AU2012202670C1

AU2012202670C1 - Plant Treatment Material

Info

Publication number: AU2012202670C1
Application number: AU2012202670A
Authority: AU
Inventors: Jonathan Dallas Toye
Original assignee: Nine IP Ltd
Current assignee: Nine IP Ltd
Priority date: 2004-07-22
Filing date: 2012-05-03
Publication date: 2020-06-11
Anticipated expiration: 2025-07-22
Also published as: AU2012202670B2; AU2011203080B2; AU2011203080A1; AU2012202670A1

Abstract

- 18 Areflective woven ground cover sheet material woven from warp and weft tapes and in which the thickness of warp tapes is increased in longitudinally extending opposite side 5 margins of the material relative to the thickness of warp tapes in a longitudinally extending centre section between the side margins of the material.

Description

FIELD OF INVENTION

The invention relates to woven materials and particularly but not exclusively to woven materials for use as ground covers or other agricultural applications.

BACKGROUND

Ground cover materials have been used in agriculture for a number of purposes. These include moisture retention, water conservation, weed or sward suppression, soil warmth retention and for Eght reflecting.

Typically where the material is used primarily as a reflective ground cover for light enhancement, tire material is rolled out in lengths onto the ground between rows of trees in an orchard, rows of tunes in a vineyard, or rows of berry fruit plants for example, to increase tire amount of light to which the plants and in particular fruit are exposed, by reflection of light from the material towards the fruit above. Each length of the material needs to be suitably secured in place such that it will not be dislodged during wind or movement of traffic over the materials. A fastening system including a multiple number of prong fastening components or “claws” may be fixed to the edges or side margins of tire sheet material by pushing the prongs of tire fastening components into the material so that prongs pierce and pass through the material. In turn the prongs are fixed to adjacent trees, or alternatively stakes or pegs inserted for that purpose, typically but not necessarily by a length of elastic cord.

The sheet material will lypicdly remain in place for some months, before being removed and reused in a subsequent growing season or on another crop in die same growing season. During the period in which the material is in place fixed to the ground wind may apply substantial loading to the fastening system by which the material is fixed to the ground.

SUMMARY OF INVENTION

In broad terms in one aspect the invention comprises a reflective ground cover sheet material woven from warp and w^Teft tapes of a plastics material in which the thickness of warp tapes is increased in longitudinally extending side margins of the material relative to

COMS ID No: ARCS-367514 Received by IP Australia: Time (H:m) 13:16 Date (Y-M-d) 2012-05-03

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-3the thickness of warp tapes in a longitudinally extending centre section between tire side margins of the material.

In some embodiments the longitudinally extending opposite side margins of the sheet material are stronger than a longitudinally extending centre section between the side margins of the material.

In some embodiments the width of warp tapes is reduced in longitudinally extending opposite side margins of the material relative to the width of warp tapes in a longitudinally extending centre section between the side margins of the material.

In some embodiments the chemical composition of warp tapes in longitudinally extending opposite side margins of the material is different to that of warp tapes in a longitudinally extending centre section between the side margins of the material to strengthen the side margins of the material relative to the longitudinally extending centre section of the material, or to increase the resistance of the side margins of the material to strength degradation from exposure to the external environment and/or aging, relative to said longitudinal centre section of the material.

In some embodiments longitudinally extending opposite side margins of the material have had applied thereto one or more agents to strengthen the side margins of the material relative to a longitudinally extending centre section of the material, or to increase the resistance of the side margins of the material to strength degradation from exposure to the external environment and/or aging, relative to said longitudinal centre section of the material.

In some embodiments the side margins extend up to about 300 mm in from either side edge of the material.

In some embodiments the side margins extend up to about 200 mm in from either side edge of the material.

In some embodiments the side margins extend up to about 150 mm in from either side edge of the material.

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-4ln some embodiments the warp tapes in the side margins have a width between about 1 and about 3 mm ad the warp tapes in the balance of the sheet material have a width between about 3 and about 5mm.

Preferably the warp and weft tapes have not been folded or twisted during weaving or have been folded or twisted minimally, so that there is not more than one fold or twist per 10m² surface area of the material at least in the centre section of the material.

Preferably the warp and weft tapes are substantially flat.

Preferably the warp and weft tapes are made of plastic material.

In some embodiments die transition between an inner edge of each side margins and the centre section of the material is marked by a line or other marking of contrasting colour.

In some embodiments the colour of all of the warp tapes in the side margins contrasts to that of the balance of the sheet material.

In one form said one or more agents are incorporated in a resin from which warp tapes of a plastics material of the side margins of the material are formed. An increase in resistance of the side margins to strength degradation can come from the type or concentration of light or heat stabilisers used, or by the type of polymer resins or additives to the main polymer resin, for these side margin tapes in die warp direction. Alternatively for example said one or more agents may be sprayed or otherwise overcoated onto the side margins of the material after manufacture of the material.

Preferably said one or more agents includes at least one light or heat stabiliser or processing aids which will increase the resistance of the side margins of die material to degradation through exposure from solar radiation or heat or chemical or environmental degradation in an external environment. Additionally or alternatively said one or more agents include at least one agent which increases the strength of a plastic material from which the side margins are formed. Another agent to increase the strength of the side margin could be the use of different polymers from the mam body of the fabric. These polymers could be either on their own or in combination polypropylene, polyester,

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2012202670 03 May 2012

- 5 polyethylene, polyvinyl acetates, low density polyethylene, linear low density polyethylene, ethylene butyl acrylate, ethylene methyl acrylate, polystyrene, styrene-butadiene, actylonitrile-butadiene-styrcne, styrene-acrylonitrile, polyethylene terephthalate, polymethylmethacrylate, polycarbonate, and ethylene alpha-olefin.

Preferably tire material has a width across a longitudinal axis of the centre section which is greater than die combined widths of the two longitudinally extending opposite side margins of the material.

In tire material of at least these embodiments the side margins of the material may be stronger than the balance of die material, so that when the sheet is fixed in place as referred to previously, the increased strength of the side margins provides more secure fixing of die material with reduced risk of tearing or enlargement, especially when under load, of the holes formed when the prongs pierce through the material. The approach here is to increase the strength of the weakest link of the material that affects its longevity, to give an overall material with a longer life in order to give users a useful choice to extend the life of the material. Alternatively the side margins of the material may have equivalent strength to that of the centre section of the material initially, but the side margins are mote slowly degraded from exposure to the external environment such as solar radiation, or from aging generally, and maintain dieir strength for longer, so that the material will remain securely fixed with reduced risk of tearing or enlargement of the holes formed in the side margins of the material when the prongs pierce through the material, then the material is subjected to wind loading for example. It may also be possible to reuse the material for more subsequent seasons than would otherwise be the case and thus achieve a longer useful life from the material.

By “porosity” is meant the percentage of the surface area of the material which is made up of holes or apertures through the material·, between spaced apart watp and weft tapes of the material for example, relative to the overall surface area of the material. For example a 30 material having watp and weft tapes spaced apart from each other so that the air space between the warp and weft tapes constitutes 8% per square metre surface area of the material will have a porosity of 8%. The porosity is made up of small evenly spaced apertures rather than large holes. Thus the porosity is generated by weaving the tapes so

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-6tliat there is some free space between the tapes, such that they are not butted up hard against each other as is the current practice.

By having a low porosity with the tapes butted up hard against each other, this leads to twisting during manufacture. This twisting and folding generates areas for dirt to collect. This reduces the light reflectivity and/or light transmission of the material or otherwise reduce the reflectivity or strength or life of the material

By “reflective” in general is meant that the material is reflective of at least 50% of visible light on at least one side of the material.

Generally it is considered essential for ground cover materials to be either extruded film materials or tightly woven materials having minimal porosity, to effectively suppress weed growth and/or maximise light reflection from the upper surface of the material. The material of the invention may be formed so as to have acceptable reflectivity while also a relatively high porosity of the material, which reduces the sail-effect of the material during windy periods as wind or air may pass through the more porous material, and reduces the mechanical loading on the fixing system which fixes the material in place and therefore reduces the likelihood of the material becoming dislodged and/or damage to the material and/or the fixing system. Additionally a more porous material allows more air movement between the ground and the air above the ground cover. Also with reflective ground covers diere can be occasions where excessive moisture is beneath the material, which can be a disadvantage particularly when the material is laid between rows of trees or vines or plants, and tractor movement over the material occurs. Excessive soil moisture beneath the ground covet can lead to tractor wheel marking and soil compaction. With a more porous material of the invention water from irrigation or rainfall can pass more readily and rapidly through the ground cover material, so that ponding (or where water from rainfall ot irrigation tuns across the material to collect at the lower areas) of water on the material is reduced, which can result in uneven water distribution to the soil underneath the material.

Typically' sheet materials of the invention will be laid out in lengths on the ground between rows of the crop being grown, which may be trees, vines, bushes etc, to increase the amount of light to which the plants and in particular the fruit are exposed, by reflection of the light from the material back up towards the crop above, and the materials are referred

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- 7to in the specification as “ground covet sheet materials”. It is possible however that the materials may be suspended or positioned above the ground in a vertical or angled position to reflect the solar radiation onto the crop, for example on either side of the crop row, for example trees, and held in position by guy ropes or attached to wires that are positioned along the row direction or poles ot a frame, and the expression “ground cover sheet material” is intended to encompass materials for such applications also.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described by way of example with reference to the accompanying drawings in which:

Figure 1 shows use of a ground covet material and fixing of the ground cover material in place by the use of a claw and cord system, including a fastening component that penetrates the side margins of die material;

Figure 2 shows a single fastening component;

Figure 3 shows a section of woven material according to one aspect of the invention;

Figure 4 shows a construction of the side margin of the material with a marker tape 40mm in from the edge marking die start of the fastener attachment area and another marker tape 160mm in from the edge marking die end of the fastener attachment area, and a batch market tape;

Figure 5 shows another construction of die side margin of the material with a marker tape 40mm in frotn the edge marking the fastener attachment area on cither side of the marker tape depending on the fastener method;

Figure 6 shows use of a ground cover material according to another aspect of the invention between two rows of trees with an attachment system including fastening components which penetrate reinforced side margins of the material where there is extra strength and lower porosity relative to the central area of the material which has higherporosity.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to Figure 1, agricultural sheeting 1 is anchored underneath agricultural crops such as tows of orchard trees 4 as a ground cover, which typically has reflective properties to

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- 8reflect solas: radiation onto the fruit trees and fruit from below. In Figure 1 only part of the sheeting is shown. Typically long sections of the sheet material are anchored along both edges between rows of orchard trees or vines. The material is woven from flat warp and weft tapes of a plastics material. Fastening claws 20 connect to the sheeting along its edges, and in turn may connect to clips 10 usually by loops or lengths of extensible or optionally inextensible material 30. The clips 10 may in turn attach to staples 5 hammered into the spaced trees 4 as shown, or alternatively to stakes or pegs hammered into the ground, or to a wire extending along the row of die trees or vines, or to twine tied around the tree trunk or vine, for example.

By way of example one form of fastening claw 20 is shown in more detail in Figure 2 and includes two arms 21 which extend to prongs 22 on either side, which prongs are in use forced through and pierce the sheeting 1. The fastening claws or equivalent fastening components may be of other forms however. The claw 20 and clip 10 are shown connected by a loop 30 of extensible or optionally inextensible material.

Figure 3 shows the side margin of one form of sheet material of the invention. The side margin area shown in Figure 3 is the area A indicated and bounded by broken lines in Figure 1. The sheet material is woven from longitudinally extending warp tapes 25a and 25b and transverse weft tapes 26. The tapes are flat plastic tapes either or both of which are formed from a polymer containing pigments which give the ground cover material the desired light reflective and transmissive properties. Typically the tapes are formed by extruding a film material from the polymer resin and then cutting the film into tapes which are in turn used to weave the woven material. The tapes from which the material is woven may be formed by any other suitable process however.

The warp tapes 25a towards the side edge 27 of die sheet material have a reduced width and higher number of warp tapes pet unit area than the warp tapes 25b making up the balance of die sheet material. Typically the width of the warp tapes in the side margins of the material will be 20-80% of the width of the warp tapes of the balance of the material.

In a particularly preferred form the warp tapes 25a tn the side margins of the material will be between 1mm and 9mm in widtii, while the other warp tapes 25b will be between 2mm and 1 Omm width. The weft tapes which extend transversely across the woven material are

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- 9 woven through both the wider warp tapes and the reduced width warp tapes at either side margin of the material. In some cases the reinforced margin may only be required on. one side of the cover.

The width of the warp tapes is reduced so that the material has a higher density of watp tapes, in the side margin between the outer edge of the material generally parallel to the warp tapes to about 40 to 200mm in from either side edge of the material towards die centre of the material.

The side margins of die material, in which the warp tapes are of reduced width and higherdensity, tend to be stronger than the balance of the material with the increased numbet of tape cross overs. When the sheet is fixed in place and using a fixing system including fastening components as shown in Figures 1 and 2 in which prongs or similar fastening components pierce dirough the side margins of die sheeting material, the increased strength of the side margins provides more secure fixing of the material, with reduced risk of tearing or enlargement of the holes formed when die prongs pierce through die material which increases risk of dislodgement of the prongs. At the same time the major part of the sheet material may be woven with warp tapes, and weft tapes, or a greater width than in these side margins, as may be desirable to optimise the reflective and transmissive properties of the material when die material is a reflective ground cover material for example, and/or to give more desired porosity properties. The wider tapes are more suited to give a higher porosity and less physical resistance or less friedon to aid in the air, water, dirt and soil movement through the material.

In an alternative form the warp tapes 25a towards die side edge 27 of the sheet material relative to the warp tapes 25b making up the balance of the sheet material, may be thicket. Typically the w’arp tapes in the side margins of the material will be 10 to 100% and preferably 10 to 50% thicker than the warp tapes of the balance of the material. Again this will strengthen the side margins of die material so that when the sheet is fixed in place using a fixing system including fastening components in which prongs or similar pierce through die side margins of the material, die increased strength of the side margins provides more secure fixing of the material, with reduced risk of tearing or enlargement of the holes formed when the prongs pierce through the material.

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- 10 The warp tapes 25a may be woven with a tighter weave in side margins of the material relative to the weave between the side margins of die material, so that the material has a lower porosity in said side margins of the material than between the side margins of the material. The tighter weave of the material in the side margins will give the side margins increased strength as referred to above.

In the preferred form a single warp tape 25c or a small number of adjacent warp tapes have a contrasting colour to the balance of the warp tapes 25a and 25b, to mark one boundary of the stronger side margin of the material. This defines to a person installing the material the higher strength side margins of the. material through which the fastening claws 20 should be inserted. Optionally a second contrasting colour warp tape or tapes 25d may be provided closer to the edge 27 of the material, to define die other side of die strip extending longitudinally of the edge of the material through which the fastening claws should be inserted. It is not desirable to insert the fastening claw very close to the edge of the material or the fastening claw may pull through or damage the edge of the material. Tape 25d where provided may be positioned 20-60mm for example 40mm, from the edge 27 of the material, and tape or tapes 25c 150-200mm and for example 160mm from the edge 27 of die material. Figure 4 is an example of a construction where marker tape 25d is 40mm in from die edge 27, and then the next marker tape 25c is 160mm from the edge 27 and a batch market tape 25e is 5mm from marker tape 25c (note the drawings are not to exact scale). Alternative to the warp tapes of contrasting colour a line or lines may be printed on the woven material after manufacture or alternatively a strip of a printed pattern or shading may be printed along the either longitudinal side margin of the material to again mark the strip through which it is desirable to insert the fastening components in use. Alternatively again the reduced width warp tapes in the side margins of the material may be formed of a contrasting colour to the balance of the material.

Where the material has a narrower width, of for example about 2.0 metres or less, it may be preferable to fix the material in place with the U-shaped staples which ate inserted through the material in the ground, and in this case the first contrasting colour warp tape or tapes 25c may be positioned between 30 and 60mm. Figure 5 is an example of a construction where the marker tape 25c is 40mm in from the edge 27. In this case the ground staple is placed in the area from the edge of the material 27 to the marker tape 25c, and for the case where a claw is used the prongs pierce in the area on the other side of marker tape 25c.

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- 11 The transition from warp tapes 25a to 25b occurs 60 to 160rnm from marker tape 25c, preferably 60mm.

Preferably woven materials of tire invention are formed from tapes which have not been lengthwise folded or twisted during weaving, or minimally so (for example not more than one fold or twist per Im², more preferably 5m², most preferably 10m² and even more preferably 25m² of material). It is common in the weaving of materials from synthetic tapes for the tapes to be folded lengthwise and crosswise during weaving. Increasing the porosity assists in reduction of folds or twists. As there are no folds for soil and dirt to lodge in and reduce the light reflectivity and/or light transmission of die material or otherwise reduce the reflectivity or strength or life of the material. The resulting reflective ground cover material has a very flat appearance without the folds.

Preferably the centre section of woven materials of the invention is woven from tapes having a width of 3mm or more preferably 3.5mm or greater, or alternatively 4mm or greater or mote preferably 4.5mm or greater, and most preferably between 3.5mm and 4.5mm in width, and the warp tapes in the side margins of the material are of reduced width to increase die side margin strength of the material. Materials formed of such wider tapes allow easier movement of air, water and soil particles through the material. Wider tapes tend to slide mote easily over and away from each other than narrower tapes. (With narrower tapes there are more tape crossovers, this tends to give a tighter construction and the tapes are less prone to slide over each other). At the side margins the material is woven with narrower warp tapes to give a tighter weave and stronger material at die side margins, so that when prongs of a fastening claw or similar device penetrate the material the hole(s) formed will not enlarge easily, to form a more secure connection. For the tapes in the main body of the material away from the edges, more movement in the tapes is acceptable as this movement is associated with more rapid air and water movement, and soil and dirt is less likely to lodge between the tapes where this movement occurs to maintain the reflective and transmission properties.

In another form of the invention the longitudinally extending opposite side margins of the ground cover material incorporate one or more agents which strengthen the side margins of the material relative to a longitudinal centre section of the material, or increase the resistance of said side margins of the material to strength degradation from exposure to the

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- 12extemal environment and/or aging, relative to said longitudinal centre section of the material. Preferably said agent(s) include at least one light or heat stabiliser which will increase the resistance of the side margins of the material to degradation through exposure to solat radiation and temperature in an external environment, such as Irganox 245, Irganox259, Irganox 565, Irganox 1010, Irganox 1035, Itganox 1076, Irganox 1098, Irganox 1135, Irganox 1141, Irganox 1330, Irganox 1425, Irganox 1520, Irganox 3052, Irganox 3114, Irganox 5057, Irganox MD 1024, Irgafos 168, Irgafos DDPP, Irgafos PEPQ, Irgafos TNPP, IrgafosTPP, Irganox PS 800, Irganox PS 802, Irganox B 215, Irganox B 225, Irganox B 551, Irganox B 561, Irganox B 612, Irganox B 900, Irganox B 921, Irganox B 1171, Itganox B 3557, Irganox B 3596, Irganox HP 3560, Irganox HP 2215, Irganox HP 2225, Irganox HP 2921, Ca 100, Chimassorb 119, Chimassorb 944, Nor 371, Tinuvin 123, Tinuvin 144, Tinuvin 622, Tinuvin 765, Tinuvin 770, Tinuvin 783, Tinuvin 791, Chimassorb 81, Tinuvin 213, Tinuvin 234, Tinuvin 320, Tinuvin 326, Tinuvin 327, Tinuvin 328, Tinuvin 329, Tinuvin 350, Tinuvin 360, Tinuvin 492, Tinuvin 494, Tinuvin 571, Tinvin 622, Tinvin 765, Tinuvin 1577, Tinuvin P, Tinuvin B 75, Tinuvin B 241, MD 1024, Ataldite 7072, A0-1, Ni-Quencher, TiO2 and Calcium Sterate. Additionally or alternatively said one or more agents include at least one agent which increases the strength of a plastic material from which the side margins are formed, such as the addition of strength enhancing polymers such as polyester, polypropylene, high density polyethylene, or linear low density polyethylene.

Said agent(s) may be incorporated in a resin from which the warp tapes of the side margins of die material are formed. Alternatively said agentfs) may be applied to the side margins of the material after forming, for example weaving, of the material. The agent(s) may for example be sprayed or otherwise overcoated onto the side margins of the material after manufacture of the material.

Optionally the warp tapes in die side margins of die material may have different reflection or transmission properties from the warp tapes in the centre and major body of the material. For example the warp tapes in the side margins of the material may’ be more opaque, black, cleat or otherwise have different reflection or transmission properties, without significantly compromising the overall effect or performance of the material, as die warp tapes in the side margins represent a relatively'· small percentage of the surface area of the material.

COMS ID No: ARCS-367521 Received by IP Australia: Time (H:m) 13:43 Date (Y-M-d) 2012-05-03

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- 13Typically a ground cover needs properties across its width that vary, thus giving more strength at the edges and higher porosity at the centre. The invention details a method by which a material such as this can be created where previous materials have the same properties across the entire width.

Referring to Figure 6, the material of the invention may be formed so as to have acceptable reflectivity while the relatively high porosity of the material reduces the sail-effect of the material under wind loading as wind or air may pass through the more porous material as indicated by arrows 50 and 51. This reduces the mechanical loading on the fixing system which fixes the material in place. It allows air and moisture movement between the ground and the air above the ground cover. It reduces excessive moisture beneath the material. Irrigation or rainfall water can pass more readily and rapidly through the ground cover material, so that ponding of water on the material is reduced, or water running across the material to collect in areas, which can result in uneven water distribution to the soil underneath the material. Also, soil and dirt can more easily pass through the material with this higher porosity. The areas indicated by 52 in Figure 6 have a lower porosity to give the extra strength required where the material is fastened but the porosity of area 53 is at a suitably higher level.

Ground covet materials may incorporate any one or more of the above aspects of the invention in combination. For example a ground cover material in which tire side margins of the material are woven to have an increased density of warp tapes to strengthen the side margins of the material may also at least in the longitudinally extending centre section of the material be woven with a relatively looser or more open weave so that the material has higher porosity, or perforated to give the material a high porosity. Optionally also in the same material the side margins of the material and for example the warp tapes may be formed from a plastics resin which incorporates one or mote pigments of agents which give the side margins of the material a higher strength, a higher resistance to solar radiation or heat degradation, and so forth.

The foregoing describes the invention including a preferred fomi thereof, alterations and modifications as will be obvious to those skilled in the art are intended to be incorporated in the scope hereof as defined in the accompanying claims.

Claims

1. A reflective woven ground cover sheet material woven from warp and weft tapes and in which the thickness of warp tapes is increased in longitudinally extending side margins of the material relative to the thickness of warp tapes in a longitudinally extending centre section between the side margins of the material, said material having an average porosity of not more than 15%, and in which the longitudinally extending opposite side margins of the sheet material are stronger than the longitudinally extending centre section between the side margins of the material, the material being reflective of at least 50% of visible light on at least one side of the material.

2. A reflective woven ground cover sheet material as claimed in claim 1 in which the width of warp tapes is reduced in said longitudinally extending opposite side margins of the material relative to the width of warp tapes in said longitudinally extending centre section between the side margins of the material.

3. A reflective woven ground cover sheet material as claimed in either claim 1 or 2 in which the chemical composition of warp tapes in longitudinally extending opposite side margins of the material is different to that of warp tapes in a longitudinally extending centre section between the side margins of the material to strengthen the side margins of the material relative to the longitudinally extending centre section of the material, or to increase the resistance of the side margins of the material to strength degradation from exposure to the external environment and/or aging, relative to said longitudinal centre section of the material.

4. A reflective woven ground cover sheet material as claimed in either of claim 1 or 2 in which longitudinally extending opposite side margins of the material have had applied thereto one or more agents to strengthen the side margins of the material relative to a longitudinally extending centre section of the material, or to increase the resistance of the side margins of the material to strength degradation from exposure to the external environment and/or aging, relative to said longitudinal centre section of the material.

5. A reflective woven ground cover sheet material as claimed in any one of claims 1 to 4 in which said side margins extend up to about 300 mm in from either side edge of the material.

6. A reflective woven ground cover sheet material as claimed in any one of claims 1 to 4 in which said side margins extend up to about 200 mm in from either side edge of the material.

7. A reflective woven ground cover sheet material as claimed in any one of claims 1 to 4 in which said side margins extend up to about 150 mm in from either side edge of the material.

8. A reflective woven ground cover sheet material as claimed in any one of claims 1 to

7 in which the warp tapes in the side margins have a width between about 1 and about 3 mm and the warp tapes in the balance of the sheet material have a width between about 3 and about 5 mm.

9. A reflective woven ground cover sheet material as claimed in any one of claims 1 to

8 in which the warp and weft tapes have not been folded or twisted during weaving or have been folded or twisted minimally, so that there is not more than one fold or twist per 10m²surface area of the material at least in the centre section of the material.

10. A reflective woven ground cover sheet material as claimed in any one of claims 1 to

9 woven from warp tapes and weft tapes and wherein the warp and weft tapes are substantially flat.

11. A reflective woven ground cover sheet material as claimed in any one of claims 1 to

10 woven from warp tapes and weft tapes of a plastics material.

12. A reflective woven ground cover sheet material as claimed in any one of claims 1 to

11 in which the transition between an inner edge of each side margin and the centre section of the material is marked by a line or other marking of contrasting colour.

13. A reflective woven ground cover sheet material as claimed in any one of claims 1 to 11 woven from warp tapes and weft tapes and in which the colour of all of the warp tapes in the side margins contrasts to that of the balance of the sheet material.

14. A reflective woven ground cover sheet material as claimed in claim 3 or 4 in which said one or more agents has been incorporated in a resin or similar material from which the side margins of the material are formed.

15. A reflective woven ground cover sheet material as claimed in claim 3 or 4 in which said one or more agents has been sprayed or otherwise overcoated onto the side margins of the material after manufacture of the material.

16. A reflective woven ground cover sheet material as claimed in claim 15 wherein said one or more agents is a plastic material.

17. A reflective woven ground cover sheet material as claimed in claim 16 wherein said one or more agents comprises one or more of polypropylene, polyester, polyethylene, polyvinyl acetates, low density polyethylene, linear low density polyethylene, ethylene butyl acrylate, ethylene methyl acrylate, polystyrene, styrene-butadiene, acrylonitrile-butadienestyrene, styrene-acrylonitrile, polyethylene terephthalate, polymethylmethacrylate, polycarbonate, and ethylene alpha-olefin.

18. A reflective woven ground cover sheet material as claimed in claim 15 wherein said one or more agents include at least one light or heat stabiliser.

19. A longitudinally extending ground cover sheet of a woven reflective material woven from warp and weft elements, the sheet comprising longitudinally extending side margins and a longitudinally extending centre section between the side margins and which has a width across a longitudinal axis of the centre section which is greater than the combined widths of the two side margins, the warp elements having increased thickness in the side margins than the centre section of the sheet, and on at least one side of the sheet being reflective of at least 50% of visible light.