Some traditional farmers use ducks in flooded paddy fields as a method of biological control for growing rice.
The ducks help the rice plants to grow because they eat insect pests and weeds.
Suggest how the ducks eating insect pests helps the rice plants to grow.
Explain how the ducks eating weeds helps the rice plants to grow.
Explain why droppings (faeces) from the ducks help the rice plants to grow.
The ducks constantly paddle through the paddy fields, loosening the surface soil and incorporating air, which increases the oxygen concentration of the soil water.
Suggest how increasing the oxygen concentration of the soil water helps the rice roots to grow.
Using ducks as a method of biological control allows the farmer to produce rice without using chemical sprays.
Suggest what is meant by the term herbicide.
Give three advantages of using biological control rather than using chemical pesticides.
