After the advent of green revolution, more emphasis is laid on the quality of the product along with the quantity of production to meet the ever-growing food requirements. Both these demands can be met when the environment for the plant growlh is suitably controlled. The need to protect the crops against unfavourable environmental conditions led to the development of protected agriculture. Greenhouse is the most practical method of achieving the objectives of protected agriculture, where the natural environment is modified by using sound engineering principles to achieve optimum plant growth and yields. In this chapter, the history, the phenomenon of greenhouse effect and advantages of greenhouses are discussed.
A greenhouse is a framed or an inflated structure covered with a transparent or translucent material in W'hich crops could be grown under the conditions of at least partially controlled environment and which is large enough to permit persons to work within it to carry out cultural operations.
The growing of off-season cucumbers under transparent stone for Emperor Tiberius, in the first century, is the earliest reported protected agriculture. The technology was rarefy employed during the next 1500 years. In the 16th century, glass lanterns* bell jars and hot beds covered with glass were used to protect horticultural crops against cold. In the 17th century, low portable wooden frames covered with an oiled translucent paper were used to warm the plant environment.
In Japan, straw mats were used in combination with oil paper to protect crops from the severe environmental conditions. Greenhouses in France and England during the same century wefe heated by manure and covered with glass panes. The first greenhouse in the 1700s used glass on one side only as a sloping roof. Later in the century, glass was used on both sides. Glasshouses were used for fruit crops such as melons, grapes, peaches and strawberries, and rarely for vegetable production. Protected agriculture was fully established with the introduction of polyethylene after the World War II. The first use of polyethylene as a greenhouse cover was in 1948, when Professor Emery Myers Emmert, at the University of Kentucky, USA, used the less expensive material in place of more expensive glass.
The total area of glasshouses in the world as per 1987 reports was estimated to be 30,000 ha and most of these were found in North-Western Europe. In contrast to glasshouses, plastic.... [download this ebook to read more]
[EBOOK] GREENHOUSE TECHNOLOGY AND MANAGEMENT, K. Radha Manohar and C. Igathinathane, Published by BSP (BS Publications)
CLICK HERE TO DOWNLOAD THIS EBOOK
Keyword: ebook, giáo trình, nhà kính, công nghệ nhà kính, quản lý nhà kính, điều hành nhà kính, nhà kính trong nông nghiệp, nông nghiệp công nghệ cao, nông nghiệp tiên tiến, quản lý công nghệ nhà kính, greenhouse, greenhouse technology, greenhouse technology and management
%20c%E1%BB%A7a%20H%C3%A0n%20Qu%E1%BB%91c.jpg)
