The technology for growing and taking good produce successfully, of the crops either before or after their natural time of cultivation is called off-season cultivation. It may be early sowing or late sowing. In this regard, summer vegetables are cultivated in the winter sunlight under the cover of polythene sheet and the heat is provided artificially to get an early crop. This technology is called Tunnel Farming.
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| Tunnel Farming |
What is meant by off-season crop ?
The cultivation and getting successful yield from any fruit or vegetable out of their normal growth season is called 'off-season crop'.
Why Off-season?
It has been human psychology to capture and buy those things which are rare or available in small quantity. Early (اگیتی) vegetables or fruits are sold at high prices. The climate in Province Sindh is quite different from rest of the provinces of Pakistan. So almost all the crops are harvested earlier then other provinces and marketed at high price. For example, bitter gourd is sold at Rs. 60 - 80 /kg and similarly the prices of other vegetables like ginger, garlic, okra, tomato, cucumber etc. But now all these and many other crops can be harvested with full success in any district of Punjab.
How is it Possible with Tunnel Technology?
Sun is the ultimate source of all the energy reaching to the earth. The light comes to Earth in the form of rays, which is composed of photons of light. The photons can easily pass through sheets of polythene, glass and transparent plastic etc. The soil absorb these rays and release back most. The rays/photons can be captured by the cover of polythene sheets and hence temperature can be raised under a tunnel to grow summer vegetables in winter.
Soil Selection
Sandy loam soils with good aeration are excellent for cultivation of vegetables. The pH of the soil should be around 6-7 and organic matter contents should be in between 5 - 10%.
Site Selection
A good site has some features like it is close to road, availability of water, free from animals, least number of trees in its vicinity, at some distance from the walking path from where it should be easily taken care of. The tunnels are set in North-South direction.
Structure of a Tunnel
It depends upon the budget allocation of the farmer. However, the used types are "U-shaped and inverted-V-shaped" tunnels. These provide good resistance to damage from wind and rains.
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| High Tunnel |
Types of Tunnel
- High tunnel
- Medium or Walking Tunnel
- Low Tunnel
For construction of these tunnels many types of material can be used from iron, t-iron, angle iron, Eucalyptus and Poplar wood, bamboo and mulberry sticks etc.
Fertilizer and Pesticide Requirements
Fertilizer and other pesticides are used according to the requirement of soil, soil type and type of crop. But in general, chemical requirements of a tunnel are far more than ordinary field. This is done in order to get a healthy and productive crop. Calender application is followed with usually two sprays every week for fungicides and other pesticides to control fungal diseases and insect problem in a tunnel. Because if the disease starts it will ultimately attack on all the vegetation under the tunnel.
Selection of Varieties
Cucumber, tomato, Capsicum, bitter gourd and squash among vegetables and melon, watermelon and strawberry among fruits are being successfully cultivated in tunnels. Hybrid seeds from various public and private seed companies are available which are being used to get good yields.
Economics
The expenses on a tunnel can be increased or decreased depending upon the financial state of the farmer and availability or non-availability of the materials required. In the starting year, much of the investment is made on the constant or fixed structure of the tunnel but during the proceeding years, only makeshift things are required which cost very low. From the statistics of last 5 years, it has been estimated that a farmer can get Rs. 2 - 4 lakh annually from this new method.
For those who are interested to know about the stats involved in planing a tunnel farm can get help from the following link:
