soils exam

What is the central idea of Hardin’s essay?

Shared resources get overused because individuals act in self-interest

How does Hardin’s essay apply to soils?

Overuse = degredation

What does Jenny’s state model (CLORPT) stand for?

Climate, organisms, relief, parent material, time

Why are NY soils considered young?

Glaciers reset them about 10-15,000 years ago

What does the process model emphasize? 

Mechanisms: weathering, leaching, clay formation, transformations

What are the particle sizes from smallest to largest

clay, silt, sand

What controls soil texture?

how they’re moved and deposited

What are the four main things that transport soils?

Wind, water, ice, gravity

till

unsorted glacial debris

outwash

sorted sands and gravels from meltwater

Lacustrine deposits

fine sediments from glacial lakes

moraine

ridge of till marking ice margins

drumlins

streamlined hills from ice movement

alluvium

river deposits (floodplains, deltas)

colluvium

material at the base of steep slopes, moved by gravity

loess

wind blown silt

name four reason why parent material matters

affects forest productivity, water retention, erosion risk, carbon storage

How does climate affect soils?

Temperature and precipitation control weathering rates, leaching, and organic matter decomposition.

How do organisms affect soils?

Plants, microbes, and fauna add organic matter, mix horizons, and alter chemistry

How does relief effect soils?

Slope and topography influence drainage, erosion, and soil depth; north vs. south-facing slopes create microclimates.

How does parent material affect soils?

Determines mineral composition, texture (sand/silt/clay), and nutrient supply.

How does time affect soils

Longer exposure = more weathering, horizon development, and leaching; young soils are less developed.

Which horizon designation indicates illuvial accumulation of sesquioxides (Fe/Al oxides)?

Bs horizon (spodic).

Which O horizon is slightly decomposed organic matter (fibric)?

Oe horizon (partially decomposed).

What is the B horizon called?

Subsoil

What is the correct designation for a transition horizon with mostly A properties but some B?

AB

Which mineral weathers to form silicate clays?

Biotite

What are the 3 most abundant elements in Earth’s crust?

Al, Si, O

What are the 4 processes in the Process Model of soil formation?

Additions, Losses, Translocations, Transformations.

What is Hardin’s (1968) “Tragedy of the Commons”?

Shared resources are overused when individuals act in self-interest, leading to degradation.

How does Hardin’s essay relate to soils

Overgrazing, over-cultivation, or excessive extraction leads to erosion and loss of fertility unless managed cooperatively.

What are the 4 components of an ideal soil and their approximate percentages?

• Mineral: 45%

• Water: 25%

• Air: 25%

• Organic matter: 5%