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Term Term description
A horizon

The top layer of a soil profile just under the surface O-horizon, usually dark-colored and containing orgagnic humus and from which soluble mineral salts may have been leached.


The non-living chemical and physical factors in the environment, including solar radiation, water, atmospheric gases, soil type and fertility, temperature, etc. that put constraints on the success of organisms.


The washing of one’s body as a religious purification.

acid mine drainage

The outflow of acidic water from (usually abandoned) metal mines or coal mines.

acid rain

Rain containing higher than normal amounts of nitric and sulfuric acids. Acid rain formation results from both natural sources, such as volcanoes and decaying vegetation, and man-made sources, primarily emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) resulting from fossil fuel combustion.


Having the properties of an acid, or containing acid; having a pH below 7. Acidic soil has a pH level less than 7. The lower the number, the higher the acidity. Soil's pH levels affect the availability of plant nutrients.


An act that one consciously wills and that may be characterized by physical or mental activity.

active carbon sink

A reservoir of living trees, algae and plants that removes CO2 from the atmosphere mainly through photosynthesis and accumulates and stores the carbon in plant materials.


The adjustment or changes in behavior, physiology, and structure of an organism allowing it to become more suited to an environment.

adaptive radiation

evolution of a number of divergent species from a common ancestor, each species becoming adapted to occupy a different environment.

adenosine triphosphate (ATP)

A nucleoside, C10H13N5O4, composed of adenine linked to ribose, that is a component of nucleic acids and of ADP, AMP, and ATP, and that plays a role in regulating various physiological functions.


The molecular attraction between substances in contact with surfaces or objects.


The property of oppositely charged molecules to adhere to each other. Attracted to other types of molecules with positive and negative charges.


Soil aeration is the process of using mechanized or manual equipment to either puncture the soil with spikes or remove approximately 1" x 2" cores of soil from the ground. Aeration may be overlooked when trying to restore a lawn but is vital to bring it back to health. It improves drainage and reduces puddles formation.


Living or occurring only in the presence of oxygen.


The science, art, or practice of cultivating the soil, producing crops, and raising livestock and in varying degrees the preparation and marketing of the resulting products.


A scientific discipline, a set of practices and a social movement. As a science, it studies how the different components of the agroecosystem interact. As a set of practices, it seeks sustainable agricultural systems that optimize and stabilize production. As a social movement, it pursues multifunctional roles for agriculture, promotes social justice, nurtures identity and culture, and strengthens the economic viability of rural areas. Family farmers are the people who have the tools to practice agroecology. They are the real guardians of the knowledge and wisdom needed for this discipline. Therefore, family farmers around the world are the key elements for producing food in an agroecological way.


The organisms and environment of an agricultural area considered as an ecosystem.


The fraction of solar energy (shortwave radiation) that is reflected from the Earth back into space. Ice, especially with snow on top of it, has a high albedo; most sunlight hitting the Earth's surface bounces back towards space. Water and land are much more absorbent and less reflective, so have lower albedo.


Unicellular or multicellular organisms formerly classified as plants, occurring in fresh or salt water or moist ground, that have chlorophyll and other pigments but lack true stems, roots, and leaves. Algae, which are now regarded as protists, include the seaweeds, diatoms, and phytoplankton.


The Muslim name for God; the one Supreme Being.

alluvial fan

a fan or cone shaped deposit of sediment crossed and built up by streams

Alpine regions

Alpine tundra is an ecosystem that occurs in mountains worldwide. The high altitude climate is too cold and windy to support a wide variety of trees. The flora of the alpine tundra is characterized by dwarf shrubs close to the ground. The cold climate of the alpine tundra is caused by the low air pressure, and is similar to polar climate.

Of or relating to the immediate surroundings, e.g. the ambient temperature is the present temperature in a given place.
amino acid

Biologically important organic compounds containing amine (-NH2) and carboxylic acid (-COOH) functional groups, usually along with a side-chain specific to each amino acid. Amino acids are linked together to make proteins prescribed by genetic code.


(NH3) A colorless gas that is a compound of nitrogen and hydrogen, has a sharp smell and taste, and is used in cleaning products and in making fertilizers and explosives. Ammonia is naturally occurring and is an important component of the nitrogen cycle, but is also artificially produced through the Haber-Bosch process for industrial purposes.


Decomposition of nitrogenous organic material resulting in the production of ammonia or ammonium compounds, usually through the action of bacteria.


A bacterium that produces ammonia from organic matter containing nitrogen.


(NH4+) An ion derived from ammonia by combination with a hydrogen ion.


A single-celled animal that catches food and moves about by extending fingerlike projections of protoplasm. Amoebas are either free-living in damp environments or parasitic.


Living or occurring in the absence of air or free oxygen.

anaerobic decomposition

The process by which microorganisms break down biodegradable material in the absence of oxygen.


anaerobic digestion

A process where microorganisms break down organic materials, such as food scraps, manure, and sewage sludge, in the absence of oxygen, produces a gas principally composed of methane (CH4) and carbon dioxide (CO2) otherwise known as biogas.

animal husbandry

Animal husbandry is the management and care of farm animals by humans, in which genetic qualities and behavior, considered to be advantageous to humans, are further developed.


People who accept animism, the view that non-human entities (animals, plants, and inanimate objects or phenomena) possess a spiritual essence.


An ion is an atom or molecule with a net electric charge due to an unequal number of protons (positive particles) and electrons (negative particles). Anions have a negative charge because they have more electrons than protons.


Total absence of dissolved oxygen supply.

Anthropocene Mass Extinction

The exponential increase in species extinction during the current geological age, within the past 200 years, as a result of  human activity.


Of, relating to, or resulting from the influence of human beings on nature.


A common mineral, calcium fluorophosphate, Ca5FP3O12, occurring in individual crystals and in masses and varying in color, used in the manufacture of phosphate fertilizers.


The breeding, rearing, and harvesting of fish, shellfish, plants, algae and other organisms in all types of water environments.


Of, in, or pertaining to water; aquatic organisms include fish, plankton, amphibians, and aquatic habitats include oceans, lakes, rivers and wetlands.

aquatic ecosystems

An ecosystem in a body of water. Two main types of aquatic ecosystems are marine and freshwater.


An underground layer of water-bearing permeable rock, rock fractures or unconsolidated materials (gravel, sand, or silt) from which groundwater can be extracted using a water well.


In agriculture, being or capable of being tilled for the production of crops.

arctic amplification

Arctic amplification refers to the greater rate of climate warming in the Arctic region than the rest of the world. The amount of land in the Northern Hemisphere allows for greater annual variation of snow cover. This fact allows for greater cooling and warming potentials when the overall climate forcing is altered. Less forcing would result in a cooling trend that would allow more snow cover and therefore a polar de-amplification effect in relation to the average temperature of the rest of the globe. More forcing, as is what happens under the influence of higher concentrations of greenhouse gases, allows for a more rapid decrease in snow and ice cover. The decrease of melting of snow and ice reduces the albedo reflectance of the poles therefore amplifying the temperature in the polar region.


A group of invertebrate animals including crustaceans, insects, and arachnids, that posess a segmented body, segmented appendages, and an external skeleton. Arthropoda is the largest phylum in the animal kingdom.

Artificial Selection

Human intervention in animal or plant sexual crossing, reproduction, or survival which selects certain desirable traits to be expressed.


An expert in astronomy, the scientific study of the individual celestial bodies (including the stars, planets asteroids, etc.) and of the universe as a whole.


A Sanskrit word that means inner self or soul, the true essence of an individual.


The envelope of gases that surrounds the Earth; consists largely of nitrogen (78%) and oxygen (21%)


A coral island or series of coral islands forming a ring that nearly or entirely encloses a shallow lagoon. Atolls are surrounded by deep ocean water and range in diameter from about 1 km (0.62 mi) to over 100 km (62 mi). They are especially common in the western and central Pacific Ocean and serve as important habitats for corals, algae and fishes.


The smallest unit of an element, having all the characteristics of that element and consisting of a very small and dense central nucleus containing protons and neutrons, surrounded by one or more shells of orbiting electrons.


A photosynthesis-inhibiting persistent herbicide C8H14ClN5 used especially to kill annual weeds and quack grass.

aurora borealis

A natural light display in the night time skies of the Northern Hemisphere created by colliding charged particles in the atmosphere, sometimes called the Northern Lights.


An organism capable of synthesizing its own food from inorganic substances, using light or chemical energy. Green plants, algae, and certain bacteria are autotrophs.


A highly mineralized complex silica ore (Hydrated Sodium Calcium Aluminosilicate or HSCAS), mined in Utah from an ancient deposit left by an volcanic eruption that filled a small nearby seabed an estimated 30 million years ago. It is used as a naturally rich soil re-mineralizer for plants, as well as a feed ingredient for animals. In a typical chemical assay, AZOMITE® contains more than 70 trace minerals which include many rare earth elements(lanthanides). Many of these elements have been depleted from soils worldwide.

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