RU2129776C1 - Hydroponic plant growing method - Google Patents

Abstract

FIELD: agriculture. SUBSTANCE: method involves growing plants on hard bulk substrates; periodically supplying nutrient solution in uniform portions from top via low-pressure pipes so that the whole amount of nutrient solution is fed at once onto the whole surface of substrate; controlling and maintaining moisture content and moistening depth of substrate by sensor which may be set for moisture content corresponding to that of given substrate, when surface adhesion between the latter and nutrient solution is provided; setting periodicity of nutrient solution supply so that this solution gradually flows into substrate and by the end of predetermined period it stops dripping from substrate due to surface adhesion forces. EFFECT: reduced plant growing cost by reduced expenditures for high-priced hydraulically isolated plant growing containers and other auxiliary equipment. 1 dwg

Description

 The invention relates to the field of agriculture, in particular to the field of growing plants on a substrate.

BACKGROUND OF THE INVENTION:
a) characteristics of analogues. There are known [1] varieties of the hydroponic method of growing plants on a granular substrate, when the substrate, placed in waterproofing soda containers, is moistened with a sub-irrigation method (that is, it is periodically first flooded with a nutrient solution from the solution tank through a pipe in the bottom of the container, and then it is drained back to mortar tank or pumped out using a pump). And after pumping out (or draining) the nutrient solution, the substrate remains moist due to the forces of surface adhesion of the solution to the substrate. In this case, in order to overcome the resistance of the substrate and quickly fill the tank, the nutrient solution is fed into the tank with a pump under pressure. (Thus, in this case, the plants are fed according to the CLOSED CYCLE of the nutrient solution supply).

 b) the characteristics of the prototype. A device [2] is known for growing plants in metal vegetation vessels, covered with a lid, in which, in order to uniformly moisten the soil substrate in them by simultaneous multi-point supply of water to it, hollow distribution channels with perforation are made along the walls of the lid, which are connected to a container for supply of moisture from it for watering plants.

CRITICISM OF ANALOGUES: such systems of industrial hydroponics are expensive, because require large expenditures for equipment and construction works. In addition, the system has other disadvantages:
a) a significant amount of email is consumed in the circulation of the nutrient solution. energy
b) in the process of circulation, the concentration and composition of the nutrient solution changes
c) the pipelines become clogged with green algae
d) the frequency (time between cycles) of the nutrient solution supply is not directly related to the need for plants
e) due to the concentration of salts on them during the evaporation of the solution, the root necks of plants rot, etc.

 CRITICISM OF THE PROTOTYPE: the design of the vegetation vessels of the prototype is complex and expensive to manufacture. Moreover, it provides uniform wetting of the substrate, not only due to the relatively uniform distribution of moisture on its surface, but also due to diffusion and capillary properties of the soil substrate.

 And for uniform wetting of a granular substrate that does not have these properties, it is not suitable.

 OBJECT OF THE INVENTION: the purpose of the invention is to eliminate the above disadvantages of analogues and prototype. And most importantly, the cheaper method by eliminating the cost of expensive waterproofing soda containers and reduce the cost of other auxiliary equipment.

 SUMMARY OF THE INVENTION: This goal is achieved by automatically maintaining the moisture content of the substrate in the entire volume at the level of surface adhesion to the nutrient solution (i.e., at the same level as in the prototype when the substrate is flooded with the nutrient solution and then drained).

 To do this, with the help of an irrigation system (supply of a nutrient solution), which ensures its uniform supply, a nutrient solution is supplied with a given frequency. The periods of supply and pauses are selected in the process of setting the automation so that the solution begins to drain during the period of supply. And he managed to completely drain during a pause into the depth of the substrate (in other words, so that the entire given portion of the nutrient solution during the supply period has time to drain into the substrate during a pause, and then stops flowing, held by surface adhesion forces). In this case, the solution, spreading over the surface of the granules of the substrate (and the root system), moistens this mass uniformly to the entire depth to the level of surface adhesion of this solution with this substrate.

 Then the cycle automatically repeats, and the solution, under the pressure of a new portion, will drain lower and deeper into the substrate, keeping humidity at the level of surface adhesion. Thus, the solution will go down until it reaches the substrate’s humidity sensor (at a set level) and is set to the humidity level corresponding to the surface adhesion of this substrate to this nutrient solution. After this, the supply of the solution automatically stops and starts again at the signal of the sensor after the nutrient solution has been absorbed by the root system of the plants (and since the supply of the solution is uniform over the entire area of the substrate, the moisture will be the same throughout the volume of the substrate). With this method of moistening the substrate, the sensor can be installed in it at such a depth that the nutrient solution will no longer go beyond the substrate (i.e., into the ground).

 In this case, there is no need to place the substrate in a waterproofing container, and it can be poured simply directly onto the ground. It is not necessary to pump out the solution from rastilen (i.e., pumps and pipelines are not needed for this).

 Since the plant nutrition cycle becomes OPEN (i.e., the solution is supplied only from the solution tank to the substrate), its concentration and composition will not change with time.

 It is obvious that this method does not have the other disadvantages listed above. The system with this method of wetting the substrate is operational when the sensor is installed in the substrate at any depth.

 However, it is rational to install it in the zone of the end of the root system of plants, so as not to moisten the non-working layer of the substrate. As the plants and their root system grow, it is advisable (from time to time) to deepen the sensor. By installing the sensor above the zone of possible penetration of roots into the substrate (for a given plant species), it is possible to purposefully limit their growth, since it will be insignificant in the dehydrated zone (and this is sometimes necessary).

 The proposed method actually, like similar ones, boils down to periodic flooding of the substrate with a nutrient solution and its discharge. Only this is done not immediately in the entire volume of the substrate, but differentially, in layers. And with controlled at the same time humidity and depth of wetting of the substrate.

Thus, the proposed method is characterized by the following essential features that are different from those of the prototype:
- the necessary depth of wetting of the substrate is supported automatically using a humidity sensor, which is adjusted to the moisture content of the substrate, corresponding to its humidity during surface adhesion of this solution with this substrate;
- the supply of the nutrient solution by irrigation is carried out periodically and evenly immediately on the entire surface of the substrate, controlled by this sensor;
- the period and duration of each cycle is set so that the feed solution has time to drain into the depth of the substrate by the end of the pause.

Wherein:
a) The claimed invention corresponds to the features of novelty, since in the known methods of hydroponics not a single analogue has been identified, characterized by features identical to the essential features noted above of the claimed invention.

 b) The claimed invention meets the inventive step, because for a specialist, the proposed method does not follow explicitly from the prior art.

 c) The identified set of essential features ensures the achievement of a technical result by reducing at the same time a number of previously required expensive equipment and construction and installation works, etc.

 g) The method is applicable industrially and can be widely used in agriculture.

INFORMATION CONFIRMING THE POSSIBILITY OF CARRYING OUT THE INVENTION:
The proposed method (in the mock-up version) is tested in a hangar greenhouse, 1 - All-Russian Institute of Plant Production named after N.I. Vavilova (see drawing). Expanded clay 2 is poured into it directly on the ground with a layer of 30 cm. At a height of 2 m, a plastic tank 3 with a capacity of 500 liters is installed, into which tap water is supplied through the float valve 4 (so that there is no overflow).

The water is heated to a temperature of 15 ^o C using an electric heater 5, and the necessary amount of concentrated salt solution (nutrient solution) necessary for the normal growth of cultivated plants is added to it.

 Initially, the sensitive element of the moisture sensor of the substrate 6 conductometric type (you can, and others), connected by a control cable 7 to the automatic control unit 8, is immersed to a depth of 10 cm. Subsequently, as the seedlings grow, the sensor is deepened several times.

 The installation begins to work after turning on the control unit 8. At the signal of the humidity sensor 6 (since expanded clay 2 is dry), the control unit 8 opens the solenoid valve 9, and the nutrient solution from the solution tank 3 through a damping device 10 (to prevent water hammer) is fed into a perforated polyethylene hose low pressure 11 (SRO systems manufactured by Simferopol AO).

At a pressure of 200 mm Hg such a hose provides uniform spraying of the nutrient solution over the entire surface of the substrate, which is wetted during the set period of the solution. (However, nozzles and other irrigation systems can be used for this purpose.)
The period of supply of the solution is selected so that it not only moistens the surface of the substrate, but also begins to drain inside. And during the pause, it will continue to flow downward, spreading along the substrate and roots until it is stopped by the forces of surface adhesion (tension).

 As long as the humidity in the zone of the sensor 6 is low, such periodic spraying of the solution will be repeated. And under the pressure of new portions of the liquid, the substrate will be moistened lower and lower until the solution reaches sensor 6, adjusted to the moisture level corresponding to the surface adhesion of this liquid to this substrate. Such humidity is sufficient for normal plant nutrition, as this is exactly what it is in well-known hydroponic installations.

 As the roots absorb the solution, the moisture will drop. And its supply through the hose 11 of the CPO system will be repeated.

 In the future, it is planned to bring this system to an industrial design for use in greenhouses. There is a prospect for the proposed method both for its use in open ground on unsuitable lands (clay, sand, rocky soil, slag dumps, soil with erosion, infected, slightly radioactive, etc.).

 Such installations can be of great help to homeowners and farmers in growing a wide variety of agricultural products.

USED INFORMATION
1. Vlasyuk P. Methods and tasks of hydroponics. "Hydroponics in agriculture." Publishing House "Kolos", M., 1990, p. 40.

 2. USSR author's certificate N 917805, cl. A 01 G 31/00, 07/07/82.

Claims (1)

 A method of hydroponically growing plants on solid loose substrates, comprising periodically supplying the nutrient solution to the substrate from above through low pressure pipes, characterized in that the nutrient solution is supplied uniformly and immediately to the entire surface of the substrate, the moisture and moisture of which are controlled and supported using a sensor, adjusted to the humidity corresponding to the moisture content of this substrate with its surface adhesion to this solution, and the frequency of supply set such so that, flowing gradually into the substrate, he ceases to drain from it towards the end of the pause, held by the forces of surface adhesion.