Soil and Natural Vegetation by bt5Rkt


									Soil and Natural Vegetation

         P. 149 #1-8
1. Describe the four components that make up soil.

•   MINERALS, which come from rock, become part of the soil when the rock is
    broken down into smaller particles sand, silt, or clay. Many of these minerals(eg.
    Calcium, phosphorous, potassium) provide nutrients to plants.
•   When ORGANIC MATERIALS, ie. Plants and animals, die, they are decomposed by
    bacteria in the soil. As bacteria breaks down these organic materials, humus is
    formed. Humus provides plants with nutrients and moisture and gives the soil its
    dark colour.
•   Plants need AIR around their roots. Humus helps produce air in the soil because
    the loose , decaying materials allow for many air pockets. Insects, worms, and
    small animals that tunnel through the soil also provide air spaces.
•   MOISTURE, ie. Water, dissolves nutrients in the soil and is taken up by plants
    through their roots. Moisture is necessary for plant survival and for the chemical
    and physical processes that weather rock and decay organic materials.
2 a. How is topsoil formed?

•   It is formed as dead plants, leaves, and animals are decomposed by bacteria.
2 a. How is topsoil formed?

•   It has taken 6000 to 10000 years to form 15-25cm of topsoil under Canada’s
    forests and 40 to 100cm under the prairies/grasslands. This is how long it has
    been since glaciers have retreated
2 c. Why does the topsoil differ in thickness in different parts of Canada?

•   The creation of soil is related to the influence of climate, which in turn affects the
    amount of vegetation in a given area. In the cold climates where there is little
    vegetation. Less material means thinner soil. The opposite is true in warmer
3. Why is the size of rock particles important to soil structure?

•   Large particles like sand= drain too quickly
•   Small particles like clay = drain too slowly
•   Even mix is the best soil.
4. Explain the difference between leaching and calcification.

       Leaching                             Calcification
                                            -   Calcification occurs in areas of
       -   Leaching occurs in areas of
                                                dry soil
           high precipitation
                                            -   The upward movement of
       -   Leaching process is a
           downward movement of water
                                            -   Water moves up through
       -   Water carries nutrients away
                                                evaporation and leaves a
                                                mineral residue on the surface
5. In your own words, explain the meaning of the term “natural vegetation”.

•   Natural vegetation refers to plants and trees that grow without any human
6. There are two classes of trees. Which one can survive in a harsher climate? Why?

•   Coniferous trees can survive in colder climates than deciduous trees because:
    long roots extract nutrients from poor soil, Sticky sap keeps needles from
    freezing, waxy needles and thick bark hold moisture better, needles conduct
    photosynthesis on warm days past the normal growing season of deciduous
7. Name the Canadian vegetation region which:

•   Largest – the Boreal and Taiga
•   Smallest – Deciduous
•   Wettest – West Coast
•   Coldest - Tundra
8. Explain, in your own words, the term “transition zone”.

•   A TRANSITION ZONE is an area where the natural vegetation of one region
    gradually changes into the natural vegetation of another region.

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