HYDROPONIC: SOIL LESS CULTURE
Hydroponics: Hydroponics or soil-less culture is a technology for growing plants in nutrient solutions that supply all nutrient elements needed for optimum plant growth with or without the use of an inert medium such as gravel, vermiculite, rock wool, peat moss, saw dust, coir dust, coconut fibre, etc. to provide mechanical support.
Hydroponics or soil-less culture is a system of growing plants which helps to reduce some of the problems experienced in conventional crop cultivation, especially land shortage in India where near metropolitan suburbs encroaching the cultivable land for various activities such as Housing, Factories, Institutes, Rospitals, recreations centres, Parks and Play grounds etc. soil is usually the most available growing medium and plants normally grow in it. It provides anchorage, nutrients, air, water, etc. for successful plant growth. Modification of a soil an alternate growing medium tends to be expensive. However, soils do pose serious limitations for plant growth, at times. Presence of disease causing organisms and nematodes, unsuitable soil reaction, unfavourable soil compaction, poor drainage, degradation due to erosion, etc. are some of them. Hydroponics offers opportunities to provide optimal conditions for plant growth and therefore, higher yields can be obtained compared to open field agriculture. Hydroponics or soil less culture offers a means of control over soil-borne diseases and pests, which is especially desirable in the tropics where the life cycles of these organisms continues uninterrupted and so does the threat of infestation. Thus, the costly and time consuming tasks of soil sterilization, soil amelioration, etc. can be avoided with hydroponics system of cultivation. It offers a clean working environment and thus hiring labour is easy for this system of cultivation of crops.
Requirement of hydroponics:
Following are the requirement of the well hydroponics or water culture.
- Nutrient solution:- Many formula for hydroponics nutrient solution have been given but they are all quite similar, different mostly in the ratio of nitrogen to potassium. Plants need less nitrogen during short or dark days and more nitrogen during long days, bright sunlight, and higher temperatures. Smaller operations often buy ready-mixed nutrient formulations; only water needs be added to prepare the nutrient solutions to standard or slightly modified formula.
- Growing medium: –
- Growing medium is used to lend support to the roots and plants.
- A variety of growing medium are utilized for their individual qualities in various types of hydroponics systems.
- The acidity or alkalinity of nutrient solution,
- ph reading run from 0-14,
- o-6 acidic, 7-neutral, 8-14 alkaline,
- The recommended PH is between 6-6.5. Few popular examples of growing medium are: sand, Brick, shards, vermiculite/Perlite, gravel, Rockwool, sawdust, polyethylene sheeting.
Type of Hydroponics
- Solution Culture: The plants are raised in pure nutrient medium containing only the desired elements. The pyre or any other clear hard glass vessels are used as containers and for plant support special engineered structures are required. To protect the roots from direct light and to check algal growth in the nutrient solution, the container are covered on their outer surface with black paper. The aeration for the root is provided with the help of vacuum lines which continuously keep on providing fresh filtered air to the nutrient solution. In case of any change due to absorption of nutrient by plant occasional PH adjustment are done and nutrient solutions are frequently changed. There are several culture media available but knops and hoaglands media is commonly used.
- Rock wool culture: Rock wool is an inert, porous, sterile growing medium made from rocks that are heated at high temperature and made into fibers. The resulting fibers can be turned into slabs or bags as a loose rockwool for bag culture. The small cubes of rockwool are used for starting transplant slabs are packaged in white irrigated by micro-irrigation with one emitter per plant. Fertilization of rockwool is accomplished by fertilization through drip irrigation system each time. In most systems, water is mixed with fertilizer to make stock solution in 1:100 ratio before it is applied to the slabs.
- Nutrient film technique (NFT): It is type of a ‘water culture’ system in which the bare roots are continuously bathed in a flowing nutrient solution. True NFT consist of growing plants in a shallow plastic-lined trough in which nutrient is flowed continuously. Roots spread out over the width of 12 inch channel and are continuously bathed in a thin film of flowing oxygenated nutrient solution. Channels are on a slope to allow the nutrient solution to flow from one end of the channel to the other end collected for return to the sump tank. Nutrient solution is pumped continuously from the sump tank back to the channels. Nutrients are added to the solution as needed and the solution may be replaced periodically to reduce the build up of salts and disease organism.
Vegetables grow hydroponically: Tomato, Egg Plant, Green bean, Beet, winged bean, Capsicum, Bell pepper, Cabbage, Cauliflower, Raddish, lettuce, etc.
By:- Mukesh Topwal
Department of Horticulture
Uttaranchal (P.G.) College of Biomedical Sciences and Hospital