FR2615687A1 - Process and device for water retention with a view to sowing or planting a plant, especially in arid soils - Google Patents

Abstract

The subject of the invention is a device for the containerisation of seeds with a view to their germination, or of plants with a view to their transplanting, also comprising water and all the nutrient elements necessary for the plant. This device is composed of a vertical tubular casing, open at both ends, intended to contain the plant, or at the very least its underground part. The casing is filled with an inorganic or organic water-retaining substance. A specific means of carrying out the invention consists in running into the casing a natural organic polymer gel such as carboxymethylcellulose, suitably laden with nutrient elements. The addition of simple or complex inorganic oxides is particularly recommended, especially with a view to transferring solar radiation more efficiently to the plant.

Description

Hydroretention device for sowing or planting a plant, especially in arid soils and method of implementing this device.

 Various methods have been described in recent years to regulate the distribution of water to plants in two categories of inventions: the first relates to irrigation, the second to the various processes of containerization, known especially under the name " hydrorétenteurs ".

Among the first we can cite for example the one protected by the French patent 2,561,064 which describes an autonomous irrigation system with tank under load and porous probes for a distribution on the ground enslaved to soil moisture. For the fertilization of sandy soils of arid zones, the French patent
No. 2,567,251 describes a recovery technique by interposition between the fertile agricultural layer and the subsoil of a layer of waterproof material.

 Among the second can be mentioned for example that protected by French Patent 2,564,285 which describes water tanks for plant container in the form of bags permeable to water, but not permeable to salts.

Moreover, the French patent N 2,554,670 of the
SODETRA describes a process for incorporating hydroretiners, such as polyacrylamines in arid soils using agricultural cartridges, which allows their homogeneous distribution.

 French patent 2,550,783 describes an amendment for soil fertilization, consisting of a mixture of lignite and a natural or synthetic polymer that retains non-biodegradable water, or weakly biodegradable.

 Finally, many patents describe devices for plant containers for gradually moistening the plant and save water.

 The disadvantage of these various processes having the purpose of improving the economy of agricultural water, lies in the need to implement a water mass usually not commensurate with the water requirement of the plants, or involves a renewal by an artificial (probe) or natural (precipitation) control system.

 However, in countries with arid soils (Mediterranean countries, arid African zones) this type of regulation is difficult to achieve and leads quickly to a prohibitive cost. The problem arises particularly in sowing or planting where the plant has a demand for water that can only be satisfied by artificial input.

 In a more general way, the water requirements, amendments, fertilizers and various inputs to the plant, essential in the germination and early development phase are provided locally and this results in a loss of the excess quantities used, because eventually disappear as a result of various physicochemical phenomena involved: evaporation, entrainment in the water table, bio or photodegradation, etc ...

 The object of the present invention is to describe devices ensuring the supply of all the nutrients necessary for germination, recovery and development of a young plant, along with a support for it.

 These devices consist of a flexible envelope preferably cylindrical or cylindroconic containing a hydroretention medium in which can be incorporated in the soluble or dispersed phase nutrients essential to the plant: nitrogen, phosphorus, potasium, trace elements, hormones with specific effects, etc ...

Optionally, the simple or complex oxides that are the subject of the French patent application
No. 8.706.946 of May 15, 1987 may be incorporated into the nutrient mass described above and in particular to the upper part of the device to allow it to better benefit from the solar irradiation necessary for its action and to obtain in accordance with the effects described in this document. Patented germination rates and high biomass production.

 The present invention may be made according to several variants.

 In the first, there will be disposed in the upper part of the optionally flared tube concavely, and provided with a reflecting surface, several seeds in the vicinity of the free surface, the remainder of the tube being filled with the hydrorétentrice composition.

 In the second, the tube will be open on a generator and in the suitably solidified hydrorétentrice composition will be arranged co-axially to the tube a profiled cavity, allowing to place the roots of the young plant. The section and the length of the tube will obviously be adapted to the size of the plant to be received, as well as the quantity of hydrorétentrices substances (content of water, salts and additives in particular) so as to provide the plant at the beginning of the recovery and its subsequent development of the elements it needs until it can autonomously draw them itself into the soil. Fig. 1.

 For this purpose, the tube may be open at its lower part, and opening primers made laterally allowing the free exit of the roots. The material of the tube may be slowly bio-degradable and thus constitute an additional amendment available for the plant. Fig. 2.

 By way of non-limiting examples, two modes of application of the invention are described below.

EXAMPLE 1 Germination of Wheat Seeds
Transparent polyvinyl chloride tubes having an outer diameter of 8 mm and a length of 15 cm are used, a copy of which is shown in FIG.

The tube (B) is filled up to 20 mm from its upper edge with an agar gel (F), prepared with a nutrient solution N, P, K at a dose of 1 per thousand by weight. The upper part of the tube, above the free surface of the gel, is slotted flange 15mm high to allow proper aeration of the seeds. These are placed at (C), at the free surface of the gel and covered by a 3mm layer of fine sand.

 Eight implant tubes are then placed under conditions reproducing an arid and hot soil represented by a box of 80cm x 35cm x 25cm filled with a mixture of sand and siliceous pebbles, as well as clay, all forming a layer about 20cm tall. An incandescent lamp ramp totaling 300w ensured 12 hours a day of lighting and heating which made it possible to obtain a temperature of 35 +/- 5 ° C during the day, 18 +/- 2 at night. The soil thus formed is rapidly dried by preliminary heating operations. The tubes are placed vertically and pushed down to the level of the collar, that is to say substantially to the free surface of the medium in which the seed has been placed.

Results
Germination of wheat seeds. after five days in five tubes out of eight, a germination rate of more than 60%. After three weeks, the roots have passed through the hydrorétentrice layer always present in its entirety, out of the tube (E) and sunk into the sand.

The height of the aerial lartie is 10cm. <D).

EXPERIENCE 2
Young 3-month-old pine pinnacles were placed in implant tubes of the type described in Figure 4, in contact with the same nutrient gel. A recovery rate of 90% is observed, higher than that of the same plantations in arid soil.

 Many seedlings of shrubs, many plantations, both in floral production, fruit and forestry, as well as reforestation operations may benefit from these devices, adapted to the plant and local climatic conditions.

 As regards the hydroretentric material, it may consist not only of a natural macromolecule, such as a cellulose derivative (for example carboxymethylcellulose), but also of artificial resins with high absorbency vis-à-vis water (polyacrylamide).

 Because of their availability and safety, alginates will be excellent starting materials for the gel, by adding water and heating the appropriate mass to a fluidity to incorporate the different substances to feed the product. plant.

 Optionally, the introduction of the hydrorétenteur gel in the casing of the device can be done by casting, and non-uniform distribution of the various components, so as to schedule the availability of these components according to appropriate laws as development progresses. plant, especially at the root level.

Claims (10)

claims A device for containerization of water and nutrients of a seed or plant, characterized in that its shell is a vertical tube filled with a hydroretentric substance. 2. Device for containerization of water and nutrients of a seed or plant, according to claim 1, characterized in that the casing is a non-biodegradable or slightly biodegradable plastic tube open at both ends, and possibly provided with lateral slots allowing the passage of the roots during development. 3. Device for containerization of water and nutrients of a seed or plant, according to claims 1 and 2, characterized in that the upper part of the casing is slotted flange to facilitate the precipitation harvesting, aeration, and the concentration of solar radiation. 4. Device for containerization of water and nutrients of a seed or plant, according to any one of the preceding claims, characterized in that the upper part of the tube is constituted by a reflective insert in its concave part so as to concentrate the sun's rays. 5. Containerization device for water and nutrients of a seed or plant, according to any one of the preceding claims, characterized in that the hydrorétentrice substance is constituted by a mineral compound absorbing water. 6. Device for containerization of water and nutrients of a seed or plant, according to any one of the preceding claims, characterized in that the hydrorétentrice substance is constituted by a synthetic organic polymer, for example a polyacrylamide.  7. Device for containerization of water and nutrients of a seed or plant, according to any one of the preceding claims, characterized in that the hydrorétentrice substance is constituted by a derivative of cellulose, for example a carboxymethylcellulose. Containerization device for water and nutrients of a seed or plant, according to any one of the preceding claims, characterized in that the necessary nutrients aa plant are added to the hydrorentrentric substance suitably hydrated. either as a solution or as a suspension. 9. Device for containerization of water and nutrients of a seed or a plant, according to any one of the preceding claims, characterized in that the nutrients may be: nitrogen, phosphorus, potassium, trace elements, plant hormones, simple or complex oxides. 10. Device for containerization of water and nutrients of a seed or plant, according to any one of the preceding claims, characterized in that the nutrients may be reported in a physically distinct manner, in particular in the vicinity of the free surface of the device, are incorporated in the hydrorétentrice substance at the time of its preparation.