Page 159 - Primary Five Science

Carbon store and maintenance of atmospheric gases:

Soils help regulate atmospheric Carbon dioxide by acting as a carbon

store.

Components of Soil

1. Soil consists of the following

2. Humus(organic matter)

3. Air

4. Water

5. Dissolved mineral salts (in-organic matter)

6. Particles of clay and sand

Examples of minerals need- Soil Profile

ed by plants Soil profile is the vertical arrange-

 Nitrates and phosphates ment of soil layers. At this level,

 Phosphorus we’ll look at three layers;

1. Top soil
 Calcium
2. Sub soil

 Magnesium and iron
3. Parent rocks

 Potassium
Top soil the most important one be-

cause it contains most of the nutri-

As it continues its way downwards through the many layers in the ground, ents needed for plant growth.