IE41491B1 - Process for preparing peat bodies especially suitable as substrates for growing seeds and plant - Google Patents

Abstract

1491940 Peat blocks as plant substrates TARVAS-REHU OY 1 July 1975 [10 July 1974] 27668/75 Heading ClB Peat blocks for use as growth substrates for plants or seeds are cut from a cleared and drained sphagnum peat bog, dried to less than 35 wt. per cent water, shaped, and pressed to 1/3-1/10 of their initial volume. Cutting may be by sawing, and plant nutrient, lime, or a wetting agent may be added to the blocks for use. The product may be cut partly through to produce several separate blocks with a common base, or several blocks may be provided with a common base of plastic or paper. Holes may be made in the blocks, to receive the seed or plant.

Description

This invention relates to a process for preparing coherent peat bodies which are especially suitable as growth substrates for seeds, plants, cuttings etc. The substrate prepared according to the invention makes the germination, the cultivation and the transfer from one place to another of plants etc. possible, making superfluous the use of separate pots or vessels for keeping the substrate together.

It has for a length of time been known to grow plants in different types of plant pots filled with top-soil or peat.

For decades pots made of clay and later of plastics have been used for keeping the substrate and the plant roots together.

Clay as well as plastics is distinguished by the fact that the roots of the plants cannot grow through the walls of the pots. This makes the pots rather unsuitable for growing plants as the plant before planting must be taken out from the pot whereby its roots are damaged causing unfavourable growth disturbances.

In order to eliminate this often very significant disadvantage, different kinds of pots have been designed which keep the growth substrate together and enable the roots of the plants to penetrate the walls of the pot whereby the plant can be planted on the site o.f growth without removing it from the pot.

A common feature of the above mentioned root penetrable as well as root impenetrable devices is that the plant substrate does not keep together without a surrounding firmer wall, which makes it necessary to use different kinds of pots, nets and boxes. 41481 It is also known to grow plants on so called soil cubes of which yearly huge amounts are prepared in different parts of the world. The soil cubes are prepared from a moist clay and peat rich soil mixture, which by means of a machine designed especially for this purpose is compressed into coherent clods. This coherent mass resembles for example a compressed soil clod kept together by the wet clay material. An advantage of this method is that the roots of the plant planted or sowed therein can grow unhindered into the surrounding earth.

Attempts have been made in many different ways to prepare coherent root penetrable plant substrates. In the U.S.A. cubic bodies from long fiber material have been prepared into which plant cuttings may be sowed or planted to root. In order to reduce transportation volume, pressed peat rondelles have been prepared, into which bitumen has been added to bind the fiber material. This method, which of the methods referred to above is the one which has been furthest developed, has the advantage that the peat clod may be pressed to about one fifth of its initial volume and that after wetting the clod swells and keeps relatively well together. However, the water absorb ing capacity is limited due to the presence of the bitumen, and as a result the pressed bodies swell to their final volume after wetting only very slowly. The bitumen also causes degradation of the growth conditions in the plant substrate in question. Furthermore, the extraction of the peat with bitument is a complicated and expensive process.

Also, according to Swedish Patent 47 203 peat is pressed into coherent bodies whereby several important advantages are achieved, but when wetting such a pressed body it swells and disintegrates and thus needs the support of a pot or vessel The same occurs in our Patent Specification No. 31694. Thus these pressed bodies are not as such suitable for plant growing According to the present invention there is provided a process for preparing peat bodies especially suitable as growth substrates for seeds and plants, which bodies swell when wetted, wherein the bodies are firstly cut as a coherent mass from a drained sphagnum peat bog, from which bog the top vegetation has been previously removed; secondly, dried to a moisture content of less than 35% by weight; thirdly, formed to an intermediate or final required size; and finally, pressed to one third to one tenth of their initial volume, with any subsequent or final sizing thereafter effected.

It has namely been found that a body cut from the bog, which has not been ground or shred, contains sufficiently plant material twisted together, substantially peat moss of the sphagnum genus, to keep the body firmly together in wet as well as in dry state. It has also been found that such a preferably almost completely undecayed peat moss with a value of 1 to 2 on the von Post scale, is very flexible making it possible to press the body together even as much as to one tenth of its initial volume. After wetting such a pressed body absorbs extremely rapidly water with a capillary action and swells instantly almost to its initial volume.

Furthermore, the material is to its technical properties obviously the best of the known substate materials for growing seeds, seedlings, cuttings, plants etc. as it is porous and ferti1izer(s) may be included. Additionally the roots can, unhindered, grow in the substrate and outside its walls, into the surrounding earth, as there is no wall preventing the penetration or directing the direction of growth of the roots, as e.g. a plastic, paper, net or peat wall.

The present invention is not to be identified with the various already long known peat production methods according to which large peat bodies are cut from the bog either with a spade or with different machines for cutting peat bodies.

These peat bodies are dried on the bog whereafter they usually in so called peat moss plants are filled into sacks to be used as peat moss or peat mould which is finely divided and does not keep together.

Preferably drying is effected until the moisture content is 12 to 28% by weight. The bodies may be formed to the required intermediate and/or final size by sawing, and are preferably pressed to one fifth or one sixth of their original volume.

It is known that a peat extracted from a bog is practically void of nutrients and its acidity is low. Thus the peat bodies prepared by the above mentioned method should be further processed in order to be applicable for extremely demanding plant growing. 61601 Accordingly the acidity (pH) of the peat body may be increased by watering the peat bodies with a lime slurry. Lime has a pH increasing effect after watering of the peat bodies. Analytical observations show that the pH in peat bodies prepared from the peat in question is from 3.3 to 3.4 when it should preferably be from 4.5 to 5.5. With the above mentioned addition of lime the pH of the peat bodies is made more suitable for the plants. Into a peat body in which the plants are allowed to grow after rooting, plant nutrients may be added.

In one example excellent results have been achieved by treating the peat bodies with a diluted whole nutrition solution. As such a solution a plant nutrient has been used containing nitrogen 5.2 g/100 ml water, water soluble phosphorus 1.2g/100ml water, and water soluble potash 3.9g/100 ml water, and additionally trace nutrients in a ratio suitable for the plants. Of this plant nutrients 0.05 percent is added to the water used for watering. When watering the peat bodies with this nutrient solution it is evenly absorbed into the whole peat body and is sufficient to ensure the supply of nutrients to the plants, The suitability for plant cultivation of the coherent peat bodies prepared according to the invention may be further improved in the following way : when the peat body has been compressed into one fifth or one sixth of its initial volume holes may be drilled therein by means of a suitable drill the diameter of the holes being for example from 4 to 6 mm.

When a thus compressed peat body swells when wetted a hole is formed in the wet peat body the depth of which is about 1 to 2 cm. When cuttings are to be introduced into the peat body to root they may conveniently be put into the holes so formed. Similarly, a seed from the plant to be cultivated may be placed into these holes already before watering the peat body and attached to the hole e.g. with a glue. Thus peat bodies may be prepared provided with different pre-sown plant seeds.

In a case like this the nutrient balance of the peat body is adjusted according to the needs of the plant.

The peat body according to the invention may furthermore be used so that the pressed dry peat bodies are placed on a base plate e.g. of plastics or paper, which may be packed in. a form suitable for the consumer markets which peat body then swells when a suitable amount of water is added to the plate.

The method may further be modified by gluing separately the peat bodies at a suitable distance from each other for example on a non-woven fabric or paper whereby the mutual distance of the separate peat bodies is adjusted according to the specific growth conditions.

It is apparent from the above that the present invention offers many different modes of application completely substituting the heretofore used different types of pots and such vessels, which have been necessary when growing plants. Additionally, the method makes it possible to improve the crop and growth as the plants may be grown without damaging the roots, when transferring the plants. As the method in addition is surprisingly simple and cheap it will apparently obtain large commercial significance in developing the plant growing stage and in the cultivation of plants and seedlings. It is namely to be observed that all such novel solutions are extremely welcome which aim at rationalizing the plant growing work which is continuously becem'u^more intensive. This applies to horticultural as well as to forest and agricultural economics in different parts of the world.

In the following some Examples_are given in order to illustrate how the method may be applied in practice.

Example 1 On a bog in southern Finland, which was well drained and from which trees, twigs, moss vegetation and stubs on the surface had been removed, and the surface of which had been levelled with a cutter in order to remove loose peat, the production of raw material for the peat body was carried out in the following manner: with a device resembling an agricultural plough, strips with a thickness of 9 cm and a width of 35 cm were cut from the surface of the bog. The strips were allowed to dry on the surface of the bog to a moisture content of about 28 percent, whereafter they were collected by means of a band conveyor onto the trailer of a tracton and transported to the refining plant.

In the plant the peat bodies were placed on a conveyor belt and formed to an intermediate size by cutting away about 1 cm from the edges of the bodies and I cm from the thickness with a saw and the bodies were then cut into pieces of 24 cm length. Thus peat bodies were obtained measuring 8X24X32 cm.

In this Example the peat bodies were pressed with a piston compressor to a thickness of 10 mm and were then formed into a final size by cutting into pieces measuring 8x8 cm.

Thus pressed peat bodies suitable as plant substrates were prepared, which when wetted swelled in about 15 seconds to bodies measuring 8X8X8 cm.

Example 2 On the bog which had been prepared in advance in the above mentioned manner the production of substrate raw material was carried out as follows: according to prior known methods pieces were cut from the bog, the pieces having a thickness of 10 cm, a length of 35 cm and a width of 25 cm. These pieces were allowed to dry on the surface of the bog. When the pieces had dried under the influence of the sun and the wind to a moisture content less than 35 percent, they were transferred to the refining plant where the pieces were further dried to a moisture content of 12 to 20 percent, whereafter the peat bodies were shaped with a saw into plate like form measuring 8X24X32 cm and partly also into a similar form but of half the length: 8X24X16 cm. Furthermore, plate like peat bodies were made having only half the thickness, i.e. having a thickness of 4 cm, a length 24 cm and a width of 16 cm. In this Example dolomite lime was spread evenly on the surface of the peat bodies in an amount of 8 kg dolomite lime per cubic meter of peat body. Thereafter the peat bodies were fed in a band compressor which pressed them into i 4 91 about one third of their initial volume, whereafter the peat bodies were automatically transferred to a hydraulic piston compressor for some time which completed the pressing, the pressing force being about 80 kg/cm . It was possible to increase the pressing force to a maximum of 180 kg/cm , whereby the peat bodies became extremely hard. In the piston compressor the peat bodies were pressed to about from one third to one tenth of their initial volume. After pressing the peat bodies were transferred to a saw which automatically sawed the peat bodies in such a manner that they were not sawed completely through, but were unsawed at their base to remain attached to a common base. From the bigger peat bodies measuring 8X8 cm and from the smaller peat bodies measuring 4X4 cm were formed. After sawing, the peat bodies were transferred to a drilling machine, where a hole of suitable size with a diameter of 4 to 6 mm was drilled simultaneously in all the peat bodies to about halfway the thickness of the peat body. Thereafter the peat bodies were transferred directly to the packing machine. Peat bodies which had been cut all the way through into separate, plate like form, e.g. of the size 40X40X8 mm, were also packed separately into boxes and some were packed directly onto the above mentioned plastics base plates provided with instructions for use. Some of these peat bodies'were transferred to a sowing machine where conifer seeds, ornamental plant seeds or vegetable seeds were sowed in the peat bodies.

In the following two examples are given illustrating the application of the peat bodies prepared according to the invention as substrates for seeds, plants, etc.

Example 1: Growing seeds For this purpose peat bodies were used which had holes drilled therein into which two pine tree seeds per hole were introduced. The pre-sowed peat bodies were placed in a plastic green house and stacked on the ground. Thereafter the peat bodies were wetted with a watering device placed in the green house. In a short time the peat bodies swelled to cover the whole ground of the green house, they did not howev er contact each other at the sawed areas. When the pine plants thus received water their growth took place in a normal period of time. When the pine plants were about 3 months old they were ready to be packed into transport cases in which they could be transported together with their root clods to be planted in the forest. For planting a planting device was used which made a hole of the same size as the growth clod of the plant, in this Example 4X4X4 cm. The plant growth cold containing nutrients as well as water was put into the hole made, and the roots stayed intact and the pine plant in question immediately started to grow, the loss of plants thus being minimized.

Example II Growing plants Into the peat bodies holes were drilled in such a manner that when the peat bodies were wetted the depth of the holes was about 15 mm. Such peat bodies were placed on a table in the green house and wetted. When the peat body had absorbed water and swelled to its initial volume in a few minutes a cutting of poinsettia was placed into the hole which cutting in a conventional manner had been treated with a hormone promoting rooting. When the poinsettia cutting thereafter was able to stay in an upright position by virtue of the coherent peat body and when it was sprayed regularly in a conventional manner it rooted very rapidly in about 14 days the roots growing into peat body. At this stage a dilute fertilization was carried out the plant receiving suitably the plant nutrients required. When the poinsettia plants had grown strong roots the peat bodies were separated from each other and the poinsettias were packed in a conventional manner for transportation to their final site of growth in the green house. Some of them were planted with their peat bodies in pots where a continued cultivation took place.

In this Example it was noted that the poinsettias, which have roots extremely sensitive to damage, thrived extremely well because the peat bodies kept together and the roots could grow unhindered into the peat bodies after the growing stage.

In the foregoing Examples only few modes of application of the coherent peat bodies have been discussed. It should however be stressed that the peat bodies in question may be used for example for growing such important cultivated plants as conifer and foliiferous tree plants, tobacco, coffee, rice, eucalytus, grapes and also several vegetable and ornamental plants.

Furthermore, from an economic point of view a very interesting sector is the one where the method is adapted for such plant cultivation which is becoming more common among amateurs.

The dimensions used in the Examples in the production of the peat bodies in question may naturally be adapted according to the requirements of the growth of the plants either so that the peat bodies are not sawed at all, or so that they are sawed either into separate parts or to pieces staying together at a common base part, or the peat bodies may be divided into all possible sizes, although generally into squares which subsequently swell into cubes, however, in such a manner that when the square is made small it may also be made to swell to be very high. Similarly the degree of fertilization may be varied freely according to the needs of the plants. The peat bodies may also be used when a substrate is to be prepared on a slanting surface, for example at road sides thus preventing the erosion of the ground and making the germination of the seeds of grass or other plants possible. The peat bodies in question may also be provided with different kinds of foils preventing the evaporation of the nutrient solutions from the peat bodies. The plastics may be attached to the peat body before sawing it to pieces, still allowing for a sufficient air circulation during the growth stage.

Claims (11)

1. A process for preparing peat bodies especially suitable as growth substrates for seeds and plants, which bodies swell when wetted, wherein the bodies are firstly cut as a coherent mass from a drained sphagnum peat bog, from which bog the top vegetation has been previously removed; secondly, dried to a moisture content of less than 35% by weight; thirdly, formed to an intermediate or final required size; and finally, pressed to one third to one tenth of their initial volume, with any subsequent or final sizing thereafter effected.

2. A process as claimed in Claim 1, wherein drying is effected until the moisture content is 12 to 28% by weight.

3. A process as claimed in Claim 1 or Claim 2, wherein the bodies are formed to the required intermediate and/or final size by sawing.

4. A process as claimed in any preceding Claim, wherein the bodies are pressed to one fifth to one sixth of their original volume.

5. A process as claimed in any preceding Claim, wherein the pressed bodies are fertilized before use as a substrate.

6. A process as claimed in any preceding Claim, wherein fertilizer is added to the peat bodies.

7. A process as claimed in Claim 6, wherein plant nutrient and/or lime and/or wetting agent is or are added to the peat bodi es.

8. A process as claimed in any preceding Claim, wherein the dried bodies are formed in such a manner that a plurality of bodies are attached to a common peat base.

9. A process as claimed in any preceding Claim, wherein several peat bodies are provided with a common base plate of paper or plastics.

10. A process as claimed in any preceding Claim, wherein holes are made in the peat bodies to receive the seed or plants

11. Peat bodies prepared by the process of any preceding Claim.