WO1989008383A1 - Procede et systeme de culture de plantes - Google Patents

Procede et systeme de culture de plantes Download PDF

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Publication number
WO1989008383A1
WO1989008383A1 PCT/DK1989/000053 DK8900053W WO8908383A1 WO 1989008383 A1 WO1989008383 A1 WO 1989008383A1 DK 8900053 W DK8900053 W DK 8900053W WO 8908383 A1 WO8908383 A1 WO 8908383A1
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WO
WIPO (PCT)
Prior art keywords
agent
liquid
plants
amounts
growth
Prior art date
Application number
PCT/DK1989/000053
Other languages
English (en)
Inventor
Lillie Andersen
Niels Erik Nielsen
Original Assignee
Lillie Andersen
Niels Erik Nielsen
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Lillie Andersen, Niels Erik Nielsen filed Critical Lillie Andersen
Publication of WO1989008383A1 publication Critical patent/WO1989008383A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
    • A01G31/00—Soilless cultivation, e.g. hydroponics

Definitions

  • the present invention relates to a method for growing plants, whereby an aqueous liquid containing a growth or health adjusting agent is supplied to plants which are arranged in a growth area with substan- tially the same growth conditions.
  • the nutrients or growth adjusting substances which are absorbed by plants, such as vegetables, are normally not poisonous in the amounts in which they are absorbed by people who eat the vegetables in qu ⁇ estion in a normal amount.
  • the plants may absorb the substances in question to a particularly high degree, which might involve a toxic effect or an effect inju ⁇ rious to the health of those persons who eat the plants.
  • nitrate may be absorbed by vegetables or other plants to a large or small extent depending on the nitrate availability and the other growth conditions during the growth of the plant.
  • Nitrate as such is not poisonous in the amounts in which it is normally eaten by people, but during passage of the mouth and the gastrointestinal canal the nitrate may to some extent be reduced to nitrite. Nitrite is far more poisonous and by reaction with secondary or tertiary amines or amides may form nitrosamines which are thought to be carcinogenic.
  • the accumulation of nitrate in plants is a result of an interaction between the amount of nitrate in the growth medium, the nitrate absorption of the plants, the nitrate reduction of the plants and the speed of incorporation of nitrogen in new tissue.
  • Nitrification inhibitors are chemical substances which prevent the microbial oxidation of ammonium into nitrate in the growth medium. The most used ones are N-serve with the active substance 2-chloro-6- (trichloromethyl)-pyridine and didrine, which consists of dicyanodi- amide. Test results show a reduction in the nitrate content of plants with the use of nitrification inhibitors, but at the same time a tendency towards a yield reduction. This may be due to a moderate ammonium poisoning of the culture.
  • nitrate reduction in plants to be obtained by reduction of the nitrate concentration in the water culture solution is strongly dependent on the time of year, and the quality of the lettuce may reach an unacceptable level.
  • the availability of nutrients or growth adjusting substances for plants also contributes to the control of the flower and fruit for ⁇ mation of the plants. There is therefore a need to control the supply of nutrients to flower and fruit plants at certain times of the growth period so as to obtain an improved flower formation and/or a larger fruit yield.
  • the invention attempts to provide a method of the type mentioned above in which it becomes possible to reduce and control the supply of nutrients to plants, for example in a manner so that the nitrate content of the plants is reduced without involving a yield reduction or quality deterioration of any significance, or so that the flower and/or fruit formation is improved.
  • the method according to the invention is characterized in that the growth area is divided into a reference area and a production area, that the plants in the reference area are supplied with a first aqueous liquid in which the growth or health adjusting agent is present in an empirically determined concentration, that the agent is continuously or intermittently added to the first liquid in such amounts that the concentration of the agent in said first liquid is substantially maintained at the empirically determined level, and that the plants in the production area are supplied with a second aqueous liquid having a second fixed, preferably lower, concentration of said agent, and that the agent is continuously or intermittently added to said second liquid in amounts controlled in dependency of the amounts of the agent added to the first liquid.
  • This first liquid is normally a plant nutrient solution
  • said growth or health adjusting agent may, for example, be a plant nutri ⁇ ent, a trace element, a hormone agent, an insecticide and/or a fungi ⁇ cide.
  • the agent is added to the first liquid in varying amounts so that the concentration of the agent in the first liquid is substanti- ally maintained at the empirically determined level, and the supply will thus correspond to the varying absorption of the agent by the plant depending on the changing growth conditions.
  • the amounts of the growth or health adjusting agent added to the second liquid which is supplied to the plants in the production area are controlled in dependency of the amounts of the agent added to the first liquid supplied to the plants in the reference area, it is possible to obtain a desired ratio between availability of the agent for the plants in the production area and the tendency or need of the plants for absorption of the agent under the changing growth conditions.
  • the supply of the growth or health adjusting agent to the plants in the production area may be controlled according to any desired pat ⁇ tern or program on the basis of the supply of the agent to the first aqueous liquid.
  • the amounts of the agent added to the second aqueous liquid may be reduced relatively more at night than in the daytime and/or reduced especially much in the period immediately before harvesting of the plants or in the period in which the flower and/or fruit formation may be particularly influenced.
  • the agent is added to the second liquid in amounts which are proportional to the amounts of the agent added to the first liquid.
  • the plants in the reference area and the production area may be separately supplied with the growth substances or nutrients they need beyond said growth or health adjusting agent, and said first and second aqueous liquids then only need to contain this agent.
  • these aqueous liquids may further contain one or more plant nutrients and/or growth or health adjusting agents.
  • an aqueous liquid may be used which contains one or more plant nutrients, the ratio between these nutrients substantially corresponding to the ratio in which the plants in question are known by experience to absorb these nutrients.
  • the plants grown by the method according to the invention may be of any type.
  • the method according to the invention may be used particularly advantageously when growing vegetables, such as for example lettuce, head lettuce, spinach, leeks, Chinese cabbage, celery, etc., and when the agent used is nitrogen or nitrate, as the nitrate absorption of these vegetables may then be controlled.
  • the amounts of nitrogen per plant unit in the production area which are added to the second aqueous liquid may advantageously constitute between 50 and 100%, preferably 60-70%, of the amount per plant unit in the reference area which is added to the first aqueous liquid. It has been found by experience that the nitrate accumulation in the plants may then be kept at a desired low level without involving any substantial yield reduction.
  • the absorption of the plants of the growth or health adjusting agent is partly dependent on the amount (availability) of the agent in the second liquid, and partly on the external environmental factors to which the plants are exposed, such as light, temperature, humidity, the carbon dioxide concentration, etc.
  • the environmental factors may thus be said to control the tendency of the plants to absorb the agent.
  • These en ⁇ vironmental factors are the same in the production area as in the reference area, but in the reference area the amount (availability) of said agent is maintained at a fixed level for which reason the amounts of the agent added here correspond to the plants' absorption of the agent, in response to the given environmental factors.
  • the invention further relates to a system for growing plants in inactive growth media, including aquaculture, of the type comprising a first water culture circuit, a supplementary liquid container and first supply means adapted to supply a supplementary liquid to the first circuit continuously or intermittently from the supplementary liquid container so that the concentration of a health or growth adjusting agent contained in a liquid circulating in this circuit is substantially maintained at an empirically determined level, and the system according to the invention is characterized in that it compri ⁇ ses a second separate water culture circuit and second supply means adapted to continuously or intermittently supply said agent to the second circuit in amounts which are substantially proportional to the amounts of the agents supplied to the first circuit.
  • Fig. 1 schematically shows a system according to the invention
  • Fig. 2 is a graph indicating the fresh weight of plants grown by the method according to the invention
  • Fig. 3 is a graphic indication of the nitrate content in lettuce plants grown partly by a conventional growth method and partly by the method according to the invention.
  • Fig. 1 shows a growth area which is divided into a reference area 10 and a production area 11, respectively, with substantially the same growth conditions, and in which plants are grown in an inactive growth medium, for example lettuce plants in water culture.
  • the reference area 10 is associated with a first liquid circuit 12 comprising a container 13 for a water culture solution with supply conduits 14 for pure, demineralized water with a control device (not shown) for maintaining a substantially constant amount of water culture solution in the liquid circuit, supply conduits 15 for sup- plementary amounts of nutrient solution(s) contained in one or more supplementary liquid containers 16, a supply conduit 17 through which the water culture solution from the container 13 is supplied to the plants of the reference area 10, and a return conduit 18.
  • a pump 19 is arranged for circulating the water culture solution in the circuit 12.
  • a measuring and control unit 20 is arranged at the return conduit 18 of the liquid circuit leading from the growth area of the referen ⁇ ce area.
  • One or more pumps 21 (only one is shown in Fig. 1) are provided to meter a supplementary solution from the containers 16 to the container 13 through the supply conduit 15, and the function of these pumps 21 is controlled by control signals A from the measuring and control unit 20.
  • the production area 11 is associated with a second liquid circuit 22 comprising a container 23 for a water culture solution with a supply conduit 24 for pure, demineralized water and comprising a control device (not shown) for maintaining a substantially constant amount of water culture solution in the liquid circuit, a supply conduit 25 for supplementary amounts of nutrient contained in one or more supplemen ⁇ tary liquid containers 26, an supply conduit 27 through which the water culture solution from the container 23 is supplied to the plants of the production area, and a return conduit 28.
  • the water culture solution is circulated in the circuit 22 by means of a pump 29 inserted into the supply conduit 27.
  • One or more pumps 30 (only one is shown in Fig. 1) , the function of which is controlled by control signals B from the measuring and control unit 20, serve to meter a supplementary solution from the container 26 to the water culture solution in the container 23.
  • a flow of water culture solution having an empirically determined concentration of one or more plant nutrients which it is desired to supply to the plants is supplied to the reference area 10.
  • the plants which, for example, are standing is open channels, then absorb nutrients in naturally controlled amounts (according to their "appetite").
  • the remaining concentration of nutrient is measured by means of the measuring and control unit 20 which passes on control signals A, B to the pumps 21 and 30, respectively, on the basis of these measurements.
  • the control signal A controls the operation of the pump 21 so that the amount of nutrient absorbed by the plants in the liquid circuit of the reference area 10 is replaced so that the concentration of the agent is substantially maintained at the empiri- cally determined level.
  • the control signal B controls the pumps 30 so that an amount of nutrient dependent on the amount of nutrient absor ⁇ bed in the reference area is supplied to the water culture solution . of the production area 11.
  • the supply is effected in such a manner that each plant in the production area has an amount of nutrient at its disposal which is a substantially fixed fraction of the amount at the disposal of each plant in the reference area.
  • Measuring and control may be effected by means of a single unit 20, as shown in Fig. 1, or the tasks may be handled by separate apparatu ⁇ ses for measuring and control, respectively.
  • the measurement is effected as a measurement of the electric conductivity and pH of the water culture solution, as the change in the conductivity reflects the amount of nutrient which has been absorbed during the circulation of the water culture solution in the reference area 10, and the pH reflects the acid/base ratio and/or the ammonium/nitrate ratio in the water culture solution.
  • the supply of supplementary liquid may be effect by a supply of nutrient from a basic (nitrate-containing) container when the pH is undesirab ⁇ ly low, and by a supply of nutrient from an acidic (ammonium-contai ⁇ ning) container when the pH is undesirably high.
  • Measurement and control may take place substantially continuously, which means that a supply of the agent is effected when the content thereof in the liquid circuit falls to a predetermined, slightly lower level, or intermittently, i.e. measurements are made at certain intervals, for example every six or twelve hours, whereupon the amount of the agent absorbed by the plants during this time interval is supplied. Measurement and control may also take place as a combi- nation of the two methods explained above by means of electrical and/or electronic apparatuses.
  • measurements of conductivity and pH may be made at the return conduit 28 of the production area.
  • the control may be made for a single nutrient (nitrogen) or for a nutrient solution containing all or several of the nutrients neces ⁇ sary for the plants, and which are comprised in the solution in the ratio in which the plants are known by experience to absorb the various substances.
  • the control may further be made for several nutrient solutions which separately contain certain of the nutrients necessary for the plants.
  • Fig. 3 shows the nitrate content of the plants measured in mg per kg fresh weight. It can be seen that the method according to the invention renders it possible to substantial ⁇ ly reduce the nitrate content in lettuce plants without any substan ⁇ tial reduction of the plant yield.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Environmental Sciences (AREA)
  • Hydroponics (AREA)
  • Cultivation Of Plants (AREA)
  • Agricultural Chemicals And Associated Chemicals (AREA)

Abstract

On cultive des plantes, par exemple des légumes, dans un milieu de culture inactif, y compris l'aquaculture, dans lequel on alimente les plantes avec un liquide aqueux contenant un agent régulateur de croissance ou de santé tel que par exemple de l'azote. La culture se fait par division d'une zone de culture en une zone de référence (10) et une zone de production (11) ayant sensiblement les mêmes conditions de culture, et par alimentation des plantes se trouvant dans la zone de référence (10) avec un premier liquide aqueux dans lequel ledit agent est présent dans un concentration déterminée empiriquement. Ledit agent est amené au premier liquide de manière continue ou intermittente dans des quantités telles que la concentration de l'agent dans ledit premier liquide est sensiblement maintenue au niveau empiriquement déterminé. On alimente les plantes situées dans la zone de production (11) avec un second liquide aqueux comportant une seconde concentration fixe de préférence inférieure dudit agent, lequel agent est alimenté audit second liquide de manière continue ou intermittente, dans des quantités régulées, par exemple proportionnellement par rapport aux quantités de l'agent ajouté au premier liquide. Ainsi il devient possible de réguler la teneur des plantes en agent régulateur de croissance ou de santé de manière, par exemple, à réduire la teneur en nitrate sans entraîner une éventuelle réduction de la production ou détérioration de la qualité.
PCT/DK1989/000053 1988-03-08 1989-03-07 Procede et systeme de culture de plantes WO1989008383A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DK123988A DK123988A (da) 1988-03-08 1988-03-08 Fremgangsmaade og anlaeg til dyrkning af planter
DK1239/88 1988-03-08

Publications (1)

Publication Number Publication Date
WO1989008383A1 true WO1989008383A1 (fr) 1989-09-21

Family

ID=8102574

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DK1989/000053 WO1989008383A1 (fr) 1988-03-08 1989-03-07 Procede et systeme de culture de plantes

Country Status (4)

Country Link
EP (1) EP0408615A1 (fr)
AU (1) AU3297289A (fr)
DK (1) DK123988A (fr)
WO (1) WO1989008383A1 (fr)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE331610B (fr) * 1965-10-01 1971-01-04 Wallco Ab

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE331610B (fr) * 1965-10-01 1971-01-04 Wallco Ab

Also Published As

Publication number Publication date
EP0408615A1 (fr) 1991-01-23
DK123988A (da) 1989-09-09
AU3297289A (en) 1989-10-05
DK123988D0 (da) 1988-03-08

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