B4.16 The Organic Alternative

Question 1

Define organic farming

Answer 1

Farming method that does not use intensive techniques and minimises the use of arti cial chemicals.

Question 2

Why do farmers use animal manure?

Answer 2

Adds minerals and improves fibre content in the soil- retains water better

Question 3

Why do farmers remove weed?

Answer 3

Removes competition from other plants- labour intensive

Some farmers use plastic sheets to prevent weeds from growing

Question 4

Why do farmers use crop rotation

Answer 4

(Planting a field with different crops in SUCESSIVE years) in a cycle.

These plants have nitrogen-fixing bacteria in nodules in their roots, which add nitrates to the soil. The process is slow, and fields gradually become lower in nitrates during each cycle.

Question 5

Define biological control

Answer 5

Using a natural predator to control a pest, instead of chemical pesticides.

Question 6

Advantages of biological control?

Answer 6

• no need for artifical chemicals
• no chemical released into environment, so no damage or kill other animals
• no need for repeat method

Question 7

Disadvantages of biological control?

Answer 7

• predator may not eat pest
• predator may eat useful species
• predator may increase in number, become out of control
• may not stay in area that it is needed in
• damage food web by removing/adding animals