1. SOIL Soil TE3 Analyze soil as an integral component of
terrestrial  ecosystems

2. What animal do you think is the most important for soil?
Living Organisms in Soil
What animal do you think is the most important for soil?

3. As earthworms move through soil, they mix organic and inorganic materials in the soil. This mixing increases the amount of nutrients available to plants.
Soil drainage is also improved by the burrowing of earthworms and other soil animals, such as mites and pill bugs.

5. Bacteria and fungi are important in the decay and recycling of materials.
Their chemical activities change complex organic materials into simpler forms that plants can use as nutrients.
Bacillus specie soil bacteria.

6. For example, some of these micro-organisms can change the nitrogen contained in organic matter into nitrogen compounds that can be used by plants.

7. Figure 1:  Many plants depend on fungi to help extract nutrients from the soil. Tree roots (brown) are connected to the symbiotic mycorrhizal structure (bright white) and fungal hyphae (thin white strands) radiating into the soil.

8. Humus (Hoo-mus): The Organic Component of Soil
Layers of Soil
Humus (Hoo-mus): The Organic Component of Soil
Humus: the organic material in soil that results from the decay of plant and animal remains
Humus builds up on the surface and eventually mixes with the top layers of mineral particles.

9. Humus increases the water-holding ability and the acidity of soil, which makes it easier for plants to absorb the nutrients.
Humus also tends to make other soil particles stick together and helps create a loose, crumbly soil that allows water to soak in and air to be incorporated.
A good soil for agriculture use will crumble and has spaces for air and water.

10. Refer to the handout on the function of nutrients in plants to answer the following questions.
Which nutrient is the plant in the photo lacking?
Explain.

11. You are starting a garden
You are starting a garden. You notice that some plants are not able to grow new leaves, some have stunted growth, and the older leaves are turning brown and dying.
Do you live in an area with high rainfall?
Explain your reasoning.