crop yield

Question 1

What factors is a plant’s rate of photosynthesis affected by?

creating ideal conditions for photosynthesis

Answer 1

• amount of light
• amount of carbon dioxide
• temperature

Question 2

What is used to give the best level of factors for photosynthesis to maximise crop yield?

creating ideal conditions for photosynthesis

Answer 2

• glasshouses (/greentunnels)
• polytunnels

Question 3

Why is a glasshouse good for plants?

creating ideal conditions for photosynthesis

Answer 3

• keeps out more pests and diseases
• can put in artifical light to allow plants more time to photosynthesise
• traps heat to keep plants warm. (In winter a heater may be used.)
• CO2 level can be increased by a PARAFIN HEATER, which makes CO2 as a by product when it burns

Question 4

Why is increasing rate of photosynthesis good?

creating ideal conditions for photosynthesis

Answer 4

• plants grow bigger and faster
• crop yields will be higher

Question 5

f

why is fertiliser used?

fertiliser

Answer 5

• to provide minerals eg nitrogen, potassium and phosphorus for compounds like proteins
• if plants do not get enough, their growth and life processes are affected

Question 6

Why can minerals be lacking in soil?

fertiliser

Answer 6

• Previous crop can use it up
• so fertilisers can replace missing minerals or provide more, increasing crop yield

Question 7

Why does pest control improve crop yield

pest control

Answer 7

• less plants are damaged or destroyed

Question 8

what are the two types of pest control

pest control

Answer 8

• pesticides
• biological control

Question 9

whats the problem with pesticide use?

pest control

Answer 9

• can be poisonous to humans- have to be closely monitored in food
• can harm other wildlife

Question 10

Define biological control

pest control

Answer 10

• used as an ALTERNATIVE to pesticides
• means using other organisms to reduce the numbers of pests by either:
• encouraging WILD organisms or adding NEW ones

Question 11

remember the 3 Ps

State biological control types of microorganisms used with examples

pest control

Answer 11

• predators (ladybirds eat aphids)
• parasites (some flies lay their eggs on slugs, one day killing them)
• pathogens (bacteria that affects caterpillars)

Question 12

PROS and CONS of biological control

pest control

Answer 12

PROS
* longer lasting effect
* less harmful to wildlife
CONS
* can cause problems (cane toads were introduced to Australia to kill beetles but poison the native species that eat them so are now a major pest)