What is Retractable Roof Polyhouse?

Q. Why is this in news?
A.

The CSIR-CMERI has recently inaugurated a “naturally ventilated polyhouse facility” and laid the foundation stone of “retractable roof polyhouse”.

Q. What is a Polyhouse?

A.

• A polyhouse is a specially constructed structure like a building where specialized polythene sheet is used as a covering material under which crops can be grown in partially or fully controlled climatic conditions.
• It is covered with a transparent material as to permit the entry of natural light. 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.

Q. What is Retractable Roof Polyhouse?

A. 

• The retractable roof system is a modular screen system for greenhouses that helps in saving costs and time along with providing stability, flexibility & durability for the greenhouse structure.
• Such polyhouse will have an automatic retractable roof which will be operated based on weather conditions and crop requirements from the conditional database using the software.

Q. What are the Advantages offered by it ?
A. 

• Ability to use the benefits of natural weather conditions
• Long life of the system and material used
• Easy assembly and installation
• Maximum insulation and complete protection from insecticides
• Easy maintenance & even easier repair work during operation

Q. Why need such polyhouse?

A.

• With rapidly rising temperatures due to mounting greenhouse gases in the atmosphere from human activities, crops are increasingly facing both threats — extreme heat and pest attacks — simultaneously.
• Crop losses in India due to insect pests are about 15 percent 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.