Soil

1. descriptions

1.1. soil it the substance we use to grow plants

2. layers

2.1. there are four layers of soil

2.1.1. topsoil

2.1.2. subsoil

2.1.3. Withered rock

2.1.4. solid rock

3. soil is made of...

3.1. Organic Matter

3.1.1. breaks down into nutrients

3.1.1.1. The three types of nutrients are nitrogen, phosphorus, potassium

3.2. withered rocks

3.2.1. sand

3.2.1.1. silt

3.2.1.1.1. clay

4. types of soil

4.1. forest

4.2. tropical grasland

4.3. desert

4.4. grass land