Soil and Its Uses

Flashcards about soil science, geologic processes, and soil conservation practices.

Crust

Layer of earth, less solid covering over the mantle

Mantel

Makes up the majority of the Earth and surrounds a small core of iron

Lithosphere

The crust and solid outer mantle.

Asthenosphere

A thin layer below the outer mantle capable of plastic flow.

Plate tectonics

The concept that the outer surface of the Earth is made of large plates of crust and outer mantle that are slowly moving over the surface of the liquid outer mantle.

Heat from the earth

Makes the pates move

Erosion

The process of loosening and redistributing particles.

Chemical weathering

Involves the chemical alteration of rock in such manner that it is more likely to fragment or dissolve

Mechanical weathering

Results from physical forces that reduce the size of rock particles without changing the chemical nature of the rock.

Weathering process

Are important in reducing the size of particles that can moved by water or air

Land

The portion of world not covered by water.

Soil

A mixture of minerals, organic material, living organisms, air, and water that together support growth of plant life.

Good soil

45% mineral 25% air 25% 5% Organic matter

Humus

The organic material resulting from the decay of plant and animal remains. It mixes with top layers of mineral particles, and supplies needed nutrients to plants and creates a crumbly soil that allows adequate water absorption and drainage.

Soil texture

Determined by the size of mineral particles within the soil.

Soil structure

The way various soil particles together

Loam

An ideal soil for agricultural use, which combines the good aeration and drainage properties of large particles with the nutrient retention and water-holding ability of clay particles.

Friable

Good soil is blank and crumbles easily

Soil profile

A series of horizontal layers of different chemical composition, physical properties, particle size, and amount of organic matter.

Horizon

Each recognizable layer of the soil profile.

Grassland soil

Usually, I have a deep topsoil layer, black bleaching results and thin layer of subsoil

Soil forest

Soil topsoil forms, subsoil that supports substantial growth

O horizon

Made of litter, undecomposed or partially decomposed organic material.

A horizon

The topsoil, or the uppermost layer. It contains most of the soil nutrients and living organisms.

E horizon

Formed from leaching darker materials and is usually very nutrient poor.

B horizon

The subsoil. It contains less organic matter and fewer organisms, but accumulates nutrients leached from topsoil.

C horizon

Weathered parent material.

R horizon

Bedrock.

Erosion

The wearing away and transportation of soil by wind, water, or ice.

Contour farming

Tilling at right angles to the slope of the land. Each ridge acts as a small dam.

Strip farming

The practice of alternating strips of closely sown crops to slow water flow, and increase water absorption.

Terracing

The practice of constructing level areas at right angles to the slope to retain water; good for very steep land.

Waterways

Depressions in sloping land where water collects and flows off the land which channels movement of water.

Windbreaks

Plantings of trees or other plants that protect bare soil from full force of the wind, reducing wind velocity, decreasing the amount of soil that can be carried.

Reduced tillage

A practice that uses less cultivation to control weeds and prepare soil, but generally leaves 15 to 30% of soil surface covered with crop residue after planting.

Conservation tillage

Further reduces amount of soil disturbance and leaves 30% or more of soil surface covered with crop residue.

Strip tilling

Tilling narrow strips that will receive seeds

Ridge tilling

Leaves ridges crop is plants on the ridges with resides left between ridges

Mulch tilling

Tilling entire surface just prior to planting

No till tilling

Involves special planters that place seeds in slides cut into the soil