FR3069751B1 - INSULATED COVER PLATE FOR CULTURE TUNNEL AND METHOD FOR GROWING ENDIVES IN EARTH - Google Patents

Abstract

The invention relates to a cover plate (1, 10) adapted to form a culture tunnel, in particular endive culture in the ground, said plate being bent having a concave lower face and a convex upper face, said plate comprising two transverse edges (5) and two longitudinal edges (4) forming piers adapted to rest on the ground so that the concave lower face facing the ground is the vault of the culture tunnel. According to the invention, at least the concave lower face of the plate (1, 10) comprises a thermal insulating layer (3; 11, 12) made of a synthetic foam. A culture method using the plate completes the invention.

Description

Technical field to which the invention relates

The present invention relates generally to the field of agricultural devices and methods. It relates more particularly to an isolated cover plate for the production of a culture tunnel as well as a method of endive culture in the ground using the tunnel thus produced.

BACKGROUND

DE202005005147U1 and EP1284099 are particularly known for trays for forcing endives as part of endive culture. The hydroponic cultivation of chicory has experienced significant development, particularly because of its yield and the possibilities of mechanization / automation. However, the endives produced have characteristics that distinguish them from endives grown in a conventional way in the open ground. However, the consumer is more and more concerned with the quality of the products he consumes and he wants to have products grown in a more traditional way and having interesting organoleptic characteristics. However, the traditional production of endive in the ground is of a higher cost in terms of time, labor, complexity and thus financially. It is therefore desirable to have means facilitating and reducing the costs of growing endive in the ground, both by devices or methods useful for this purpose.

Also known are documents FR2807915, FR2807916, FR2807917and EP1245145 relating to the mechanization of the harvest of endives grown in pots in the ground.

Object of the invention

In order to overcome the aforementioned drawbacks of the state of the art, the present invention provides a cover plate adapted to form a culture tunnel, in particular endive culture in the ground, said plate being bent around a substantially horizontal longitudinal axis, with a concave bottom face and a convex upper face, said plate having two transverse edges and two longitudinal edges forming pawns adapted to rest on the ground so that the concave lower face, oriented towards the ground, constitutes the vault of the culture tunnel.

According to the invention, the plate comprises at least on its underside concave, a thermal insulation layer consisting of a synthetic foam. Other nonlimiting and advantageous features of the opening plate according to the invention, taken individually or in any technically possible combination, are the following: the synthetic foam is spread over at least a part of one of the two faces of the plate, - synthetic foam is a closed-cell foam, - synthetic foam is an open-cell foam, - synthetic foam is deposited on the cover plate by projection, - the synthetic foam is deposited on the cover plate by soaking, - the synthetic foam is polyurethane foam, - the polyurethane foam is obtained by application to the plate of two components, a polyol and an isocyanate, - the synthetic foam of the plate has a density of between 33 kg / m3 to 45kg / m3, - the synthetic foam of the plate has a thickness between 2 cm and 8cm, - the synthetic foam of the plate has a thickness of thickness between 3 cm and 4 cm, - the synthetic foam has a substantially constant thickness over the extent of the plate, - the synthetic foam has different thicknesses over the extent of the plate, - the synthetic foam has a zero or reduced thickness at a determined height along the two longitudinal edges forming plate crosspieces to facilitate the laying and possible insertion into the ground of the longitudinal edges of the plate, - the synthetic foam has a thickness of zero or reduced over a determined width along the at least one of the two transverse edges of the plate to facilitate partial overlapping of two plates placed side by side, - the plate is chosen from: a metal sheet, a plate of plastic material, a cellulose fiber plate, a mesh or wire mesh , a mesh or mesh made of plastic material, - the metal sheet or the plate made of cellulose fibers is corrugated, - the trellis liner or mesh is corrugated, - the mesh or mesh is trapped in the synthetic foam, - the metal sheet or the plate is perforated, - the plate is a perforated metal sheet or mesh and the synthetic foambouche perforations of the sheet or the openings of the mesh, - the layer of thermal insulation made of a synthetic foam is disposed on the concave lower face of the plate, - the thermal insulation layer consisting of a synthetic foam is disposed on the convex upper face of the plate, - The thermal insulation layer consisting of a synthetic foam is disposed on the concave lower face and the convex upper face of the plate, in particular because of the use of a perforated plate or a grill for the plate, - the plate further comprises gripping means, - the gripping means are on the convex upper surface of the plate, - the gripping means are grips or straps, - the plate further comprises ground anchoring means, - the anchoring means on the ground are removable pegs ground anchoring, - the plate has on its concave lower face at least one hooking device adapted to hold at least one pipe, in particular a conduit of a liquid or air. The invention also proposes a method of endive culture in England in which endive roots are installed in crates and the crates are placed on the surface of a culture pit and the culture pit comprising the crates of a layer of earth or peat or their mixture, then we proceed to a watering to divide the earth or latourbe or their mixture so that the collar of the root springs out of the layer of ground or peat or their mixture, then one assembles a tunnel cultivation by edge-to-edge cover plates according to the invention, preferably partial overlap of the edges of plates.

In one embodiment of the method, in addition, before the assembly of the culture tunnel, the roots are covered with a forcing veil. The invention also relates to a culture tunnel obtained by edge abutting cover plates according to the invention.

Detailed description of an example of realization

The description which follows with reference to the accompanying drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be achieved.

In the accompanying drawings: FIG. 1 shows a corrugated corrugated sheet type roofing sheet with a thermal insulating layer on the concave lower face, seen in perspective, and FIG. 2 showing a cutaway portion of a roofing plate. made from a grid on which thermal insulation has been spread.

Device

The insulated cover plate of the invention is intended to form the vault of a culture tunnel and has a thermal insulation. It is used for growing endive in the ground. This substantially rigid plate is removed and has a concave bottom face, oriented towards the ground and forming the ceiling / roof and piers of the culture tunnel and a convex upper face, oriented outside and subject to the external environment. This plate is elongated in a direction perpendicular to the axis of the formed tunnel and has two transverse edges in planes parallel to each other. The transverse edges of two adjacent plates partially overlap during the constitution of the tunnel by edge abutting the plates.

The plate has two longitudinal edges forming pawns substantially parallel to each other, these longitudinal edges rest on the ground so that the concave lower face facing the ground is the vault of the tunnel culture. These longitudinal edges forming piers have a directionally vertical or at least well inclined relative to the horizontal so that the internal height of the tunnel is sufficient. In variants, the plate is bent, preferably in an arc or semicircle. The curved end-circle or half-moon shape of the insulated plates makes it possible to store them one on the other without the risk of damaging them when they are not used to form a culture tunnel. The piers may, depending on the case, be straight or uncut. The end of each longitudinal edge may be oriented in the general continuity of the pedestal (vertical / straight or in an arc) or be curved to the outside to form a flat with extended support surface coming posersensibly horizontally on the soil and prevent this end from sinking into the ground contrary to the previous case of continuity of orientation. The ends of the longitudinal edges forming piers may be provided with ground anchoring means and, for example, through holes for removable ground anchoring stakes of the insulated cover plate.

At least some parts of the concave underside of the plate comprises a layer of thermal insulation consisting of a synthetic foam. Preferably, this synthetic foam is spread over most of the concave lower surface of the plate, the areas along the However, edge-to-edge mounting edges may be devoid of them, as may the ends of the longitudinal edges forming piers coming into or on the floor. The convex upper face may also comprise a thermal insulating layer consisting of a synthetic foam, that is to say over parts, or for the most part as indicated above for the concave lower face.

To form the layer (s) of thermal insulation and thus render the plate insulating, it is projected between 3 and 4 cm of polyurethane foam on the plate and preferably under the plate, on its concave underside. This gives a thermal insulation cover plate by synthetic foam which has a great thermal insulation and increased rigidity. Polyurethane foam can also be projected convex upper face. The thickness of foam can be adapted according to the geographical location of use of the insulating plates: the cold regions having a thickness of polyurethanesuperior foam and / or polyurethane foam on both sides. The insulation created by the foam also makes it possible to limit air and water / moisture exchanges with the outside and makes it possible to close the virtually hermetic culture tunnel. The containment is better and it saves heating while having a more stable internal temperature. However, it is possible to provide on the plates, preferably towards their tops, removable tramps that can be opened to allow communication between the inside of the tunnel and the outside if the need arises. These traps may correspond to openings or circular holes of at least 200 mm in diameter made at the tops of the plates. The closure of these hatches / holes can be done by any means and for example with styrofoam plugs. Indeed, it may be useful to renew the tunnel air from time to time. However, means for circulating air and water / moisture inside the tunnel may be implemented under the control of a controller for regulating the internal atmosphere at the tunnel and which regulates the exchanges between the interior and outside the tunnel. The foam insulation is obtained by an expansive polymerization-type chemical reaction rendering the foam solid, the solid term being opposed to the fluid, the solid foam being able to have flexibility and / or elasticity variable depending on the needs. In particular in the case of the use of a mesh or mesh can be achieved a deformable insulated cover plate within certain limits. Preferably, the synthetic foam is a closed cell foam to prevent it from behaving like a sponge or may be a carrier for the growth of moss or lichen or convey parasites. However, it is possible to use open-cell foam, but it is desired to avoid these problems. The cells will be closed on the surface, for example by deposition of a continuous layer of a plastic film or a varnish or equivalent or, then, gluing. a sheet of plastic material.

The plate itself may be metallic or plastic. In the case of the plastic material, it may be transparent or translucent and areas of the plate not covered with synthetic foam may be provided to allow light to pass, a removable cover may be placed on said area to prevent the passage of light if necessary, the cover can be synthetic foam. It may be noted that the same result can be obtained with a lattice or grating having a zone without synthetic foam. The plate can be a corrugated metal sheet that has been bent. It can also be a initially planar plate that has been bent or even be a lattice or mesh sandwiched by the synthetic foam that makes the plate mesh / wire insensibly rigid while being lightweight.

FIG. 1 shows the case of a cover plate 1 formed of corrugated metallic sheet 2 bent on the concaved underside of which a layer of synthetic foam 3 has been spread. This plate has two transverse edges 5 and two edges longitudinal 4 forming rights. In this example, the synthetic foam layer 3 does not descend to the ends of the longitudinal edges forming piers, the latter being intended to be driven into the ground.

In order to manufacture the insulated trellis / light grid cover plate, it is possible to use a model master of curved shape on which it is made. One prepares a segment of wire that is placed and hung on the model master. We move spacers between the master model and the curved mesh and then we project polyurethane foam on the curved mesh so that it is sandwiched in the seine polyurethane foam. In a production variant, after bending the wire mesh, the wire forming the wire mesh is cut at certain places and the cut wire is bent at 90 ° from the surface of the wire mesh. The bent wires then forming spacers are now spaced apart. surface of the grill belonging to the model master. Once the foam has solidified, it is possible to remove from the mastermodel the ultralight insulated cover plate obtained. In another manufacturing variant, spacers are not used and the mesh will be serosensibly on the surface of the foam, a layer of polyurethane foam may optionally be projected additionally on the face of the mesh to have a sandwich of the latter by the foam.

In Figure 2, there is shown the case of a cover plate 10constituated a lattice or mesh. In Figure 2 were removed some of the sponge synthetic foam to allow to see the lattice / mesh 13 trapped in two layers of synthetic foam 11, 12. We considered layers of synthetic foam 11, 12 with reference to the two faces of the mesh / mesh 13 but in practice the fact that the foam passes through the openings of lattice / mesh 13 when it spreads the latter is actually continuous.On can however provide the case of using a foam of a first type on a face and d Another type on the other side, this as well for a plate or sheet continuous or breakthrough or for a lattice / mesh.

The plate itself may be continuous / solid or, preferably, be discontinuous and have openings / holes or consist of a lattice or mesh. In the case of a discontinuous plate, the thermal foam insulation layer (s) clog the openings / holes or voids of the mesh / grid so that the insulated plate appears globally continuous and there is no direct communication between the two faces of the initially discontinuous plate.

Preferably, the layer (s) of synthetic foam are opaque and in particular in the case where the plate is discontinuous (plate openings / holes / grilling) to prevent the daylight can reach the roots.

In these examples, the insulated cover plate is a piece / monoblock between its two piers. In variants, it may result from the assembly of several pieces to form the vault of the culture tunnel, for example in two parts with a straight piece having the right-angled pane and a left piece having the left-hand side pane, the two parts meeting at the top of the vault partial recovery with, preferably attachment means for securing them in the partial hardcover area.

Depending on the case, the insulated cover plates have a length of 1.5 m to 3 m as measured along their surface between the two ends of the longitudinal edges 4 forming piers. Typically, this length is 2.1 m. Depending on the case, the insulated cover plates have a spacing between spaces of 1 m to 2.5 m. Depending on the case, the insulated cover plates have a width of 50 cm to 200 cm as measured between their two transverse edges5. Typically, this width is 0.9 m which allows handling of the plate by a single person.

The insulated plate may comprise accessories such as for example one or straps or strap attachment means forming a means for preventing its handling. It may also comprise concave underside, towards its apex, hooking means for hoses and / or air circulation or electrical cables flowing up the tunnel.

Process

We will now describe a method of endive culture in the ground from roots harvested in an earlier stage. Endives that can be grown include red endive or endive barb type nasturtium.

Typically, these harvested roots were put in the fridge for storage without development before their use, that is to say their cultivation.

When it is desired to grow endives, the roots are collected at the end of the fridge. These roots are crated after a possible cutting of the root to the upper part of the root side bud and / or base of the root. This cross-cutting can be considered if the tear of the root to put in storage in the previous step is too far or if too much was left during storage. It should be noted that the overabundance of leaves can cause health problems when forcing endive.

Each box has about 90 roots. The crating can be done on the ground or with the help of equipment consisting of a hopper, a thin carpets and an inclined plane for the comfort of the operator.

The crating of the roots makes it possible to simplify the later manipulations but is not obligatory for the success of the culture. It also allows, during the onset of a disease, that the contamination is reduced to the same space of the body, which limits the spread both to other roots nearby but also to the ground. This crating has other advantages such as the possibility of splitting up the time of the works, the possibility of mechanizing the cultivation, from crating to harvesting, the possibility of depositing a newspaper sheet in the bottom of the crate in order to conserve from the root a quantity of ground necessary for the resumption of shoot, thepossibility of easily integrating a pot of variable diameter, type pot of flower, in order to loosen the roots in the box. Finally, if chemical / phytod treatments are to be carried out, they are limited and targeted because the roots are collected in boxes.

This crating technique gives independence and more roots to each other to develop greater potential and therefore more yield and endive more beautiful and more regular.

It can be noted that once crating has been done, it is possible to store the rooted crates again in a fridge if they are not used / grown immediately. For storage longer than two weeks, it is best to cover the crates with plastic sheeting to limit drying that could cause a loss of root potential. The use / cultivation of the roots corresponds to a setting in layer, that is to say a setting in ground of the roots. This step consists of depositing the floor or the roots directly in case it is not used to cash, in order to grow the endive in the ground.

Prior to layering, the soil is finely worked on about 20 cm to decompact the soil and a substantially equal thickness of soil is removed at the height of the root or the crate or about 10 to 15 cm of thickness. It will therefore remain a height of land decompacted 5 to 10 cm under the roots or the body. This preliminary step makes it possible to obtain a layer of culture. It is important to disburse the soil in order to create this pit of culture because it allows during the waterings to keep the water at the place of the culturemais also to reduce the heat losses caused by the borders.

In addition, since preferably a heating network is installed in the soil between -40 to -50 cm from the initial level of the soil (not disbursed), cédécaissage allows to bring the roots of this heating network. Heating network may consist of electric heating film or electric conductors.

Still in this preliminary step, the surface of the cultured tank is flat and rapped in order to obtain a perfect contact between root and earth. It is for this reason that when placing crates in the culture pit, before depositing each crate, it is best to erase the holes or bumps caused by possible trampling / no staff responsible for laying crates. Indeed, a hole in the ground under the body will cause the nondevelopment of the root lying above this hole because, not having contact with the ground, it does not have access to the water and the necessary nutrients in development, especially at the beginning of the cycle. This root will then tap into its reserves, dry out and not be able to produce consumable endive.

At the stage of the establishment of the roots directly or by crates on the culture hole one obtains what one can call a planted culture pit.

After the roots have been placed on the growing pit, it may be possible to cover the edges of the cultivation pit planted with soil and to carry out possible chemical / phytosanitary treatments of the cultivation pit and its roots.

Layering ends with a capping and rooting operation with about 5 cm of soil or peat or their mixture in order to obtain what may be called a covered planted culture pit. Note that in case of chemical / phytosanitary treatment we will wait for some time drying and / or action of the treatment before covering with these about 5 cm of soil and / or peat the whole of the planted culture pit.

If peat is used, care should be taken that it is not overhead, which could lead to rehydration difficulties with root dehydration and therefore non-production.

It may be useful, in order to facilitate the descent of the soil and / or the peat between the roots, to pass a hard broom, like a yard broom, on the covered planted cultivation pit. However, it is most preferable to proceed in all cases to water the planted culture pit covered, for example directly to the pipe, in order to get the soil and / or the peat cover down and stick it around the root. This watering can also dehydrate the root after storage. Watering should continue until the bottom of the root has come out of the ground, but must stop before any dirt is removed from the crate.

The implementation of a soil and / or covering peat remaining in part around the root is very useful and it has several functions: to facilitate the hydration of the root, to create a barrier against heat loss, to produce rootlets furthermore around / at the periphery, from the root. These rootlets allow the bud of the root to grow without lack of hydration. These radicels will give a heavier endive, brighter, more beautiful. It should be noted that because of the peripheral arrangement of these rootlets, there is little depotential loss in relation to the case where it is only necessary to rely on the rootlets at the end of the root to draw nutrients and which are longer to obtain because of cut that was made during the initial harvest of the root.

Once the watering is finished, cover is carried out with at least one opening of the covered planted culture pit. In particular, to reduce edge effects causing a lower yield and caused by heat loss, is deposited around / around the edge of the coated culture pit, about half of the first box, a felt, for example geotextile type 340 gr / m2, to increase the confinement. Then, we come to deposit on all cases a forcing veil, for example type P17, double thickness which increases the hygrometry rate closer ducollet of the root. In fact, the endive transpires naturally during the shoot and by increasing the hygrometry by the forcing veil, the bud must warm up more and therefore push to continue to sweat. The forcing veil makes it possible quickly to obtain a favorable growth environment also by the thermal insulation that it brings: the root will start to grow and thus generate heat that is favorable to the growth. Note that this veil of forcing can have a role of control of the shoot. Indeed, if the endive does not grow correctly there is little perspiration and starter of forcing will be rather dry or, at the very least, little wet . If, on the contrary, the endive normally pushes then the forcing veil will be wet due to the large swirl. It can therefore be a simple visual control of endive growth.

It is important to note, however, that felt and / or foreshoes are not necessarily essential and that even in some cases they may be harmful for the cultivation of certain varieties, batches or quality of roots. This adverse effect is characterized by rotting or poor post-harvest preservation. We can also provide, depending on the growth desendives, to set up the forcing veil, remove it and then put it back ...

Then come the tunneling step.

Although it is possible to cover the endives directly on the collar with a canvas or a tarpaulin or straw we prefer to use tunneling to get a growing atmosphere in a defined space. To this end, it is known to use corrugated corrugated sheets, covered with a black plastic tarpaulin for light-tightness and then cover the whole of a straw thickness for thermal insulation. The advantage of this known technique is that straw is cheap and often comes from the farm of the endive producer. On the other hand, the work of installation and removal of the straw is not very rewarding and has a cost in nonnégligeable personnel. In addition, this only gives a weak thermal insulation which ends up degrading when the straw becomes moist and besides it can set in manure. As a result, an oscillating temperature curve is obtained in the tunnel. However, for a good result of the culture and a good valorization of the lot of chicory, the temperature of shoot must be the most linear constant possible.

It is therefore preferred to use in the context of the invention the cover plate with thermal insulation by synthetic foam described above. With this last, the variations of temperature can be erased and one obtains a curve of temperature much more linear, and thus of very good conditions of shoot for the endive.

Curved, typically corrugated, thermally insulated cover plates are placed side by side, parallel to one another, to form a continuous channel over the covered planted culture pit. Preferably, the plates are placed side by side overlapping a wave so that the interior of the tunnel forms a "box" which is well sealed to light andthermically with respect to outside temperatures. The installation of the plates partially covering the transverse edges 5 can be facilitated byapplication a paint for locating the transverse edge of the plate that does not include foam: the transverse edge without foam (spotted by lapeinture) a plate being attached in overlap with the transverse edge with foam of the next plate.

It is then created through the heating which is preferably implemented, a particularly thermal atmosphere much more constant and thus favoring foam. It is understood that the two ends of the tunnel thus formed are closed by walls which are themselves preferably insulated similar to those of the tunnel in the case of metal plates or which are in an insulating material.

In the case of a standard culture layer of 9.2 m long subtunnel, 11 plates are typically used, about three of which have hatches or hatches of the hole type for the aeration of the tunnel, these plates having third-stage openings, 6th and 9th positions along the tunnel.

After this tunneling, the endive forcing can take place in an efficient manner.

Thanks to the thermal insulation afforded by the thermal insulation cover plates, it is easier to keep the temperature level necessary for the growth during frost periods, but also at the beginning of the season. On the other hand, at the end of the season in March and April, the outside temperatures are sometimes too high for the correct growth of chicory and the thermally insulated opening plates allow to keep a cooler atmosphere in the tunnel under the plates and thanks to watering. of the cultivated pit covered and tunneled. A more homogeneous shoot is obtained by the linearity of the temperatures which gives a denser, brighter and more crisp endive.

It may be envisaged to cover the thermally insulated cover plates with an additional tarpaulin or canvas at the producer's discretion.

Comparative tests of endive culture between a traditional method and the method of the invention with its thermal insulation cover plates have been carried out. Of the five tests, similar results were obtained: from -30% to -40% of energy consumption for heating and an average gain of at least 0.5 kg of endive per case of production.

At the apex can be provided cover plates, concave underside / inner side of the tunnel, hooking means for especially irrigating pipes and / or air circulation possibly regulated temperature and / or humidity, or even mixed pipe , air and / or water that can be fed into the pipe. The temperature of the irrigation water can also be regulated. The pipe used will be drilled, preferably of the drip type, along its length in the tunnel. About 50 liters of water per m2 and per week are required for the production of endives during forcing.

The tunnel forcing can be carried out over a period ranging from 21 to 28 days plus according to the choice of the producer. The 28-day endive of forcing with the culture method of the invention is really different from the endive cultured enhydroponic. The endive obtained with the culture method of the invention has had the time to grow and to draw in the soil, the water and the nutrients necessary for its growth, which makes it possible to increase the rate of dry matter compared to hydroponics. The earthy endive obtained in a better taste and better conservation and it can be kept up to 3 to 4 weeks while a hydroponic endive will not exceed or with difficulty the 2 weeks of conservation.

At the end of the forcing time, the endive harvesting takes place.

In the case of a culture without a box, the harvest is done on its knees, in the cultivated seedbed covered after removing the thermal insulation blankets, thus being subjected to climatic hazards. On the other hand, in the case of a culture with crates, it is possible to use adapted tools that allow to quickly bring back the crate with its endives in a room where the ondispose of more comfort.

At least two methods of harvesting can be used: - by hand, the endive is separated from the root as it would be for the uncut cultivation, but this while the operator is in a local and at the same time 'shelter. A peeling is then done. - Mechanized, an operator takes the root with the endive above, the deposit in a machine that through a knife will perform the breaking step. The cost of the endive, the first peeling leaves fall making the peeling still easier and faster. The endive after being separated from its root and its first leaves falls on a conveyor belt and joins the peeling and conditioning area.

It is understood that the cover plate of the invention can be implemented with other subculture tunneling processes and / or to cultivate other plants than those more particularly described above.

Claims (10)

1. A cover plate (1, 10) adapted to form a culture tunnel, in particular endive culture in the ground, said plate being bent around a substantially horizontal longitudinal axis, with a concave lower face and a convex upper face, said plate having two transverse edges (5) and two longitudinal edges (4) forming pawns adapted to rest on the ground so that the concave lower face, facing the ground, constitutes the vault of the culture dish, characterized in that the plate (1, 10) comprises at least on its concave underside, a thermal insulating layer (3; 11, 12) made of a synthetic foam. 2. Cover plate (1, 10) according to claim 1, characterized in that the synthetic foam (3; 11, 12) is polyurethane foam. 3. Cover plate (1, 10) according to any one of the preceding claims, characterized in that the synthetic foam (3; 11, 12) of the plate (1, 10) has a density of between 33 kg / m3 to 45 kg / m3. 4. Cover plate (1, 10) according to any one of the preceding claims, characterized in that the synthetic foam (3; 11, 12) of the plate (1, 10) has a thickness of between 2 cm and 8 cm. 5. Cover plate (1, 10) according to claim 4, characterized in that the synthetic foam (3; 11, 12) of the plate (1, 10) has a thickness of between 3 cm and 4 cm. 6. Cover plate (1, 10) according to any one of the preceding claims, characterized in that the plate is chosen from: a metal foil (2), a plastic plate, a cellulose fiber plate, a trellis or mesh (13) made of metal, a lattice or mesh (13) made of plastic material. 7. Cover plate (1, 10) according to claim 6, characterized in that the plate is a perforated metal sheet or a mesh (13) and in that the synthetic liner (11, 12) plugs the perforations of the sheet or the openings of the mesh (13). 8. Cover plate (1, 10) according to any one of the preceding claims, characterized in that it further comprises means of préhension. 9. A cover plate (1, 10) according to any one of the preceding claims, characterized in that it comprises on its underside concaveau minus a hooking device adapted to maintain suspended at least oneeconduite, including a conduct of a liquid or air. 10. A method of endive culture in the ground in which endive roots are installed in crates and the crates are placed on the surface of a culture trough and then the culture trough comprising the crates of a layer of soil is covered or peat or their mixture, then we proceed to a watering allowing to distribute the earth or the peat or their mixture so that the collar of the laracine comes out of the layer of ground or peat or their mixture, then one assembles a tunnel of culture by putting edge-to-edge cover plates (1,10) according to any one of the preceding claims, preferably partially covering the edges of the plates.