WO1996028010A1

WO1996028010A1 - Seed-containing medium

Info

Publication number: WO1996028010A1
Application number: PCT/GB1996/000549
Authority: WO
Inventors: Dermot Christopher John Barrow; David Howard Holloway
Original assignee: Dermot Christopher John Barrow; David Howard Holloway
Priority date: 1995-03-09
Filing date: 1996-03-08
Publication date: 1996-09-19
Also published as: AU4949696A; GB9504792D0

Abstract

The invention provides a seed germination medium in sheet form having upper (3) and lower (4) surfaces between which are disposed seeds (6) for one or more plant species, at least the said surfaces (3, 4) being formed from a material which is biodegradable, and the medium being sufficiently flexible and durable to be folded or formed into a roll without disintegrating. In a particular embodiment the invention provides a seed germination medium in elongate sheet form having upper (3) and lower (4) surfaces between which are disposed seeds (6) for one or more plant species, at least the said surfaces being formed from a material which is biodegradable, the medium being packaged in a folded form or in the form of a roll.

Description

SEED-CONTAINING MEDIUM

This invention relates to a medium for encouraging the germination of seeds and protecting the seedlings germinating therefrom. More particularly, the invention relates to a seed germination and protection medium which may be of cheap and simple construction, and which can be used in harsh conditions, such as those encountered in desert or near desert areas.

Desertification and soil erosion are growing problems in many parts of the world and, for example in many parts of Africa, the encroachment of desert is taking place at an alarming rate.

The harsh climatic conditions and poor soil quality, as well as the lack of water, encountered in areas where desertification is taking place, means that it can be extremely difficult to reverse the desertification process since most plants will not grow efficiently under such conditions. Whereas various means have been suggested for arresting the desertification process, or converting desert into usable land, there remains a need for a system which encourages plant growth in such harsh and arid conditions yet is simple to use and inexpensive to make and supply. Furthermore, it is important that any such system should be essentially non-polluting and should not give rise to breakdown products which are generally harmful to the environment. It is an object of the present invention to provide a means for solving or at least alleviating the aforementioned problems.

In one aspect, the invention provides a seed germination medium in sheet form having upper and lower surfaces between which are disposed seeds for one or more plant species, at least the said surfaces being formed from a material which is biodegradable, and the medium being sufficiently flexible and durable to be folded or formed into a roll without disintegrating.

The biodegradable material is preferably formed from a cellulosic material and may, for example, be a biodegradable paper. The biodegradable paper may be recycled paper or other low grade paper and is preferably unbleached. The biodegradable paper may, with advantage, be an air-laid paper, e.g. an air-laid latex bonded paper. The air-laid paper may, for example, be formed from fluff pulp and a latex binder.

In one preferred embodiment, the seed germination medium comprises a biodegradable paper sheet having upper and lower layers and plant seeds disposed therebetween.

In another aspect, the invention provides a seed germination medium in elongate sheet form having upper and lower surfaces between which are disposed seeds for one or more plant species, at least the said surfaces being formed from a material which is biodegradable, the medium being packaged in a folded form or in the form of a roll.

The medium may contain, in addition to plant seeds, one or more additional components selected from fertilisers, pesticides, water retaining substances and/or other agents to ensure germination and plant establishment. It is most preferred that the medium contains water- retaining substances, and in sufficient quantities to maintain the medium in a moist condition for a prolonged period after warer has been added ro the medium, preferably even in the hot dry conditions encountered in a desert or near-desert environment.

Water retaining substances include silica gels and so- called "super absorbents" such as the super absorbent acrylic polymers manufactured under the trade name "Salsorb 90" by Allied Colloids Limited, Bradford, Yorkshire, UK.

Fertilisers may be either artificial or organic (eg composted animal, human or plant material) or a combination thereof.

The pesticides will be selected in accordance with the pests found in the local environment and most preferably are in dry form. In particular, the pesticides may be presented as granules.

In addition to fertilisers, pesticides and water retaining substances, other agents may be present to assist in plant germination and establishment. Examples include plant growth hormones, and also rhizobial fungi which are useful for ensuring and promoting the germination of plant seeds, such as some coniferous species.

The medium, or at least the surfaces thereof may be provided in a variety of colours to assist soil warming/cooling or to exclude light so as to suppress weed growth and aid plant establishment. The medium may have different colours on its upper and lower surfaces to enhance or reduce the absorption of radiation on one surface and produce the opposite effect on its other surface. Irrigation tubes may be disposed between the upper and lower surfaces of the sheet medium, for example, irrigation tubes of the trickle irrigation tube type. Such trickle irrigation tubes typically comprise strips of a plastics material such as polyethylene folded over and stitched along one side to form a pipe or tube-like structure having a leaky seam down one side. Water passing along the inside of the pipe or tube-like structure will leak gradually through the seam to irrigate the contents of the seed germination medium.

An alternative to, or in addition to, the trickle irrigation tubes, the seed germination medium may be provided with a super-absorbent water-retaining substance as indicated above. The water retaining-substance will absorb and retain the water provided either by the trickle irrigation tube or by external means thus ensuring that the seeds have moist surroundings in which to germinate and grow.

The seed germination sheet medium of the invention is typically provided in elongate strips which are sufficiently flexible to be packaged in a folded form or roll form without disintegrating. Typically a given roll will be prepared so as to provide ground cover of known dimensions, eg 0.1 hectares.

The strip will typically be provided in lengths of at least 5 metres, more usually at least 100 metres. The width of the strip may vary between 1 metres and 5 metres, for example.

The seed germination medium is preferably constructed in the form of an open lattice. To this end the medium may, with advantage, be slit longitudinally such that, when stretched laterally, it forms a lattice. The lattice arrangement may be advantageous in that it will assist the sheet to be anchored more effectively and be mere resistant to displacement by wind. Thus, in desert areas, sand will pass through the openings in the lattice thereby holding the lattice down. In addition, by stretching the sheet into a lattice form, the ground cover provided by a given roll of sheet will be greatly increased. Moreover, the lattice arrangement will tend to encourage rooting of the seeds within the lattice and discourage dependence upon water retained within the sheet. A further advantage is that the seed germination sheet can degrade more quickly in lattice form than in plain form.

The seed germination sheet may be used in conjunction with a cover sheet which may be separate from or connected (e.g. bonded) to the seed germination sheet.

The cover sheet can be formed from any one or more of a variety of materials, the properties of which may vary according to the environment within which the germination medium is to be used. For example, where the seed germination medium is intended for use in arid and semi arid desert areas, in which the germinating seeds need shelter from the strong sunlight, the cover sheet may be formed of a translucent material. The translucent material may be a biodegradable paper material similar to the paper material used to form the seed germination sheet.

Where the seed germination medium is intended for use in colder areas, the cover sheet may be made of a transparent material such as a transparent polymeric sheet, eg a perforated polyethylene sheet or a polyester fleece, in order to create a protective microclimate between the cover sheet and seed germination medium.

In order to increase its mechanical strength, the cover sheet is preferably provided with areas of reinforcement for example in the form of ribs which may, for example, be raised in a grid pattern over the surface of the sheet. The reinforcing ribs allow the cover sheet to be tied or staked to the ground.

The cover sheet may incorporate insecticidal or pesticidal materials, subject to the appropriate pesticides regulations and label conditions, thereby reducing risk to operator and environment, or may incorporate repellant materials for repelling pests, and other animals.

The seed germination sheet and cover sheet, in one preferred embodiment, are linked by means of integral side walls, thereby forming a closed system which can protect the seeds and seedlings from pests such as birds, insects (e.g. locusts) and other animals, as well as preventing desiccation and aiding establishment of the seedlings. For example, the side walls may be in the form of re-entrant folds or gussets allowing for expansion as the plants grow within the interior of the system.

In one preferred aspect of the invention, there is provided a device for promoting seed germination and protecting germinated seedlings against the surrounding environment, which device comprises:

(a) an elongate base sheet which forms a seed germination medium, the base sheet having upper and lower surfaces between which are disposed seeds for one or more plant species, at least the surfaces of the base sheet being formed from a material which is biodegradable.

(b) an elongate cover sheet; and

(c) side walls connecting the base sheet and side walls; the base sheet, cover sheet and side walls together defining a protective chamber within which seedlings germinated from the seeds may grow. The invention also relates to cover sheets per se. Thus, in another aspect, the invention provides a coversheet in elongate strip form, the cover sheet being formed from a biodegradable material such as a biodegradable paper, and having an array of reinforcing ribs on its surface, the cover sheet optionally being impregnated with a pesticidal and/or pest repellant substance.

The seed germination medium may be provided at an end thereof with a header tube, the header tube being oriented laterally across the end of the sheet, the header tube having an opening at one end thereof for connection to a water supply, and one or more lateral openings for connecting to the irrigation tubes within the sheet. Each lateral opening may extend into a short section of tubing which fits snugly within the said irrigation tubes. The header tube may be formed from a collapsible material such as a polymeric sheet eg polyethylene sheet.

The header tube may have linked thereto a container containing a source of water-soluble fertiliser or liquid fertiliser. The container for the fertiliser may be a collapsible bag eg formed from a polymer such as polyethylene, and typically will be linked to the interior of the header tube by means of one or more non-return valves. The fertiliser container and header tube may be formed integrally from the same sheets of polyethylene materials.

The fertiliser container will generally be provided with soluble fertiliser in granular form, for example monoammonium phosphate, potassium nitrate and optionally other micronutrients, a water inlet being provided such that the granular fertiliser may be dissolved and then washed into the header tube for dispersing into the seed germination medium. The fertiliser container may be constructed so as to be capable of being opened to replenish the stock of fertiliser therein. The fertiliser container is also preferably reusable.

The seed germination sheet will typically be supplied in roll form and the roll may be provided with a central core of sufficient rigidity to function as a handle for carrying the roll. The central core may be in the form of a mains irrigation pipe formed of a relatively rigid material.

The seed germination sheet of the invention may be used not only in desert or near desert areas, but also in any environment when it is desired to provide temporary protection for seeds and seedlings against external climatic conditions or pests or predators. For example, the sheet may be used in the repair or development of grass areas for sporting use, such as golf courses, football and rugby pitches etc. The sheets may also be used in wet conditions, e.g. in the development of paddy fields.

It will be apparent from the foregoing that in a further aspect, the invention provides for the use of the seed germination medium as hereinbefore defined in a method of cultivation.

The invention will now be illustrated, but not limited, by reference to the accompanying drawings of which: -

Figure 1 is a perspective view of a roll of seed germination sheet according to one embodiment of the invention;

Figure 2 is a view from above of part of the sheet from the roll of Figure 1; Figure 3 is a sectional elevation along line I-I in Figure 2;

Figure 4 is an enlarged view of the section A B C D shown in Figure 3;

Figure 5a illustrates a roll of the type shown in Figure 1 but enclosed in a containing sleeve;

Figure 5b shows the roll and enclosing sleeve of Figure 5a in expanded form;

Figure 6 illustrates an end of the roll having attached thereto a header tube-

Figure 7 illustrates an end of the roll of germination sheet having attached thereto a header tube and fertiliser container arrangement;

Figure 8a illustrates a portion of the germination sheet shown in Figures 1 to 7 having an array of longitudinal cuts;

Figure 8b shows the sheet material of Figure 8a in expanded lattice form;

Figure 9 illustrates a seed germination sheet according to a second embodiment of the invention, incorporating a cover sheet; and

Figure 10 illustrates the embodiment of Figure 9 in expanded form.

Referring now to Figures 1 to 4, it can be seen that according to one embodiment of the invention, there is provided a seed germination sheet 1 in elongate strip form which may conveniently be formed into a roll as shown in Figure 1, about a central core 2 which m this embodiment is an irrigation pipe. The irrigation pipe 2 acts as a handle to assist lifting and manoeuvring of the roll.

A cross-sectional view of the strip 1 is shown in Figures 3 and 4 which it can be seen that the sheet comprises upper 3 and lower 4 surface layers and intermediate layers 5 formed from a biodegradable paper material. The biodegradable paper material is for example an air-laid biodegradable latex bonded paper comprising fluff pulp and latex binder.

Located m the spaces between adjacent layers 3,4 and 5 are seeds 6 which may be of any desired plant species. Seeds 6 are surrounded by a water retaining medium 7 which comprises a silica material or a super-absorbent polymer such as a super-absorbent acrylic polymer ("super acrylic") of the type available from Allied Colloids Bradford, Yorkshire, UK under the name "Salsorb 90". In addition to the super-absorbent material, the absorbent medium also contains an artificial and/or organic fertiliser material and optionally a pesticide, the nature of the pesticide being selected according to the environment m which the product is used and the nature of the local pests and pesticide regulations.

Arranged longitudinally through the sheet are a plurality of bonded trickle irrigation tubes S. Trickle irrigation tubes 8 are formed from strips of polyethylene material folded over and stitched along one edge 9 to form a tubular construct. In use, water is passed along the interior of the tube 8 but, since the seam 9 is not entirely waterproof, water trickles through the seam and into the surrounding medium.

In use, the roll of sheet material is unrolled to cover a desired area of ground, eg a prepared surface in a desert or near desert region, and water is passed along the trickle irrigation tubes using an arrangement which will be described below. Water trickles out of the tubes 8 and into the surrounding medium 7 which, thanks to the absorbent nature of the medium, retains the water thereby keeping the medium 7 moist, and assisting germination of the seeds 6. In the absence of the water-absorbing medium, the water would simply diffuse into the surrounding or underlying soil or sand and would be lost.

Although the seed germination sheet is illustrated in Figures 2 to 4 as having irrigation tubes running along its length, such irrigation tubes can be dispensed with and an alternative means of delivering water to the sheet provided. As shown in Figures 5a and 5b, a roll 21 of the material can be encased in an expandable sleeve 22, the expandable sleeve being provided with a water inlet 23. In this embodiment, the material contains a high loading of a water-absorbing, water retaining substance such as silica gel or a super-absorbent polymer. Prior to unpacking and unrolling, a desired quantity of water is introduced into the opening 23 such that the roll is thoroughly soaked. The water is absorbed and retained by the silica gel or super-absorbent polymer and the roll consequently expands as shown in Figure 5b. Once expanded, the sleeve is removed and the sheet unrolled.

In Figure 6 there is shown a header device 31 for supplying water to the trickle irrigation tubes 8. Header device 31 in this embodiment is in the form of a collapsible bag formed from a suitable polymeric material such as polyethylene. Container 31 has a water inlet 32 at one end thereof and a water outlet 33 at the other end thereof. Water outlet 33 may be connected to the inlet of a header arrangement of an adjacent strip, or may be sealed, eg by folding over and clamping shut. The header container is provided with a plurality of lateral outlets 34 which are either integrally formed with the trickle irrigation tubes 8, or are connected thereto by means of a permanent or removable connection.

Water is supplied to inlet 32 from an irrigation pipeline.

A modified version of the arrangement shown in Figure 6 is illustrated in Figure 7. In this embodiment, the header tube 41 has two compartments, one of the compartments 42 having disposed therein granules of a water soluble fertiliser material such an monoammonium phosphate and potassium nitrate, the fertiliser compartment 42 being connected to main compartment 43 by means of one way valves 44. One way valves 44 typically are flap type valves of known construction. Compartments 42 and 43 are provided with inlets 45 and 46 respectively for connection to a water supply, eg an irrigation pipe. In use, water is caused to pass through inlet 45 to dissolve the fertiliser disposed therein, the fertiliser solution then passing into compartment 43 from which it is distributed along the trickle irrigation tubes 8 of the strip. When the fertiliser supply has been exhausted, the compartment may be replenished with fertiliser via a suitable sealable opening (not shown).

In a particularly preferred form of the invention, the sheets are cut in a lengthwise direction to provide alternating rows of elongate slits 51 as shown in Figure 8a. By virtue of the arrangement of slits 51, the sheet may be expanded by stretching it laterally to open up the lattice arrangement. In this way, the width of the sheet may be increased by up to 200 % of the original width of the sheet.

The advantages of the lattice arrangement include the ability of the sheet to cover a greater ground area, improved anchoring dbility _ιs _t t-ault uf the underlying soil or sand passing through the openings 52, and improved resistance to displacement by wind, to name but a few advantages.

A second embodiment of the invention is illustrated in Figures 9 and 10. This embodiment is in the form of a device providing an enclosed environment in which seeds may be germinated and the resultant seedlings protected from the external environment. Thus the device has an elongate base sheet 61 of generally similar construction to the germination sheet medium described in Figures 1 to 8, and having a plurality of trickle irrigation tubes 62 passing therethrough. The device is also provided with a covering sheet 63 formed of a translucent biodegradable paper material of a similar type to that from which the base sheet 61 is formed. The cover sheet 53 is provided with reinforcing ribbing 64 which enhances the mechanical strength of the cover sheet.

The cover sheet and base sheet are secured together by means of side walls 65 which are in the form of gussets or re-entrant folds allowing for expansion of the volume enclosed by the device as the plants grow. The fully expanded device is illustrated in Figure 10. In this embodiment, the cover sheet is formed from a translucent paper material and such a form of construction is particularly suited for use in regions where there is strong sunlight, from which the germinating plants need to be at least temporarily protected. In colder regions, however, the translucent paper cover sheet may be replaced by a transparent material, for example a transparent polymeric material such as polyethylene film or polyester fleece.

As with the embodiments shown in Figures 1 to 8, the arrangement shown in Figures 9 and 10 is sufficiently flexible to be formed into a roll for ease of transport.

The advantages of the seed germination sheets of the present invention is that they provide temporary protection for plants and seedlings at the periods in their life cycle when they are particularly susceptible to harm from local climatic conditions or from pests. Thus the germination sheets provide a moist environment in which the seeds can germinate, even in harsh desert or near desert conditions. Thanks to the water-absorbing and retaining properties of these sheets, trickle irrigation provides sufficient water to allow for germination and growth of the seedlings. Without the water-absorbing materials, water would seep away into the underlying soil and be lost to the plants. After a week or two, the germination sheet breaks down, through the influence of sunlight and/or water and provides a useful mulch which acts as a further source of nutrients for the plants and helps to bind the surrounding soil together. Since the germination medium is formed from natural materials, its use does not result in pollution of the surrounding environment.

Where the germination medium contains trickle irrigation pipes, these may be lifted at an appropriate time, or may be left in place to continue the irrigation of plants. Similarly, where cover sheets are used, these may, if formed from biodegradable materials, be left in place to rot naturally. Alternatively, where they are formed from non-biodegradable materials, they may be simply be lifted and reused elsewhere.

The seed germination medium of the invention has numerous potential applications and may be used for example to assist in the establishment of indigenous or other plant species (e.g. grass) in hostile environments to impede or reverse desertification, soil erosion or soil loss. It may also be used for the protection of germinating and establishing plant species from the effects of cold, wind, sun-scorch, droughts and pestilence in hostile and favourable conditions.

It will be apparent that numerous modifications and alterations may be made to the embodiments illustrated in the accompanying drawings without departing from the principals underlying this invention, and all such alternations and modifications are intended to be embraced by this Application.

Claims

1. A seed germination medium in sheet form having upper and lower surfaces between which are disposed seeds for one or more plant species, at least the said surfaces being formed from a material which is biodegradable, and the medium being sufficiently flexible and durable to be folded or formed into a roll without disintegrating.

2. A seed germination medium according to claim 1 wherein the biodegradable material is formed from a cellulosic material.

3. A seed germination medium according to claim 2 wherein the cellulosic material is a biodegradable paper.

4. A seed germination medium according to claim 3 wherein the biodegradable paper is recycled paper.

5. A seed germination medium according to claim 4 wherein the recycled paper is unbleached.

6. A seed germination medium according to claim 3 wherein the biodegradable paper is an air-laid paper.

7. A seed germination medium according to claim 6 wherein the biodegradable paper is an air-laid latex bonded paper.

8. A seed germination medium according to claim 7 wherein the air-laid paper is formed from fluff pulp and a latex binder.

9. A seed germination medium according to any one of the preceding claims which comprises a biodegradable paper sheet having upper and lower layers and plant seeds disposed therebetween.

10. A seed germination medium in elongate sheet form having upper and lower surfaces between which are disposed seeds for one or more plant species, at least the said surfaces being formed from a material which is biodegradable, the medium being packaged in a folded form or in the form of a roll.

11. A seed germination medium according to claim 10 wherein contains, in addition to plant seeds, one or more additional components selected from fertilisers, pesticides, water retaining substances and/or other agents to ensure germination and plant establishment.

12. A seed germination medium according to claim 11 wherein the medium contains water-retaining substances in sufficient quantities to maintain the medium in a moist condition for a prolonged period after water has been added to the medium.

13. A seed germination medium according to claim 12 wherein the water retaining substances comprise silica gels or super absorbent acrylic polymers.

14. A seed germination medium according to any one of claims 10 to 13 wherein irrigation tubes are disposed between the upper and lower surfaces of the sheet medium.

15. A seed germination medium according to claim 14 wherein the irrigation tubes are of the trickle irrigation tube type.

16. A seed germination medium according to claim 15 wherein the trickle irrigation tubes comprise strips of a plastics material folded over and stitched along one side to form a pipe or tube-like structure having a leaky seam down one s de.

17. A seed germination medium according to claim 15 or claim 16 which is provided with a super-absorbent water-retaining substance.

18. A seed germination medium according to any one of the preceding claims which is provided m elongate strips which are sufficiently flexible to be packaged m a folded form or roll form without disintegrating.

19. A seed germination medium according to any one of the preceding claims the seed germination medium is constructed m the form of an open lattice.

20. A seed germination medium according to claim 19 which is slit longitudinally such that, when stretched laterally, it forms a lattice.

21. A seed germination medium according to any one of the preceding claims which is in sheet form and is provided with a cover sheet which is separate from or connected (e.g. bonded) to the seed germination sneer.

22. A seed germination medium according to claim 21 wherein the cover sheet is formed of a translucent material.

23. A seed germination medium according to claim 22 wherein the translucent material is a biodegradable paper material similar to the paper material used to form the seed germination sheet.

24. A seed germination medium according to claim 21 wherein the cover sheet is formed of a transparent material .

25. A seed germination medium according to claim 24 v/herein the a transparent material is a transparent polymeric sheet, eg a perforated polyethylene sheet or a polyester fleece.

26. A seed germination medium according to any one of claims 21 to 25 wherein the cover sheet is provided with areas of reinforcement.

27. A seed germination medium according to ciaim 26 wherein the areas of reinforcement are in the form of ribs.

28. A seed germination medium according to claim 27 wherein the areas of reinforcement are in the form of ribs which are raised in a grid pattern over the surface of the sheet.

29. A seed germination medium according to any one of claims 21 to 28 wherein the seed germination sheet and cover sheet are linked by means of integral side walls, thereby forming a closed system.

30. A seed germination medium according to claim 29 wherein the side walls are in the form of re-entrant folds or gussets.

31. A device for promoting seed germination and protecting germinated seedlings against the surrounding environment, which device comprises:

(b) an elongate cover sheet; and (c) side walls connecting the base sheet and side walls; the base sheet, cover sheet and side walls together defining a protective chamber within which seedlings germinated from the seeds may grow.

32. A coversheet in elongate strip form, the cover sheet being formed from a biodegradable material such as a biodegradable paper, and having an array of reinforcing ribs on its surface, the cover sheet optionally being impregnated with a pesticidal and/or pest repellant substance.

33. A seed germination medium as defined in any one of the preceding claims which is provided at an end thereof with a header tube, the header tube being oriented laterally across the end of the sheet, the header tube having an opening at one end thereof for connection to a water supply, and one or more lateral openings for connecting to the irrigation tubes within the sheet.

34. A seed germination medium according to claim 33 wherein each lateral opening extends into a short section of tubing which fits snugly within the said irrigation tubes.

35. A seed germination medium according to claim 34 wherein the header tube is formed from a collapsible material such as a polymeric sheet eg polyethylene sheet.

36. A seed germination medium according to claim 35 wherein the header tube has linked thereto a container containing a source of water-soluble fertiliser or liquid fertiliser.

37. A seed germination medium according claim 36 wherein the container for the fertiliser is a collapsible bag eg formed from a polymer such as polyethylene, and optionally is linked to the interior of the header tube by means of one or more non-return valves.

38. A seed germination sheet according to any one of the preceding claims which is supplied in roll form and the roll is provided with a central core of sufficient rigidity to function as a handle for carrying the roll.

39. A seed germination medium according to claim 38 wherein the central core is in the form of a mains irrigation pipe formed of a relatively rigid material.

40. The use of a seed germination medium as defined in any one of the preceding claims in a method of cultivation.