soils

Question 1

how much nitrogen does organic matter add to the soil

Answer 1

90-95%

Question 2

How much extra sulfur and phosphorus does organic matter put in the soil

Answer 2

25%

Question 3

how does organic matter aid soil structure

Answer 3

helps with aeration

increases aggregation of soil particles

Question 4

what is organic matter

Answer 4

it is soil made up of many different plant and animal residues

Question 5

what are the 4 different soil development processes

Answer 5

1) Accumulation of materials
2) Leaching and losses
3) Transformation and illuviation
4) Podsolisation and Translocation

Question 6

what is the accumulation of materials?

Answer 6

where different materials gather, might be by water, ice, wind. the start of soil formation

Question 7

what is leaching and losses

Answer 7

where the different minerals and materials are washed out or taken up by plants. physical and chemical properties of the soil and parent material changed

Question 8

what is transformation and illuviation

Answer 8

3rd stage of soil formation where materials transform due to chemical weathering. soil is washed from upper horizons into lower ones. animals and plants speed up this process

Question 9

what is podsolisation and translocation

Answer 9

final stage of soil formation when clay minerals are broken down by strong acidic solutions then distributed among the different horizons. this process is also responsible for the colour changes in soil.

Question 10

what are the 5 different soil forming factors

Answer 10

1) parent material
2) biological activity
3) climate
4) topography
5) time

Question 11

what is the size of a transmission pore? in micrometers

Answer 11

50

Question 12

what is the size of a storage pore? in micrometers

Answer 12

50-0.5

Question 13

what is the size of a residual pore in micrometers

Answer 13

smaller than 0.5

Question 14

what is the function of a transmission pore? 3 answers

Answer 14

drainage

root penetration

gas movement

Question 15

what is the function of a storage pore?

Answer 15

holds water for plant growth

Question 16

what is the function of a residual pore? 2 answers

Answer 16

holds water that is unavailable to plants, controls the mechanical strength of the soil

Question 17

Rocks with a lower Si content break down more quickly?

T/F

Answer 17

true

Question 18

H2O = H(+) +OH(-) is the equation for?

Answer 18

Hydroloysis

Question 19

What are the 5 soil functions

Answer 19

• medium for plant growth
• recycling system
• habitat for soil organisms
• engineering medium
• system for water supply and purification

Question 20

what are the 5 different soil horizons that can be found in a soil profile?

Answer 20

• O
• A
• E
• B
• C

Question 21

what does the O horizon consist of?

Answer 21

organic matter which is made up of plant and animal residues

Question 22

what does the A horizon consist of?

Answer 22

mixture of minerals and organic matter

Question 23

what does the E horizon consist of?

Answer 23

zone where soil is depleted of most of its materials due to leaching and losses

Question 24

what does the B horizon consist of?

Answer 24

The zone of accumulation (translocated humus, translocated silicate clays)

Question 25

what does the C horizon consist of?

Answer 25

Parent material

Question 26

what are the two main types of parent material?

Answer 26

Sedentary (pre-glacial geology) Transported (Drift)

Question 27

what are the 4 different transport processes that cause material drift?

Answer 27

- Ice: glacial - Water: glacial, alluvial - Wind: aolian - Gravity: colluvial

Question 28

whats the difference between soil structure and soil texture?

Answer 28

soil structure is the arrangement of soil particles into groups or aggregates. soil texture is the relative proportions of various sized particles (sand, silt, clay) within a given soil.

Question 29

how does the soil structure influence plant growth? 3 answers

Answer 29

- aids water movement - aids aeration - helps with heat transfer

Question 30

whats the difference between bulk density and particle density?

Answer 30

Bulk density is the mass of soil particles and pore space combined Particle density is the mass of soil particles without pore space

Question 31

Why is soil water so important? 5 answers

Answer 31

- Its a Crop requirement - its a Solvent - it creates Chemical reactions - helps with Transport of nutrients - Air and temperature regulator

Question 32

name the two micropores

Answer 32

storage and residual pores

Question 33

a transmission pore is a type of pore from which class? micropores or macropores

Answer 33

macropore

Question 34

how do soil colloids effect plant growth

Answer 34

nutrient ions used by plants are held on the colloid surface

Question 35

what is the optimum temperature for nitrogen fertilisers?

Answer 35

25-30 degrees

Question 36

amount of organic nitrogen in soil?

Answer 36

94-98%

Question 37

amount of mineral nitrogen in the soil?

Answer 37

1-2%

Question 38

All the soil pores are water filled - is the definition of?

Answer 38

saturation

Question 39

what is gravitational water?

Answer 39

water held in the saturated soil that drains away under gravity

Question 40

field capacity is defined as?

Answer 40

when all of the gravitational water has drained away after heavy rain

Question 41

permanent wilting point is?

Answer 41

when the plant can no longer obtain water rapidly enough to recover from turgidity overnight

Question 42

available water is defined as?

Answer 42

the amount of water held in the soil between the limits of field capacity and wilting point

Question 43

Unavailable water is defined as?

Answer 43

amount of water held in the soil that is beyond permanent wilting point