Hydroponics from the Greek "hudōr" 'water' and "ponos" 'work or effort' is the culture of plants on substrate neutral and inert that is regularly irrigated after water of mineral salts, trace elements and nutrients essential to the development of the plant. Hydroponics still called 'culture above ground' is very present in horticulture and force some vegetables, greenhouse grown.
It grew in aeroponics and ultraponic.
It allows to speed up the maturation of the fruit by reducing the frequency of day and night, allowing multiple annual crops.
For optimum growth of plants, there are:
• The natural or artificial light
• A stable and temperate temperature
• A controlled air humidity
• Good oxygenation of the roots
• Balanced nutrition consisting of water, mineral salts and trace elements.
The plant uses light to activate its metabolism that allows him to assimilate the food by its roots. In nature, water is responsible to the passage in the Earth of salts, minerals and trace elements but often unbalanced and random way; It is indeed rare to have a perfect floor, and if we take in more weather variation in nature, all these facts explain why from one year to the other, the harvest can vary from simple to double.
Above ground under greenhouse culture to deal with these unknowns by setting all these factors at the fair, thus saving water and nutrients.
The Chinese use the culture on gravel for thousands of years.
The hanging gardens of Babylon were soilless culture.
The Aztecs grew on rafts made of rushes and reeds and covered with silt.
Soilless culture such as we know was born in the 19th century in Germany as part of studies on feeding plants. Isn't that in 1930 as a first hydroponic system was marketed in Germany. Then the second World War soldiers US cultivated in hydroponics vegetables on volcanic islands of the Pacific to ensure the need for vitamins of the troops.
Today culture above ground has millions of hectares in the world and a large number of fresh vegetables like tomato, Zucchini, cucumber, lettuce, pigments, pepper, spinach, beans, broccoli, herbs, among other emerged, like the majority of cut flowers in florists.
The fertilizer and nutrients:
It's a chemistry teacher, Baron Justus von Liebig (1803-1873) was the forerunner of scientific research on the fertilizer. It is by observing and analyzing just the ashes of plants he made burn he concludes that nitrogen, potash and phosphorus present in these ashes feeding the plant and that it drew these minerals in the soil and the atmosphere and transformed organic matter. So he opened the door of agricultural chemistry.
In 1905 Fritz Haber, German, chemist to develop a process transforming the nitrogen in the air in liquid ammonia consists of 80% nitrogen. He joined in 1915 Karl Bosch engineer to design and build the first ammonia plant, which unfortunately also served to design first devastating chemical weapons.
Fritz Haber received the Nobel Prize in chemistry in 1918, because ammonia is used in many industrial areas beneficial to society.
At the end of the second world war, many industrial sites producing ammonia gave birth to Dupont, Dow Chemical, Monsanto, American Cyanamid groups that began the mass production of mineral fertilizers.
Appearance of soilless culture:
In the 17th century, it was thought that plants were forming from water, when John Woodward concluded, following experiences of crops without soil, that it was the Earth and not the water that created the plant. In 1758, Duhamel de Monceau resumed the ideas of John, did germinate seeds in sponges, and then plunged the roots in water containing dissolved minerals. Positive results launched several research on this type of culture that fully ended after the discoveries of Justus von Liebig. The name hydroponics appeared simultaneously with that of hydroculture, of the German Hydrokultur.
The hydroponic system as we know has been demonstrated scientifically by two researchers Germans, Knops, and Sachs, highlighting the role of water, air and soil, and especially the ability to artificially recreate all these actors.
Hydroponic soilless culture has grown strongly as it has many advantages: no matter the nature of the soil, exposure to the Sun, the season; better risk management, diseases insects, water requirement reduced by 70-90%, performance leveraged sq m, regularity of the harvest...
A substrate is unable to interact with other substances inert matter, and which is used as a support for the cultivation of plants, mainly in soilless culture.
The main substrates are:
- Perlite, siliceous sand of volcanic origin expanded industrially by cooking at 1200 ° C. Looking for cat litter, he has a very large capacity of water retention from 4 to 5 times its weight, and has a PH of 7 to 7.2.
- Vermiculite, expanded silicate of alumina by cooking, very light and high water retention capacity about 370 liters per m3 with good drainage.
- Substrates of volcanic origin, uninteresting
- The balls of clay, obtained by expansion hot, very good power insulating of the roots, 15% of its mass water Retention, ideal for small hydroponic systems.
- Rock wool, not totally inert, unpleasant to use, free from fiber.
- Fiber of coconut, difficult job, specific request for fertilizer.
The latest techniques
- The NFT designed in 1979 by Mr. Cooper, technical without substrate, liquid nutrient driven by a pump circulates on a thin like a movie under the roots, leading to the hit a very good oxygenation, where the name 'Nutrient Film Technic. Widely used in soilless cultivation method.
- Aeroponics: the nutrient solution is sprayed onto the roots, in a closed environment and closed circuit and the plant has its roots in the air, without substrate. The results are really exceptional because plants develop a mass of roots thinner and larger. Watering is done by fogging intermittently. It is one of the best-performing soilless culture systems today, 90% of consumption of water and less, no pollution of the soil, yields increased...
- Hydroponics; soilless culture economic and simple system. It is fed by irrigation or spray the roots placed in a substrate with a nutrient solution and a perfect pH and electrical conductivity management. Low maintenance, genetic potential of the plant pushed to its maximum with bigger flowers, vegetables more tasty and medicinal plants to the more concentrated active ingredients.
- Hydroponics at tide: ditto previous but substrate plants are placed in watertight containers filled regularly nutrient solutions during a certain period of time before you get him out, allowing an oxygenation of the roots
- Drip system: a system popular with simply a discontinuous watering from the top of the substrate using one or two emitters.