GB2245555A

GB2245555A - Horticultural material

Info

Publication number: GB2245555A
Application number: GB9113817A
Authority: GB
Inventors: Arnold Rainbow; Robert William Daniels
Original assignee: Fisons Ltd
Current assignee: Fisons Ltd
Priority date: 1990-06-30
Filing date: 1991-06-27
Publication date: 1992-01-08
Anticipated expiration: 2011-06-27
Also published as: GB2245555B; GB9014611D0; GB9113817D0

Abstract

There is provided a horticultural sheet comprising a web of fibres, fertilizer and a water absorbent polymer. It may be used as a plant feed mat.

Description

Horticultural material This invention relates to a new horticultural sheet material.

Horticultural sheet materials for the watering of plants are known. For example capillary matting is commonly used in the absent care of houseplants. Also known are "feed and grow" mats which comprise a sheet material and a fertilizer. However, all of these known materials suffer from the disadvantage that the uptake and/or discharge of water is difficult to regulate.

We have now found a material which overcomes or mitigates this problem.

According to the invention we provide a horticultural sheet material comprising a web of fibres, fertilizer and a water absorbent polymer.

We have found that when materials having ion exchange properties, in particular cation exchange properties are incorporated into the sheet material, the sheet material has a tendency to conserve certain plant nutrients, eg metal ions and ammonium salts.

We particularly prefer the water absorbent polymer to have ion exchange properties. Surprisingly we have found that sheet material incorporating swellable polyacrylamide superabsorbent gels, eg sodium polyacrylamide gel or ammonium polyacrylamide gel are capable of supplying nutrients to the root ball of a plant and of retaining those nutrients once supplied. This material has a further advantage that it can retain water. A particular application of the sheet material incorporating superabsorbent gel is in the long term feeding of hanging baskets.

The amount of water absorbent polymer may vary according to the application intended for the sheet material. However, we prefer the amount of water to be from 1 to 50% w/w, preferably from 1 to 30% w/w, more preferably from 5 to 20% w/w, eg. 12% w/w.

The fibres may be natural or synthetic. Synthetic fibres include, nylon viscose and Terylene. However, we prefer the fibres to be natural. In particular we prefer cellulose fibres, eg wood pulp, distillers grains or cotton. Particularly preferred cellulose fibres include chopped straw and wood chips. We have found that a suitable length for the fibres is from 0.5 to 10 mm, eg 2 to 6 mm mean length. The fibres may be uniform or heterogeneous in length.

Milled peat, preferably sphagnum peat, may also be used as a source of fibre in the web.

The fertilizer may be, for example, powdered or granulated. The fertilizer may be soluble or partially soluble in cold water. We prefer the fertilizer to include sources of nitrogen, phosphorus and potassium. Suitable sources of nitrogen include ammonium salts, eg ammonium sulphate, and nitrates. Suitable sources of phosphorus include phosphate, for example superphosphate or triplesuperphosphate. Suitable sources of potassium include potassium sulphate. We prefer the ratio of nitrogen to phosphorus to potassium to be 16:4:8 (N:P205:K20) The ratio of fibrous material to fertilizer may be from 1:10 to 10:1 w/w, preferably 1:5 to 5:1 w/w, more preferably from 1:3 to 3:1 w/w, eg 2:1 w/w.

The web may include a binder. Binders may take the form of natural or synthetic lattices, eg natural rubber latex, polyvinyl acetate, polyvinyl alcohol, melamineformaldehyde resins or they may comprise solutions of starch, carboxymethyl cellulose, methyl cellulose or sodium silicate.

The web may be layered or interwoven on one or both sides with a scrim, to form a laminated sheet. The scrim may be for example nylon, polyester, cotton, viscose, glass cloth, paper, flannelette or polypropylene. The laminated web will in general have enhanced strength whilst still retaining the other properties of a similar sheet without the scrim.

The material may be manufactured and, where appropriate, bound to the supporting material by known processes, eg processes described in UK Patent Specification No. 1283721.

The thickness of the sheet material will be determined to some extent by the manufacturing process and by the desired use. However, the thickness can be readily varied from 0.5 to 10 mm. the material has a preferred thickness of from 1.0 to 3.Omm.

When the thickness of the sheet is between 1.0 and 3.0mum, the fertilizer is preferably incorporated such that the sheet contains from about 100 to 750, eg 200 to 500g per square metre.

The sheet material according to the invention has a wide range of horticultural uses. for example the sheet can be cut, eg to form a circular or hexagonal mat and placed in contact with or in close proximity to a plant root ball to act as a long term source of fertilizer for the plant.

The invention is illustrated by the following preferred Examples: Examples 1. Plant feed mats A mixture 95 parts coating mixture A and 5 parts polyvinyl alcohol was deposited from a hammer mill onto a paper scrim using a latex binder (12 parts), after the methods described in UK 1 283 721. The sheet material produced was dried to a moisture content of 6%, rolled to a thickness of 2mm and weighed 720g/m2.

Mixture A comPrised Fertilizer 42% w/w Swellable polyacrylamide gel 8% w/w Sphagnum peat 2.5% w/w Wood chip 47.5% w/w A small amount of water insoluble brown pigment was incorporated into this mixture, to colour the feed mats.

Feed mats, eg discs of 15cm diameter prepared from the sheet material, can be placed under pot plants and are capable of supplying nutrients over several weeks, eg 8 weeks.

2. Feed mats for hanging baskets Feed mats for hanging baskets were prepared in a similar manner to that described in Example 1, save that the coating mixture comprised: (Dry Weight) Fertilizer 21% w/w Swellable polyacrylamide gel 12% w/w Sphagnum peat 9% w/w Wood chip 58% w/w The coating mixture was applied to a polypropylene scrim. The dry coating mixture was impregnated with water containing a small amount of surfactant and then water soluble latex binder (Polysar latex 6171) was applied at a rate of 10%.

The sheet material was dried using infra red heaters and steam heated rotating steel drums to a moisture content of 15% w/w, had a thickness of 1.5 mm and had a dry weight of 550g/m2.

Feed mats, in the form of 46cm diameter discs, contained 18.7g of fertilizer. Tests showed that these discs supplied nutrients to plants throughout the growing season. In addition, there was no tendency to mould growth or other visible biodegradation. In general hanging baskets incorporating the discs required fewer waterings and were easier to water.

*The Fertilizer comprised: % w/w Ammonium sulphate 75.45 Triple superphosphate 8.71 Potassium sulphate (50% K20 15.84 Giving a N:P205:K20 ratio of 16:4:8

Claims

We claim: 1. A horticultural sheet material comprising a web of fibres, fertilizer and a water absorbent polymer.
2. A horticultural sheet material according to Claim 1 wherein the absorbent polymer has ion exchange properties.
3. A horticultural sheet material according to Claim 1 wherein the absorbent polymer is a.polyacrylamide gel.
4. A horticultural sheet material according to Claim 1 wherein the amount of water absorbent polymer present is from 1 to 50% w/w.
5. A horticultural sheet material according to Claim 1 wherein the fibres are natural.
6. A horticultural sheet material according to Claim 1 wherein the fibres are cellulose fibres.
7. A horticultural sheet material according to Claim 1 wherein the fibres are of a length of from 0.5 to 10 mm.
8. A horticultural sheet material according to Claim 1 wherein the fibres comprise milled peat.
9. A horticultural sheet material according to Claim 1 wherein the fertilizer includes a source of nitrogen, phosphorus and potassium.
10. A horticultural sheet material according to Claim 1 wherein the ratio of fibrous material to fertilizer is from 1:10 to 10:1 w/w.
11. A horticultural sheet material according to Claim 1 wherein the web includes a binder.
12. A horticultural sheet material according to Claim 1 wherein the web is layered or interwoven on one or both sides with a scrim to form a laminated sheet.
13. A horticultural sheet material according to Claim 1 which has a thickness of from 0.5 to 10 mm.
14. A horticultural sheet material according to Claim 13 which has a thickness of from 1.0 to 3.0 mm.
15. A horticultural sheet material according to Claim 14 containing from 100 to 750 g of fertilizer per square metre.
16. A horticultural sheet material according to Claim 15 containing from 200 to 500 g of fertilizer per square metre.
17. A horticultural sheet material according to Claim 1 incorporating an ion exchange material.
18. A horticultural hanging basket liner comprising a horticultural sheet material according to one of the preceding claims.
19. A horticultural feed mat comprising a horticultural sheet material according to one of the preceding claims.