Polyhouse

Polyhouse

Subject: Science and Technology

Context: Mr. Harish Hirani, director of Indian Council of Scientific and Industrial Research’s Central Mechanical Engineering Research Institute (CSIR-CMERI), Durgapur, recently inaugurated a “naturally ventilated polyhouse facility” and laid the foundation stone of “retractable roof polyhouse” its Ludhiana centre.

Concept:

What is a polyhouse?

• Polyhouse or a greenhouse is a house or a structure made of translucent material like glass or polyethylene where the plants grow and develop under controlled climatic conditions.
• The size of structure can differ from small shacks to big-size buildings as per the need. Above all, a greenhouse is a glass house whose interiors become warm when exposed to sunbeams as the house stops the greenhouse gas to leave. So when it is cold outside, the temperature inside is survival friendly and warm for the plants.
• Polyhouses are also helpful in reducing threats such as extreme heat and pest attacks in crops.
• This is especially important for crops growing in the open field with no protection from the weather, and therefore its yield, quality, and crop maturity timings are changed
• A combination of open field conditions and conventional greenhouse conditions is a more robust way to deal with climate change and associates problems in the future.
• Crop losses in India due to insect pests is about 15 per cent at present and this loss may increase as climate change lowers the plant defense system against insects and pests.
• Conventional greenhouses have a stationary roof to reduce the effect of weather anomalies and pests. However, there are still disadvantages due to roof covering which sometimes lead to excessive heat and insufficient light (early morning). Besides this, they are also prone to insufficient levels of carbon dioxide, transpiration and water stress.

Retractable Roof Polyhouse Technology

• It will have an automatic retractable roof which will be operated based on weather conditions and crop requirements from the conditional database using PLC software.
• This ongoing development will be useful in our country with its 15 different agro-climatic zones and will help farmers to cultivate off-season crops that can fetch higher value and income
• The retractable roof would be used to manipulate sunlight quantity, quality & duration, water stress, humidity, carbon dioxide levels as well as crop and soil temperatures.

Difference between Greenhouse and Polyhouse Farming

• Polyhouse is a type of greenhouse or we can say that it is a smaller version of greenhouse, where polyethylene is used as the cover. In developing countries like India, polyhouse farming is a popular greenhouse technology due to its low cost of construction and easy maintenance. Lath house is one more greenhouse technology where wood is used as the cover.
• Poly house is cheaper as compared to greenhouse but the later is more long-lasting than polyhouse.

Crops grown in Polyhouse

• Fruits that can be grown are Papaya, Strawberry etc.
• Vegetables that can be grown include Cabbage, Bitter Gourd, Capsicum, Radish, Cauliflower, Chili, Coriander, Onion, Spinach, Tomato etc.
• Flowers like Carnation, Gerbera, Marigold, Orchid, and Rose can

Benefits of Polyhouse Farming

• Polyhouse is very beneficial for the farmers specially those who prefer organic farming.
• The plants are grown under controlled temperature thus there is less chances of crop loss or damage.
• You can grow crops throughout the year and will not have to wait for any particular season.
• There are less pests and insects in a polyhouse.
• External climate will not have any impact of the growth of crops.
• Quality of produce is obviously higher in polyhouse.
• Good drainage and aeration
• Propagation of Ornamental Crops can also be done effortlessly in a polyhouse.
• Poly House gives the right environmental facilities to your plants in any season.
• It also increases yield for about 5 to 10 times.
• Less cropping period
• Fertilizer application is easier and is controlled automatically with the help of drip irrigation.

Types of Polyhouse

Based on environmental control system, polyhouse are of two types:

• Naturally ventilated polyhouse – This type of polyhouse or greenhouse does not have any environmental control system except for sufficient ventilation and fogger system to save the crops from bad weather conditions and natural pests and diseases.
• Environmental controlled polyhouse – They are constructed primarily to extend the growing period of crops or to increase the off-season yield by controlling the light, temperature, humidity, etc.