environmental study guide

Soil

A complex, regenerative ecosystem composed of disintegrated rock, organic matter, water, gases, and microorganisms that supports plant growth.

Parent material

The base geological material (such as volcanic ash or glacial till) in a specific location from which soil is formed.

Bedrock

The continuous mass of solid rock that comprises the Earth’s crust.

Weathering

The physical and chemical breakdown of rocks and minerals into smaller particles through exposure to the atmosphere, hydrosphere, and biosphere.

Soil horizon

A distinct layer of soil characterized by specific chemical and physical properties (e.g., the O, A, E, B, and C horizons).

Soil profile

A vertical cross-section of all soil horizons at a specific location, extending from the surface down to the parent material.

Clay

The smallest mineral particles in soil (less than 0.002 mm), known for high water retention and low permeability.

Silt

Mid-sized soil particles (0.002 to 0.05 mm) that feel smooth or floury.

Sand

The largest mineral particles (0.05 to 2 mm) which provide high aeration and rapid drainage.

Loam

A soil texture with a balanced ratio of sand, silt, and clay; generally considered the most fertile for agriculture.

Soil degradation

The decline in soil quality caused by improper use, usually resulting in a loss of nutrients, organic matter, or structural integrity.

Intercropping

A method of planting different crops in mixed arrangements to maximize nutrient use and reduce pest outbreaks.

Crop rotation

The practice of growing different crops in a specific field in a planned sequence to maintain soil fertility and break pest cycles.

Cover crop

A crop (like clover or rye) planted primarily to manage soil erosion, soil fertility, and water quality during off-seasons.

Shelterbelt

A row of trees or shrubs planted to act as a windbreak, preventing the loss of topsoil to wind erosion.

Tilling

The mechanical agitation of soil to prepare it for crops, which can increase aeration but often accelerates erosion and carbon loss.

Terracing

A soil conservation technique where steep slopes are converted into a series of flat platforms to prevent runoff.

Contour farming

Plowing and planting across the changing slope of land, rather than up and down, to create natural dams for water.

Overgrazing

Allowing livestock to feed so heavily on a patch of land that the vegetation cannot recover, leading to soil compaction and erosion.

Desertification

The process by which fertile land becomes desert, typically as a result of drought, deforestation, or inappropriate agriculture (defined as a 10% loss in productivity).

Irrigation

The artificial application of water to land to assist in the production of crops.

Salinization

The accumulation of salts in the soil, often caused by the evaporation of irrigation water in arid climates, which can become toxic to plants.

Pesticide

Any chemical substance used to kill, repel, or control certain forms of plant or animal life that are considered to be pests.

Traditional agriculture

Farming that relies on human and animal labor, hand tools, and organic fertilizers.

Yield

The amount of agricultural product harvested per unit of land area.

Industrial agriculture

A modern farming system characterized by high capital input, heavy machinery, synthetic fertilizers, and chemical pesticides.

Green Revolution

A period of rapid technological diffusion in the mid-20th century that increased global food production through high-yield crop varieties and advanced irrigation.

Biological pest control

The use of natural predators, parasites, or pathogens to manage pest populations without synthetic chemicals.

Integrated Pest Management (IPM)

An ecological approach to pest control that uses a combination of biological, cultural, and chemical tools to minimize economic and environmental risks.

Pollinator

Biotic agents (such as bees, bats, and birds) that transfer pollen from the male anthers of a flower to the female stigma to enable fertilization.

Arable land

Land that is physically and chemically capable of being plowed and used to grow crops.

Food security

The state of having reliable access to a sufficient quantity of affordable, nutritious food.

Malnutrition

A condition resulting from a diet that is either insufficient or excessive in specific nutrients, affecting physical and mental development.

Genetic engineering

The laboratory process of altering the genetic makeup of an organism by adding, deleting, or changing specific DNA sequences.

Genetically Modified (GM) Organism

An organism whose genome has been engineered in the laboratory in order to favour the expression of desired physiological traits.

Biotechnology

The application of biological systems and organisms to technical and industrial processes, specifically in developing specialized crops.

Feedlot

A high-density facility where livestock are fed energy-rich rations (like corn) to reach market weight quickly.

Aquaculture

The controlled cultivation of aquatic organisms, such as fish, crustaceans, and algae, for human consumption.

Seed bank

A facility used to store seeds as a source for planting in case seed reserves elsewhere are destroyed.

Sustainable agriculture

Farming methods that meet society's present food needs without compromising the ability of future generations to meet their own needs.

Organic agriculture

A production system that sustains the health of soils, ecosystems, and people by relying on ecological processes and biodiversity rather than synthetic inputs.

what is soil

a complex substance that forms through weathering, deposition, and decomposition

what does desertification do?

reduces productivity of arid lands

what does a soil profile consist of

layers know as horizons

how can soils be classified?

by color texture, structure and PH

what farming practices can erode soil

overgrazing, not covering crops

what farming practices can protect soil

intercropping. crop rotation, crop cover

what do the U.S. and international agricultural organizations promote

soil conservation

what are the 6 soil horizon

O horizon- litter layer (dead leaves etc)

A Horizon- Topsoil

E Horizon- leaching layer

B Horizon- subsoil

C Horizon- weathered parent material

R Horizon- Parent material

About how much of earth’s land surface is used for Agriculture?

38 percent

what does the organic material in soil include

Living and decomposing organisms

what are 3 benefits of intercropping

1. reduces soil erosion

2. natural pest resistance

3. improves soil fertility