L12 - Intro to Soil Science and Soil Formation

Question 1

How are soils essential for life?

Answer 1

1. Deliver ecosystem services and functions
2. Provide anchorage for roots
3. Hold water and nutrients
4. Host millions of species of living organisms
5. Humans build on, in and with soil

Question 2

What are human threats to soil?

Answer 2

Sealing, destruction of humus, compaction, acidification (agrochemicals), accumulation (pesticides)

Question 3

Sealing

Answer 3

blocking of soil functions important to ecology

Question 4

Static view of soil

Answer 4

soil is the end product of combined effects of climate, topography, organisms etc on parent material over time. Soil thus differs from parent in texture, structure, colour etc. - object

Question 5

Dynamic view of soil

Answer 5

soils are dynamic, open systems with influxes and effluxes of matter and energy. Layered organic and inorganic material which supports life. - store and transfer energy, fluxes determine characteristics

Question 6

What is the composition of soil?

Answer 6

Three phase system; solids, fluids and gases
Ratio determines physical and chemical characteristics

Question 7

Soil horizons?

Answer 7

O (organic layer), A (topsoil), E (elevation layer), B (subsoil), C (parent rock), R (bedrock)

Question 8

What determines soil properties?

Answer 8

Soil ecosystem functions e.g. climate and water regulation, nutrient cycling, biodiversity

Question 9

What are the main 5 soil forming factors?

Answer 9

Parent material, time, climate, biota and topography (relief)

Question 10

Where would you expect the highest amount of OM?

Answer 10

Boreal forests

Question 11

Where would you expect the most soil?

Answer 11

Wetlands
This is due to high organic input, slow decomposition due to anaerobic conditions, low erosion, and sediment-trapping properties.