soils

Question 1

what are zonal soils?

Answer 1

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

Question 2

what are the 5 essential soil functions?

Answer 2

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

Question 3

what is nutrient cycling?

Answer 3

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

Question 4

what is food, biodiversity and habitat?

Answer 4

the diversity and productivity of living things depends on soil

Question 5

what is the hydrologic buffer?

Answer 5

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

Question 6

what is filtering and buffering?

Answer 6

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

Question 7

what is physical stability and support?

Answer 7

soil structure provides a medium for plant roots

Question 8

what are different layers of the soil?

Answer 8

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

Question 9

what are the 2 types of soil profile?

Answer 9

tropical red latosol

podsol

Question 10

what is the humus layer?

Answer 10

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

Question 11

what is the topsoil?

Answer 11

this layer is rich in humus and minerals from the rock

so it is good for growing crops

Question 12

what is the subsoil?

Answer 12

it has little humus but is rich in minerals

Question 13

what is rock that is being weathered?

Answer 13

it has been broken into chunks already

Question 14

what is the bedrock?

Answer 14

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

Question 15

what is rill erosion?

Answer 15

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

Question 16

what is sheet erosion?

Answer 16

as raindrops loosen soil the overland flow can transport topsoil

Question 17

what is saltation?

Answer 17

main process of soil transportation

Question 18

what is creep?

Answer 18

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

Question 19

what is wind erosion?

Answer 19

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

Question 20

what is gully erosion?

Answer 20

if rills are unattended to they grow into larger gullies

Question 21

what is river bank erosion?

Answer 21

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

Question 22

repeated erosion reduces the fertility of the soil by…

Answer 22

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

Question 23

this in turn can lead to…

Answer 23

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

Question 24

damage to the environment includes…

Answer 24

• 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

Question 25

what are the causes of soil erosion?

Answer 25

deforestation

Question 26

what are the solutions to soil erosion?

Answer 26

plant fast growing trees

place terraces and small dams to hold soils

Question 27

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

Answer 27

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

Question 28

what is salinisation?

Answer 28

a build up of salts in the soil

Question 29

what are the problems with salinisation?

Answer 29

excessive water application - rainwater contains salts

Question 30

how much farmland is affected by salinisation?

Answer 30

estimated 10-20%

Question 31

what are the 4 soil structures?

Answer 31

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

Question 32

granular and crumb structures?

Answer 32

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

Question 33

blocky structures

Answer 33

soil particles that cling together in nearly square or angular blocks

Question 34

prismatic and columnar structures

Answer 34

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

Question 35

platy structures

Answer 35

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