AU600474B2 - Horticultural mulch matting - Google Patents

Description

ij 600474 FORM COMMO N WEALTH OF AUSTRALIA Patents Act 1952 COMPLETE SPECIFICATION (Original) FOR OFFICE USE: Class Int. Class Application Number: 677/ 1 7 Lodged: Complete Specification Lodged: Accepted: Published: Priority: STi S dn: f-t conti n; ihe made u11 49 and is correct hjr 0000 0 0 0 0 Related Art: Name of Applicant: Address of Applicant: ARTHUR BRIAN SPOTTISWOOD 8 O'Hagan Street Latham 2615 Australian Capital Territory Actual Inventor(s): ARTHUR BRIAN SPOTTISWOOD Address for Service: DAVIES COLLISON, Patent Attorneys, 1 Little Collins Street, MELBOURNE VIC 3000 Complete Specification for the invention entitled: HORTICULTURAL MULCH MATTING The following statement is a full description of this invention, including the best method of performing it known to me 1 i, 1A- A TECHNICAL FIELD This invention concerns the growth of plants. More particularly, it concerns a form of matting that enables water to be distributed to soil in the vicinity of plants while protecting the soil from excessive water, heat and preventing the growth of weeds. This type of matting has been termed "mulch matting".

10 BACKGROUND ART Mulch matting of different types is regularly used in garden agriculture. For many years, gardeners have used a simple form of mulch matting when they have 04 laid black plastic sheeting over soil to prevent weed °0 15 growth and have cut holes in the sheeting to provide access to the soil for plants, shrubs and trees, and to permit water to be supplied to the soil.

0 Normally such sheeting is covered with tan bark, pine chips, shredded eucalyptus or other suitable mulch, or with stones, to improve the appearance of the garden, to prevent the soil from becoming too hot (due to incident radiation being absorbed by or transmitted through the sheet) and to prevent the sheet material being blown by the wind.

While such sheeting is economical to use, it has a number of disadvantages. It is not easy to provide an adequate supply of water to the soil with this type of sheeting, and weed growth in the mulch -2 material or in the soil trapped by stones placed on the sheeting is common. Thus other types of mulch matting have been developed. Included in such developments are several types of porous mulch matting which permit water to be supplied to the soil over a significant area while acting as a weed growth inhibitor and permitting the soil to "breathe".

One example of porous mulch matting is the knitted fabric mulch mat described in the specification of Australian patent No 467,392 (to Gulf States Paper Corporation). That mulch mat is an open-mesh knitted fabric with inserts threaded into the knitted mesh.

The inserts include irrigation tubing, water-impervious strips, light-reflecting strips, and seed tapes (optionally being biodegradable and incorporating a plant nutrient, a fertiliser, a pesticide and/or a fungicide). Slots or holes can be formed in such a mulch mat for plants, shrubs, trees and the like. Unfortunately, such mulch matting is expensive to produce, and its open mesh permits the growth of weeds in the soil under the matting.

A more recent development in mulch matting is described in the specification of International patent application No PCT/GB84/00211, which was published by the World Intellectual Property Organization as WIPO publication No W085/00003. That specification, which is also the specification of Australian patent application No 30693/84, is primarily concerned with a new type of hose for 3 3 distributing liquid slowly to plants without the fall-off in water pressure, with the consequential reduction in the discharge of water from the outlets in a conventional watering hose provided with spaced outlets along its length, that is alleged to occur with long watering hoses of conventional design.

However, that specification also discloses the way in which such a new type of hose can be formed integrally with a plastic sheet to create a mulching mat for plants that penetrate through slits formed by tearing short lengths of perforations that have been o° provided in the plastic sheet.

00000 SA major disadvantage of the hose and matting described in WIPO publication No W085/00003 is that 00 '4 0 o 15 they are relatively expensive to produce, and thus o C o they are only suitable for irrigation of long strips of land, where the alleged fall-off in water pressure could occur should long, conventional hoses be used .o to supply water to the soil.

o Other forms of prior art mulch matting are disclosed in the specifications of U.S. patents Nos 3,205,619 (to J W Henry) and 3,302,323 (to J Popa). The disclosures in these two specifications both involve conduits, with apertures formed in the lower portion thereof, to provide water outlets. In J W Henry's arrangement, a conduit is attached to a plastic sheet. Perforations in the underside of the conduit (which may be formed separately from or integrally with the plastic sheet) ensure that substantially all Y 4 the irrigation water is supplied under the sheet, thus minimising evaporation losses. Slits in the sheet permit cultivated vegetation to grow therethrough. J Popa's mulch mat is the simple black plastic sheet, referred to above, with apertures therein for plants, laid over a matrix of irrigating conduits which supply liquid to the soil underneath the black plastic sheeting.

DISCLOSURE OF THE PRESENT INVENTION It is an object of the present invention to provide a new type of mulch matting which is economical to produce, can be used for small or large areas of o cultivated land or gardens, and which effectively o einhibits weed growth while supplying controlled 15 quantities of water to plants growing in soil in the region of predetermined spaces within the matting.

This objective is achieved by providing a modular mulch mat which is formed from a double layer of thermoplastic material. The layers of the modular mulch mat are heat sealed together at predetermined regions to provide an array of liquid conduits extending over the mat and an access point for the supply of liquid to such conduits. The mat is also provided with slots formed therein, extending parallel to one or more of the conduits, to provide access to the soil over which the mat is laid for the planting of seedlings, shrubs or the like. The two layers of thermoplastic material are also sealed together at the edge of the modular mat.

A number of the modular mulch mats can be used to cover any area of cultivated ground. This enables a small area of land to be irrigated initially, and for the irrigated area to be extended as additional tracts of land are prepared for cultivation, and/or as additional capital is available for increasing the irrigated area.

Thus, according to the present invention, there is provided a modular mulch mat comprising an upper layer of a thermoplastic material and a lower layer of a thermoplastic material, each layer being substantially equal in area and having the same shape, the two layers being heat sealed together at or near the edges thereof; the two layers also being heat sealed together at predetermined regions thereof to form: a) a plurality of conduits for liquid, formed as an array of conduits extending over the mat, a series of perforations being formed in each conduit in at least the lower layer of thermoplastic material, whereby liquid within the conduit can pass to the exterior thereof; b) an inlet point at an edge of the mat, the inlet point connecting the inside of the plurality of conduits with the outside of the mat and being adapted to have a hose or other water supply means connected thereto; and c) a plurality of narrow, elongate, enclosed regions, the enclosed regions being slittable or removeable to form slots in the mat.

The perforations in the conduits will normally be established only in the underside of the conduits.

Normally the modular mat will be rectangular in shape, to enable areas of soil to be covered efficiently by forming a closely spaced linear or rectangular array of modular mats with their adjacent edges abutting.

Part, or all, of the upper surface of the modular mulch mat may be coated with, or formed from, a reflective material.

Other features that may be present in the modular mulch mat are the provision of holes or moulded circular regions at spaced intervals around the edge of the mat, through which pegs or spikes can be inserted to hold the mat on to the ground when a wind o blows, and (ii) the inclusion of a blind extension o from the array of conduits, which can be used to a -enable two of the mulch mats to be joined end-to-end a with their arrays of conduits also conjoined.

The present invention also encompasses an irrigation system constructed using a number of modular mulch I mats, with independent control of the volume of liquid supplied to each mat. In such a system, the control may be in response to signals from a plurality of moisture sensors, located in the soil under respective mulch mats.

7 To illustrate the features of the present invention, including some optional features, embodiments of the invention will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Figure 1 is a plan view of the underside of a modular mulch mat, constructed in accordance with the present invention.

Figures 2 and 3 each illustrate, schematically, an array of modular mulch mats laid over soil for commercial cultivation thereof.

O -DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS The mulch mat 10 illustrated in Figure 1 consists of two substantially rectangular and equi-dimensioned "on layers of thermoplastic miterial superimposed one on top of the other, with the edges thereof joined together by a thermal weld 11 around almost the entire periphery of the layers. The peripheral thermal weld 11 becomes discontinuous in the region between two thermal welds 12 which extend inwardly from one edge of the thermoplastic layers to join with another thermal weld 13 which, in conjunction with further thermal welds 14, defines a plurality of channels or conduits 15 extending over the thermal mat. Typically, the distance between the thermal welds defining the conduits 15 is about 2 cm. The 8 thermal welds 12, 13 and 14, and the other thermal welds in the mulch mat, join together the thermoplastic layers of the mat.

The short thermal welds 12 convert the thermoplastic layers in the region which lies between welds 13 into a tubular entry point 16 for the supply of water to th conduits 15. A hose or other suitable liquid supply means that is a close fit into the tubular entry point will normally be inserted into the entry point 16 to supply liquid (usually water) to the conduits 15. If necessary, a hose connecting member may be affixed to the entry point 16 (which may be extended, if necessary, beyond the edge 17 of the mulch mat for this purpose, as shown in dashed on 15 outline 16A in Figure for ease of connecting the Sconduits 15 of the mulch mat to feeder hoses extending from a main water supply line.

A series of additional thermal welds 18 define elongate strips 19 of thermoplastic material which are removable from the mulch mat to provide slots a therein. To facilitate the removal of the strips 19 from the mulch mat, perforations will normally be provided along the thermal welds 18, adjacent to the strips 19. When the mulch mat is in use, seedlings may then be planted in the soil in the region of the slots in the mat with the foliage of the seedlings above the mulch mat.

9 The mulch mat of Figure 1 is also provided with a series of circular spot thermal welds 20, usually in pairs, at intervals near the edge of the mat. These spot welds 20 may be perforated in their centres, or they may be ring-shaped to leave a small region of unwelded thermoplastic material at their centres.

Stakes, pegs or spikes or the like can be inserted through the centres of at least some of the thermal welds 20 and into the soil underneath the mulch mat, to ensure that the mulch mat, when in use, is held in position when the wind blows.

A short extension 21 from the array of conduits in the mat is provided by a short curved thermal weld 22, adjacent to the edge of the mat that is remote from the entry point 16. This extension 21 can be o used, if necessary, to provide an interconnection for the conduits of two mulch mats, supplied with water from a single feeder hose. An aperture formed in extension 21 enables a connection to be made between extension 21 and the entry point 16 of an adjacently positioned mulch mat.

The underside of the mulch mat shown in Figure 1 has a series of small perforations 23 at intervals along the length of the material defining the conduits Such small perforations 23 provide outlets for liquid in the conduits 15 to the soil underneath the mulch mat, thus irrigating any seedling planted in the region of one of the slots 19.

10 The top layer of the mulch mat may comprise a thermoplastic sheet which has a reflective surface, to minimise the transfer of heat and other radiation from the sun to the underside of the mulch mat and to inhibit weed growth and the development of an insect population on plants growing in the mulch mat. The reflective surface provides a higher incidence of light to plants growing in the mulch mat, thus promoting the growth of plants. Alternatively, part only of the surface of the upper layer of thermoplastic material may be reflective, to control but not eliminate the radiant energy that is transferred to the underside of the mulch mat. Thus the top surface of the mulch mat may be a variegated 15 surface partly reflective, partly absorptive to control the proportion of incident radiant energy that is reflected by the mulch mat.

Manufacture of the mulch mat is simply and cheaply achieved by a continuous process utilising a high frequency pqa welding equipment. In this process, two sheets of thermoplastic material are separately fed into the welding machine. The lower sheet is then perforated by heated needles to form the perforations 23 that act as water outlets. The top and bottom sheets of thermoplastic material are then welded together using a high frequency welding die. The welding process forms the welds that define the water channels or conduits 15, the growing slots and the stake down points 20, and seals all edges according to the pattern required. When the welding 11 process is completed, the horticulatural garden matting can either be cut into modular lengths or rolled up to form a longer continuous product.

The mulch mat of the present invention has been designed so that a plurality of the modular mulch mats can be laid over the area of soil to form an array of mulch mats with their adjacent edges abutting each other or closely spaced apart from each other. A main water supply line may then be laid alongside each row of the array, with connections from the main supply line to the entry points 16 of the mulch mats in the row. Alternatively, a single water supply line may be connected to the entry points 16 of the mulch mats in the row at the edge of the array, with water supplied to the second and subsequent rows of mulch mats by interconnections between the extension region 21 of one mulch mat and the inlet point 16 of the adjacent mulch mat in the next row.

The water supply to the mulch mats may contain plant nutrients, fertiliser, a pecticide, a fungicide or other chemicals to be supplied to the soil covered by the mulch mat.

The commercial cultivation arrangement shown schematically in Figure 2 comprises a linear array of mulch mats 30, having respective entry points 31 to which water from a main supply line 33 is supplied via connecting hose 32. A control unit 34 is located

A

12 in the connecting hose 32 (which may be a rigid conduit). The control unit 34 is adapted to inject fertiliser, pesticide or the like into the water passing through the hose or conduit 32. The control unit 34 is also adapted to control the flow rate of water through the hose or conduit 32, in response to signals from a moisture detector 35 which is located in the soil under the respective mulch mat The moisture detector 35 and its associated flow control arrangement is known technology, as is the technology for injecting chemicals into a conduit o through which water flows.

Figure 3 illustrates, schematically, a rectangular array of three rows and four columns of mulch mats 40. Water from a main supply line 43 is supplied to the inlet points of the first row of mulch mats 40 by respective hoses or conduits 42.

The mulch mats of each row have connections 44 between their respective extension regions 21 and the inlet points of the adjacent mulch mats in the next row. Thus the entire area covered by the array of SK mulch mats is irrigated at the same time.

It will be appreciated by those skilled in this art that irrigation and mulching arrangements (such as those illustrated in Figures 2 and 3) using the present invention are easy to install and enable crops to be cultivated with very little input of human labour. Because the mulch mats are economical 13 to produce, the cost of such installations is substantially less than the cost of installing other types of irrigation systems with known forms of mulch matting.

Those skilled in this art will also appreciate that modifications of the illustrated and described forms of the mulch mat of this invention may be made without departing from the present inventive concept.

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Claims (9)

1. 2. A modular mulch mat as defined in claim 1, in which the conduits are substantially parallel to each other and the elongate direction of said enclosed regions is substantially parallel to said conduits.
2. 3. A modular mulch mat as defined in claim 1 or claim 2, in which the upper layer of thermoplastic material has a top surface which is made from or is coated with a reflective material.
3. 4. A modular mulch mat as defined in claim 3, in which said perforations are formed only in the lower layer of thermoplastic material. A modular mulch mat as defined in any preceding claim, including a plurality of ring-shaped or circular thermal welds at spaced-apart intervals near to the periphery of the mat.
4. 6. A modular mulch mat as defined in any preceding claim, including an extension of said array of conduits formed by a thermal weld which extends from said array of conduits generally towards the edge of the mat that is remote from the edge at which said inlet point is located.
5. 7. A plurality of modular mulch mats as defined in any preceding claim, arranged as a linear or rectangular array of mulch mats, with water 16 supplied to each mulch mat through a respective feeder hose or feeder conduit connected to the inlet point of its associated mulch mat, said feeder hoses or feeder conduits being also connected to a main water supply line.
6. 8. A linear or rectangular array of modular mulch mats as defined in claim 7, including a) a respective moisture sensor located in the soil under each mulch mat of the linear or rectangular array; and b) a respective control unit included in each said feeder hose or feeder conduit, each said control unit being responsive to signals from the moisture sensor located under its associated mulch mat to control the supply of water to its associated mulch mat.
7. 9. A linear or rectangular array of modular mulch mats as defined in claim 8, in which each said control unit is also adapted to inject nutrients, fertilisers, a pesticide, a fungicide and/or other chemicals into the water supplied to its associated mulch mat. A plurality of mulch mats as defined in claim 6, arranged as at least one linear array of mulch mats supplied with water from a feeder hose or conduit connected to the inlet point of the first 17 mat in said or each linear array, the inlet points of the subsequent mat or mats in said or each linear array being connected to the extension of the first or of the last preceding mat in the linear array.
8. 11. A modular mulch mat substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.
9. 12. An array of modular mulch mats, substantially as hereinbefore described with reference to Figure 2 or Figure 3 of the accompanying drawings. Dated this 23rd day of May 1990 ARTHUR BRIAN SPOTTISWOOD By his Patent Attorneys DAVIES COLLISON