WO2021074037A1

WO2021074037A1 - Method for producing and harvesting a plant mat having a predetermined thickness

Info

Publication number: WO2021074037A1
Application number: PCT/EP2020/078456
Authority: WO
Inventors: Jérôme GUDIN; Edmond-Pierre Picard
Original assignee: Natural Grass
Priority date: 2019-10-14
Filing date: 2020-10-09
Publication date: 2021-04-22
Also published as: FR3101752B1; FR3101752A1

Abstract

This method comprises the following steps: - preparing and levelling a support plot consisting of a support substrate (1) capable of being cultivated; - installing on said support plot a stack of superposed geosynthetic sheets consisting of at least two geosynthetic sheets, through which the roots of the plant mat can pass, and that are able to be separated from one another; - spreading a growing substrate (4) on the geosynthetic sheet on the top of the stack in order to form a layer of constant thickness which is equal, once said growing substrate (4) has been compacted and levelled, to said predetermined thickness; - growing a plant mat (5) on said growing substrate (4); - harvesting said plant mat (5) by separating two directly superposed geosynthetic sheets from one another in order to lift said growing substrate (4) and the plant mat (5) which are laid on top of said stack and in order to cut roots of said plant mat passing through the stack of superposed geosynthetic sheets.

Description

Title of the invention: [Method for producing and harvesting a plant mat having a predetermined thickness]

Technical area

The present invention relates to a method for producing and harvesting a plant mat having a predetermined thickness, in particular for the maintenance of herbaceous surfaces such as sports fields.

Technological background

[0002] [Regarding the cultivation of sod turf and the recovery of this sod, it has long been known to produce sod in full mass in a field and then to harvest it, once it has grown and its roots are sufficiently dense, using a vehicle with a horizontal vibrating blade moving back and forth in the ground. This blade cuts grass roots to the depth of the blade as the vehicle moves through the field. It is also known that the strip of this grass, the roots of which have just been cut and the lateral edges cut, can be wound on itself around a support cylinder and then transported in the form of rolls of grass, the thickness of which corresponds to the cutting depth by the horizontal cutting blade. These turf rolls can then be unrolled and installed on another land, or host land, previously prepared: the roots, and therefore the turf, begin to develop again in the substrate of the host land, if however the soil has has been adequately prepared, if the time between recovery and installation is not too long and if proper care is given to the newly installed turf.

This well-known method of cultivating sod turf or other ground cover plants in full mass is by far the most classic method: the roots are in no way constrained during the period of sod cultivation, which allows thus having a stock of living sod in the sod which can be kept waiting to be harvested or recovered for a fairly long time, ranging from a few months to a few years.

[0004] Alongside this so-called full-mass cultivation technique, there is also known a technique of soilless cultivation which consists in cultivating plants (grass or ground covers) on a support that is impervious to the roots, most often on very low thicknesses, to produce plates or small, thin rolls of a lawn: it is then harvested very young and transported intact, without cutting the roots, with a very thin layer of substrate and keeping 100% of the roots that this young grass has developed in this thin layer of substrate. This method has the advantage of offering a very young and intact product, which therefore takes root and develops very quickly, being harvested at about 3 months (instead of a minimum of 9 to 18 months for a grass in open ground). This grass has, in addition to the advantage of being harvested with 100% of its roots, of not containing in principle any weeds (except for example those possibly contained in the seeds of the sowing) thanks to this method of production outside. ground. The downside, on the other hand, is that it is a turf whose roots are not yet able to bind a thick layer of soil and that the turf patches produced cannot therefore constitute a strong mechanical mass. as is the case with a thick plate of full-mass veneer turf, and a fortiori with a thick plate of fiber substrate. In addition, this grass cannot be kept for long in a sod: indeed the grass must be harvested as soon as it is ripe, otherwise the roots are obliged to line the waterproof support to the roots on which the thin layer is installed. of substrate, which then makes it unsuitable for use as a sod, so that it no longer needs to be harvested and expires in a few weeks. As a result, the stock of "living" sod expires very quickly after the date on which it becomes usable.

[0005] In recent years, a traditional cultivation in full mass of turf grown on a fiber substrate with the aim of harvesting it and placing it elsewhere on a reception area has already been practiced; these lawns cultivated on fiber-reinforced substrate were then harvested in the traditional way, i.e. using a cutter fitted with a horizontal knife moved back and forth to cut the substrate and the roots to the desired depth.

Often, the tires of the cutter or the tractor pulling the cutter slip and damage the grass to be harvested. In other cases, it has been found that the sod appears to be cutting correctly but that in reality the rolls of sod stretch several meters and then tear during installation. Other experiments give the impression of correct cutting, but at the cost of less fiber in the growing medium. However, a sufficiently reduced fiber density to facilitate cutting is then insufficient because the result no longer corresponds to the desired objective of a lawn not only in rolls of a constant thickness, as must be the veneer rolls, but also and above all a subsequent resistance to any mechanical stress which is very significantly greater than that of a roll of non-fiber sod.

[0007] However, an analysis of the phases of the traditional process of full mass removal and tackling on the new ground makes it possible to clearly highlight the critical points of traditional techniques when cutting and winding the turf around a cylinder. to form rolls of veneer sod. Careful analysis of these critical points then shows the reasons why this traditional technique is both compatible with a non-fiber substrate which does not resist. much to the back and forth of the knife, but however incompatible with a fiber substrate, especially thick and especially for wide rolls.

[0008] These main critical points of dysfunction of traditional plating operations in full mass according to the conventional technique can be identified in the 4 main phases of the traditional process which are:

- cutting or cutting the grass with a horizontal blade moving back and forth;

- winding the turf in rolls around a support cylinder, this winding being most often carried out during cutting, on the same machine and jointly with this cutting;

- the transport of rolls of grass comprising a substrate;

- unwinding of the rolls during installation.

[0009] It is sometimes observed that it is the winding itself which can be the direct cause of elongation of the sod rolls. There are also many situations where it is the uncoordinated combination of cutting and rewinding that produces the damage. However, it is most often observed that the problem of elongation of the rolls is prepared or created during the cutting phase and that it then materializes during winding (potentially continuing during unwinding).

A first cause of elongation identified during winding is linked to winding the roll of grass with an insufficient radius of curvature. This effect is all the greater when the strip of cut grass is thick and the substrate is fiber-reinforced; in fact, the more the substrate is fiber-reinforced, the more the substrate exerts a force opposing the curvature of the strip of cut grass and this is the effect ultimately sought in the field. Also, the more fiber-reinforced the substrate and the greater the thickness of the grass roll, the greater the resistance to curvature of the grass strip. As a result, winding is more difficult on a small diameter roll and this winding cannot then take place without ultimately deteriorating the characteristics of the product. So if we try to force a thick strip of cut and strongly fiber-reinforced grass to wind up with a radius of curvature that is too small, we end up with:

- either the fiberization is resistant enough to block the system;

- either that the torque developed by the system to force the winding, by a kind of rolling during the winding of the grass strip, ends up tearing the fiber substrate, visibly or not, by stretching all the fibers in the direction of the curvature until the restoring forces of the fiber-based substrate are broken, the ul ter efficiency of which may then be greatly reduced.

A second cause frequently highlighted by the analysis of the winding phases according to conventional methods is the poor coordination of the kinematics of the various components, due in particular to a vehicle which moves forward with a belt which pulls the roll of grass and a winder which turns at a certain angular speed and with too strong a winding torque or a poor adaptation of the forward speeds of the vehicle, the speed of traction by the belt and the tangential winding speed around the roll. If the tangential winding speed, which is equal to the angular speed of rotation multiplied by the outer radius of the roller, is greater than the forward speed of the tractor, this mechanically creates a tension of the strip of grass between the ground and the roller and it follows that the speed difference between the tangential speed and the forward speed is done in 3 ways:

- part of the speed difference is absorbed by the sliding of the roller on its drive support (ie a reduction by disengagement of the angular speed of the roller relative to its angular drive speed). This effect can be maintained permanently.

- part of the speed difference is absorbed by the sliding of the grass strip on the roller which drives it (i.e. a difference in speed of rotation between the actual winding of the grass and the angular speed of rotation of the roller). This effect can only dampen a very short difference in speed but is quickly limited because the turf roll quickly reaches its maximum degree of tightening.

- finally, all the difference in tangential speed which has not been absorbed by the successive skidings of the roller on its drive support and of the strip of grass itself on this roller is absorbed by an elongation of the roller of grass. - even, whether on the roll itself or between the ground and the roll.

However, for a constant angular speed of rotation, the tangential speed at the edge of the roll increases in proportion to the outside diameter of the roll of grass which itself increases from turn to turn during the winding of the strip of grass, in adding 2 times the thickness of the veneer substrate with each wrap around the roll. Thus, for a constant roller rotational speed, the tangential speed difference increases in proportion to the increase in diameter.

Considering, for example, a roll diameter of 20 cm at the start of winding and an outer diameter of 150 cm at the end of winding, this would make a 700% variation in diameter and therefore tangential speed for a constant angular speed, which therefore implies, in order to adapt to these very important variations, the need to be able to permanently adjust the winding speed and torque. A lack of adjustment is then a cause of traction on the strip of grass, such as to stretch it detrimentally.

A third cause of elongation identified during winding relates to the imperfect coordination of the two cutting and winding operations, generally combined. Thus, if you pull too hard to roll up the strip of freshly sod cut, it may happen that the cut strip is lifted directly behind the cutting blade instead of falling back on the floor a sufficient distance to allow the cut not to be influenced by the subsequent rewinding which should principle, to be an independent operation. In this case, it is observed that the jolts associated with the difficulty of cutting in the fiber-based substrate while pulling on the strip of grass being cut have a high probability of transforming into elongation. This situation can possibly relieve the knife and give the illusion that the cut goes easily despite the fiberizing of the substrate, the grass roll being in reality continuously torn due to the traction linked to the winding instead of being cut. in the mass by the knife. In fact, this disturbance is a situation frequently encountered with particularly resistant fiber substrates because it is precisely the settings which give the impression of cutting the fiber substrate well and which very often are those which allow the knife not to be blocked, despite the resistance of the fiber drawing, by the effect of the winding traction according to the process described above and which in fact leads to tearing the wound strip of grass, this process resulting in a deep deterioration of the roll of grass, not detected when moving but only visible at the time of installation. The fourth cause of dysfunction is the cutting operation itself by the horizontal knife moving back and forth.

If the three causes described above depend on the way of implementing the traditional method of harvesting, this fourth cause of malfunction is intrinsically linked to the conventional method of cutting by a horizontal knife.

When winding by pulling on a strip of grass freshly cut by the horizontal cutting knife, the damage is all the more important as the strip of grass has already been weakened or as its shape moves away from a parallelepiped with the shape of a perfect rectangle on the surface and a perfectly constant thickness. Also, even before undergoing the negative effects described above during the winding phase proper or due to the combination of winding and cutting, it is obvious that it is the cutting phase which is by itself the most problematic dom mageable phase in the case of lawns grown on fiber substrate according to the processes already described above.

[0016] There are thus three main usual factors of weakening of the strip of grass during cutting by a horizontal blade animated by a back-and-forth movement:

- the vertical cutting of the edges by the two vertical axes which support the horizontal recovery blade;

- the shape and movement in space of the horizontal blade;

- the local cut of the horizontal blade. In the case of a fiber substrate, it is simply necessary to have an animated rotating disc (like a grinder) to cut the grass in front of each of the two vertical axes which support the horizontal recovery blade. This detail can therefore be resolved quite easily.

[0018] The same is not true for the other two factors stated above.

[0019] In fact, the resistance to cutting linked to the presence of fibers which oppose the advancement of the knife causes two fundamental problems:

- some of the fibers in the path of the knife are not cut but are dragged by the knife and stretched in the direction of travel of the vehicle: this phenomenon intrinsically weakens the cut grass strip and destabilizes the lower part over a certain height of the fiber substrate near the bottom where this strip of grass is cut and, moreover, the fibers accumulate thus causing an irregularity of the cutting conditions during advancement;

- the cutting resistance generated by the presence of the fibers creates resistance forces to the advancement of the knife which affect the knife and the entire cutting assembly and modify the geometry and kinematics of the knife movement.

The essential lepéié malfunction factor in this cutting phase is the width of the rollers. Indeed, the geometry and the kinematics of the movement of the knife change almost exponentially with the width of the grass roll.

Indeed, the traditional technique implies that the horizontal knife driven by a reciprocating movement is held at both ends, at a distance equal to the width of the roll of grass strip. However, when an elongated metal blade of this type and held at both ends meets strong resistance, it cannot retain its perfect shape as a horizontal segment: it undergoes a deflection and twists. Thus, even if the horizontal blade is ideally assumed to be perfectly horizontal and moved back and forth in the direction of movement, it is not in reality. In addition, for a given resistance density, the blade deforms all the more, by flexing and twisting as the two ends of the horizontal knife are far from each other. When, for example, we double the length of the blade (that is to say the width of the strips of cut grass) we double at the same time the resultant of the resistance forces on the knife; and simultaneously, we double the length of the blade and therefore the moment on the ends of the forces exerted in the middle and, by integrating the moment on the length of the blade, we multiply at least by 10 the amplitude of the distortions (arrow, twist ) of the blade, until either the blockage or breakage of the blade or its supports or an aberrant cutting geometry is reached. Also, narrower rolls would be required to successfully cut grass rolls from fiber substrate, but there is still a demand in the market for wide and thick rolls of grass to allow grass strips to be stable upon installation. It is precisely to improve immediate stability and long-term stability that we choose a fiber substrate: it is therefore essential to find a technology for harvesting fiber grass that is not penalized by the width of the rollers. of turf.

[0022] Another problematic factor during cutting is that the tractor, which pulls the cutter (or the cutter itself if it is self-propelled), rolls over the grass to be harvested and which this tractor must necessarily, in order to overcome the horizontal forces which oppose the advancement of the knife, exert in the opposite direction on the grass a horizontal force equal in intensity to the resultant of these forces. When the forces opposing the advancement of the knife are considerable due to the presence of the fibers, the points of support of the tractor on the grass therefore tend to slip and the only way to avoid the slip is then to have a heavy tractor and relatively narrow tires to exert sufficient vertical force so that the frictional force parallel to the turf surface is in the Coulomb cone with respect to the take-up of the tractor weight on the fulcrum in question. Due to the fact that the weight of the tractor is also distributed over the same contact surface, the only solution not to slip, despite a significant tangential resistance force, is therefore to have a significant tractor weight in relation to this surface of tire-turf contact. The result is that grass is often damaged before it is even cut.

summary

The method according to the present invention, developed to allow the cultivation of grass in fiber or non-fiber substrate, the harvest of this grass having a predefined thickness and the laying of this fiber grass combines the advantage, on the one hand , cultivation in full mass which allows the grass to be harvested in thick rolls and a living storage of a few months to a few years of said grass ready to be harvested, and, on the other hand, as for above-ground lawns, the fact of not requiring the use of a vehicle equipped with a horizontal vibrating blade animated by a back and forth movement in the ground to cut the roots of the grass to the depth of the blade during the advancement of the vehicle in the field.

[0024] The main objective of the method according to the present invention is to overcome the many problems which have arisen during harvesting tests or during the laying of cultivated lawns on substrates, in particular fiber-reinforced substrates, with the conventional method of a stripper. equipped with a horizontal knife moving back and forth to cut the roots and the substrate to the desired depth. In addition, the development of the process has simultaneously made it possible to develop other advantages and applications, including for non-fiber lawns, which will appear later.

[0025] Also, a main aim of the present invention is to provide a method making it possible to harvest rolls of grass strip, produced in particular on a fiber substrate. with a high density of fibers, of a large predetermined thickness and of a great width, without however exerting forces liable to damage these rolls of strips of grass or rolls of grass.

Another object is to provide a method for harvesting rolls of sod, fiber or not, of a large predetermined thickness and a large width without significant investment cost for the recovery equipment.

[0027] A further object of the present invention is to provide a method for harvesting the sod of the predetermined thickness and for winding it into rolls of sod of said thickness without using an animated horizontal knife and without having to cut the sod. substrate.

Another object of the present invention is also to make it possible to avoid the elongation of the strip of grass during its winding or during its unwinding by the tensile forces exerted on the roll of grass during winding. or during unwinding.

These goals, as well as others which will appear subsequently, are achieved by a process for producing and harvesting a veneer plant mat having a predefined thickness, which is characterized, according to the present invention, in that '' it includes the following steps:

[0030] Preparation and leveling of a support plot consisting of a support substrate suitable for cultivation;

[0031] Installation on the support plot of a stack of superimposed geosynthetic layers consisting of at least two geosynthetic layers, capable of being crossed by the roots of the plant cover, and of being separated from each other;

Spreading a culture substrate on the top geosynthetic sheet of the stack to form a layer of constant and equal thickness, once the substrate is compacted and leveled, to said predetermined thickness;

Cultivation of a plant mat on said cultivation substrate, for example until the roots of said plant mat are sufficiently developed to colonize said cultivation substrate and to have passed through all the layers of the stack to the substrate - support;

Harvesting of said plant cover by separation, one from the other, of two directly superimposed geosynthetic sheets, by exerting on one said lower geosynthetic sheet a force adapted to hold it in place above said parcel-support and by exerting on the other said upper geosynthetic sheet a force adapted to detach it from the lower geosynthetic sheet on which it rests, to lift said culture substrate, and the plant mat placed above on said pile and to sectioning the roots of said vegetal mat crossing the stack of superimposed geosyn thetic layers.

In a more economical configuration, the method is implemented with a battery two geosynthetic sheets, the lower geosynthetic sheet directly placed on the support plot and the upper geosynthetic sheet placed directly on the lower geosynthetic sheet, the growing substrate being placed directly on the upper geosynthetic sheet.

In this configuration, the culture substrate and its plant cover are placed directly on the upper geosynthetic sheet, which is itself directly placed on the lower geosynthetic sheet, itself directly placed on the support plot.

It is generally sufficient that only the lower geosynthetic sheet remains in place to strengthen the surface. However, in other cases, we can have a geosynthetic web under the lower web to also leave it on the support plot during removal to maintain a reinforced surface to facilitate the next crop.

[0038] It can also happen that a geosynthetic sheet is placed above the upper geosynthetic sheet to have a role of reinforcing the placed plating roll, especially when the upper geosynthetic sheet is removed during the plating. However, the most frequent case is to leave the upper geosynthetic sheet in place when we want to strengthen the veneer and to remove it if not to reuse it in a new crop. The main advantage of a sheet above the upper geosynthetic sheet is to be able to leave in place on the host site a geosynthetic sheet with different characteristics, more flexible and more open, for example.

However, it can also be advantageous from an economic point of view to install a stack of several geosynthetic sheets and to extract only the sheet from the top of the stack during the displacement because this makes it possible to minimize interventions on the plot between the different cultures. However, this way of proceeding means that the second web from the top will be a lower web for the first crop and an upper web for the next crop. This variant of the process has the economic advantage of a single intervention for several crops, but does not differentiate the type of water table between the upper geosynthetic water table and the lower geosynthetic water table.

Advantageously, the culture substrate spread over the upper geosynthetic sheet is a fiber substrate.

Preferably, the fiber-reinforced culture substrate spread over the upper geosynthetic sheet is a substrate comprising fibers, sand and a part of cork, where the cork represents at least 5% by apparent volume of the fiber-reinforced culture substrate spread. on the upper geosynthetic sheet.

Advan tageusemen t, for a veneer application for a sports field, the cork represents more than 30% by apparent volume of the fiber culture substrate spread over the upper geosynthetic sheet.

Advantageously, the cultivated and harvested vegetal carpet is a lawn of grasses. According to an alternative embodiment, the plant mat is a carpet of ground cover plants.

Preferably, the growing substrate, the plant mat and the upper geosynthetic sheet are lifted together during the separation of the two geosynthetic sheets and are also wound together on a roll.

According to embodiments, the roller has a diameter greater than or equal to 50 cm, or even a diameter greater than or equal to 1 m.

Advantageously, a torque is exerted on the roller and causes said roller to rotate which in turn exerts a tensile force on the assembly, wound around the roller, comprising the growing substrate, the plant mat and the web upper geosynthetic layer and that this traction which propagates along the upper geosynthetic sheet from the roller to the ground is the force which makes it possible to take off said upper geosynthetic sheet from the lower geosynthetic sheet, while lifting the growing medium, said vegetal carpet and while cutting the roots crossing the two superimposed geosynthetic layers which oppose their separation.

Preferably, the roller with the assembly wound around the roller rolls on the ground under the effect of the thrust of a vehicle having a device adapted to cooperate with the roller, this thrust generating a rotational torque which makes it possible to rotate said roller, to stretch the upper geosynthetic sheet and to finally take off the latter from the lower geosynthetic sheet, by lifting the growing substrate, the plant mat and cutting off the roots which oppose it.

Advantageously, the geosynthetic layers have a basis weight of between 30 g / m2 and 125 g / m2.

Preferably, the lower geosynthetic sheet is a rigid geogrid pressed onto the support parcel by staples.

Advantageously, the lower geosynthetic sheet is a geogrid having a mesh whose holes are delimited by fairly rigid and sharp edges to clearly cut the roots of said plant mat opposing the movement of unsticking of the upper geosynthetic sheet when said roots are stretched and pressed against said edges.

Preferably, the support substrate of the support parcel is a fiber substrate.

In fact, this allows the roots to be held by friction at the top and bottom of the geosynthetic layers during harvesting and thus to stretch and thus to be sheared clearly at the level of the place of separation of the geosynthetic layers. In addition, this allows to have a support that can be erected once and for all and which then remains flat despite repeated passages during the installation of the growing medium or during maintenance or harvesting, whatever whatever the season and the humidity conditions during these repeated passages. Thus, not only during the first culture but also during the following cultures on the same plot, the support substrate remains ready, which allows to chain cultures without loss of time and without repeating an investment of overhaul each time. .

In addition, it is advantageous that the support substrate is a resistant substrate, but also a support which does not compact too much to remain a support favorable to the development of the roots, harvest after harvest. This effect can be promoted by the introduction of cork into the support substrate.

Advantageously, the fiber-based support substrate of the support parcel comprises fibers, sand and a part of cork, the apparent volume of which represents at least 5% of the apparent volume of the support substrate.

Thus, unlike the conventional technique where it is necessary to cut the substrate and the fibers in the separation plane, it is not necessary according to the method of the invention to cut the fibers or the substrate because there is no has neither fibers nor substratum but only through roots in the plane of separation, ie between the two superimposed geosyn thetics.

According to the invention, a geosynthetic sheet is placed on another geosynthetic sheet, without any force to overcome to separate them from one another, except the force necessary for the breaking of the through roots . The forces opposing the separation of the upper geosynthetic sheet are therefore, on the one hand, the forces exerted by the roots crossing the two superimposed geotextiles which oppose the separation of the two geosynthetic sheets and, on the other hand, the weight of the substrate above the upper geosynthetic sheet which must be lifted at the same time as this upper geosynthetic sheet.

[0057] The present invention also relates to a process for revegetation of a surface, characterized in that the revegetation of said surface is carried out by installing a plant mat produced and harvested by the above process.

According to a first embodiment of the invention, the installation of the vegetal mat on the surface is carried out by unwinding one (or more) roll of vegetable mat produced and harvested by the above method and by removing the web upper geosynthetic as the roll of plant mat is unwound, in particular by rewinding the upper geosynthetic sheet on a counter-rotating cylinder as the roll of plant mat is unwound.

According to a second embodiment, the installation of the vegetal mat on the surface is carried out by unrolling on the surface one (or more) roll of vegetable mat produced and harvested by the above process while retaining the upper geosynthetic layer to strengthen and reinforce the plant mat thus laid. Brief description of the figures

[0060]. The following description, which is in no way limiting, should be read in conjunction with the appended figures, among which:

[0061] [fig.l] - Figure 1 is a schematic side view of a device for harvesting a plant mat produced according to one embodiment of the invention, in a case where the stack of geosynthetic sheets only comprises two tablecloths;

[0062] [fig.2] - Figure 2 is an enlarged view of the right part of Figure 1; and,

[0063] [fig.3] - Figure 3 is a side diagram of an installation for laying the harvested vegetation mat.

Description of the embodiments

[0064] The substrate-support 1 of the plot of substrate-support suitable for the cultivation of any plant cover is most often the soil in place. The present exemplary embodiment relates to a lawn without this being any limitation.

As an option, it can also be a support substrate 1 specially set up to promote the descent and growth of the roots, the maintenance in all seasons of the flatness and the bearing capacity of the plot and of favorable characteristics such as humidity and ventilation.

The substrate-support 1 constituting the substrate-support plot is suitable for cultivation. It can be full soil, or any other suitable substrate-support in which the grass roots can develop, with satisfactory circulation of water and air and sufficient mechanical strength to circulate over it without deforming the surface during operations of setting up geosynthetic layers and the substrate or during operations of cultivation and maintenance and harvesting of turf or more generally of a vegetal carpet.

Advantageously, the substrate-support 1 of the plot is a fiber substrate.

This substrate is advantageously composed of an essential part of sand, with fibers and possibly with a small part of organic material and / or clay

In a preferred version, the substrate-support 1 of the plot is a substrate composed of sand and fibers and cork, where the cork represents at least 5% of the substrate by apparent volume, specially developed to serve as support for the land to allow movement on the plot without deformation or settlement while guaranteeing air and water permeability thus promoting deep rooting in the plot.

Once the plot is perfectly leveled, the support substrate is isolated from said plot by installing different layers of geosynthetic layers, 2 and 3, followed by spreading, compacting and adjusting the growing medium 4 to the predetermined thickness of the turf 5. All types of permeable geosynthetic sheets can be used, such as for example geosynthetic sheets grouped together under the different names of geotextiles, geogrids, geonates, geocomposites, bionates, etc. However, the geosynthetic sheets used, woven or non-woven, must be permeable and the choice of geosynthetic layers (weight and resistance) must be made according to the cultivation time and the end use.

For a better result, the geosynthetic sheets can preferably be more resistant, thinner and more slippery geogrids than geotextiles and in particular thermo-bonded geogrids.

A preferred solution, object of this exemplary embodiment, is the installation of two geosynthetic sheets, a lower geosynthetic sheet 2 intended to remain in place on the support plot, and an upper geosynthetic sheet 3, placed on the sheet lower geosynthetic 2, intended to be rolled up during harvesting.

The lower geosynthetic sheet 2 must allow the shearing of the roots of the grass 5, but has another important action which consists in ensuring the bearing capacity of the substrate-support 1.

The upper geosynthetic sheet 3 must be flexible to wrap around a roller 6 and must pass without tearing the tensile force which will allow the roll of sod 7 to be lifted off and carried; it also has a useful function as an anti-earthworm barrier vis-à-vis the growing medium, but it must allow the roots to pass.

It is also desirable that the geosynthetic layers do not tear. In particular, the top geosynthetic sheet 3 must be both flexible enough to roll up, but tensile enough to carry the weight of the growing medium 4 between the roller and the field while transmitting the pulling forces which allow the grass roots 5 to be sheared between the two geosynthetic layers 2 and 3.

A preferred solution is to have a thermo-bonded root guard above and a geogrid below, that is to say an upper geotextile sheet which is a thermo-bonded root guard and a lower geotextile sheet which will allow the shearing while ensuring the bearing capacity of the support.

The material constituting the geosynthetic sheets can be any of the materials generally used for geosynthetics, such as, for example, polypropylene.

The important thing is also that the lower geosynthetic sheet 2 is well held in place and sufficiently rigid so that the relative movement of this sheet with respect to the grass roots cuts them clean by shearing. It is therefore preferable that the geosynthetic sheet constituting the lower sheet 2 is a sheet of geogrid held rigid by its very nature and by clips arranged in a suitable manner. It is also preferable that the holes of the mesh are delimited by rigid and sharp edges.

Preferably, the geosynthetic layers 2 and 3 will therefore have a density greater than 30 g / m2 so as not to tear.

It is also essential for the very principle of the method that the grass roots can cross the two superimposed geosynthetic layers 2 and 3.

Part of the roots must in fact be able to pass through the thicknesses of geosynthetic layers to ensure the sustainability of the crop for several months or years.

[0084] As a result, geosynthetic webs are not only permeable to water and air, but also the size of their holes or mesh allows the roots of the turf to pass through the various geosynthetic webs.

However, some discomfort caused by the geosynthetic layers when the grass roots pass is nevertheless desirable and even sought after for the positive effect consisting in increasing the root density in the thickness of the growing substrate above the geo layers. -synthetic. Tests have shown that a weight of 125 g / m2 may be suitable but begins to interfere too much with the passage of the roots and a fortiori a higher density has more disadvantages than advantages.

[0086] A basis weight of 68 g / m2 seems an ideal density so that the geosynthetic sheets do not tear and do not oppose too much the passage of the grass roots.

It is also possible to arm the plating with a layer of geogrid (not shown in the figures). Instead of installing two geosynthetic sheets, 2 and 3, one above the other, we can install three, the upper one being a geogrid sheet intended to remain positioned at the bottom of the veneer during its installation on the new reception area. Given the nature and favorable condition of the underlying plot, on the one hand, and the spreading technique of the growing medium 4, on the other hand, it must be laid and leveled on the geosynthetic layers laid on said plot without impacting the planimetry of the plot, knowing that the thickness of the growing substrate 4 spread will be the thickness harvested.

Harvesting is then done by separating two geosynthetic layers (without oscillating movement of the blade of an edger).

The lower geosynthetic sheet 2 in contact with the earth 1 of the support plot remains thereon.

The upper geosynthetic sheet 3 in contact with the growing medium 4 is rolled up with the grass; it will possibly be removed at the time of installation in a stadium, for example: it increases the stability of the grass roll 7 during transport.

The principle of the invention is therefore to exert on the upper geosynthetic sheet 3, directly or indirectly, a force suitable for taking off this geosynthetic sheet, cutting the roots and carrying the growing substrate 4 with the grass. In a preferred version, judiciously positioned clips will also make it possible to block the lower geosynthetic sheet 2 so that the edges of the holes in the mesh through which the roots pass can withstand the tensile forces exerted by said through roots on said edges until they are finally severed under the effect of this resistance force.

It is thus possible for example very simply and manually to take off small strips of grass in the context of the present invention, without even any recovery tool but quite simply by directly entering the upper geosynthetic sheet 3 by one end and by lifting it at an angle to the other end of the strip.

If the bands have been separated beforehand and the vertical edges of the bands are kept separate by fixed separators installed beforehand, it is not even necessary to cut the edges vertically: it is then possible to "tear off »Small strips or plates manually, cleanly and without any tools.

If the strips are not separated beforehand, it is also possible to start by cutting the edges of the strips vertically, then it suffices to pull on the upper geosynthetic sheet 3 to “tear” the strip of grass.

It is important that the thickness of the growing substrate 4 is significantly less than the depth of prospecting for the roots of the plants chosen to constitute the plant cover, whether it is grass of grasses or cover plants. soil, so that the roots cross geosynthetic sheets 2 and 3, and develop in the underlying substrate 1. This implies that this substrate-support 1 is suitable for prospecting for roots and that the geosynthetic layers 2 and 3 used do not constitute an impassable or difficult to cross barrier.

Other crops can be grown and harvested with this method, in particular for green roofs. Figure 1 illustrates the harvest of sod rolls in the case of a growing medium placed on two geosynthetic sheets laid on the perfectly leveled parcel of land.

As shown in Figure 1, when a roller 6 is pushed by a vehicle 8, the direction of travel being represented by the arrow F, it rolls on the turf 5 in place while the vehicle 8 is rolling on the lower geosynthetic sheet 2 which remained on the leveled plot of land 1. As a result, the vehicle 8 does not run over the grass 5 to be harvested and therefore does not damage it; Likewise, the leveled plot 1 is protected by the lower geosynthetic layer 2 which distributes the forces exerted by the tires or tracks of said vehicle 8.

The roll of grass 7, winding around the roll 6 in a known manner, the winding direction being represented by the arrow Fl can only be pushed; but it can also be partially carried by the vehicle 8, so as to leave enough weight to roll without slipping but enough weight not to damage the sod wound on roll 6 or sod 5 in place. Likewise, it would be possible not to even put the roller 6 by carrying it fully and to adjust the winding torque and angular speed by a motorized torque.

[0100] Figure 2 illustrates the tensile forces taken up by the upper geosynthetic sheet 3 during winding around the roller 6.

[0101] When the roller 6 is pushed and rolls on the grass 5, its rotation drives the upper geosynthetic sheet 3 which absorbs the tension because it is more resistant to traction than the growing substrate 4 fiber-reinforced grass placed on it in the field. and who just goes with the flow.

[0102] While the sheet of grass should expand to resist traction, the upper geosynthetic sheet 3 withstands significant tensile forces without distending and the sheet of grass is thus found carried, overturned and rolled up under. the upper geosynthetic ply 3 when winding on the roll 6 without having to exert any tensile force, all the tensile force being completely taken up by the upper geosynthetic ply 3.

[0103] As a result, the tensions on the strip of grass between the roller and the ground which posed problems of elongation of the plate in the traditional technique, are on the contrary used here as the main force which enables the geo-web to take off. upper synthetic layer 3 at the point of contact and rupture with the lower geosynthetic layer 2, by pulling the upper geosynthetic layer 3 upwards, by "carrying" the fiber sod placed on it and by shearing between the two geosynthetic layers 2 and 3 the roots that run through them.

[0104] In order for the shearing of the roots to take place between the two geosynthetic layers 2 and 3, the force of resistance to sliding upwards or downwards must be greater than the breaking force of the roots.

[0105] As shown in Figure 2, the grass root is subjected to a force due to the upper geonate and the growing medium which move upwards and forwards while the lower geonate and the support substrate remain. motionless.

Consider a root crossing the geonates and located at the point of divergence between the two geonates. As long as the frictional forces between the root and the growing medium prevent this root from sliding downwards, the top of the root is integral with the growing medium animated by an upward and forward movement and as long as the frictional forces between the root and the support substrate prevent this root from sliding upwards, the bottom of the root is integral with the support substrate. It follows that the lower part of this root remains immobilized while the upper part of this root is pulled up and forward. Moreover, supported on the edges of the mesh of the geonates, this root will undergo the effect of shearing of the edges of the geomats. This root stretches and then breaks if the force necessary to reach its rupture by tension and / or shear is less than the downward holding forces of its lower part and the upward and forward tensile forces of its upper part.

[0107] During movement, the roots undergo both a tensile force and a shear force.

[0108] The tensile force is due to the fact that the mass of substrate of the upper part in which the upper part of the root is stuck is pulled upwards while the bottom of the root is stuck in the mass of substrate of the lower part held in place by the lower geosynthetic sheet 2.

[0109] During the progress of the harvest, the point S of separation of the two geosynthetic layers 2 and 3 advances and it is at this point S of separation that the shearing of the roots which cross these two geosynthetic layers takes place. in the vicinity of this point S.

[0110] The forward tensile forces force the root wedged against the edges of the mesh of the lower geosynthetic layer 2 through which the root passes to lean against this edge which ends up shearing the root cleanly, as soon as the root pulled from above must advance while the part of the root located below this point S is blocked and the edge of the mesh of the lower geosynthetic sheet 2 on which the root rests is itself even held in place, especially if it is stiff and sharp enough.

[0111] The severing of the root at this location is favored by the fact that the root is relatively constrained by the size of the holes in the lower geosynthetic sheet 2, by the angular shape of the edge of the mesh of this sheet and by the stiffness edges of the holes in the mesh of this tablecloth. The other factor which favors this sectioning, is the longitudinal tension of the root which must be stretched in order to be able to cut itself clean and it is on the other hand the considerable forces of resistance to sliding in the mass of growing medium 4 which allow to 'get the result.

In the preferred case of a fiber culture substrate 4 and a fiber support substrate 1, the friction between the roots and the fibers maintain the root well without damaging it at the top in the culture substrate as at the bottom. , in the support substrate 1 and it results from this tensile force on the root, exerted by friction upwards in the upper part and downwards in the lower part, that this root is maintained in tension and is stretched by resting forward on the edge of the mesh, itself blocked and therefore preventing the root from advancing, which results in a shearing of the root at the level of the separation of the two geosynthetic layers 2 and 3, making it possible to obtain thus the expected root cutting result.

[0113] Thus, the fiber-reinforced support substrate 1 which was an obstacle for the technique of cutting by a knife is on the contrary in the technique according to the invention a considerable advantage to allow a clean and precise sectioning of the through roots, just at the level of the lower geosynthetic layer 2, i.e. at the bottom of the veneer, which makes it possible to obtain, on the one hand, clean rolls of grass 7 and of thickness by factement regular and, on the other hand, a root surface cut clean for a perfect subsequent recovery of the veneer.

The turf rolls 7 can be placed on a trailer and then taken up by an unwinding tool similar to the winding tool but having in addition an additional roller 11 intended to wind the upper geosynthetic sheet 3 in order to lo lidarize it from the sod roll 7 when unrolling on a field 10, as shown in figure 3. If the unrolling tool moves in the direction of arrow F ', the roller 6 supporting the sod roll 7 will rotate in the direction of arrow F2 and the additional roller 11 will rotate in the direction of arrow F3 opposite to that of arrow F2.

[0115] The upper geosynthetic sheet 3, after allowing harvesting, thus makes it possible to protect the grass during transport from damage possibly linked to tremors.

The geosynthetic rollers recovered during unwinding, having their dimensions and characteristics unchanged, can therefore be reused for a new crop of turf intended to be plated.

[0116] In another version, the upper geosynthetic sheet 3 can be left under the grass when unrolling, for friendi and lenfuieei the latter in its new reception site.

[0117] In another version, the upper geosynthetic sheet 3 directly placed on the lower geosynthetic sheet 2 which remains in place and which, raised during harvesting, allows the strip of grass to be taken off during this harvest can be recovered. during unwinding while a third geosynthetic sheet is left in place, previously laid during installation in a sod above this upper geosynthetic sheet 3 directly placed on the lower geosynthetic sheet 2 which remains in place. In particular, this makes it possible to reinforce the veneer sod with a geogrid sheet located above the upper geosynthetic sheet 3 directly placed on the lower geosynthetic sheet 2 which remains in place on the plot: this geogrid sheet is thus harvested at the same time as the strip of sod and is left in place below the growing medium 4 during replanting. This solution can be particularly advantageous for grass paths laid on unstable supports.

[0118] By using a fiber-reinforced culture substrate, the better cohesion of the upper part of the substrate, thanks to the fibers, allows the roots not to slip into the culture substrate and not to be broken by solidarity of resistance between roots and fibers. in a network, so that a net shearing of the root as desired is precisely favored by the good fiberizing of the upper part.

If, moreover, the support substrate is itself a fiber substrate, we have the same advantage to have the lower part of the roots firmly attached to the substrate-support under the geosynthetic layers, so that a through root stretches well and therefore shears more easily at the point of detachment of the upper substrate during winding.

[0120] Thus, it can be seen that this resistance induced by the fibers, which was a drawback for the traditional harvesting method by horizontal cutting of the roots with a vibrating knife, on the contrary becomes a major advantage with the new method according to the invention for sharpness. of the shearing of the roots between the lower 2 and upper 3 geosyn thetic layers during the winding of the latter.

[0121] Apart from grass turf, the method according to the present invention can be implemented successfully in fiber-reinforced growing substrate and in non-fiber-growing growing substrate with ground cover plants to constitute wide and thick mats of plants. ground cover, such as periwinkles. In this type of culture, we improve the technique of the already known soilless culture because the culture can be practiced more simply and naturally, with plants not or little irrigated but which develop their natural capacities of life in full nature, which allows to constitute a living stock and which does not perish of hardened plants which can live in full nature.

A preferred variant of this technique is to install a thin veneer of ground cover growing in non-fiber soil and to place it on a thick layer of fiber substrate laid according to the method on two geosynthetic sheets laid on a support substrate. adequate. Thus, we prepare a living stock that does not expire but on the contrary densifies, strengthens and becomes ready for use to form a layer of ground cover. The advantage of a soilless culture at the same thickness is manifest when the thickness of the substrate layer is significantly less than the natural prospecting thickness of the roots of the considered ground cover plant. In this case, instead of the traditional lining of the roots, detrimental in the long term in the case of cultivation without soil, the shearing of the roots according to the process of the present invention makes it possible to "rejuvenate" the roots and to promote their implantation in the soil. host substrate, which on the contrary promotes the subsequent resistance of the plants on their final host site.

[0123] According to an alternative embodiment, the vehicle 8 comprises a disc 9 (cf. FIG. 1) making it possible to cut the grass 5 vertically in order to delimit the edges of the roll.

[0124] Another option is to separate the rollers as soon as they are installed in the turf by installing separators at the edges of the rollers.

[0125] The advantage of separators is that they do not have to cut the grass 5 and have rolls of grass 7 which are from the start perfectly calibrated in thickness and width.

A first drawback of separators is that the operation of installing the substrate in a sod farm is complicated by this additional task of installing separators.

[0127] A second disadvantage, more restrictive, is that this also implies having a predefined width of the rolls while cutting during harvesting without vertical separators gives full freedom of choice of widths and lengths at the last moment, so that the stock of living sod, the thickness of which has already been determined, remains more versatile in terms of the width of the rolls. The same stock can then be used to be sold in rolls of different widths and lengths.

[0128] Furthermore, independently of the technical difficulties described above relating to obtaining rolls of wide and thick fiber sod by the traditional technique, an economic disadvantage of this traditional recovery technique using an animated horizontal knife is that the cost of obtaining wide and thick rolls is linked to the investment cost of this type of recovery tool. However, this cost increases drastically with the thickness and width of the rolls. This investment cost is even completely prohibitive for small units and is therefore economically incompatible with the installation of very small units of cultivation of fibrous turf near each fiber site, although this would nevertheless advantageously make it possible to easily make repairs to the grass. small areas deteriorated eL whereas this would in particular make it difficult for clubs to have grass areas always ready to be used to renovate their stadiums, without the cost of harvesting or unnecessary transport.

[0129] Thus, the solution according to the invention makes it possible to simultaneously achieve a triple objective:

[0130] - allow the cultivation of thick fiber-reinforced turf of quality without the prejudices linked to the resistance of the fibers during the harvesting of the rolls (protection when harvesting, when transporting and when unrolling)

[0131] - allow the cultivation of rolls as wide as desired without the detriment of the cumulative effect of fiber strength as a function of the width of the rolls when harvested

[0132] - allow a technology with a very low economic cost of the grass harvesting operation (including investment) to be able to install and make profitable small areas of grass cultivation intended to be moved and replanted nearby, whether this grass is fiber or not

[0133] A preferred version of this process is to wind the strips of sod, during harvesting, on rolls of sufficient diameter to avoid the problems described above of insufficient radius of curvature which weaken the substrate, during processing. winding, especially in the case of a thick and fiber-reinforced substrate.

A preferred solution to avoid these problems of radii of curvature described above is to wind on rollers which have a diameter greater than 50 cm instead of rolls conventionally used with a diameter of less than 20 cm.

[0135] However, with culture substrates particularly resistant to curvature forces, fibers and veneer thicker than 3 cm, which exert forces of resistance to the curvature of the turf greater than less thick lawns and not very resistant to stresses. mechanical, it is preferable to wind on rollers of even larger diameters.

[0136] Another preferred solution is to wind the strips of grass on rolls having a diameter greater than or equal to 1 meter.

Now, at each turn, twice the thickness of the substrate is added, a little less if the substrate is crushed and a little more if it is not completely tight but with the method according to the invention which works by constantly tightening to exert the tension which makes it possible to take off, the estimate consisting in adding twice the thickness of the strip of grass is very close to reality.

[0138] Thus, for example for a strip of grass with a thickness of 5 cm, 10 cm in diameter is added to the roller, so that 10 turns then give 1 meter of additional diameter.

[0139] Thus, for example, for a strip of grass grown on a 5 cm thick fiber-reinforced substrate, a preferred solution for solving the problem of the radius of curvature consists in winding on rolls which have a diameter of 1.5 meters. Thus, a roll that would have an internal diameter of 1.5 meters and an external diameter of 2.5 meters would be approximately 70 meters long, which makes it possible to tackle a width of land with a single roll of sod.

[0140] Another advantage of the process is of an economic nature.

[0141] To cut large rolls, the cutting device requires very heavy investment and large rolls are therefore inaccessible to small sod farms or a fortiori to stages wishing to have a mini-sod farm for their occasional repairs

[0142] With the method according to the invention on the contrary, the apparatus for cutting large rolls is no longer a major investment impossible to amortize for small volumes of plating turf since, with the new method, this apparatus is of cutting of large rolls is simply eliminated. Thus, while the knife which cuts in the mass in the traditional method has a resistance which increases exponentially with the width, the method according to the invention therefore makes it possible to make rolls of fiber sod as wide as desired, without specific investment in cutting.

[0143] In order to wind or unroll the lawn, it suffices to have a vehicle such as a loader or a telescopic handler to push or pull the lawn reel, respectively. This type of vehicle is already present in most farms or can be rent without delay and for a very low price from public works equipment rental companies.

[0144] To wind up the lawn, a vehicle can be used to pull the lawn reel or to push it. However, it is preferable to push it because in this case the vehicle pushing the roller rolls behind the grass reel and therefore rolls on the lower geonatte placed on the support substrate and therefore does not roll on the grass to be moved.

[0145] The only tool that must be available is a lawn retractor-type tool as there is conventionally and having an adaptation corresponding to the vehicle used.

[0146] It is therefore conceivable, within the framework of the method according to the present invention described above, to have a network of small areas near each stage, for example where fiber-reinforced grass is cultivated ready for use for repairs. All you need is a vehicle capable of pushing a cylinder around which the turf will wrap around and carrying it to put it on the truck. The same vehicle can then be used to flatten the grass by adding a small additional device to separate the upper geosynthetic sheet 3 from the remainder of the roll of grass 7.

[0147] Another particularly advantageous advantage when the reel is pushed by a vehicle is that one does not run over the turf which is going to be moved in the method according to the invention, unlike conventional stripping technology.

[0148] The forces exerted to move the grass have in fact an equal reaction force exerted in the opposite direction by the vehicle on the ground at the level of the wheels and the greater the resistance of the grass, the more the wheels therefore exert a force of great traction on the turf surface, so that a turf exerting forces of resistance to the advancement of the cutting blade at the limit of the resistance of the blade creates a similar force on the turf surface due to the 'intermediary of the wheels of the vehicle pulling the stripping machine, which greatly damages the surface of the turf intended to be moved.

[0149] In addition, with the recovery process according to the invention, the turf grows normally in a sod field and can be harvested at any time during a period which goes from a few weeks only after its sowing to a few years if it is. properly maintained. As well for a professional sod farm as for a stadium which wants to have a small back-up sod with fiber sod, it is a considerable advantage not to have a product which expires quickly and which can be used at any time, at any time. moment, not planned in advance, when it is needed.

[0150] In addition, the method according to the invention has additional qualitative advantages over the traditional technique.

[0151] Due to the presence of geosynthetic layers which hinder the passage of the roots without preventing it, the roots succeed in passing and therefore there is therefore no carpet or bun which accumulates at the level of the roots. geosynthetic layers, but the roots are however stimulated in the area above the two geosynthetic sheets and the root mass above these sheets is therefore densified, with more new roots able to anchor themselves quickly in the new substrate during replanting and better mechanical strength due to the higher root density above these geosynthetic layers.

[0152] Due to the presence of geosynthetic layers, the roots of Kentucky bluegrass (poa pratensis), when there is some in the mixture, tend to concentrate in the upper part, which is also an advantage for the plant. new transplanted turf.

[0153] As a result of the process, it is also possible to immediately move and replant the grass on the spot to force it to make new roots, which can constitute a method for "rejuvenating" the grass shortly before it starts to grow. harvest it again to put it back definitively on a stage, forcing it to react in order to have particularly active roots at the time of the final programmed transplant. This possibility comes from the fact that the lower geosynthetic sheet which remains in place is not destabilized by the winding of the turf which shears the roots as it passes through this lower geosynthetic sheet and leaves a clean and neat place ready to directly welcome a new one. substrate to cultivate sod again or to receive again the roll which has just been harvested and which can be unrolled again in the same place.

Claims

[Claim 1] A method for producing and harvesting a veneer vegetal mat having a predetermined thickness, characterized in that it comprises the following steps:

- Preparation and leveling of a support plot consisting of a support substrate (1) suitable for cultivation;

- Installation on said support plot of a stack of superimposed geosynthetic sheets consisting of at least two geosyn thetic sheets, capable of being crossed by roots of the vegetal carpet, and of being separated from each other;

- Spreading of a cultivation substrate (4) on the top geosynthetic layer of the pile to constitute a layer of constant and equal thickness, once said cultivation substrate (4) has been packed and leveled, to said predetermined thickness;

- Cultivation of a plant cover (5) on said growing medium (4);

- Harvesting of said plant cover (5) by separation, one from the other, of two directly superimposed geosynthetic layers, by exerting on one said lower geosynthetic layer (2) a force adapted to hold it in place above of said support plot and by exerting on the other said upper geosynthetic sheet (3) a force adapted to detach it from said lower geosynthetic sheet (2) on which it rests, to lift said culture substrate (4) and the carpet plant (5) placed above on said pile and for cutting roots of said plant cover (5) crossing the pile of perposed geosynthetic layers.

[Claim 2] A method according to claim 1, characterized in that the plant cover (5) is cultivated on said growing medium (4) before being harvested until the roots of said plant cover (5) are sufficiently developed to colonize said culture substrate (4) and to have passed through all the layers of the stack to the substrate-support (1).

[Claim 3] A method according to any one of claims 1 to 2, characterized in that the stack of geosynthetic sheets consists of two geosynthetic sheets, said lower geosynthetic sheet (2) being directly placed on the support plot and the upper geosynthetic sheet (3) being placed directly on said lower geosynthetic sheet (2), the culture substrate (4) being placed directly on said upper geosynthetic sheet (3). [Claim 4] A method according to any one of claims 1 to 3 characterized in that the culture substrate

(4) spread over the stack of geosynthetic sheets is a fiber substrate.

[Claim 5] A method according to claim 4, characterized in that the fiber-reinforced culture substrate (4) spread over the stack of geosynthetic sheets comprises fibers, sand and a part of cork, the apparent volume of which represents at most. less 5% of the apparent volume of the growing medium.

[Claim 6] A method according to any one of claims 1 to 5, characterized in that the support substrate (1) is a fiber substrate.

[Claim 7] A method according to claim 6, characterized in that the fiber-based support substrate (1) comprises fibers, sand and a part of cork, the apparent volume of which represents at least 5% of the apparent volume of the support substrate.

[Claim 8] - A method according to any one of claims 1 to 7, characterized in that the plant cover (5) is a lawn of grasses.

[Claim 9] A method according to any one of claims 1 to 7, characterized in that the plant mat (5) is a carpet of ground cover plants.

[Claim 10] A method according to any one of claims 1 to 9, characterized in that the culture substrate (4), the plant mat (5) and the upper geosynthetic sheet (3) which are lifted together during the separation of the two geosynthetic layers are also wound together on a roll (6).

[Claim 11] A method according to claim 10, characterized in that the roller (6) has a diameter greater than or equal to 50 cm.

[Claim 12] A method according to claim 11, characterized in that the roller (6) has a diameter greater than or equal to 1 m.

[Claim 13] - A method according to any one of claims 10 to 12, characterized in that a rotational torque is exerted on the roller (6) and causes said roller to rotate which in turn exerts a tensile force on the roller (6). the assembly wound around the roller (6) comprising the culture substrate (4), the vegetal mat (5) and the upper geosynthetic layer (3) and that this traction which propagates along the upper geosynthetic layer (3) from the roller (6) to the ground is the force which makes it possible to peel off said upper geosynthetic sheet (3) from the lower geosynthetic sheet (2), while lifting said growing medium (4) and said plant mat (5) ) and while cutting the roots crossing the two superimposed geosynthetic layers (2 and 3) which oppose their separation.

[Claim 14] A method according to claim 13, characterized in that the roller (6) with the assembly wound around the roller (6) rolls on the ground under the effect of the thrust of a vehicle (8) having of a device adapted to cooperate with the roller (6), this thrust generating a rotational torque which makes it possible to rotate said roller (6), to stretch the upper geosynthetic sheet (3) and finally to take off the latter, by lifting said cultivation substrate (4) and the plant cover (5) and by cutting off the roots which oppose them.

[Claim 15] A method according to any one of claims 1 to 14, characterized in that the geosynthetic layers have a basis weight of between 30 g / m2 and 125 g / m2.

[Claim 16] A method according to any one of claims 1 to 15, characterized in that the lower geosynthetic sheet (2) is a sheet of rigid geogrid pressed onto the support parcel (1) by staples.

[Claim 17] A method according to any one of claims 1 to 16, characterized in that the lower geosynthetic sheet (2) is a geogrid sheet having a mesh whose holes are delimited by fairly rigid and sharp edges to clearly sever the roots of said vegetal mat (5) opposing the detachment movement of the upper geosynthetic layer (3) when said roots are stretched and pressed against said edges.

[Claim 18] A method of vegetating a surface, characterized in that the vegetation of said surface (10) is carried out by installing a plant mat produced and harvested by the method according to any one of claims 1 to 17.

[Claim 19] - Method according to claim 18, characterized in that the installation of the plant mat on the surface (10) is carried out by unwinding a roll of plant mat (7) produced and harvested by the method according to one any one of claims 1 to 17 and removing the upper geosynthetic sheet (3) as the roll of plant mat (7) is unwound.

[Claim 20] A method according to claim 19, characterized in that the upper geosynthetic sheet (3) is removed by re-winding it on a cylinder (11) in counter-rotation as the unwinding of the roll of carpet progresses. vegetable (7).

[Claim 21] A method according to claim 18, characterized in that the installation of the plant mat (5) on the surface (10) is carried out by unwinding a roll of vegetal carpet (7) produced and harvested by the method according to any one of claims 1 to 17 while retaining the upper geosynthetic layer (3) to reinforce and reinforce the vegetal carpet (5) thus laid.