B4h: Farming

Question 1

Disadvantages of pesticides (3)

Answer 1

they are artificial chemicals which can enter and build up in food chain (bioaccumulation) causing a lethal dose to predators

some pesticides are persistent and can directly affect human health

chemicals could be toxic for organisms which are not pests and may damage environment

Question 2

How can plants be grown without soil(2)

Answer 2

Using hydroponics

-roots are exposed to a regulated recycling flow of solution containing the minerals they need

Question 3

What is hydroponic usually used in(2)

Answer 3

Growing tomatoes in glass houses

Growing plants in areas with barren soil

Question 4

Advantages of hydroponics (4)

Answer 4

plants can be grown in areas w/ poor soil, because no soil is needed

better control of the type and concentration of minerals needed by the plant

diseases can be controlled

several rows of plant can be stacked above one another; better use of space

Question 5

Disadvantages of hydroponics (2)

Answer 5

no support for plant as roots are not anchored in soil - frame/tray needed

no soil to hold and store minerals - fertilisers need to be added constantly as dissolved minerals

Question 6

Advantages of intensive farming(3)

Answer 6

Improves efficiency of energy transfer and increases energy available for growth(or egg production)

• reduces energy transfer to to pests and competing plants (weeds)
• reduces energy lost as heat via respiration since animals cannot move around as much and are kept warmer

Question 7

Disadvantages of intensive farming(2)

Answer 7

ethical dilemas - less humane as animals have no freedom to move around

rapid spread of disease as they are always so close together

Question 8

Organic methods to improve plant growth (4)

Answer 8

animal manure or compost instead of artificial fertilisers

weeding

crop rotation to avoid build up of soil pests, include nitrogen fixing crops as part of the rotation

variation of seed planting times to avoid certain times of the life cycle of insect pests

Question 9

Advantages of organic farming methods (3)

Answer 9

uses -chemicals, -risk of toxic chemicals remaining on food

-chance of polluting river w/ fertiliser; -pesticides, food chains not disrupted, wildlife unharmed

ethical treatment of animals; no battery farming

Question 10

Disadvantages of organic farming methods (3)

Answer 10

requires +space than intensive farming; more land has to be farmland rather than for wildlife

+labour-intensive so more expensive

-food produced

Question 11

What is organic farming

Answer 11

farming methods that do not use intensive techniques, artificial chemicals/fertilisers or pesticides

Question 12

What is biological control

Answer 12

using a natural predator to control/kill pests, instead of using chemical pesticides

Question 13

Advantages of biological control (3)

Answer 13

no need for artificial chemicals to be used
-no chemicals to escape into environment and damage or kill other animals/no bioaccumulation

repeat treatments not needed if predators survive for a long period(unlike when using chemicals)

Question 14

Disadvantages of biological control (5)

Answer 14

predator may not eat pest

predator may eat other useful species

predator may increase in number and become out of control

predator may not stay in required location

adding/removing organisms from any food web may have an impact on numbers of other organisms in that web; other pests may rise in number