food production (crop plants)

how do glasshouses/ polyethene tunnels (polytunnels) increase crop yield

- helps keep free from pests + diseases

- helps control water supplied

- can trap the Sun's heat/ could be able to use heater in winter

- can inc CO2 levels

how could a farmer help plants photosynthesise after dark

supply artificial light

how can farmers inc CO2 levels

- using a paraffin heater

- as the paraffin burns, CO2 is made as by-product

if photonsynthesis increases...

plants will grown bigger + faster and crop yields will be higher

how can fertilisers help inc crop yield

- sometimes minerals missing from soil bc used by a previous crop

- fertilisers replace/ provide more of the minerals

- inc crop yield

why do plants need minerals and what happens if they don't get them

needed to make important compounds such as proteins

their growth + life processes affected

what do pests include

microorganisms, insects and mamals

how does reducing pests inc crop yield

- pests feed/ transmit diseases on crops

- getting rid of pests = less plants damaged or destroyed

- inc crop yield

what is pesticides

form of chemical pest control

negatives of pesticides (2)

- often poisonous to humans so need to be used carefully

- some harm other wildlife

advantages of pesticides (2)

- relatively cheap

- accessible

what is an alternative to pesticides

biological control

what is biological control

using other organisms to reduce the number of pests

helpful organisms could be:

- predators

- parasites (that kill the pest)

- disease-causing (that affect the pest)

advantages of biological control (2)

- longer-lasting effect on pests

- less harmful to wildlife

disadvantages of biological control (3)

- predator can turn + eat the crops also

- slow process

- could eat useful organisms