B6e: Life in soil Flashcards Preview

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Flashcards in B6e: Life in soil Deck (10):
1

Describe clay soil(particle size, air spaces, permeability to water)

small

few and small air spaces

low ­ water retained in soil, soil can flood

2

Describe loam soil(particle size, air spaces, permeability to water)

mixture of small and large;

many air spaces and variable in size

medium permeability ­- water retention is good

3

Describe sandy soil(particle size, air spaces, permeability to water)

large (0.05 ­ 2 mm)

many air spaces and large

high - little water retained in soil

4

What is loam soil

soil that contains a mixture of clay and sand

5

What is humus

dead material in soil that is largely decomposed

6

Experiments to compare the humus, air and water content of different soils (3)

humus: weigh, burn, reweigh

air: add water to sample until the water reaches the top and measure volume of water added

moisture: weigh, bake, reweigh(evaporates the water)

7

What does life in soil depend on and why? (2)

supply of oxygen for respiration

supply of water to carry out reactions in cells

8

Explain the importance of humus in the soil (2)

decomposes to release minerals needed for plant growth

improved aeration, +air/oxygen content; helps retain water

9

Explain why earthworms are important to soil structure and fertility (4)

bury organic material in soil for decomposition by bacteria/fungi, improving nutrient content

burrows aerate soil, increase oxygen content; allow water to drain, ­reduce waterlogged and reduce ­chance of flooding

mix up soil layers, distributes nutrients more equally and allows dead material to be decomposed

neutralises acidic soils to grow more crops as neutral/alkaline soil are more fertile(plants will not grow if pH is too low)

10

What did Charles Darwin do in terms of agriculture?

highlighted importance of earthworms in agriculture: improving the fertility and structure of the soil