ICAR AICE-JRF/SRF Protected Cultivation & Greenhouse Engineering: practice questions

1 · Greenhouse types and orientation · hard

Which statement about structural design codes for commercial greenhouses (for example EN 13031-1 in Europe and IS 14462 in India) is correct?

1. Codes ignore crop loads because plants hung on wires weigh far less than any snow load
2. Codes set one fixed wind pressure for every greenhouse in a country, whatever the local wind climate or terrain
3. Codes treat greenhouses as temporary sheds, so no anchorage calculation is required
4. Codes allow film houses a shorter design life than permanent buildings, which lowers the design wind speed

2 · Forced ventilation · medium

What is the purpose of horizontal air-flow (HAF) fans hung in the canopy of a closed greenhouse?

1. To stir the inside air so that temperature and humidity are even and leaves dry faster
2. To replace exhaust fans by exchanging inside air with outside air during summer
3. To pressurise the house so that insects cannot enter through gaps in the cover
4. To push carbon dioxide out of the house so that the crop does not over-enrich

3 · Shading · medium

A 30% shade net and a 50% shade net are used together, one above the other. What is the combined shade?

1. 80%
2. 35%
3. 15%
4. 65%

4 · Shading · medium

Low tunnels of thin transparent film over hoops are used in cold winters to raise crops such as cucurbits ahead of the field season. How are they managed as days warm?

1. They are sealed tighter each week with soil on the edges, because warming spring days call for more heat retention
2. They are sprayed with black paint inside, so that the crop is shaded and kept dormant
3. Holes are cut or the edges raised for ventilation, and the tunnels are removed when outside temperatures allow
4. They are filled with fog from a high-pressure line, so that the crop stays humid

5 · Hydroponics and aeroponics · easy

In the nutrient film technique (NFT), the roots of the crop

1. hang in a closed chamber and are sprayed with a fine mist at short intervals
2. sit in rafts floating on a deep tank of aerated solution that rarely moves
3. lie in shallow sloping channels with a thin film of solution flowing past them
4. grow in slabs of rockwool fed by drippers, with the drain run to waste

6 · Hydroponics and aeroponics · hard

Which soilless system gives the crop the most time to survive if the circulation pump fails on a hot day?

1. Aeroponics, since roots in a misted chamber need no water for several days
2. Deep-water floating-raft culture, since the large aerated tank buffers water and temperature
3. Nutrient film technique, since the thin film of solution left in the channels keeps roots moist for a week
4. Ebb-and-flow benches, since pots hold all the water a crop needs for weeks

7 · Micro-irrigation and fertigation in greenhouses · medium

A 2,000 m² greenhouse has a crop water use of 5 mm/d and a drip application efficiency of 90%. There are 6,000 plants, each on one 1.6 L/h dripper. How long must the system run each day?

1. 63 min
2. 69 min
3. 1.2 min
4. 694 min

8 · Micro-irrigation and fertigation in greenhouses · easy

How is fruit set in greenhouse tomatoes usually ensured, since there is no wind to shake the flowers?

1. By spraying the flowers with water at noon to wash pollen onto stigmas
2. By removing all leaves so that light reaches the flowers and opens them
3. By planting male tomato plants between the rows as a pollen source
4. By bumblebee colonies in the house or by vibrating the flower trusses

9 · Micro-irrigation and fertigation in greenhouses · medium

In a greenhouse integrated pest management programme, the parasitic wasp Encarsia formosa is released to control

1. two-spotted spider mite
2. greenhouse whitefly
3. western flower thrips
4. root-knot nematode

10 · Plastics in agriculture: mulch and lining · hard

A square farm pond is 30 m × 30 m at the top, 2.5 m deep, with side slopes of 2:1 (horizontal:vertical). What area of liner covers the bottom and the four sloping faces, before anchor trench and overlaps?

1. 900 m²
2. 650 m²
3. 959 m²
4. 1,459 m²