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Geography - population and the environment > soils > Flashcards

Flashcards in soils Deck (35):
1

what are zonal soils?

a soil which has experienced the max effect of the climate and natural vegetation

2

what are the 5 essential soil functions?

physical stability and soils
hydrologic buffer
food biodiversity and habitat
nutrient cycling
filtering and buffering

3

what is nutrient cycling?

carbon, nitrogen, phosphorus and many nutrients are stored, transformed and cycled in the soil

4

what is food, biodiversity and habitat?

the diversity and productivity of living things depends on soil

5

what is the hydrologic buffer?

soil helps control where rain, snowmelt and irrigation water goes.

6

what is filtering and buffering?

the minerals and microbes in the soil are responsible for filtering, buffering and detoxifying organic and inorganic materials

7

what is physical stability and support?

soil structure provides a medium for plant roots

8

what are different layers of the soil?

O -humus
A- topsoil
B- subsoil
C- rock being weathered
D- bedrock

9

what are the 2 types of soil profile?

tropical red latosol
podsol

10

what is the humus layer?

it is a thin layer of rooting vegetation - such as grass and leaves

11

what is the topsoil?

this layer is rich in humus and minerals from the rock
so it is good for growing crops

12

what is the subsoil?

it has little humus but is rich in minerals

13

what is rock that is being weathered?

it has been broken into chunks already

14

what is the bedrock?

solid rock, mot yet weathered but it will be one day

15

what is rill erosion?

when rainfall does not soak into the surface it can gather on the surface and runs down hill forming channels called rills

16

what is sheet erosion?

as raindrops loosen soil the overland flow can transport topsoil

17

what is saltation?

main process of soil transportation

18

what is creep?

occurs when particles greater than 0.5mm are too heavy to be lifted by wind

19

what is wind erosion?

occurs when forces exerted by wind overcome the gravitational and cohesive forces of soil particles

20

what is gully erosion?

if rills are unattended to they grow into larger gullies

21

what is river bank erosion?

soil is washed away by unmanaged rivers as they meander across floodplains

22

repeated erosion reduces the fertility of the soil by...

-removal of topsoil
-reduction in depth of soil
-reducing infiltration

23

this in turn can lead to...

loss of seeds, fertilisers and pesticides
young plants being sand blasted
increased difficulty of field operations

24

damage to the environment includes...

-deposition of sediment onto roads land and into dams
-manage to quality of water courses
-increased run-off and sedimentation causing greater risk to flooding

25

what are the causes of soil erosion?

deforestation

26

what are the solutions to soil erosion?

plant fast growing trees
place terraces and small dams to hold soils

27

the key to reducing soil erosion by rainwater is to reduce the amount of surface flow water by...

installing field drains
reducing the amount of water running onto fields
use of manure to stabalise topsoil
protecting the soil in winter

28

what is salinisation?

a build up of salts in the soil

29

what are the problems with salinisation?

excessive water application - rainwater contains salts

30

how much farmland is affected by salinisation?

estimated 10-20%

31

what are the 4 soil structures?

granular and crumb structures
blocky structures
prismatic and columnar structures
platy structures

32

granular and crumb structures?

individual particles of sand, silt and clay grouped together in small nearly spherical grains

33

blocky structures

soil particles that cling together in nearly square or angular blocks

34

prismatic and columnar structures

soil particles which have formed into vertical columns or pillars separated by verticle cracks

35

platy structures

made up of soil particles aggregated in thin plates or sheets piled horizontally on one another