soils

Question 1

what is a zonal soil

Answer 1

• mixture of solid, liquid and gas occurring in
  1. major soil groups
  2. taking a long time to form
  3. dependant on climate

Question 2

what are the 5 fuctions of soil

Answer 2

1. filtering and buffering
2. hydrological buffer
3. food biodiversity and habitat
4. nutrient cycle
5. physical stability and support

Question 3

what is the (O) of the structure of soil

Answer 3

the thin humus layer

Question 4

what is the (A) of the structure of soil

Answer 4

the topsoil

• rich in nutrients
• good for growing crops
• good for roots

Question 5

what is the (B) of the structure of soil

Answer 5

• subsoil
• little humus
• rich In nutrients

Question 6

what is the (C) of the structure of soil

Answer 6

• rock that has been weathered

- few signs of life

Question 7

what is the (D) of the structure of soil

Answer 7

bedrock

-soild rock

Question 8

where is the tropical red latasol

Answer 8

in the tropics, due to the hot damp climate the nutrients are washed away

Question 9

where is the podsol

Answer 9

associated with cold climates with less precipitation and a poor nutrient cycle

Question 10

what are the 4 types of water erosion

Answer 10

1. sheet
2. rill
3. gully
4. river bank

Question 11

what are the 4 types of wind erosion

Answer 11

1. creep
2. saltation
3. abrasion
4. suspension

Question 12

what is sheet erosion

Answer 12

• water erosion

- when rain loosens soil and overland flow transports topsoil

Question 13

what is rill erosion

Answer 13

• water erosion

- rain doesn’t soak into soil it gathers on the surface forming channels of rills

Question 14

what is gully erosion

Answer 14

• water erosion
• rills unattended create larger gullies
• land cant grow crops

Question 15

what is river bank erosion

Answer 15

• water erosion

- soil washed away by unmanaged rivers as they meander floodplains

Question 16

what is creep erosion

Answer 16

• wind erosion
• the movement when particles are greater in size and cant be lifted
• wind rolls along the surface being hit by other particles

Question 17

what is saltation erosion

Answer 17

• wind erosion
• main process
• suspended particles are lifted by wind then fall back onto the ground, bouncing

Question 18

what is abrasion erosion

Answer 18

• wind erosion
• fall back on the ground
• hit other particles and break into smaller particles

Question 19

what is suspension erosion

Answer 19

• wind erosion
• small particles lifted into air are transported
• most settle back to the ground

Question 20

what is salinisation

Answer 20

it refers to a build up of salt in soil, eventually becoming toxic for plants

Question 21

why is salt toxic to plants

Answer 21

because it affects how much water it can hold

Question 22

what happens during salinisation

Answer 22

the water evaporates and the salt is left on the surface

Question 23

how do you treat salinisation

Answer 23

flush the soil in lots of water

Question 24

what are the problems of salinisation

Answer 24

1. rainwater contains salt
2. evaportation from dry surfaces leaves salt behind
3. hard for soil where the water table is less than 1m drown
4. all irrigation water contains salt

Question 25

what is the structural deterioration of soils

Answer 25

the arrangement of soil particles into groups, called 'peds' which form distict shapes

Question 26

what is the granular and crumb structure

Answer 26

- individual particles of sand, silt and clay grouped together - water circulates easily - permeable

Question 27

what is the blocky structure

Answer 27

- soil particles cling together in almost squaure blocks - large blocks are resisyant to the movement of water - moderately permeable

Question 28

what is the prismatic and columnar structure

Answer 28

- formed into verticle columns sepearated by cracks - water circulates with difficulty and drainage is poor - moderately permeable

Question 29

what is the platy structure

Answer 29

- soil particles aggregate in thin plates piled horizontally - often overlap - low permeable

Question 30

what happens during normal conditions

Answer 30

the breakdown of soil is rare

Question 31

how can soil structures be divided

Answer 31

- into 2 catagories | 1. those associated with net reduction in soil organic matter in topsoil

Question 32

what are the 2 main reasons for soil structures

Answer 32

1. cultivation of soil causing physical fracturing and mixing of soil which stimulates background 2. less organic material is returned to the soil in the form of decaying plants bevause its removed in arable farmining

Question 33

what happens when soil organic matter declines

Answer 33

theres a breakdown in soil structure because bonds become weak

Question 34

what happens when soil is exposed to heavy rain

Answer 34

soils form a surface crust that impedes the movement of water

Question 35

how is the compaction of soil created

Answer 35

by combining the pressure and sliding forces are applied | forces include tractors, wheels etc

Question 36

what does the way a soil reacts to pressure depend on

Answer 36

texture, moisture, hardness and depth

Question 37

name 5 ways to manage soil

Answer 37

1. terracing 2. contour ploughing 3. crop rotation 4. strip cropping 5. direct drilling 6. selective afforestation 7. controlled grazing 8. improved drainage to prevent water logging 9. careful management of irrigation to reduce risk of waterlogging