Study notes on hydroponics, sand cultures and aeroponics!
Hydroponics (Tank Culture):
The technique of growing plant in water cultures (or nutrient solution) without soil as a rooting medium is known as hydroponics or tank farming.
Some vegetables and ornamental plants like tomatoes, carrot, lettuce and roses are grown in hydroponics in European countries.
Plants are grown in concrete tanks filled with nutrients in water. The nutrients solution is changed from time to time and aeration of roots is also done mechanically. Wire netting covering the tanks provide support to plants.
Hydroponics are useful in regions having thin, infertile and dry soils. Additional advantage is that the plants grow free of soil pathogens and weeds. These plants give better yields. Besides, out- of season vegetables and flowers can also be obtained.
Sand Cultures:
In these cultures, the plants are grown in sand supplied with nutrient solution. Here, big vessels are filled with acid and distilled water-washed pure sand. Nutrient solution is added into the sand from time to time. Here the roots of plants get natural aeration.
However, these cultures, though provide solid media for growth, yet suffer from following disadvantages:
(i) Since the sand is highly alkaline in nature; it has to be washed with add before use;
(ii) The sand gets very warm during summer and very cool during winters and thus may damage the roots of the plants;
(iii) The water-holding capacity of sand is very low, and, therefore, needs frequent watering. Sand cultures are mainly used for experimental work in the laboratories.
Aeroponics:
In this type of culture, the rooted plants are placed in a special kind of box with their shoots exposed to the air and roots inside the box. The nutrient solution is kept in the bottom of the box. Then the nutrient mist (a cloud of moisture in the air) is sprayed on the roots. This system too is used for research purposes in the laboratories.