds, after the soil of a land surface portion is improved to be a soil where a common plant is easy to grow by replacing it.

[0003]

However, both of these methods require a lot of working and a considerable amount of effort.

[0004]

On the other hand, as a proposal with respect to a side material for a vegetation bed form body and a vegetation bed form body that are light in weight and thin in thickness and can relatively simply and easily form a bed for vegetation without being limited in construction places, and with respect to a forming method of vegetation using the same, there are proposals with respect to a side material for a tubular vegetation bed form body formed of a circular knitted fabric, in which the cover factor value based on JIS LI 018 in indication of constant yarn count of a knitted fabric obtained by knitting synthetic fiber yams is from 5 to 20 and the bursting strength is 300 kpa or more, and with respect to a vegetation bed form body filled with a culture (Patent Document 1).

[0005]

However, in the method proposed in Patent Document 1, deterioration due to ultraviolet rays is small when the whole knitted fabric is covered using a ground covering plant or the like. However, when a plant that does not cover the whole knitted fabric is used, there has been a problem that the knitted fabric in a portion not covered is deteriorated by ultraviolet rays with time.

[0006]

Further, there is a proposed method of making an opening in a part of a side surface of a similar tubular knitted fabric to allow a culture in the inside thereof to expose, planting seeds or seedlings therein, and allowing them to take roots (Patent Document 2). However, there has been a problem that the culture leaks from the opening, or that the knitted fabric splits from the opening portion (Patent Document 2).

[0007]

Furthermore, as a technique of planting a plant in a desert region or the like to green it, there is a proposed method of using sandbags each formed of a cylindrical knitted fabric, in which the inside is filled with sand, and placing them on sand at specific pitches. This method prevents the movement of sand due to wind in the desert region to allow the plant to take roots in the desert, thereby forming and improving vegetation. Specifically, this is a sand movement preventing method of placing a plurality of tubular sandbags each formed of the tubular knitted fabric, in which the inside is filled with sand, on the sand ground in a crossed state, thereby preventing the movement of sand. Preferably, this is a sand movement preventing method in which the placing pitch of the tubular sandbags is from 3 to 30/10m and the cross-sectional area of the tubular sandbag is from 10 to 400 cm2. As a result, there is a proposed method for forming and improving vegetation that the desired plant is cultivated on the sand ground between the tubular sandbags placed in the crossed state and the other tubular sandbags (Patent Document 3).

[0008]

However, in the method proposed in this Patent Document 3, seeds or seedlings of plants are directly planted on an innutritious exposed surface of the ground, so that the growth of the plants has been unstable after all. A vegetation bed that allows the plant to grow positively has been expected.

Prior-Art Documents Patent Documents [0009]

Patent Document 1: JP-A-2009-261265 Patent Document 2: JP-A-2005-110590 Patent Document 3: JP-A-2008-291636 [0009a]

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0009b]

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

[0010]

In view of the points as described above, an aspect of the present invention is to solve the problems of the conventional vegetation beds and the conventional vegetation methods, and to provide a method for greening wasteland where a plant is difficult to grow, a method for cultivating a plant even in a place where there is originally no soil, and a vegetation bed that can be suitably used therein.

[0011]

That is, in some aspects, the present invention relates to the following (1) to (5). (1) A vegetation bed, in which a tubular knitted fabric knitted with a multifilament fiber comprising an aliphatic polyester is adjacently apposed and an inside of the knitted fabric is filled with a culture. (2) The vegetation bed according to (1), wherein the aliphatic polyester comprises a polylactic acid. (3) The vegetation bed according to (1) or (2), wherein a culture is further placed in a concave portion produced in an upper part of an adjacent part of the tubular knitted fabric. (4) A method for cultivating a plant, comprising planting a seed or a seedling in the culture placed in the concave portion of the vegetation bed according to (3), and allowing a plant to grow. (5) A method for cultivating a plant, comprising arranging the vegetation beds according to any one of (1) to (3) so as to constitute a plurality of parallel ridges, and allowing a plant to grow.

[0011a]

In another aspect there is provided a vegetation bed, in which a tubular knitted fabric knitted with a multifilament fiber comprising an aliphatic polyester is adjacently apposed and an inside of the knitted fabric is filled with a culture, the vegetation bed has a boundary surface between the tubular knitted fabrics which are adjacent to each other, and a seed or a seedling is placed on/above the boundary surface.

[0011b]

In a further aspect there is provided a method for producing the vegetation bed according to embodiments described herein, the method comprising: filling an inside of a knitted fabric with a culture, thereby obtaining a tubular knitted fabric; apposing the tubular knitted fabrics adjacently, thereby forming a boundary surface between the tubular knitted fabrics which are adjacent to each other; and planting a seed or a seedling on/above the boundary surface.

Advantageous Effects of the Invention [0012]

According to the vegetation bed of aspects of the present invention described herein, there is an effect that deterioration due to ultraviolet resistance is small. When moving or transportation is wanted according to a request, particularly even after formation of vegetation, mobility or transportability that makes it possible is excellent. Besides, the vegetation bed excellent in plant cultivation can be simply provided at low cost.

[0013]

According to the method for cultivating a plant of aspects of the present invention described herein, a desired plant (a ground cover plant or an agricultural crop) can be cultivated using the vegetation bed of the present invention described above even in a place having no culture at low cost.

[0014]

According to the vegetation bed of aspects of the present invention described herein, a desired plant (mainly an agricultural crop cultivated in a field) can be cultivated by desired culture soil controlled.

Brief Description of the Drawings [0015] [FIG. 1] FIG. 1 shows a state of use of the vegetation bed of the present invention, and is a schematic cross-sectional view cut in a direction perpendicular to the ground.

[FIG. 2] FIG. 2(a) and 2(b) each shows an example of a state of use of the vegetation bed of the present invention, and are each a plan view in which a state thereof placed on the ground is viewed from above. FIG. 2(a) shows a state in which a tubular knitted fabric is placed in parallel in a zig-zag manner, and FIG. 2(b) shows a state in which a tubular knitted fabric is placed so as to be wound in a spiral form.

[FIG. 3] FIG. 3 show another example of a state of use of the vegetation bed of the present invention, and is a schematic cross-sectional view cut in a direction perpendicular to the ground, similarly to FIG. 1.

[FIG. 4] FIGs. 4(a) and 4(b) each shows an example of a state of use of the vegetation bed of the present invention, are each a partial perspective view in cross section in which a state thereof placed on the ground is viewed from obliquely above, and an example in which tubular knitted fabrics are placed straight in parallel two by two to constitute one ridge and a plurality of the ridges are arranged at appropriate intervals to form a field over a wide area. FIG. 4(a) corresponds to the use method of the case shown in FIG. 1, and FIG. 4(b) corresponds to the use method of the case shown in FIG. 3.

Mode for Carrying Out the Invention [0016]

The vegetation bed and the method for cultivating a plant of the present invention are described in detail below with reference to the drawings and the like.

[0017]

The vegetation bed of the present invention is characterized in that it is formed by adjacently apposing tubular knitted fabrics which are knitted with a multifilament fiber (yam) comprising an aliphatic polyester and are filled with a filler such as a culture.

[0018] FIG. 1 shows a state where the tubular knitted fabrics are adjacently apposed. The reference numeral 1 designates a tubular knitted fabric knitted using a multifilament fiber (yam) comprising an aliphatic polyester. A state where the inside thereof is filled with a culture 2 and where the tubular knitted fabrics 1 are adjacently apposed on the ground 4 is shown. In FIG. 1, six tubular knitted fabrics are adjacently apposed. However, the number thereof may be any, as long as it is two or more, and is not particularly limited. In the present invention, “adjacently apposed” means “placed in parallel, substantially in contact with each other”, not only simply “placed next to each other”, and this is important.

[0019]

This embodiment shown in FIG. 1 is a preferred embodiment, and shows a state where a culture 3 is placed to use in a concave portion produced on/above a boundary surface formed by side surfaces of two tubular knitted fabrics apposed next to each other. The vegetation bed of the present invention can also be used in a state where the culture 3 is not particularly placed in the concave portion.

[0020]

The outer shape, size and the like of the vegetation bed in the present invention is not particularly limited, and may be any, as long as the vegetation bed is constituted by adjacently apposing the above-mentioned tubular knitted fabrics. The outer shape of the vegetation bed may be any of, for example, square, circular and parallelogram shapes, and is not particularly limited. A plant takes roots in the culture placed inside the tubular knitted fabric through mesh spaces of the tubular knitted fabric to grow up.

[0021] FIG. 2(a) shows an example in which one elongated tubular knitted fabric 1 is folded in a zig-zag manner so as to show an approximately rectangular outer shape, thereby being adjacently apposed. FIG. 2(b) shows an example in which one elongated tubular knitted fabric is spirally wound to form a shape, thereby being adjacently apposed. In each of the embodiments of FIG. 2, a culture 3 is placed in the concave portion produced on/above the boundary surface formed by the side surfaces of the tubular knitted fabric 1, and the filling degree of the culture and the properties of the knitted fabric are adjusted so as to form such a concave portion. Further, a plurality of the elongated tubular knitted fabrics, not one knitted fabric, may be used in a series or parallel state.

[0022]

That of FIG. 2(a) may be placed in a stacked manner in a box such as a wooden frame. If it is placed in a stacked manner, it is preferred to be stacked in two or more stages, although varied depending on the length of roots of a plant to be cultivated. Draining properties are improved by placing in a stacked manner. Further, an air-containing layer is formed between the beds, so that the cultivation of a plant is improved.

[0023]

The vegetation bed of the present invention is constituted taking into consideration that the configuration and function are both maintained as the vegetation bed for several years after installation, and thereafter, the vegetation bed is naturally decomposed by biodegradability of the tubular knitted fabric. In particular, this is achieved by using polylactic acid multifilament fiber that is little in deterioration by ultraviolet resistance and is a biodegradable fiber in the tubular knitted fabric. The configuration and function are both maintained as the bed for several years after installation, and thus, as long as within that period after installation, the followings can be relatively easily conducted: moving of an installation (placing) position of the vegetation bed as a whole, or removing and transporting of the vegetation bed, followed by replacement with new one.

[0024]

As the aliphatic polyester in the present invention, one obtained by polycondensation of a saturated dicarboxylic acid and a diol or one obtained by polycondensation of a hydroxycarboxylic acid are preferably used. Examples of these aliphatic polyesters obtained by polycondensation include polylactic acid, polyglycolic acid, poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-3-hydroxy valerate) copolymers, polycaprolactone, polypivalolactone, polyesters of glycols such as ethylene glycol and 1,4-butanediol and dicarboxylic acids such as succinic acid and adipic acid, and the like.

[0025]

Above all, the multifilament fiber comprising polylactic acid is preferred.

The polylactic acid multifilament is a multifilament fiber mainly comprising a polymer obtainable by polymerizing an oligomer of lactic acid, such as lactic acid or a lactide.

If the optical purity of an L-form or a D-form is 90% or more, the melting point becomes high, and the yam strength and light resistance also become preferable.

Further, a component other than the polylactic acid may be copolymerized within a range not impairing properties of the polylactic acid, particularly biodegradability and ultraviolet deterioration resistance. Furthermore, a polymer other than the polylactic acid or an additive such as particles, a flame retardant, an antistatic agent or a delusterant may be appropriately contained. However, it is preferred for environmental protection to utilize a lot of biomass materials, and from the viewpoint of biodegradability of the material, it is desirable to adjust a lactide structure in the polymer to 50% by weight or more. A lactic acid monomer is preferably 75% by weight or more, and more preferably 96% by weight or more.

[0026]

In addition to the fiber and yam in which two kinds of optical isomers of the L-form and the D-form are simply mixed, the above-mentioned two kinds of optical isomers may be blended and formed into a fiber or a yam, followed by subjecting to high-temperature treatment at 140°C or more to form a racemic crystal as a stereo complex, and then, by obtaining a knitting yam therefrom, the melting point can be dramatically increased. This is therefore more preferred.

[0027]

It is preferred that the weight average molecular weight of the aliphatic polyester is from 50,000 to 500,000, because of a good balance between mechanical properties and fiber-forming properties. The molecular weight of the polylactic acid is more preferably from 100,000 to 350,000 in terms of weight average molecular weight.

[0028]

Further, if a fatty acid bisamide and/or an alkyl substitution type fatty acid monoamide are allowed to be contained as a lubricant in the filament fiber comprising the aliphatic polyester, the resulting fiber is excellent in smoothness. Accordingly, productivity of the tubular knitted fabric is improved, so that this is preferred.

[0029]

In a place requiring higher durability, it is also possible to block carboxyl-terminal groups in the filament fiber comprising the aliphatic polyester. The carboxyl terminal concentration is preferably 30 equivalents/ton or less based on the whole fiber. Hydrolysis of the polylactic acid fiber can be suppressed by adjusting it to 30 equivalents/ton or less, and the moderate rate of degradation can be obtained, when used as the vegetation bed. Further, although it is sometimes used at a slowed rate of degradation depending on the intended use, it is preferably 10 equivalents/ton or less in that case.

[0030]

As an agent for blocking the carboxyl-terminal groups, it is preferred to select a tri- or more functional epoxy compound as a terminal-reactive material. Further, it is preferred from the viewpoint of improving hydrolysis resistance that the tri- or more functional epoxy compound is allowed to react with at least a part of the polylactic acid, desirably at least a part of terminals of the polylactic acid. The tri- or more functional epoxy compound is a compound having three or more epoxy groups in one molecule thereof.

[0031]

Although the total fineness of the filament fiber (the fineness of a knitting yarn) comprising the aliphatic polyester is not particularly limited, it is preferably from about 50 to 300 decitex. The thickness of this knitting yam may be appropriately selected depending on the gauge of a knitting machine used, the type of a desired knitted fabric, and the like. However, if one that is too thin is used, the strength of the tubular knitted fabric tends to become weak. Further, if one that is too thick is used, knitting becomes difficult. Furthermore, the grade of the resulting knitted fabric is deteriorated, and the tubular knitted fabric tends to become coarse and stiff. As a result, it is sometimes deteriorated in handling ability when the vegetation bed form is used later. The more preferred range of the total fineness of the polylactic acid multifilament fiber used as the knitting yam is from 100 to 200 decitex.

[0032]

The monofilament fineness of the filament fiber comprising the aliphatic polyester is preferably from about 1 to 10 decitex. If one that is too thin is used, the strength of the circular knitted fabric becomes weak due to the occurrence of fluffs, and the like, during handling or during the use as the vegetation bed form body. Further, if one that is too thick is used, the circular knitted fabric tends to become coarse and stiff, and therefore, handling in subsequent construction work of the vegetation bed form body becomes not easy. Taking into consideration biodegradability, ultraviolet deterioration resistance characteristics and the like, it is more preferably from about 3 to 5 decitex.

[0033]

As the configuration of the multifilament yam comprising the aliphatic polyester, the followings are exemplified: a straight drawn yam having no crimp, a false-twisted textured yarn having bulkiness and stretchability caused by crimps given by heat and twists after formation of a multifilament yam in a straight state, a bulky textured yarn having loop-shaped fluffs in a longitudinal direction of a side surface of the yarn by utilization of air turbulent flows, and various textured yams represented by a different shrinkage filament mixed yam obtained by mixing different material filaments.

[0034]

From the handling ability, ease of taking roots of a plant, and the like, it is preferred to use a bulky false-twisted crimped textured yarn having fine and uniform three-dimensional crimps (spiral crimps). The false-twisted textured yam has both bulkiness and stretchability, so that the whole knitted fabric is softened by this yarn, and spaces between knitted stitches and spaces between filaments are relatively freely movable. The roots of the plant pass therethrough to easily take roots. This is therefore preferred.

[0035]

If the false-twisted crimped textured yam is used as the multifilament fiber yam comprising the aliphatic polyester, the CR value (the index value for indicating the crimp fastness) as an index of crimp properties is preferably 10% or more. If the CR value is 10% or more, good bulkiness and stretchability are obtained in the tubular knitted fabric. The CR value is preferably 15% or more, and more preferably 20% or more, and the upper limit of the preferred range is 40%.

[0036]

Further, if the boiling water shrinkage rate of the multifilaments comprising the aliphatic polyester is 25% or less, dimensional stability of the tubular knitted fabric is good. This is therefore preferred. The boiling water shrinkage rate is more preferably 20% or less, and still more preferably 18% or less, and the lower limit of the preferred range is 3%.

[0037]

In the tubular knitted fabric formed of the multifilaments comprising the aliphatic polyester, it is preferred that the bursting strength of the knitted fabric based on JIS L 1096 (2010) is adjusted to 500 kpa or more. If this breaking strength is too small, there is a possibility that the tubular knitted fabric of the vegetation bed form is broken when the tubular knitted fabric is filled with the culture, during transportation of a plant after raising seedling, and further during installation after transportation. This breaking strength is preferably 550 kpa or more. Further, although the upper limit of the bursting strength is not particularly limited, it is generally preferably up to about 2,000 kpa. It is considered that the bursting strength of a level exceeding that is generally unnecessary, and even up to about 1,000 kpa is practically sufficient in a usual case. Furthermore, the air permeability of the tubular knitted fabric is preferably from 50 to 500 cc/cm2/sec. When the vegetation bed is formed, an air permeability of less than 50 cc/cm2/sec causes a problem that roots of a plant do not grow into the tubular knitted fabric, and the growth of a plant generally becomes poor because of poor air permeability and poor water permeability. It is particularly preferably from 100 to 400 cc/cm2/sec.

[0038]

Further, the basis weight of the tubular knitted fabric is preferably light in weight during transportation, and preferably from 10 to 30 g/m. The “basis weight of the tubular knitted fabric” in the present invention is represented by weight (g) per unit length (m), while that of common fiber fabrics is represented by weight per unit area. Furthermore, the tubular diameter of the tubular knitted fabric is preferably from 10 to 40 cm as the width of the knitted fabric when the cylinder is squashed.

[0039]

It is preferred that the tubular knitted fabric formed of the multifilaments comprising the aliphatic polyester is excellent in ultraviolet deterioration resistance characteristics, is less likely to deteriorate against ultraviolet irradiation, and is strong. When a deterioration test according to a sunshine weather meter test based on JIS B 7753 (2007) is performed as a factor of the ultraviolet deterioration resistance characteristics, the bursting strength retention rate after 450 hours is preferably 70% or more. According to the finding of the present inventors, if the bursting strength in the test is 70% or more, the configuration can be maintained for 2 years or more in the case where the vegetation bed is used in a place exposed to sunlight outdoors for equal to or more than half a day. It is more preferably 80% or more.

[0040]

The culture to be filled is preferably one excellent in nutrient retention rate and water retention ability, and natural soils such as Akadama (red granular) soil, black soil and Kanuma soil, artificial soils such as leaf mold, bark compost, vermiculite and peat moss, in addition, sawdust, charcoal, cinder of coal, mixtures thereof and the like may be appropriately used, depending on a place or a plant. Further, in the case of use in a low-rainfall desert area or the like, it is also possible to mix a water absorptive polymer as a part of the filler to use.

[0041]

As the method for filling the tubular knitted fabric with the culture, it is preferred that one side of the tubular knitted fabric cut to a predetermined length is tied, it is put over a plastic tube of about 1 m, the filler is fed from a mouth of the plastic tube, and the other side of the tubular knitted fabric on the opposite side is tied after filling with the filler, thereby completing filling.

[0042]

In the vegetation bed of the present invention, it is important that the tubular knitted fabrics formed of the multifilaments comprising the aliphatic polyester are filled with the culture, and are adjacently apposed.

[0043]

The vegetation bed is constituted of the tubular knitted fabric, and knitted stitch loops have shrinkage properties. Accordingly, the vegetation bed is capable of allowing roots of a plant to pass therethrough with growth of the plant, but not allowing soil to leak. Further, the knitting yams linked by the loops can be movable, so that it does not happen that a bending portion is broken when adjacently apposed.

[0044]

In the case of the adjacently apposing, its configuration is not particularly limited, and any configuration such as the quadrilateral vegetation bed as a whole in which the tubular knitted fabric filled with the culture is folded in a zig-zag manner (FIG. 2(a)), the circular vegetation bed in which the knitted fabric is placed in a spiral form (FIG. 2(b)), the vegetation bed in which the knitted fabrics are linearly apposed two by two next to each other (FIG. 3) or the vegetation bed in which three or more of the knitted fabrics are apposed (FIG. 1), can be taken.

[0045]

Further, use of the tubular knitted fabric filled with the culture makes it possible to obtain moderate air permeability and water retention ability. For water retention ability, excess water is discharged from a side surface of the tubular knitted fabric when much water is contained. On the other hand, during drying, the culture can be suppressed from being dried by preventing light from the sun with the knitted fabric.

[0046]

As the culture to fill the inside of the tubular knitted fabric, one different from the soil constituting the ground on which the vegetation bed is placed may be used.

Then, soil improvement and modification of that land can also be promoted in parallel with cultivation of plants by filling the healthy soil and culture not having a problem such as contamination to use, and it is also possible to achieve desired soil improvement after several years.

[0047]

As shown in FIG. 1, FIG. 2(a) and FIG. 2(b), the culture and plant seeds or seedlings are put in the concave portion formed on/above the boundary surface between the tubular knitted fabrics apposed next to each other, and raising seedling can be performed by germination and entering of roots of the planted seedlings into the tubular knitted fabric from the knitted stitches thereof. This method is one preferred use method.

[0048]

By accumulating the culture in the concave portion and planting the seeds or the seedlings in this manner, drying of the seeds is prevented, or the roots become easy to enter the vegetation bed, thereby improving plant germination or growth. Further, one plant root grows into each of the vegetation beds next to each other, thereby being able to firmly integrate the apposed tubular knitted fabrics. After the plant has been subjected to raising seedling or allowed to grow for a predetermined period, the vegetation bed as a whole can be easily moved to another place, followed by installing it therein.

[0049]

As another use method, as shown in FIG. 3, a use method of disposing two or more tubular knitted fabrics 1 next to each other as close as possible, so as rather not to form, to the utmost, the concave portion produced on/above the boundary surface formed by the side surfaces of the two or more tubular knitted fabrics next to each other, and planting the seeds or the seedlings in an upper portion 5 in that boundary surface, can be taken. By such use, an effect similar to that of the case of forming a ridge in a field and planting seeds or seedlings in the center thereof can be obtained. FIG. 3 shows an example in which two ridges are formed by using four tubular knitted fabrics in such a manner.

[0050]

When thus used so as to constitute the ridges in the field, it is possible to cultivate a plant in the same manner as in the ridges in the field. Further, it is also possible to increase or decrease the distance therebetween or to move the vegetation bed on the basis of the vegetation bed unit, depending on the growth of the plant, the season and the like. Thus, the cultivation of a more optimum plant (e.g. agricultural crop) can be controlled. For example, the same plant can also be raised in the same place every year, while preventing injury by continuous cropping.

[0051] FIG. 4(a) and FIG. 4(b) each shows an example of a state where the vegetation bed of the present invention is used so as to constitute a ridge in a field, and are each a partial perspective view in cross section in which a state thereof placed on the ground is viewed from obliquely above. The tubular knitted fabrics are placed straight in parallel two by two to form one ridge-like shape and a plurality of sets having such a shape are arranged in parallel at appropriate intervals. In this case, it shows an example of forming a field having several ridges over a wide area. FIG. 4(a) corresponds to the use method of the case shown in FIG. 1, and FIG. 4(b) corresponds to the use method of the case shown in FIG. 3. The shape of the ridge to be formed may be either straight or appropriately curved depending on the land form. If a plant is cultivated in this way, it becomes easy to perform cultivation in a desired culture, while enjoying an advantage of cultivating the plant in the ridge.

[0052]

The kind of plant allowed to vegetate using the vegetation bed of the present invention is not particularly limited, and various short grasses and flowers can be cultivated, such as lawn grasses such as Korean lawn grass and Noshiba (Japanese lawn grass), sedums such as Sedum mexicanum, Sedum morimura, Sedum reflexum and Sedum coral carpet, herbs such as lavender, cotton lavender and rosemary, and hederas. Such a use method that the vegetation bed thoroughly covers a specific region of the ground, as shown in FIG. 2, is suitable for such plants.

[0053]

Further, under a combination with a desired culture, various agricultural crops and vegetables such as com, spinach, strawberry, eggplant, tomato and cabbage and plants such as sunflower, field mustard, lupine and cosmos can also be cultivated. For cultivation of such agricultural crops, vegetables and plants, it is suitable to use in such a manner as to form the ridge-like shape in the field as shown in FIG.3 and FIG. 4.

[0054]

That is to say, the desired plant (mainly the agricultural crop cultivated in the field) can be cultivated in the ridge formed by the controlled desired culture particularly by arranging the vegetation bed in the ridge shape, and the agricultural crop can be allowed to grow under optimum conditions of the controlled culture (soil), place and the like.

[0055]

Further, also when a home vegetable garden or a flowerbed is made in a narrow place limited and originally having no soil, the method of the present invention is effective, and the use methods as shown in FIG. 2, FIG. 3, FIG. 4 and the like are each optimum.

[0056]

Furthermore, a picture, a pattern and the like can also be relatively easily drawn on a surface of the ground as desired by forming vegetation by changing plants different in color of flowers or leaves for each vegetation bed.

[0057]

In addition, a maze using a tall plant such as sunflower, field mustard or cosmos, can also be easily formed by placing the vegetation beds of the present invention according to the shape of the maze and cultivating the plant.

[0058]

Further, it is also possible to plant seeds or seedlings in the vegetation beds of the present invention, to grow them to a certain size under optimum conditions of a greenhouse or the like, to transport or move the whole vegetation beds after the growth to the certain size, and to cover a wasteland or desert necessary to be greened with the whole vegetation beds, followed by allowing the plant to grow, or to perform open culture or greenhouse culture.

[0059]

The place where the vegetation bed is installed is not particularly limited. It is also possible to grow a plant by installation thereof in a wasteland or desert where the plant is difficult to grow or on a slope where the land is liable to slide, or on the ground paved with asphalt or concrete.

[0060]

Further, when used in a dry region, it is also possible to water the vegetation beds installed next to each other through a perforated tube. In that case, when the vegetation beds are watered, it is only necessary to water a smaller area than the case of directly watering the ground, because the internal filler has a water-retaining function. Thus, water can be saved.

[0061]

After the vegetation bed of the present invention is installed in a wasteland or the like, roots of the plant can further grow from the culture of the vegetation bed into the ground through the knitted fabric depending on the kind of the plant. Further, the knitted fabric of the present invention almost completely biodegrades 5 to 10 years after installation, resulting in disappearance thereof, so that thereafter, the plant grows in the periphery of the remaining culture.

[0062]

After the vegetation bed of the present invention is installed in an agricultural land, it can be used in such a manner that biodegradation completely proceeds. Alternatively, the vegetation bed can also be appropriately replaced depending on a cultivating crop, before it completely biodegrades.

Examples [0063]

The present invention is described in more detail below with reference to examples, but the present invention should not be construed as being limited to these examples.

[0064]

The parameters in the above-mentioned description are values measured as follows.

[0065] A. Weight average molecular weight of polylactic acid A solvent obtained by dissolving an aliphatic polyester in a chloroform solution. Using gel permeation chromatography (GPC), this was subjected to measurement using chloroform as a carrier solvent, and the weight average molecular weight was determined in terms of polystyrene.

[0066] B. Width of tubular knitted fabric A tubular knitted fabric was cut open at a center thereof, and the width thereof was measured. The average was determined, taking the number of n as 5.

[0067] C. Boiling water shrinkage rate

The boiling water shrinkage rate is a value determined by the following equation:

Boiling water shrinkage rate (%) = [(L0-Ll)/L0]x 100 wherein LO is an original length of a hank obtained by reeling a drawn yarn, which is measured under an initial load of 0.09 cN/dtex, and LI is a length of the hank after the hank measured for L0 is treated in boiling water in a substantially load free state for 15 minute and dried in air, which is measured under an initial load of 0.09 cN/dtex.)

The sample length of the hank was 40 cm, and the average value was determined, taking the number of n as 5.

[0068] D. CR value of false-twisted crimped textured yarn A false-twisted crimped textured yarn was reeled, treated in boiling water in a substantially load-free state for 15 minutes, and dried in air for 24 hours. This sample was subjected to a load corresponding to 0.088 cN/dtex (0.1 gf/d) and immersed in water, and the hank length L’0 after 2 minutes was measured. Then, the hank corresponding to 0.0088 cN/dtex was removed in water, and exchanged to a minor load corresponding to 0.0018 cN/dtex (2 mgf/d), and the hank length L’ 1 after 2 minutes was measured. Then, the CR value was measured by the following equation: CR (%) = [(L’0-L’l)/L’0]xl00 (%)

[0069] E. Breaking strength

The bursting strength is the value measured by JIS L 1018 8. 17. 1 Method A (Mullen type method).

[0070] F. Air permeability

The air permeability is the value measured by JIS L 1906 (Frajour) method.

[0071] G. Ultraviolet deterioration test A tubular knitted fabric was irradiated for 450 hours in accordance with JIS B 7753 under the conditions of one cycle of irradiation 180 min/rainfall 12 min, a black panel temperature of 63°C and a humidity of 50% Rh, using a sunshine weather meter (manufactured by Suga Test Instruments Co., Ltd.). The bursting strength was measured before and after the irradiation to thereby determine the strength retention rate (%). The average value was determined, taking the number of n as 5.

[0072] H. Carboxyl terminal concentration

The carboxyl terminal concentration was determined by dissolving a sample precisely weighed in o-cresol (water content: 5%), adding an appropriate amount of dichloromethane to this solution, and thereafter, performing titration with a 0.02N KOH methanol solution. At this time, oligomers such as a lactide as a cyclic dimer of lactic acid are hydrolyzed to produce carboxyl terminals, so that the carboxyl terminal concentration of the totaled all carboxyl terminals of the fiber is determined.

[0073] I. Evaluation of vegetation bed A tubular knitted fabric was filled with a commercially available culture, spirally arranged outward, centered on an end thereof, and placed so as to be next to each other. Seeds of Kamchatka stonecrop (a perennial) were planted at 15-cm intervals in a center of a concave portion where the knitted fabric is next to each other, and allowed to stand outdoors on a base having a concrete surface. Water was periodically sprayed to perform cultivation. After 2 months, the cultivated plant was moved together with the vegetation bed, which was installed on the ground. Transportability was evaluated, and the cultivation state and the appearance of the vegetation bed after 1.5 years were confirmed. Ranking evaluation of 4 stages was performed by the following criteria:

Excellent: the growing state is very good, there is no change in the appearance of the vegetation bed at all, and portability is good.

Good: the growing state is good, there is no change in the appearance of the vegetation bed, and portability is good.

Ordinary: Although the growing state is somewhat poor, there is no change in the appearance of the vegetation bed, but it is difficult to carry.

Bad: the growing state is bad, and the vegetation bed is significantly deteriorated to retain no appearance, or it is difficult to carry.

[0074] [Production of polylactic acid and the like] (a) Production Example 1 (Production of polylactic acid) A lactide produced from L-lactic acid having an optical purity of 99.5% was polymerized in the presence of tin bis(2-ethylhexanoate) catalyst (lactide:catalyst molar ratio = 10000:1) under a nitrogen atmosphere at 180°C for 140 minutes to thereby obtain polylactic acid PI. The weight average molecular weight of polylactic acid obtained was 145,000.

[0075] (b) Production Example 2 (Production of polylactic acid containing 4% by weight of EBA)

Polylactic acid PI and ethylenebisstearic acid amide (EBA) [trade name “ALFLOW H-50S” manufactured by NOF Corporation] were dried, and thereafter, supplied to a twin-screw kneading extruder having a cylinder temperature of 220°C, while metering and continuously adding heat-melted EBA to PI so as to give PI :EBA=96:4 (weight ratio), thereby obtaining polylactic acid P2 containing 4% by weight of EBA.

[0076] (c) Production Example 3 (Production method of polylactic acid multifilaments)

The raw materials were chip-blended so as to give polylactic acid PI : polylactic acid P2 = 3:1 by weight ratio (EBA: 1.0% by weight), dried under vacuum with stirring at 100°C for 8 hours, and thereafter, melted and extruded through an extruder type melt extruder at 220°C. Then, the melt polymer was introduced to a spinning pack mounted in a spin block heated at 220°C, and a yam was spun from a spinneret having a hole diameter of 0.3 mm, a hole depth of 0.5 mm and the number of holes of 26, followed by taking up at a spinning speed of5,000 m/min to thereby obtain an undrawn yam. Spinnability was good, no occurrence of yarn breakage and fluff was observed, and there was little smoke generation just under the spinneret. Further, the undrawn polylactic acid yarn was unwound, and the physical properties thereof were measured. As a result, the total fineness was 117 dtex, the boiling water shrinkage rate was 15%, and the carboxyl terminal concentration was 22 equivalents/ton.

[0077]

Then, two of the undrawn yarns were paralleled, and subjected to draw friction false twisting (draw textured yarn (woolly yarn) processing) with a draw friction false twisting machine (belt type) at a draw ratio of 1.5 times and a heater temperature of 120°C to thereby obtain a false twisted crimped textured yam of 167 decitex and 52 filaments. Productivities were also good, and no attachment of tar and scum on a heater, a twister, various kinds of guides and the like occurred. Thus, stable processing was possible.

[0078]

The boiling water shrinkage rate of the resulting false twisted crimped textured multifilament yam (167 decitex, 52 filaments) was 8.2%, and the CR value was 18%. Thus, it showed excellent dimensional stability and crimp property.

[0079]

Example 1

The polylactic acid multifilament yam obtained in Production Example 3 was knitted with a 22 gauge circular knitting machine (width: 17 cm) having a cylinder diameter of 3.5 inches to thereby prepare a tubular knitted fabric having a basis weight of 15 g/m, a breaking strength of 554 kpa and an air permeability of 311 cc/cm2/sec, and further, this tubular knitted fabric was filled with a commercially available culture soil to prepare a vegetation bed form (length: 3 m). Further, the strength retention rate of the resulting tubular knitted fabric after the ultraviolet deterioration test was as very good as 80%.

[0080]

Furthermore, the field test according to “I. Evaluation of vegetation bed” described above was performed for the resulting vegetation bed. As a result, the growing state was very good, there was no change in the appearance of the vegetation bed at all, and the evaluation result was “excellent”.

[0081] A part of the vegetation bed subjected to the field test was transported and installed for the purpose of wasteland greening. There was no breakage during transportation, and installation properties of the vegetation bed were also good.

[0082]

Example 2

Two of the false-twisted crimped textured yams used in Example 1 were paralleled and knitted using the same circular knitting machine as in Example 1 to thereby prepare a tubular knitted fabric (width: 11 cm) having a basis weight of 45 g/m, a breaking strength of 2080 kpa and an air permeability of 59 cc/cm2/sec, and further, this knitted fabric was filled with a commercially available culture soil to prepare a vegetation bed form (length: 3 m). Further, the strength retention rate of the resulting tubular knitted fabric after the ultraviolet deterioration test was as good as 78%.

[0083]

Furthermore, the field test according to “I. Evaluation of vegetation bed” described above was performed for the resulting vegetation bed. As a result, the growing state was somewhat poor, because of its lower air permeability than in the case of Example 1, but there was no change in the appearance of the vegetation bed, and the evaluation result was “good”.

[0084]

Example 3

In the vegetation bed of Example 1, a culture was put in a concave portion formed on/above the boundary surface, and the field test was performed. As a result, the growing state was very good, there was no change in the appearance of the vegetation bed at all, and the evaluation result was “good”.

[0085] A part of the vegetation bed subjected to the field test was transported and installed for the purpose of wasteland greening. There was no breakage during transportation, and installation properties of the vegetation bed were also good.

[0086]

Example 4 A culture soil was put in the tubular knitted fabrics comprising the polylactic acid multifilaments, which were used in Example 1, to prepare a plurality of linear vegetation beds having a length of 20 m. The resulting vegetation beds were adjacently apposed on asphalt as shown in FIG. 4(a), and a culture soil was put in a concave portion formed in the upper portion 5 in the boundary surface between the tubular knitted fabrics next to each other as shown in FIG. 4(b). Corn seeds were planted therein to cultivate com. As a result, the growing state was very good, and there was no change in the appearance of the vegetation bed at all.

[0087]

Comparative Example 1 A commercially available false-twisted crimped textured polyester yam (draw textured yarn (woolly yarn) processing type) of 167-decitex and 48-filament was knitted wih a 22 gauge circular knitting machine having a cylinder diameter of 3.5 inches to thereby prepare a tubular knitted fabric (width: 17 cm) having a basis weight of 15 g/m, a breaking strength of 604 kpa and an air permeability of 289 cc/cm2/sec, and further, this tubular knitted fabric was filled with a commercially available culture soil to prepare a vegetation bed (length: 3 m).

[0088]

The strength retention rate of the resulting tubular knitted fabric after the ultraviolet deterioration test was 46%, and the ultraviolet deterioration was large.

[0089]

Further, the vegetation bed was formed into a circular form and subjected to the field test according to the above-mentioned “I. Evaluation of vegetation bed”. As a result, a part of the vegetation bed not covered with the plant was deteriorated by ultraviolet rays of the sun to fail to retain the shape, resulting in an inferior result.

Thus, the evaluation result was “bad”.

[0090]

Comparative Example 2

Using the same tubular knitted fabric (width: 17 cm) as in Example 1, a vegetation bed form was formed, and seeds were placed, without being embedded, in the concave portion of the vegetation bed rolled and adjacently apposed. The seeds moved during water spraying because the seeds were not embedded, resulting in biased germination. Accordingly, the growing state was somewhat poor, and further, the vegetation bed rolled and adjacently apposed was not sufficiently joined by roots, so that transportation thereof was difficult. Thus, the evaluation was “ordinary”.

[0091]

Comparative Example 3

Using the tubular knitted fabric comprising the polyester used in Comparative Example 1, the cone cultivation was performed in the same manner as in Example 4.

However, the tubular knitted fabric comprising the polyester was partially deteriorated by ultraviolet rays to get a hole therein, and the culture soil put in the tubular knitted fabric was leaked and blown about by wind to thereby change the configuration of the vegetation bed. There was therefore brought about a state where the plant fell down or the like to cause a poor cultivation state. Thus, the evaluation result was “bad”.

[0092]

While the present invention has been described in detail with reference to particular embodiments, it is obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention.

This application is based on Japanese Patent Application No. 2011-225798 filed on October 13, 2011, the contents of which are incorporated herein by reference.

Description of Reference Numerals and Signs [0093] 1: Tubular knitted fabric 2: Culture (in a tubular knitted fabric) 3: Culture (on a concave portion of a tubular knitted fabric) 4: Ground 5: Upper portion in a boundary surface of tubular knitted fabrics next to each other

Claims

1. A vegetation bed, in which a tubular knitted fabric knitted with a multifilament fiber comprising an aliphatic polyester is adjacently apposed and an inside of the knitted fabric is filled with a culture, the vegetation bed has a boundary surface between the tubular knitted fabrics which are adjacent to each other, and a seed or a seedling is placed on/above the boundary surface.

2. The vegetation bed according to claim 1, wherein the aliphatic polyester comprises a polylactic acid.

3. A method for producing the vegetation bed according to claim 1 or 2, the method comprising: filling an inside of a knitted fabric with a culture, thereby obtaining a tubular knitted fabric; apposing the tubular knitted fabrics adjacently, thereby forming a boundary surface between the tubular knitted fabrics which are adjacent to each other; and planting a seed or a seedling on/above the boundary surface.