High Tech Commercial Agriculture
Hydroponics/ Soil-Less Culture
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. Further, continuous cultivation of crops has resulted in poor soil fertility, which in turn has reduced the opportunities for natural soil fertility build up by microbes. This situation has lead to poor yield and quality. In addition, conventional crop growing in soil (Open Field Agriculture) is difficult as it involves large space, lot of labour and large volume of water. And in some places like metropolitan areas, soil is not available for crop growing. Another serious problem experienced since of late is the difficulty to hire labour for conventional open field agriculture.
Why Hydroponics/ Soil-less Culture?
Hydroponics or soil-less culture is a system of growing plants which helps reduce some of the above mentioned problems experienced in conventional crop cultivation. 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
Hydroponics/ Soil-less Culture What Is It?
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, rockwool, peat moss, saw dust, coir dust, coconut fibre, etc. to provide mechanical support.
History of Hydroponics
Hydroponics was practiced many centuries ago in Amazon, Babylon, Egypt, china and India where ancient men used dissolved manure to grow cucumber, watermelons and other vegetables in sandy riverbeds. The "hanging harden of Babylon" and the Aztec's floating farms were actually prototypes of hydroponic systems. Later, when plant physiologists started to grow plants with specific nutrients for experimental purposes, they gave the name "nutriculture." Interest in practical application of "nutriculture" developed in 1925 when the green house industry expressed interest in its use. Green house soils had to be replaced frequently to overcome problems of Soil structure, fertility and pests. As a result, researchers became interested in the potential use of nutriculture to replace conventional soil culture.
A polytunnel is a tunnel made of polyethylene used to grow plants that require a higher temperature and/or humidity than that which is available in the environment. Polytunnels are mainly used in temperate regions. They are similar in principle to greenhouses and cloches (row covers). Modern designs allow sowing and harvesting machines to move inside the structures so as to automate production.
Construction of a Polyhouse
The polyhouses are constructed with the help of ultraviolet plastic sheets, so that they may last for more than 5 years. The structure is covered with 1501 m thick plastic sheet. The structure is prepared with the bamboos or iron pipes. Iron pipe structure is costly but more durable than bamboo. Generally the length of the polyhouse is 25-30 feet and width 4-5 feet. The direction of polyhouse is always East to West, so that the maximum sunshine is available. The house should not be constructed in shade. The size of polyhouse may differ depending on the necessity. The polyhouses are kept cold or hot depending upon the season.