Soil and Productivity

1

Importance of Soil

• Soil: the layer of material that covers the land – Where plants anchor and grow– Made of weathered rock, decomposing plant and

animal matter– Has spaces for air and water movement– Soils differ in organic content which effects the

ability to support plant life.

2

Layers of composition

• 3 major types of soil– Horizon A: Topsoil– Horizon B: Subsoil– Horizon C: Parent Rock– Horizon D: Bedrock

• Each layer has different characteristics depending on where it is found.

3

Grasslands

• Horizon A is deep and supports root growth; small particles of rock mixed with decaying plant and animals (Humas).

• Horizon B is the subsoil (mix of dirt and rock).

• Horizon C is mostly large pieces of rock.

• Horizon D is bedrock solid rock.

4

Forest

5

Deserts

• Horizon A: limited plant growth so little decomposition, so thin top soil or none at all.

6

Disturbing soils

• Soils change over time naturally

• Human impact: deforestation leads to increased erosion of topsoil (no roots to hold soil in place)

7

8

Feeding the Human Population!

9

Productivity of Ecosystems

• Ecosystems have different productivities, based on light availability, soil types, precipitation, temperature, nutrients.

• Productivity: the quantity of biomass of plants produced each year on a given area (g/m2)

10

Productivity of different ecosystems:

11

Sustaining life

• Biotic: living part of the environment. Ex: plants and animals

• Abiotic: non-living part of the environment. Ex: elements, air, and water.

12

The key events - respiration and photosynthesis

• Respiration takes carbohydrates and oxygen, combines them to produce carbon dioxide, water, and energy.

•Photosynthesis takes carbon dioxide, water and energy to produce carbohydrates and oxygen.

13