SPECIFICATIONComposite mulchThis invention relates to a composite mulch.
Flower, vegetable, shrub and tree growers have used various types of mulch, such as farmyard manure, straw, peat, compost, grass cuttings, sawdust, bark and black polythene sheet to control weeds by smothering them, and to assist plant growth by conserving moisture, keeping the roots cool and supplying nutrients as the material decomposes. They all have one or more inherent disadvantages in that they are malodourous, unsightly, unhygienic, lack nutrients or have to be used in large quantities to be effective.
The principal object of the present invention is to provide a mulch that is free from the aforementioned disadvantages.
Accordingly, the present invention consists of a composite mulch which comprises a solid fertilizer, which only disperses slowly, a weed suppressant, peat, and shredded or pulverized bark, all of said fertilizer, said weed suppressant, said peat and said bark being incorporated in a cellulose fibre and lignin binder. Said weed suppressant should be of the pre-emergence residual type of herbicide that is only effective against freshly germinated weed seeds, and is not harmful to established plants. Said solid fertilizer may be either wholly organic or a chemical "controlled release" or encapsulated fertilizer.
It has been found that a composite mulch according to the invention is far more efficient than existing mulches discussed in the second paragraph of this description because the composite mulch need only be spread to a thickness of five millimetres instead of at least twenty millimetres for existing mulches.
The weed suppressant effectively kills any weed seeds as they germinate and because the fertilizer is maintained in an evenly dispersed condition in the composite mulch, it releases nutrients evenly to existing plants.
It is at present considered that the following percentages by weight, give a satisfactory composition from which a composite mulch according to the present invention can be madeCellulose fibres and lignin from 10% to 80% but preferably 23.50%Fertilizer from 10% to 60% but preferably 30.00%Peat from 10% to 60% but preferably 15.00%Bark from 10% to 60% but preferably 30.00%Weed suppressant from 0.1% to 10% but preferably 1.50%The organic fertilizer which is mentioned by way of example and which has been used so far, with excellent results, is waste material from deep litter houses in which poultry are intensively reared. This waste is wood shavings and poultry manure; this is allowed to rot down or compost for about one to three months, and is then milled into small fragments and particles and dried.Solid chemical fertilizers are, however, available which are of a so called "controlled release" or encapsulated kind and it is thought that these could be used instead of, or to supplement, a wholly organic fertilizer with excellent results.
The fertilizer is then mixed with the peat, bark, and weed suppressant and is incorporated as uniformly as possible into the mass of cellulose fibres and lignin binder obtained from waste newspapers, magazines, books, cardboard or kraft paper by suitable treatment. In one form, said suitable treatment is by passing the said materials through a suitable hammer mill and granulator to break them down into a fibrous mixture.
When required for use the composition can be spread evenly over the surface to be mulched and then saturated by spraying water gently over it. Another method of application is to mix the composition with sufficient water to form a pulp. This pulp is then spread, or sprayed, evenly on the surface to be mulched. The water will drain and evaporate from the pulp to leave a mulch having all the advantages of this present invention.
According to a further method of carrying the invention into effect the dry composition is formed into compressed pellets of 2mm to 6mm in diameter. Said pellets are then spread evenly over the surface to be mulched and are soaked with water from a suitable appliance to bed them down and to activate the ingredients in the composite mulch.
The composite mulch may be pigmented, either by the inclusion of a pigment added to the dry composition, or by addition of a pigment when the composition is pulped with water.
According to a further method of carrying the invention into effect a fibrous sheet material is manufacture from the composition on a paper making machine. The fibrous sheet material can then be laid on the surface to be mulched, and dampened with water to become malleable and conform to the contours of the surface on which it has been laid.
According, therefore, to a further aspect of the present invention a method of sowing seeds comprises the steps of forming a pulp from the composition comprising said cellulose fibres and lignin, said fertilizer, said peat and said bark to the percentages by weight given above, but excluding the weed suppres sant. To this pulp the seeds to be sown are added and mixed thoroughly. This pulp can be spread, or sprayed, onto the surface where the seeds are to grow.
It has been found by using this method of sowing that the seeds are bound in place by the cellulose fibres in the composition and are maintained in an evenly dispersed condition as the seeds cannot be blown away by the wind as happens with the existing sowing system of mixing seeds with poultry manure.
According to a further method of carrying the invention into effect a fibrous sheet material is manufactured on a paper making machine from the composition comprising said peat, said bark, said fertilizer and said cellulose fibres and lignin, and the seeds that are to be sewn. The fibrous sheet material can then be laid on the surface where the seeds are to be grown; dampened with water to become malleable and conform to the contours of the soil on which the fibrous sheet material has been laid.
It has been found that where a more aerated texture to the composite mulch is required, this can be achieved by adding a suitable foaming agent to the composition. It has further been found that by adding a suitable surfacant to the composition this improves the adhesion of the material when positioned in place before dry. It has further been found that the water retention properties of the mulch can be considerably enhanced by adding water absorbing polymers.
The preferred source, at present, of the cellulose fibres and lignin is old newspapers, which are fairly easy to buy in suitably large quantities. An alternative source of these materials is waste magazines, books, cardboard, kraft paper, and other sources (such for example as straw) may be found eventually.
Horse, cow or pig manure with, or without, the usual additional straw or other bedding material would also be suitable as the organic fertilizer.