It’s a green world

1. It’s a green world Farming Part 1

2. Starter We can buy a range of herbicides and pesticides from a garden centre. Why do we use them?

3. Farming Learning objectives Success criteria • Explain how pesticides may accumulate in food chains. • Describes how plants can be grown without soil. • Describe how intensive farming methods can increase productivity but raise ethical dilemmas. Students should be able to: • Describe how pesticides accumulate in the food chain • Explain the advantages and disadvantages of hydroponics • List the arguments for and against intensive farming

4. Why is maximizing yields important? Many farmers use intensive farmingmethods to maximize their yields. Why do they do this? • More food produced in the same amount of space. • Cheaper food for consumers. • Lower costs for farmers. • Increased energy efficiency. In what ways can farmers maximize their yields? Greenhouses, battery hens, fish farms, hydroponics

5. How can losses be reduced? Not all of a crop planted will be harvested. What happens to the rest? 13% lost to disease 58% harvested 13% lost to pests 16% lost to weeds What chemicals are used to cut competition? Herbicidesare used to kill weeds, and pesticidesare used to kill pests, such as insects (insecticides) and fungi (fungicides).

6. Pesticides What problem may occur when we use pesticides? Pesticides may enter and accumulate in food chains.

7. Pesticide accumulation How do pesticides accumulate along food chains? snails on the corn are covered with the pesticide corn is sprayed with a pesticide shrews eat the snails owls eat the shrews the accumulated pesticide in the owl results in weak eggs that break easily

8. Task • Complete worksheet B4f1 - Polar bears and DDT • phytoplankton  herbivorous zooplankton  arctic cod  habour seal  polar bear phytoplankton  herbivorous zooplankton  arctic char  capelin  harbour seal  polar bear phytoplankton  herbivorous zooplankton  arctic cod  polar bear • DDT will accumulate in organisms; polar bears depend on hundreds of fish and seals; fish and seals move and migrate

9. What is hydroponics? Hydroponics is a technique used to grow plants without soil. The plants gain all their nutrients and minerals from specially-treated water circulating around their roots. Other conditions, such as the levels of light and carbon dioxide, are also closely controlled. Many salad crops, including tomatoes, lettuces and cucumbers, are grown in this way.

10. Why use hydroponics? There are many advantages of using hydroponics. These include: • Lower risk of crops becoming diseased from soil-based pathogens and pests. • Fewer weeds. • A reduced need for pesticides and herbicides. • Crops can be grown in places with poor soil or little water for irrigation. However, hydroponics requires expensive equipment and technical knowledge and so will not be suitable for all situations.

11. How can livestock be farmed efficiently? Chickens and pigs lose energy through movement and thermoregulation. How could a farmer increase the yield of meat from livestock? The efficiency of meat production increases if animals are kept at a constant temperature and their movement is restricted. They can also be fed concentrates – food that leaves very little waste – and given antibiotics to combat infections. Is efficiency always the most important consideration?

12. What are the problems of livestock farming? If animals are kept in extremely cramped conditions, they may start to develop abnormal behaviour. For example, chickens may pluck out each other’s feathers. Animals are also more likely to catch diseases if they are living in a cramped, enclosed environment. To help prevent these problems, farmers must comply with EU regulations, but some people do not think these regulations are strict enough.

13. The Meatrix - animation • Task - Create a table and list the reasons for and against intensive farming

14. Plenary Citizens’ panel

15. Farming Learning objectives Success criteria • Explain how pesticides may accumulate in food chains. • Describes how plants can be grown without soil. • Describe how intensive farming methods can increase productivity but raise ethical dilemmas. Students should be able to: • Describe how pesticides accumulate in the food chain • Explain the advantages and disadvantages of hydroponics • List the arguments for and against intensive farming