Diseases and Management of Crops under Protected Cultivation

(Diseases and Management of Crops under Protected Cultivation)
Irrigation Techniques for Protected Cultivation
P. K. Singh
Department of Irrigation and Drainage Engineering, G.B.P.U.A.&T., Pantnagar- 263 145 (UK)
Plants depend on water and within the protected structure with no rainfall to supply it
naturally and the added warmth to make the soil dry out more quickly. However, near zero wind
velocity under many protected environments such as polyhouses, poly tunnels, low tunnels etc.,
the water requirement of many crops decreases significantly (Rana et al, 2010). Traditional
watering-cans are, of course, the simplest solution to the problem. They are particularly useful in
providing very specific, targeted watering for individual plants, particularly if they are being grown
in pots or containers. However, as a means of achieving mass watering, they are far too labourintensive
to be practical for anything other than the smallest of greenhouses. Many gardeners are
inclined to try to overcome the limitations of the watering can by using a hosepipe instead, but this
approach itself has its problems – chiefly in terms of achieving the delivery of water where it is
really needed, rather than on the leaves and soil surface. The traditional method of irrigation as in
case of open filed condition creates lot of disease under protected environment because of the
increased level of relative humidity along with increased temperature. Therefore, the appropriate
irrigation techniques having the characteristics of frequent application of water in small quantity as
per crop need at right location in right manner is essential for obtaining the maximum benefit of
protected cultivation. Micro irrigation has ability to provide right amount of water, at right time, at
right place in right manner. Similarly, nutrients may also be applied precisely along with irrigation
water using the fertigation device along micro irrigation. In this way significant amount of two
important agricultural inputs (water and nutrients) could be saved significantly besides controlling
the environmental
(non- point source / agricultural) pollution. Further, it has the potential to
increases crop yield. There is an additional positive environmental impact from precision irrigation
in that farm runoff, a major source of water pollution, can be reduced. The major limitations
associated with precision irrigation are high initial cost; operation and maintenance need skilled
work force.
1. Protected Cultivation
Protected cultivation practices can be defined as a cropping technique wherein the micro
environment surrounding the plant body is controlled partially/ fully as per plant need during their
period of growth to maximize the yield and resource saving. With the advancement in agriculture
various types of protected cultivation practices suitable for a specific type of agro-climatic zone
have emerged. Among these protective cultivation practices, green house/poly house cum rain
shelter is useful for the hill zones. The green house is generally covered by transparent or
translucent material such as glass or plastic. The green house covered with simple plastic sheet is
termed as poly house. The green house generally reflects back about 43% of the net solar
radiation incident upon it allowing the transmittance of the "photosynthetically active solar
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