AU660643B2 - Plant growth medium and plant cultivation method - Google Patents

Description

AUSTRALIA 660643 Patent Act COMPLETE SPECIFICATI ON

(ORIGINAL)

Class Int. Class Application Number: Lodged: **fee: Complete Specification Lodged: Accepted: Published: Priority: Related Art: S S *ee Names(s) of Applicant(s): ROBERT RIDDELL Actual Inventor(s): Robert Riddell Our Address for service is: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street MELBOURNE, Australia 3000 Complete Specifica.ion for the invention entitled: PLANT GROWTH MEDIUM AND PLANT CULTIVATION METHOD The following statement is a full description of this invention, including the best method of performing it known to applicant(s): PLANT GROWTH MEDIUM AND PLANT CULTIVATION METHOD This invention relates to a plant growth medium and a plant cultivation method. It relates particularly but not exclusively to materials and a method for growing plants wherein the materials are used as a substitute for, or in conjunction with, soil.

Two problems are frequently faced in the cultivation of healthy plants. The first of these is the provision of nutrients to the plant as it grows, and the second is the avoidance of secondary or parasitic growth, such as weeds, which may prevent plants from achieving full maturity.

Various solutions to these two problems have been proposed. Numerous different types of fertilizers are available in order to provide nutrients to growing plants.

Some of these have deleterious side effects, and the usage of "natural" fertilizers such as manure is generally preferred.

However, various contaminants, such as seeds, are often present in manure, so the use of manure frequently leads to S21( secondary growths.

Various techniques have been developed for preventing secondary growth. One of the most common of these is the *sees: application of selective herbicides, designed to retard only the secondary growth. However, appropriate selective 25 herbicides are not always available and many herbicides have 0**S harmful side effects such as soil contamination.

The soil-less cultivation of plants, sometimes known as hydroponics, has been developed as a solution to both of the above mentioned problems, Soil-less cultivation generally involves the planting of plants in an inert material such as sand containing water impregnated with nutrients. The artificial situation thus created enables the horticulturist to ensure that contamination such as foreign seeds which may result in secondary growth is avoided, while at the same time ensuring that the necessary nutrients are provided. The prevention of secondary growth is achieved by ensuring that contaminating elements are not admitted into the system.

However, hydroponic culture is generally suitable only on a small scale and in respect of a narrow range of plants.

2 A frequently used method of natural fertilization is known as "mulching". Mulching involves the spreading over the soil surface of a layer of material that protects the soil and adds valuable nutrients. Mulching reduces the temperature fluctuations in the soil, and prevents the loss of moisture by evaporation. It encourages the development of surface roots and reduces weed growth. Mulching also reduces compaction of the soil in the upper layer, allowing aeration. Mulch materials are generally coarse and porous.

Common mulch materials include pine bark, red gum chips, straw, newspaper, grass clippings, shredded leaves, pine needles, wood turnings, prunings, rice hulls, pebbles and gravel.

According to one aspect of the present invention, there is provided a plant growth medium consisting of o* compacted units comprising: a mulch material; a nitrogen source; and optionally a fertilizing agent.

The mulch material may be any suitable mulch material. It is preferred although not essential that the mulch material be a straw. Suitable types of straw include wheaten, oaten and barley straws. Other suitable alternatives to straw as a mulch material include pine bark, red gum chips, eucalyptus mulch, sawdust, newspaper, grass clippings, shredded leaves, pine needles, wood turnings, prunings, rice hulls and seaweed. The mulch material may comprise a combination of different mulch materials.

The nitrogen source may be any suitable source of nitrogen. It may be a natural or artificial nitrogen source. It is preferably a legume.

The legume may be any suitable type or types of legume. The most preferred type of legume is lucerne. The use of legumes in the plant growth medium is advantageous as legumes provide a source of fixed nitrogen.

The fertilizing agent may be any suitable fertilizing agent or combination of fertilizing agents. It may be any substance which increases production of the soil. It may be a natural or artificial source of one or more of the elements 3 nitrogen, potassium, phosphorus, calcium, magnesium, sulphur or the trace elements iron, manganese, copper, zinc, boron and molybdenum. It is preferred that the fertilizing agent be a naturally occurring fertilizer rather than an artificially created fertilizer, in order to reduce the possibility of deleterious side effects.

It is preferred that the fertilizing agent be decontaminated to ensure that it contains no seeds or other forms of contamination which may give rise to secondary growth.

The mulch material and legume may be present in any suitable relative quantities. It is preferred that the mulch material comprise between ten percent and ninety percent of the volume of each unit, with the legume also comprising I 15 between ten percent and ninety percent of each unit. It is more preferred that the mulch material comprise at least fifty percent of the volume, wi 1 -h the most preferred amount being approximately seventy percent. It is preferred that the fertilizing agent comprise less than five percent of the total volume.

The units into which the plant growth medium is compacted may be of any suitable size and shape. It is preferred that the size be sufficiently small to allow the units to break down easily when water is added. It is preferred that the volume of each unit be between one cubic centimetre and one thousand cubic centimetres, with the most preferred volume being about forty cubic centimetres.

It is preferred that the units further include a binding agent in order to keep the components of the unit together. The binding agent may be any suitable binding agent or combination of binding agents. One suitable binding agent is bentonite. Where a binding agent is used it is preferred that the binding agent comprise less than five percent of the total volume of each unit.

It is preferred that units comprise the following relative quantities by weight: mulch material 50 to nitrogen source 10 to fertilizing agent less than binding agent less than One of the advantages of the plant growth medium of the present invention is that, because the mulch material and the legume are substantially free of seeds and other contaminants which may lead to secondary growth, and the fertilizing agent can be decontaminated, the plant growth medium provides a substantially weed-free environment in which plants can be grown without the necessity of selective herbicides.

According to another aspect of the present invention, there is provided a method for cultivating plants using the above described plant growth medium by inserting a number of the units of the plant gro ;ch medium into a container, adding Swater to create a mulch, and then planting seeds or plants in 15 the mulch.

According to another aspect of the present invention, there is provided a method of fertilizing a plant comprising placing a number of units of the above described plant growth medium around the base of the plant and adding water to create a mulch.

An advantage of the method of the present invention is that the plant growth medium of the present invention when placed around the base of a plant or tree will not be blown r away by wind as is the case with many conventional mulches.

The invention will hereinafter be described in greater detail by reference to the attached illustrations which show an example form of the invention. It is to be understood that the particularity of those illustrations does not supersede the generality of the preceding description of the invention.

Figure 1 is a perspective view of some cylindrical compact units according to one embodiment of thA present invention.

Figure 2 is a side perspective view of substantially cubical compact units according to a more preferred embodiment of the present invention.

Figure 3 is a top perspective view of some substantially cubical compact units according to an i<C P'43< embodiment of the present invention.

The compacted units of plant growth medium of the present invention comprise a mulch material and a nitrogen source.

The pellets of Figure 1 are substantially cylindrical, having a diameter of approximately one centimetre and an average length of two to four centirnetres.

These units can be manufactured in a stock feed compacting machine having one centimetre diameter cylindrical dies. The mulch material and other components are chopped and ground into small pieces before being forced into the cylindrical dies and compacted. However, it has been found that the components of plant growth medium in units of such small size are frequently too small to be of use in io mulching applications. The preferred length of the straw or other mulch material in the compacted units is between one, centimetre and six Nentimetres; mulch materials of shorter length do not provide all the qualities required of a mulch material and they are susceptible to being blown away.

Compacted units of the types illustrated in Figures 2 and 3 are preferred.

0o00. 15 The illustrated units are approximately square in cross-section, with sides of about three centimetres and lengths from about 2mm to 20cm, with an average of about 2 to 4cm. The units illustrated in Figure 2 comprise a grass straw as the mulch material lucerne as the nitrogen source a fertilizing agent derived from a combination of blood bone, animal manure, fish meal, and seaweed S" 20 extract with bentonite being used as a binder to keep the cube together. The units were manufactured on a stock feed compacting machine having square dies, The mulch material and other components were chopped into small pieces before being forced into the square dies and compacted. The compaction occurred without the addition of water.

The cubes illustrated in Figure 3 use a rye straw as the mulch material, and a decontaminated chicken manure as the fertilizing agent.

Because of the amount of friction generated in the unit compacting machine, the compacted units are heated to a high temperature as they are created, It is believed that this temperature is sufficient to sterilize any seeds present -6k6 C INNWORDWMNRMSUCOM1OISIM OW in the plant growth medium, so that the plant growth medium does not stimulate secondary growth.

It is to be understood that various modifications, alterations and/or additions may be made to the components previously described without departing from the ambit of the present invention.

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Claims (7)

1. 2. A plant growth medium according to claim 1 further comprising a fertilizing agent.
2. 3. A plant growth medium according to claim 1 or claim 2 wherein the nitrogen source is a legume. Sao*" 4. A plant growth medium according to claim 3 15 wherein the legume is lucerne.
3. 5. A plant growth medium according to any one of claims 1 to 4 wherein the plant growth medium has been treated to deactivate seeds which may give rise to secondary growth.
4. 6. A plant growth medium according to any one of claims 1 to 5 comprising the following relative quantities by weight: 0.04: mulch material 50 to nitrogen source 10 to 25 fertilizing agent less than binding agent less than
5. 7. A plant growth medium according to any one of claims 1 to 5 further comprising a binding agent.
6. 8. A plant growth medium according to any one of claims 1 to 7 wherein the compacted units are about three centimetres by three centimetres in cross-sectional area, with an average length of about two to four centimetres.
7. 9. A method of cultivating plants using a plant growth medium according to any one of claims 1 to 8, the method comprising inserting a number of the units into a container, adding water to create a mulch, and then planting seeds or plants in the mulch. A method of fertilizing a plant using a plant 9 growth medium according to any one of claims 1 to 8, the -8- method comprising placing a number of the units around the base of the plant, and adding water to create a mulch. DATED: 12 August 1994 PHILLIPS ORMONDE FITZPATRICK Attorneys for: I ROBERT RIDDELL A/4'cer2 4: 6 0 0 4* 9 (2456v) -9- ABSTRACT A plant growth medium is provided in compacted units, comprising a mulch material and a nitrogen source such as lucerne. The compacted units preferably further include a fertilizing agent and a binding agent, and the preferred volume of each unit is around 40 cubic centimetres. The plant growth units are useful either for growing plants in soil-less cultivation or as a fertilizing mulch spread on top of soil. 9 f to )goo L 0 goo 1 a 00 i* 0 V...r gr,