Lecture 7

Question 1

pedogenesis

Answer 1

rebuilding of soils

Question 2

factors of soil formation person

Answer 2

Hans Jenny 1941

Question 3

high rainfall ___ soil acidity through element leaching

Answer 3

increases

Question 4

biomes and soil types show strongly linked distribution associated with

Answer 4

climate

Question 5

formation of soil is the function of

Answer 5

climate 
organisms 
relief (topography)
parent material 
time 
stochastic factors e.g. fire, floods, humans

Question 6

plants and associated microbiota can alter soil - making it __

Answer 6

more or less favourable for their own growth

Question 7

evolution of land plants and the earths development

Answer 7

• 450/470 mya probs form symbiotic mycorrhiza-like symbiosis
• roots & vascular systems ~407mya
• first ‘trees’ ~385 mya

Question 8

the life cycle of soils

Answer 8

• bare rock & broken rock
• weathering of parent material and accumulations of mineral grains
• vegetation accelerates weather and traps particles
• soil horizons
• mature profile of fine material enriched in organic matter, clay and sesquioxides
• vegetation lost; cultivation,landslide,fire,ice age and REPEAT

Question 9

soil erosion =

Answer 9

loss of organic matter, clay and sesquioxides

Question 10

starting materials for soil =

Answer 10

water
rocks
plants
microbes ==> interact with primary minerals –> organic matter resulting in clays and sesquioxides (Fe and Al hydrous oxides)

Question 11

individuals tree species and soil

Answer 11

as they require diff things, there soils underneath are different

Question 12

what is the primary source of P in most ecosystems and P fertilisers

Answer 12

apatite ( a form of calcium phosphate found in basalt and other rocks)

Question 13

stones provide nutrients (phosphorous) ..

Answer 13

for a bit of time

Question 14

____ promote chemical weathering on silicate rocks to a greater extent than microbial communities alone

Answer 14

plants

Question 15

plants convert solar energy into chemical energy that can accelerate rates of

Answer 15

mineral weathering

Question 16

atmospheric CO2 fell by ___% coincident with he rise of land plants with increasingly deep roots

Answer 16

90%

Question 17

why did land plants form symbioses with soil fungi?

Answer 17

Ca, Al, Fe, Si bond with P in soil

-weathering of calcium phosphate apatite provides > 95% of the primary P source in soils

Question 18

soil weathering rates: plants, mycorrhizal and combination

Answer 18

both increase individually, even more so combined

Question 19

plants have changed the atmosphere through

Answer 19

weathering process’

Question 20

saving climate change through plant weathering?

Answer 20

-potential of adding basalt to draw CO2 back out of atmosphere