an ecosystem created by agriculture; typically it has low genetic, species, and habitat diversity


production of food from aquatic habitats

cash crop

farm crop grown to be sold or traded rather than used by the farm family

chronic hunger

enough food to stay alive but not enough to have productive & satisfactory lives

crop rotation

the practice of rotating use of different fields from crop to crop each year, to avoid exhausting the soil.

demand-based agriculture

agriculture with production determined by economic demand and limited by that demand rather than by resources

drip irrigation

a method of supplying irrigation water through tubes that literally drip water onto the soil at the base of each plant


a field left unplowed and unseeded without harvesting for at least one growing season

genetically modified crop

crop species modified by genetic egineering to produce higher crop yields, and increased resistance to drought, cold, heat, toxins, plant pests, and disease

green revolution

name attached to post World War II agriculture programs that have led to the development of new strains of crops with higher yield, better resistance to disease, or better ability to grow under poor conditions


a technique of growing plants (without soil) in water containing dissolved nutrients

Law of the Minimum

the concept that the growth or survival of a population is directly related to the life requirement that is in least supply and not to a combination of factors


a crude approximation of a chemical toxicity defined as the does at which 50% of the population dies on exposure


the lack of specific components of food, such as proteins, vitamins, or essential chemical elements


production of food from marine habitats

maximum sustainable yield

the maximum amount of any biological resource that can be harvested indefinitely


agricultural practice of producing or growing one single crop over a wide area

optimum sustainable yield

largest yield of a renewable source that is able to be achieved over a long period without decreasing the ability of the population or the environment in which it is located to support the continuation of this yield level


land where grass and other plants grow and where cattle, sheep, etc. can graze

per-capita demand

the economic demand per person

per-capita food production

the amount of food produced per person

resource-based agriculture

agriculture with production limited by the availability of resources


an animal, such as a cow or sheep, with an elaborate, multicompartmentalized stomach specialized for an herbivorous diet

subsistence crops

a crop grown to be used on the farm where it was raised

synergistic effect

when the change in availability of one resource affects the response of an organism to some other resource


the lack of sufficient calories in available food, so that one has little or no ability to move or work


elements required in large amounts by all living things, these are required in large amount to sustain life; there are 6 most important nutrients: oxygen, carbon, sulfur, hydrogen, nitrogen, phosphorus


chemical elements required in very small amounts by at least some forms of life; such elements include things such as boron, copper, chlorine, iron, manganese, molybdenum, nickel, and zinc

organic farming

producing crops and livestock naturally by using organic fertilizer (manure, legumes, compost) and natural pest control (bugs that eat harmful bugs, plants that repel bugs, and environmental controls such as crop rotation) instead of using commercial inorganic fertilizers and synthetic pesticides and herbicides


land that is not intensively managed and is used for grazing livestock

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