GB2313797A

GB2313797A - Plant root regulating fabric

Info

Publication number: GB2313797A
Application number: GB9611680A
Authority: GB
Inventors: Andrew Downey; Paul Sopp; Bernard Webber; Anthony Mccormack; Wilson Yeates; Mark Crawford; Hamid Ullah; John Chandler
Original assignee: FARGRO Ltd; SYNTHETIC TEXTILES Ltd; TILDNET Ltd; Griffin Corp
Current assignee: FARGRO Ltd; SYNTHETIC TEXTILES Ltd; TILDNET Ltd; Griffin Corp
Priority date: 1996-06-05
Filing date: 1996-06-05
Publication date: 1997-12-10
Also published as: GB9611680D0

Abstract

A plant root regulating fabric comprises a sheet formed of intertwined (e.g. woven) strips and/or fibres of plastic material, coated over at least a major portion of at least one surface with a plant root growth regulating chemical composition (preferably containing copper (II) hydroxide) in an amount sufficient to restrict or prevent passage of growing plant roots through the sheet. The fabric is suitably formed by applying the root growth regulant in liquid (e.g. dissolved or dispersed) form to the sheet and allowing the liquid to dry.

Description

PLANT ROOT REGULATING FABRIC The present invention relates to a plant root regulating fabric.

Modern nursery plant production is heavily oriented towards container-grown production, as opposed to the field cultivation techniques used in former times. It is estimated that more than half of all landscape plants sold in the USA are container-grown.

The advantages of container-grown production are well known, including (1) more plants produced per hectare, (2) plants of a more uniform size and quality, (3) quicker transplanting, (4) easier transporting and (5) year-round transplanting, in comparison with field cultivation.

Disadvantages of container-grown production, however, include the tendency for the plant roots to escape the container through underside drainage holes and to invade any surface on which the container is resting. If that surface is granular, particulate, or has cracks or crevices, the plant roots can rapidly become entwined and trapped in the surface. When the container is lifted, the root system can break off ("root tear"), so that a significant portion of the fine outer root system, essential to the plant's wellbeing, is lost. The point of root tear can also be an access point for infection to the plant. Furthermore, the root system behind the point of root tear typically does not properly regenerate ("root check").

Even if root tear and root check can be avoided, the escaped root system is unsightly in a commercial nur8ery setting and can render the plant unsaleable, or at least lower its sale value. The overall appearance of the point of sale can suffer from masses of exposed roots.

Moreover, the escaped root system is vulnerable to weather damage and disease.

The present invention aims to go at least some way towards overcoming the above disadvantages of containergrown plant production.

It is also known to use protective cover fabrics or mulches for such functions as reduction of evaporation, maintenance of even soil temperatures, prevention of erosion, control of weeds, enrichment of soil, provision of irrigation, provision of a growth-enhancing system, and provision of a physical barrier on or within earth, gravel or the like. In many cases it is desirable for the passage of growing plant roots through such fabrics to be restricted or prevented. The present invention aims to go at least some way towards meeting this requirement.

According to the present invention, there is provided a plant root regulating fabric comprising a sheet having first and second major surfaces and formed of intertwined strips and/or fibres of substantially water-impermeable material, wherein the sheet is coated over at least a major portion of at least one major surface with a plant root growth regulating chemical composition in an amount sufficient to restrict or prevent passage of growing plant roots through the sheet.

The water-impermeable material from which the strips and/or fibres are formed is preferably a plastic such as high density polyethylene or polypropylene. The mesh density of the sheet (i.e. the proportion of the sheet area which is occupied by the strips and/or fibres) is suitably greater than about 65%, more suitably greater than about 70%, preferably greater than about 80% and most preferably greater than about 90%. The sheet is preferably constructed from strips, each having widths in the range of about 1 to about 5mm. The sheet can suitably be constructed from a woven array of such strips, running in orthogonal (warp and weft) directions in a conventional weaving arrangement. The sheet can be formed in any desired size, for example 1 x lOm, 2 x lOOm, 3.25 x 50m or 4 x 50m.

The plant root growth regulating chemical composition is coated over an area occupying at least 50% of one or both surfaces of the sheet (e.g. at least about 70%, more suitably at least about 80%, most preferably about 90% to 100% of the surface area). The composition is suitably coated on the surface of the strips and/or fibres in such a way that the composition is present in the form of a solid coating of microscopic thickness, adhering to the surface so that it does not substantially leach out under artificial or natural irrigation.

Plant root growth regulating compositions containing transition metal ion active agents are preferred, more particularly copper-based formulations. Copper (II) hydroxide may be particularly mentioned as a suitable active agent. The composition may suitably contain additional inert components such as conventional fillers and binders, to assist in adhering to the sheet and to restrict leaching of the active agents.

The fabric of the invention is suitably prepared by applying the plant root growth regulating chemical composition, in the form of a liquid in a suitable solvent or dispersing medium, to the sheet using' any suitable conventional application method (e.g. using spray, roller or brush applicators). The liquid is then allowed to dry, if necessary under heating, so that the coating of the root growth regulator dries onto the strips and/or fibres of the sheet.

By selecting the concentration of the initial liquid form of the root growth regulator, the method of application, and the number of applications, a worker of ordinary skill in the art can readily arrange for the desired amount of root growth regulator to be deposited on the sheet. In the case of copper hydroxide, it has been found that at least about 2 g of copper hydroxide (dry weight) per square metre of fabric should be deposited on one or each side of the sheet, in order to provide acceptable bioactivity. Typically, somewhat larger doses of copper hydroxide (e.g. from about 2.5 to about 3 g per square metre) should be deposited, to provide acceptable activity in conditions of light use. In conditions of heavy use, for example in anti-tree root fabrics which are to be buried in moist earth for a number of years, doses of up to about 15 or more g per square metre may be required.

Copper hydroxide is suitably applied to the sheet by brush-application of a weak somewhat alkaline (pH typically about 8 to 10) suspension (e.g. up to about 13% by weight, more generally up to about 10% by weight, suitably about 6 to 7% by weight) of copper hydroxide in a water carrier. Such a liquid formulation, containing additionally inert components, is commercially available under the name of SPINOUT-(Griffin Corporation, Valdosta, Georgia, USA). This formulation contains a metallic copper equivalent of 4.6%. To deposit 3 g of copper hydroxide per square metre, typically about 20 g per square metre of dry residue from commercial SPINOUT is deposited onto the sheet, the balance of the dry residue being the inert inorganic and/or organic components (e.g.

latex filler).

For further illustration of the present invention, and to show how the same may be performed, an embodiment will now be described by way of example, and without limitation, with reference to the accompanying drawings, in which: Figure 1 shows a perspective view of a fabric sheet formed of intertwined strips of a substantially waterimpermeable material, and Figure 2 shows a schematic view of a fabric coating apparatus for coating the fabric sheet of Figure 1 with a plant root growth regulating chemical composition.

Referring to the Figures, there is shown a fabric comprising a foraminous sheet 1 of woven strips 2 of polymeric material. The sheet has two major surfaces 3,4. The strips have widths ranging from about I to about 3mm, and are thin and flexible so that the woven fabric has the appearance of sacking.

To provide the plant root regulating fabric of the present invention, the sheet is coated over at least a major portion of at least one major surface with a plant root growth regulating chemical composition, in an amount sufficient to substantially prevent passage of growth plant roots through the sheet 1. The plant root growth regulating composition comprises the dry residue of a water based liquid formulation of copper hydroxide and conventional fillers and binders.

The coating apparatus is shown in Figure 2. An approximately 6 to 7% by weight liquid formulation of copper hydroxide (metallic copper equivalent 4.6%), e.g.

SPINOUT (Griffin Corporation) is applied as a viscous liquid from a composition tank 5 to a roller 6, which is then rolled onto one surface 3 of the sheet 1 and the deposited liquid allowed to dry under conditions of heat.

The sheet 1 is pulled over the roller 6 by driven nip rollers 7,8 in conventional manner. The liquid formulation is suitably applied in amounts such that, after drying, the dry residue of copper hydroxide and inert fillers and binders is approximately 15 to 20 g per square metre.

The deposited plant root growth regulating chemical has been found not to leach out when the ground cover fabric is left out of doors with container-grown plants resting on it. The treated fabric in practice can remain effective at preventing root penetration, and confining the roots to the containers, for a number of growing seasons. Furthermore, the treated cover fabric of the invention has been found to be more resistant to growth of weeds, moss and algae than conventional cover fabrics.

The fabric of the present invention can serve as a mat or support for container-grown plants prior to transplanting or transportation, and effectively confines root growth to the interior of the container. In addition, the fabric can be used in other situations (e.g. on or in earth, gravel etc) where plant root growth is to be barred while still retaining permeability and drainage, such as where invasion of tree roots is to be restricted.

The foregoing broadly describes the invention without limitation to any particular embodiments. Variations and modifications are possible, as will be readily apparent to readers of ordinary- skill in this art; all such variations and modifications are to be considered as included within the scope of the invention.

Claims

1. A plant root regulating fabric comprising a sheet having first and second major surfaces and formed of intertwined strips and/or fibres of substantially waterimpermeable material, wherein the sheet is coated over at least a major portion of at least one major surface with a plant root growth regulating chemical composition in an amount sufficient to restrict or prevent passage of growing plant roots through the sheet.

2. A fabric according to claim 1, in which the waterimpermeable material from which the strips and/or fibres are formed is a plastic.

3. A fabric according to claim 2, in which the plastic is high density polyethylene or polypropylene.

4. A fabric according to any one of the preceding claims, in which the sheet has a mesh density greater than about 65%.

5. A fabric according to claim 4, in which the sheet has a mesh density greater than about 70%.

6. A fabric according to claim 4, in which the sheet has a mesh density greater than about 80%.

7. A fabric according to claim 4, in which the sheet has a mesh density greater than about 90%.

8. A fabric according to any one of the preceding claims, in which the sheet is constructed from strips, each having widths in the range of about 1 to about 5 mm.

9. A fabric according to claim 8, in which the sheet is constructed from a woven array of the strips.

10. A fabric according to any one of the preceding claims, in which the plant root growth regulating chemical composition is coated over an area occupying at least 50% of one or both major surfaces of the sheet.

11. A fabric according to claim 10, in which the coated area occupies at least about 70% of the surface area of one or both major surfaces.

12. A fabric according to claim 10, in which the coated area occupies at least about 80% of the surface area of one or both major surfaces.

13. A fabric according to claim 10, in which the coated area occupies about 90% to 100% of the surface area of one or both major surfaces.

14. A fabric according to any one of the preceding claims, in which the plant root growth regulating chemical composition is present in the form of a solid coating of microscopic thickness, adhering to the surface so that it does not substantially leach out under artificial or natural irrigation.

15. A fabric according to any one of the preceding claims, in which the plant root growth regulating chemical composition contains one or more transition metal ion active agent.

16. A fabric according to claim 15, in which the transition metal is copper.

17. A fabric according to claim 16, in which the active agent is copper (II) hydroxide.

18. A fabric according to claim 17, in which the copper hydroxide is present at a level of at least about 2 g of copper hydroxide per square metre of fabric surface area.

19. A fabric according to claim 18, in which from about 2.5 to about 3 g per square metre of copper hydroxide is present.

20. A fabric according to claim 18, in which up to about 15 g per square metre of copper hydroxide is present.

21. A fabric according to claim 18, in which more than about 15 g per square metre of copper hydroxide is present.

22. A method of manufacturing a fabric as claimed in any one of the preceding claims, which comprises applying the plant root growth regulating chemical composition, in the form of a liquid in a suitable solvent or dispersing medium, to the sheet, and then allowing the liquid to dry, optionally under heating, so that the coating of the root growth regulator dries onto the strips and/or fibres of the sheet.

23. A method according to claim 22, in which the liquid is applied to the sheet by spraying.

24. A method according to claim 22, in which the liquid is applied to the sheet by rolling.

25. A method according to claim 22, in which the liquid is applied to the sheet by brushing.

26. A method according to any one of claims 22 to 25, in which the root growth regulator contains copper (II) hydroxide.

27. A method according to claim 26, in which the copper hydroxide is applied to the sheet in a weak alkaline suspension in a water carrier.

28. A method according to claim 27, in which the suspension contains up to about 13% by weight copper hydroxide.

29. A plant root regulating fabric, substantially as herein described with reference to Figure 1 of the accompanying drawings.

30. A method of manufacturing a plant root regulating fabric, substantially as herein described with reference to Figure 2 of the accompanying drawings.