WO1988006839A1

WO1988006839A1 - Seed capsule and process for the preparation of a seed capsule

Info

Publication number: WO1988006839A1
Application number: PCT/SE1988/000134
Authority: WO
Inventors: Dieter Neidhardt
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-03-17
Filing date: 1988-03-16
Publication date: 1988-09-22
Anticipated expiration: 1989-09-17
Also published as: SE8701099A0; SE8701099D0

Abstract

Seed capsule comprising a blend of a moisture retaining agent and a disintegrating agent in which one or more seeds are embedded, the hole being sealed, for instance the capsule being coated at least partially with a protective layer. The moisture retaining agent comprises 80-20% of peat and 20-80% of microcellulose, and a disintegrating agent in an amount of up to 10% by volume of the moisture-retaining agent is preferably admixed thereto. The optional protective layer comprises a water-soluble or water-swellable film. The seed capsule can be prepared by blending peat and microcrystalline cellulose in an amount ratio of 4:1 to 1:4 and optionally a disintegrating agent, after which the resulting blend is compressed to tablets, at least one hole being made in each tablet, for example by punching or boring, and at least one seed being introduced into each hole and the tablet optionally provided with a protective layer. The seed capsule is intended for sowing, especially of trees such as conifer, the seed capsule being placed on the ground or possibly somewhat below ground.

Description

Seed capsule and process for the preparation of a seed capsule

This invention relates to a seed capsule and a process for the preparation thereof. The seed capsule according to the invention comprises specifically a blend of a moisture retaining agent and optionally an disintegrating agent wherein one or more seeds are inserted in a cavity, the compound optionally being surrounded at least partially by a protective layer.

It has been found that the use of seed capsules or seed pellets provides an improved germinating rate of seed, and due to this the required number of seeds and consequently the costs of sowing can be considerably reduced.

WO 84/04651 discloses a seed capsule consisting of a compressed envelope in two parts, at least one part being provided with a cavity in which one ore more seeds are inserted. The capsule is finished by applying the second part to the first. The material in this capsule is preferably peat but can be some other water absorbent material such as cellulose pulp.

DE-A-1 937 512 describes seed pellets prepared by coating a seed completely with sugar and thereafter with finely beaten cellulose. The sugar is thereafter dissolved.

According to US-A-3 690 034 a seed capsule is prepared in that a seed is embedded in a resilient material surrounded on two sides by a more compressible material, after which the capsule is compressed. The compressible material is preferably vermiculite but may contain peat and/or mechanical cellulose pulp. The resilient material is preferably soluble and sorbitol is indicated as suitable. The seed capsule is preferably pressed with a higher pressure at the periphery. A seed ampoule with one or more seeds embedded in peat or the like is described in SE-A-8 104 894-4. Further peat containing "fertilizer" etc. can be applied on any side of this seed capsule and at least this part is wrapped up in a piece of newspaper or a similar absorbent material. Norwegian patent 148 977 teaches a seed carrier containing peat and fibrous material. The fibrous material is preferably a cellulosic material or mineral fibers. When the fibrous material comprises a cellulosic material is it above all waste paper. The peat and the fibrous material are prepared to a slurry, optionally together with the seeds, after which a sheet-like object is prepared, for example by usual papermaking technique. The resulting "paper" with the seeds therein is the seed carrier. Swedish patent 73 523 relates to a machine for preparation of briquettes containing seed. The briquettes should be prepared from a suitable material and provided with holes into which earth, seed and finally earth again over the seed are introduced. The briquettes have apparently been pressed in usual manner at a low pressure.

International application WO 86/00001 relates to a seed pellet and a process for the preparation thereof. The seed pellet consists of at least one seed in an organic substrate and, moreover, contains earth. Nutrients, organic fertilisers, fungicides, pesticides etc. can be present. The organic substrate can consist of a plant material that is not lignified. Wetting agents may promote the wetting of the outer surface. One bitter principle is also included. The pellet is also provided with a semi-permeable casing of a starch and/or latex. The pellets are prepared in that the material is mixed and thereafter pressed.

However, all these known seed capsules, seed pellets or sowing pellets have disadvantages, either a low germination rate and/or difficulties in or costs of preparation or in another way.

Now, it has been found that these disadvantages are eliminated by means of a seed capsule characterized in that the moisture-retaining agent consists of 80-20% of peat and 20-80% of microcellulose and optionally a disintegrating agent up to an amount of 10% by volyme of the moisture retaining agent, the compound of moisture retaining agent and disintegrating agent being in the form of a tablet compressed under a pressure of at least 100 MPa and the possible protective layer around the seed capsule consisting of a water-soluble or water-swellable film.

The peat used has preferably been taken from a peat bog and pressed and/or dried in the usual way for use as additive to garden earth. The moisture content based on dry peat is preferably 15±5%. The peat is preferably passed through a sieve having a mesh size (opening) of 2-4 mm, i.e. the peat is finely fractionated. It is also suitable to eliminate small particles, i.e. such passing a sieve having a mesh size of 1 mm or less. The peat is conveniently used in an amount of 70-30% by weight, preferably 60-40% by weight, for example 50% by weight of the moisture-retaining agent.

Microcrystalline cellulose is not a native cellulose of a fibrous structure. The microcrystalline cellulose is a partially depolymerized cellulose and has a levelled out degree of polymerization. As is apparent from its name it consists of microcrystals.

The microcrystalline cellulose used according to the invention has preferably been prepared by acid hydrolysis of cellulose (normally cellulose pulp that has been prepared from wood in usual manner). This acid-hydrolyzed cellulose with levelled out degree of polymerization is preferably ground and dried, for example by drying in bulk or by spray drying. A microcrystal of such a cellulose can for example have a size of 150 x 15 × 10 nm. A suitable microcrystalline cellulose is that manufactured by FMC, USA, by the name of Avicell ^®, for example Avicell ^® PH. The microcrystalline cellulose is preferably used in an amount of 30-70% by weight, preferably 40-60% by weight, for example 50% by weight, of the moisture retaining agent. The disintegrating agent, when used, consists of a material capable of swelling to a heavily large extent at absorption, and it should also be highly absorbent. Suitable such agents are for instance cross-linked cellulose ethers such as cross-linked sodium carboxymethyl cellulose. A suitable one is that prepared by FMC Corp. USA, by the name of

AC-Di-Sol^® . The disintegrating agent is preferably used in an amount of 1-7% by volume, preferably 2-6% by volume, for example 3-4% by volume, of the moisture-retaining agent. However, it is obvious that the disintegrating agent is no necessary constituent in the present seed capsules.

In the preparation of the seed capsule according to the invention peat and microcrystalline cellulose are blended in the intended ratio and optionally together with a disintegrating agent. The resulting blend is thereafter compressed to tablets of a suitable form, for example ball form, egg formo or the like. The machine pressure when forming the tablets is that which is usual in tablett making, e.g. at least 100 MPa up to 200 MPa or more. The resulting tablets are provided with a hole, e.g. by punching, boring or the like, optionally during the very tablet making process, after which preferably one seed, but also two or more seeds are placed in the hole made. The tablet may thereafter be coated at least partially with a film, the primary object of which is to maintain the seed(s) on place. The film should not be watersoluble but easily dispersible in water. For example, it can consist of some partially substituted hydroxyalkyl ester of cellulose together with a polyethylene glycol derivative, e.g. partially substituted hydroxypropyl methyl cellulose and polyethylene glycol stearate prepared by Seppi, France, by the name of Sepifilm^®. However, the most preferable way is to put a minor amount of peat or blend used for the tableting as a plug into the hole without coating the tablet.

It is possible to add fertilizer, fungicides and other additives to the moisture-retaining agent. Dyes, fungicides etc. can be included in the optional film layer. These agents are by no means necessary but for example dyes may be suitable for identification of the seeds. The object of the film layer is i.a. to prevent birds from getting at the seed but also to reduce the evaporation from the near surroundings of the seed The present seed capsules are useful for all kinds of seed, such as seed of forest trees, but they are especially intended for conifer seed and above all for pine seed but also seed from spruce.

The process according to the invention for preparation of a seed capsule is characterized in that peat and micro-cristalline cellulose in an amount ratio of 4:1 to 1:4 and optionally a disintegrating agent are blended, after which the reslting blend is compressed to tablets, that at leat one hole is made in each tablet, for exemple by punching or boring, that at least one seed is introduced into each hole and that the tablet is optionally provided at least partially with a protective layer. In principle, the hole can be made on any side of the tablet.

The present seed capsule is used in sowing , espec ially of trees, such as conifer, the seed capsule being placed on the ground, or optinally somewhat below the ground surface, and the seed capsules being spaced from each other. The distance between the seed capsules is dependent on the kind of seed, for conifer such as pine for example about 0.2-0.5 m.

The present seed capsule in the form of a tablet can be easily transported in bulk. For example in bags, without any risk for damage. The tablet can thereafter be easily transported to the place of sowing and treated in sowing machines. As the seeds in the tabletts have a high germinating rate sowing with the present seed capsules give evenly distributed plants with the intended density (intended distance between the plants).

Thus, by the present seed capsules sowing of seed is possible and plants can be brought direct to the place of growth without the need of expensive forest nurseries. By the design given to the seed capsule the seed obtains optimum conditions for germination and a following growth on the place where it is planted.

Claims

Claims 1. Seed capsule comprising a blend of a moisture retaining agent and optionally a disintegrating agent, wherein one or more seeds are inserted in a cavity, said blend optionally being coated at least partially with a protective layer, c h a r a c t e r i z e d in that the moisture retaining agent consistε of 80-20% of peat and 20-80% of microcellulose, a disintegrating agent in an amount of up to 10% by volume of the moisture retaining agent preferably being admixed to the moisture retaining agent, the blend of moisture retaining agent and disintegrating agent being in the form of a tablet compressed under a pressure of at least 100 MPa and the optional protective layer consisting of a waterεoluble or water-swellable film.

2. Seed capsule according to claim 1, c h a r a c t e r i z e d in that the peat is a finely fractionated peat.

3. Seed capsule according to claim 2, c h a r a ct e r i z e d in that the peat passes a sieve having a mesh size of 2-4 mm.

4. Seed capsule according to any of claims 1-3, c h a r a c t e r i z e d in that the microcrystalline cellulose is an acid hydrolyzed cellulose with a levelled out degree of polymerization.

5. Seed capsule according to any one of claims 1-4, c h a r a c t e r i z e d in that the moisture retaining agent comprises 70-30% by weight, preferably 60-40% by weight of peat and 30-70% by weight, preferably 40-60% by weight of microcrystalline cellulose.

6. Seed capsule according to any one of claims 1-5, c h a r a c t e r i z e d in that the disintegrating agent comprises a cross-linked cellulose ether in an amount of 17% by volume, conveniently 2-6% by volume, preferably 3-4% by volume, based on the moisture retaining agent.

7. A process for the preparation of a seed capsule according to claim 1, c h a r a t e r i z e d in that peat and microcrystalline cellulose in an amount ratio of 4:1 to 1:4 and optionally a disintegrating agent are blended, after which resulting blend is compressed to tablets, that at least one hole is made in each tablet, for example by punching or boring, that at least one seed is introduced into each hole and that the hole is clogged, optionally by providing the tablet with an at least partially covering protective layer.