1. Cultivation

2.  Cultivation is the digging over of the top layer of the soil

3.  Cultivation changes the soil structure  Provides a suitable environment for sowing seeds  Removes weeds  Brings nutrients to the surface  Improves drainage and oxygen levels

4.  Soil has distinct layers

5.  Plants only use the topsoil layer  The goal is to produce a topsoil layer that is suitable for the crop you are growing

6.  Plants need oxygen and carbon dioxide to survive.  Stems and leaves get enough oxygen for respiration from the air around them.  Roots get oxygen from air in the soil  Plants grow best in soils that contain equal amounts of air and water  Cultivating creates more space for air in the soil