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Hydroponics Technology: Farming Without Soil




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     The term soil less culture is synonymously used in Hydroponic technology. The word means ?the working water?.In other words, the cultivation of plants in water is referred as hydroponics. However in a broader sense, the cultivation of crops in any growing substrates, whether organic that is, peat moss, coconut fibre, straw bales, grapes residue, etc. or inorganic perlite, vermiculite, rock wool, sand etc., in the absence of soil is referred to as Hydroponics.

    The greenhouse structures are based on the available sources as the capital investment. These structures are constructed to control the growing climatic condition mainly including light, temperature, air circulation, humidity etc. for proper growth and development of the crops. The structures should be erected in such a manner that optimum advantage should be taken from the prevalent seasonal weather conditions. The direction of greenhouse is also important factor to make use of better crop production by consuming the sunshine entering into the structure from a certain direction. The structures are designed with a specific shape, viz. raised cutters and screen of green net is usually introduced to give shade to the plants during scorching heat or when the plants need less light for the proper growth.The rainwater consumed for crop production can efficiently be collected in the form of reservoir and this idea has negated the claim that Hydroponic crop production need surplus water. Rather this technique drastically saves the water and is a potential and practical application of modern but well established technique for getting higher and quality yield of a number of crops. The rain water falling in the surrounding area and dropped through the raised cutters of greenhouses are collected into the channels constructed nearby and is ultimately accumulated in the reservoirs.

    It should be kept in mind that if circumstances do not permit for water harvesting through such reservoirs, even then a limited amount of water could serve the purpose to canalize the production routine. In many a countries of the world, the drainage water after proper treatment based on latest technology, enables the water to be reused for crop production. The arrangement of irrigation can be manipulated by applying mist system; drip irrigation and also the controlled cooling pad system to maintain the requisite humidity in the greenhouse. In greenhouse production, the introduction of supplemental CO2 inside the plant growing environment is made to enhance the crop growth. The logical reasoning of CO2 that plants use this gas to manufacture their food under the action of a biological process called photosynthesis.The sources of plant nutrients (salts) for macro (nitrogen, phosphorus, potassium, calcium, magnesium, etc.) and micro (zinc, sulphur, iron, cupper, molybdenum, manganese, etc.) elements are acquired from the reliable source. A suitable air system has to be installed to regulate the heating and cooling in accordance with the temperature requirement of the crop schedule. This is heavily practiced in most of the greenhouses.
    However, in the areas where energy crises prevail and the fuel cost is hard to bear, in such instances cold glasshouses (unheated glasshouses) are undertaken for production objective. And the use of energy for the sustainability of temperature inside the greenhouses is to the level at critical stage when temperature either very low or very high to operate the heating or cooling system. This kind of exercise is done to overcome the critical moments in plants to avoid the risk of high mortality under adverse climatic conditions. Some of the climatic components are automated with the help of computer and are very common and cost effective when compared with the manual routine where the labor charges come out exorbitant. 
    The crops grown by hydroponics have a sizable volume of market within the country and a lot of prospects that have been explored to export the crop like tomato, lettuce, strawberry, cut flowers etc. For example, tomato is grown in thousand tonnes of volume around the world moreover different types of tomatoes including beefsteak, cluster, cherry etc. are produced by hydroponics. The seeds must be hybrid in nature to get the optimum yield. The crop can be obtained round the year without any break followed by a strict schedule.Hydroponics is the most intensive technology for growing plants in nutrient solutions (water containing fertilizers) with or without the use of an artificial medium to provide mechanical support. Food for plants are dissolved in water and fed directly to roots.Plants absorb essential mineral nutrients as inorganic ions in water. In natural conditions, soil acts as a mineral nutrient reservoir but the soil itself is not essential to plant growth.When mineral nutrients in soil dissolve in water, plant roots are able to absorb them. When the required mineral nutrients are introduced into a plant?s water supply artificially, soil is no longer required for the plant to thrive. Almost any terrestrial plant will grow with hydroponics, but some will do better than others.
    Hydroponics is also a standard technique in biology research and teaching and a popular hobby. There has been an increasing interest in the use of hydroponics or soil less techniques for the production of greenhouse horticultural crops but there is little commercial value because of it being more expensive than the traditional agriculture.The two main types of hydroponics are solution culture and medium culture. Solution culture does not use a solid medium for roots, just the nutrient solution. The three main types of solution culture are static solution culture, continuous flow solution culture, and aeroponics.The medium culture method has a solid medium for roots and is named for the type of medium, e.g., sand, gravel, or rock wool culture. There are two main variations for each medium, sub-irrigation and top irrigation. For all techniques, most hydroponics reservoirs are now built of plastic but other materials have been used including concrete, glass, metal and wood. The containers should exclude light to prevent algae growth in nutrient solution.The principle advantages of hydroponics include high-density planting, maximum crop yield, crop production where no suitable soil exists, freedom from the constraints of ambient temperatures and seasonality, more efficient use of water and fertilizers, minimal use of land area, and suitability for mechanized production and disease control.
    A major advantage of hydroponics, as compared with culture of plants in soil, is the isolation of the crop from the underlying soil which may have problems associated with disease, salinity, or poor structure and drainage. The costly and time-consuming tasks of soil sterilization and cultivation are unnecessary in hydroponics systems, and a rapid turnover of crops is readily achieved.In this system no soil is required and chances of soil borne diseases are virtually eliminated. The problems due to weeds are virtually eliminated with less or no use of pesticides.Edible crops are not contaminated with soil. Water use can be substantially less than with outdoor irrigation of soil-grown crops. Solution culture hydroponics does not require disposal of a solid medium or sterilization and re-use of a solid medium. Solution culture hydroponics allows greater control over the root-zone environment than soil culture. In solution culture hydroponics, plant roots can be seen. This system is considered high-tech and futuristic and so appeals to many people. Hydroponics is excellent for plant teaching and research.The principal disadvantage of hydroponics, relative to conventional open-field agriculture is the high cost of capital and energy inputs, especially if the structure is artificially heated and cooled by fan and pad systems.
    A high degree of competence in plant science and engineering skills are required for successful operation. This system usually requires more and more frequent maintenance than geoponics. If timers or electric pumps fail, or the system clogs or springs a leak plants can die very quickly in hydroponics system. Because of its significantly higher costs, successful applications of hydroponics technology are limited to crops of high economic value in specific regions and often at specific times of the year, when comparable open-field crops are not readily available.
    A weakness in any number of technical or economic links snaps this complex chain. Deficiencies in practical management or scientific and engineering support results in low yields of nutrient-deficient and unattractive crops; plant diseases; insect infestation; summer overheating; winter chilling; under-capitalization; and indifferent cost accounting, all of which, separately or together, have caused hydroponics businesses to fail. There is no margin for poor management or mistakes.
    Hydroponics has been exaggerated as miraculous. There are many widely held misconceptions regarding hydroponics, and the following facts should be noted. Hydroponics will not always produce greater crop yields than with good quality soil; plants cannot be spaced closer together than soil-grown crops under the same environmental conditions; produce will not necessarily be more nutritious or delicious than soil-grown produce. With hydroponics, capital costs are several orders of magnitude higher than those for open-field crops, and the types of food crops feasible for hydroponics are severely limited by potential economic return. Agronomic crops are totally inappropriate. A decade ago, it was calculated that the highest market prices ever paid would have to increase by a factor of five for hydroponics agronomy to cover the cost. Since then, hydroponics costs have more than doubled, while crop commodity prices have remained constant. Repeated pricing studies have shown that only high-quality garden type vegetables like tomato, cucumber, potato, sweet peppers, melon, and specialty lettuce can cover costs or give a return in hydroponics systems. As the consumer becomes increasingly aware of quality differences, especially the high quality of tomatoes, cucumbers, and leafy vegetables coming from hydroponics, the demand will increase. This, along with the increased emphasis on eating more vegetables for dietary and health reasons, will surely help the hydroponics industry.
    In Pakistan, the use of hydroponics for crop production is not promoted. This may be due to the lack of knowledge and awareness. The hydroponics introduction at commercial level has been introduced by an entrepreneur near Rawalpindi incurring heavy investment with good skill utilization. The trend indicates that people have started showing interest in this area of crop production which is a health sign on the part on implementation of new technology in Pakistan. But still a lot have to do to catch the real goal and objectivity. The work on hydroponics at university level can change the face of the agriculture sector in crop production technology.
    The present government has shown its seriousness to promote the intensive cultivation for increasing per acre yield. This is only possible if innovative technology of hydroponics is introduced and should be induced deep into the farmer community. Needless to say that introducing the hydroponics greenhouse production will raise the future column and can give a boost to such productive technologies in our country.
    In advanced countries, every component of greenhouse system is directly attached with the computer control, thus has been monitored in the office. Any fault in any part of the system in the greenhouse can certainly be identified instantly to rectify the problem within no time. As an example, the flow of feed provided to the plants in the greenhouse can give clear-cut indications for the level of pH, EC, amount of micro and macronutrients etc. If any interruption appears in the smooth channeling of the solution flow, it will be localized through computer screen, and the concerned individual will remove the chocking thus maintains the flow in the channel.
     
    By: Muhammad Ahmad and Dr. M. Ishaque

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