soil - properties and processes

Question 1

why is soil important?

Answer 1

grows crops/food

stores carbon - helps mitigate environmental pollution

building foundation

ecosystems - supports life/ nutrients

influences quality of surface and groundwater resources

Question 2

where does soil come from?

Answer 2

from pure black rock from fresh volcanic fields

this weathers over of 100s of years

creates rusty brown rock with few plants/lichen

100 yrs later

broken down into soil creating fully functioning ecosystem colonised by life.

Question 3

name the 9 elements which make up earths crust?

Answer 3

iron 
silicon 
calcium
sodium
aluminium
hydrogen
oxygen
magnesium
potassium

Question 4

how much pedigrams of carbon in soil?

Answer 4

1.5 to 2.5 thousand

400-600 for vegetation

Question 5

name the 4 soluble cations?

Answer 5

sodium
magnesium
potassium
calcium

Question 6

define soluble

Answer 6

easily leaches/dissolved in water

Question 7

define cation

Answer 7

positively charged ion

Question 8

name the 5 less soluble cations?

Answer 8

oxygen
hydirgen
iron
aluminimum
silicon

Question 9

what does it mean by less soluble cations

Answer 9

they remain in soil as clays or oxyhydroxides

Question 10

define soil

Answer 10

natural body with solids, liquids and gases

distinguished horizons or layers

losses/additions/ transfers of energy

supports rooted plants

Question 11

what is the composition by volume of a topsoil

Answer 11

air - 25%
water - 25%
solid - organic matter 5% (humus 80% - roots 10% - organisms 10%)

mineral particles 45% (Clays/sands)

Question 12

how is soil an open system

Answer 12

inputs
outputs
transfers
transformations

Question 13

inputs into soil

Answer 13

rain
solar energy
manure
harvesting

Question 14

outputs of soil

Answer 14

erosion - wind and water

human activity

Question 15

transfers in soil

Answer 15

water transfer to streams

ground water percolation

veg uptake of water and nutrients

mechanical mixing

Question 16

transformations in soil

Answer 16

clay mineral formation

mineral weathering

Question 17

what makes up the topsoil

Answer 17

o horizon

a horizon

e horizon

Question 18

what makes up subsoil

Answer 18

b horizon

Question 19

what makes up the transition region?

Answer 19

c horizon

Question 20

whats at the bottom of the soil profile ?

Answer 20

unweathered parent material

Question 21

O horizon

Answer 21

loose

particially decayed organic matter

thin

Question 22

A horizon

Answer 22

mineral matter mixed with humus
animals help mix it

acididic - leaching can occur

thick

Question 23

E horizon

Answer 23

zone of eluviation and leaching

white

Question 24

B horizon

Answer 24

accumulation of clay

transported and leaching from above

rich in chemical weathering products

Question 25

C horizon

Answer 25

partially altered parents material can be glacial till

Question 26

name 5 main uk soils

Answer 26

``` brown earth podzol lithomorphic gley peat ```

Question 27

Define brown earth

Answer 27

humus well mixed leaching lead to slight acidifcation nutrient rich - goof for farming base rich parent material

Question 28

define podzol

Answer 28

mor humus poorly mixed strongly acidic leaching iron and aluminimum found in conifer areas as pine needles acidic base deficient parent material eg granite

Question 29

define lithomorphic soil

Answer 29

limestone dissolves as it weathers leaving no soil minerals not great for farming alkaline from calcide grasslands/beech lowlands freely draining

Question 30

define gley soils

Answer 30

peat accumulation poorly drained oraganic rich at top oxidation and reduction reactions craete orange soil acididic to neutral boggy

Question 31

define peat soils

Answer 31

organic matter accumulation in waterlogged conditions forms peat - paludification poor drainge boggy acidicic - neutral

Question 32

describe soil distribution in uk

Answer 32

north - gley wales/cornwall - podzol south - brown with lithomorphic bits peats least disttibuted in uplands

Question 33

what controls soils distribution in the uk

Answer 33

rainfall more in west than east glacial till location - clay rich has poor drianage bedrock type - underlying rock - south its chalk and clay altitude - peat high up

Question 34

what 2 things control soil thickness

Answer 34

supply kinetic

Question 35

what is supply

Answer 35

rate at which soil forming material are delivered to surface

Question 36

what is kinetics

Answer 36

rate at which bio/chem/phys processes act on soil

Question 37

define supply limited soil

Answer 37

soil growth limited by delivery of appropriate earth material akin to weather limited sloped

Question 38

define kinetic limited soil

Answer 38

soil growth limited by speed at which soil forming processes progress akin to transport limited slopes

Question 39

what soil does supply limited contol?

Answer 39

gley peat lithomorphic

Question 40

what soil does kinetic limited control

Answer 40

brown earth | podzol