Chapter 15 Flashcards
Bioaccumulation
The process whereby a toxic chemical that enters a food chain at a low trophic level becomes more concentrated in organisms higher up the chain.
Compost
Fertilizer formed by the decay of organic matter. Consumer An organism that takes in the matter and energy of other organisms.
Decomposer
An organism in the soil that transforms once-living matter to nutrients.
Horizon
A layer of soil.
Humus
The organic matter of topsoil.
Integrated crop management
A whole-farm strategy that involves managing crops in ways that suit local soil - climatic - and economic conditions.
Integrated pest management
A pest-control strategy that emphasizes preventing - planning - and using a variety of pest-control resources.
Microirrigation
A method of delivering water directly to plant roots.
Mixed fertilizer
A fertilizer that contains the plant nutrients nitrogen - phosphorus - and potassium.
Nitrogen fixation
A chemical reaction that converts atmo- spheric nitrogen to some form of nitrogen usable by plants.
Organic farming
Farming without the use of pesticides or synthetic fertilizers.
Pheromone
An organic molecule secreted by insects to communicate with one another.
Producer
An organism at the bottom of a trophic structure. Salinization The process whereby irrigated land becomes saltier as irrigation water evaporates.
Straight fertilizer
A fertilizer that contains only one nutrient.
Trophic structure
The pattern of feeding relationships in a community of organisms.
