It can be defined as the growing out of season crops which are cultivated in a controlled atmosphere like heat, air, pressure, etc. inside the tunnels for protecting vegetables, fruits, small flowers both in summer and winter. It gains acceptance among farmers as it requires less than 40% water, fertilizer and other resources. In this farming the entire farming is covered by transparent polythene sheath fixed over D-shaped bamboo/steel / aluminium pipes. It is a widely accepted farming system in the context of Nepal. It is mainly done to produce off season vegetables and fruits. The use of transparent polythene in this farming is to pass the light inside the tunnel and the field is covered by black polythene which absorbs the heat through it. There are three types of tunnel farming. They are categorised as follows:
- High tunnels
- Walk in tunnels
- Low tunnels
In tunnel farming it involves constructing a tunnel like a greenhouse. Certain shape is given for the construction of tunnel farming. D-shaped structure constructed through wood or steel or aluminium and is covered by transparent polythene through which light passes inside the tunnel for the better production of plants inside it.
Talking about method it can be studied in the following ways:
- High tunnels: It is constructed for gaining maximum yield. Mostly big land owners invest in such tunnels. Examples: tomato, cucumber
- Walk in tunnels: It is constructed for gaining better yield as compared to low tunnels. It doesn’t cost as much as compared to high tunnels. Examples: sweet pepper and hot pepper
- Low tunnels: Mostly small landowners practise this type of farming system. Different operations like spraying, soil preparation, and picking is difficult in this system of farming. Examples: melons, squash
There are many vegetables suitable for this type of farming. They are:
- Tomato (Lycopersicum esculentum )
- Cucumber ( Cucumis sativus)
- Carrot ( Daucus carrota)
- Black Pepper (Piper nigrum)
- Lettuce (Lactuca sativa)
In the context of Nepal, strawberry (Fragaria ananassa) is mostly cultivated sub-tropical fruit in tunnel farming.
This type of farming cost is estimated according to the type of tunnels.
- Low tunnels: it cost Rs. 30,000 per acre.
- Walk in tunnels: it cost Rs. 120,000 per acre.
- High tunnels: it cost Rs. 600,000 per acre.
ADVANTAGES OF TUNNEL FARMING
- It enhances the farmer to gain high productivity and extra revenues.
- Farmers can grow any type of crops at any time.
- Through this farming vegetables have high nutritious value and creates high yields.
- Improves the economic condition of farmers.
- There is 43% food insecurity and 18% food shortage according to the World Food Program, thus aid consumers and producers.
DISADVANTAGES OF TUNNEL FARMING
- Different possible disorders due to controlled temperature.
- In comparison to other systems it can be costly.
- Increase in the level and the amount of management needed to grow the crops.
- For pollination it should be hand pollinated or brought in pollinators.
- IPM strategies and pest scouting must begin when the plants are set out.
Writer : Rachana Tandan