Agriculture Reference
In-Depth Information
7.6 ZERO ENERGY NATURALLY VENTILATED GREENHOUSES
FOR HIGH VALUE VEGETABLE CULTIVATION
Naturally ventilated greenhouses are the protected structures where no
heating or cooling devices are provided for climate control. They are
simple and medium cost greenhouses which are erected with a cost of
Rs.700-800 per sq. mt. and these greenhouses can be used successfully
and efficiently for growing year round parthenocarpic slicing cucumber,
off season muskmelon, tomato and sweet pepper crops for 8-9 months
duration. These structures are having a manually operated natural ven-
tilation system, as and when required (Singh and Kumar, 2006). Look-
ing to the year round increasing demand of high quality vegetables like
parthenocarpic slicing cucumber, standard tomatoes, cherry tomatoes and
colored peppers, muskmelon in urban areas of the country specially in up
markets of the metro viz. stared hotels, shops of embassies or high com-
missions of various countries situated in Delhi and other big cities has
raised the opportunities for peri-urban farmers to fetch very high price
of the season and off-season high quality produce. Greenhouse vegetable
production is a highly intensive enterprise requiring substantial labor and
strong commitment, which restrict the adoption of this technology. But
now the time has come when unemployed educated youths are required
be motivated and trained in various parts of the country to use naturally
ventilated greenhouse technology for cultivation of high value vegetables
for high profits.
The basic prerequisite of implementing the technology is to depend-
ing upon selection of appropriate design based on the climatic conditions,
market available and the type of vegetable crop. Under arid and semi arid
conditions maximum ventilation up to 40-50% is required to make the
structure efficient and successful to raise vegetable crops. Under extreme
hot periods (May-July) rooftops of the greenhouses should be covered
with shade nets (preferably with black color) allowing a space between
the shade net and roof surface for air movement. Such greenhouses can be
equipped with low-pressure drip irrigation system to make them energy
efficient ecofriendly model (Singh and Hasan, 2011).
