crop yeild

Question 1

why are polytunnels

Answer 1

(big tube- like structures made from polythene)

Question 2

greenhouses/polytunnels

Answer 2

Keep plants enclosed to keep out pest and disease
Water supply to crops
Apply articficl light when sun goes down
Glasshouses trap the suns heat to keep the planet warm
Increase the level of carbon dioxide using a paraffin heater - co2 by product when burns
By increases temp, co2 conc and light can increase photosynesis so crops yeild will be higher

Question 3

fertilisers

Answer 3

Plants need minerals such as nitrogen, potassium and phosphorus to make proteins
If don’t get enough their growth and life process are affected
Sometimes minerals are missing from soil due to being used by previous crop
Can use fertilisers to replace these missing minerals or provide more of them
Increasing yeild

Question 4

pest control

Answer 4

Killed using various methods of pest control so fewer plants are damaged increasing crop yeild
Pesticide are a form of chemical pest control. Posionous to human. Use carefully to keep the food in below a safe level

Question 5

biological control

Answer 5

Biological control can be used. Using other organisms to reduce the number of pests. Adding new animals the helpful organism can be a predator, parasite or disease causing

Question 6

advantages of biological control

Answer 6

Can have a longer lasting effect and be less harmful to wildlife. Can cause problems such as poison native species that eat them