Unit 4- Earth Systems and Resources

Soil that has at least 3 horizons and has taken 1000’s of years to develop.

Poorly developed soil with only 1 or 2 horizons; less organic matter & fewer nutrients.

Bedrock and unbroken up rock and fragments, moss and lichen.

Rock that makes up Earth’s crust; also the solid rock layer beneath the soil. R horizon.

The layer of soil that differs in color and texture from the layers above or below it.

A vertical section through a soil, from the surface down to the parent material, revealing the soil layers or horizons.

A naturally occurring grainy material made of finely divided rock and mineral particles; the most common ingredient is silica. Large particle size from 0.06 mm to 2.0 mm.

A grainy material with grain size between sand and clay. It is weathered from soil or rock. Has the consistency of flour.

A small soil particle. Only seen under an electron microscope. Important in determining soil characteristics- has the greatest surface area.

Soil’s ability to hold nutrients and to supply nutrients to a plant.

the capacity of a soil for ion exchange of cations between the soil and the soil solution. CEC is used as a measure of fertility, nutrient retention capacity, and the capacity to protect groundwater from cation contamination.

The process that breaks down rock and changes the chemical composition. (Hydrolysis, Oxidation, Carbonation, Acid Rain, Acidic Plants)

The process that breaks down rock without a chemical change. (Climate changes, animals burrowing, pressures from pushing and shoving, freeze/thaw, expansion, condensing)

Processes by which rock, sand, and soil are broken down and carried away (i.e. weathering, glaciation).

The organic horizon at the surface of many soils, composed of organic detritus in various stages of decomposition. Able to retain water and nutrients. Has an organic composition from 20%-30%. Surface plant and animal litter forms humus.

Rich, dark organic material formed by decay of vegetable matter, essential to soil’s fertility.

Top soil; composed of decomposed organic matter (humus) and some inorganic mineral particles. Help hold water and nutrients.

Horizon of Accumulation. Subsoil, Reddish or yellowish in color. Composed of clays, aluminum, and iron deposited by illuviation, which is materials deposited from above.

Deposition of leached material in the lower layers of soil.

Process in which various chemicals in upper layers of soil are dissolved and carried to lower layers and, in some cases, to groundwater.

The downward movement of water through soil and rock due to gravity.

Part of the O horizon that is dead and decaying plant and animal materials especially fallen leaves that cover the soil.

Basic building blocks of rocks they are composed of elements bonded together. They are inorganic (metal to a non-metal).

Perfect agricultural soil with optimal portions of sand, silt, clay (40%, 40%, 20%).