the result of a diet that consistently supplies less chemical energy than the body requires
the long-term absence from the diet of one or more essential nutrients
the consumption of more calories than the body needs for normal metabolism
provides food for grazing and browsing animals w/o plowing and planting
land where grass and other plants grow and where cattle, sheep, etc. can graze. Often managed by periodic plowing and planting.
the practice of raising fish and other water dwelling organisms for food
The rearing of marine organisms (fishes, seaweeds, and shellfish) for human consumption; a subset of aquaculture.
the total interaction between crops and farm animals and their environment within a farming and ranching operation
farming strategy in which large fields are planted with a single crop, year after year
Complex form of intercropping in which a large number of different plants maturing at different times are planted together.
The planting of different crops in a field each year to maintain the soil's fertility. Also serves as a natural pest control by confusing pests from year to year.
condition that restricts a population's growth, such as space, disease, and food availability
A chemical substance that an organism must obtain in relatively large amounts
Nutrients required in small or trace amounts. Some examples are phosphorus, sulfur, and potassium.
when a change in the availability of one nutrient affects the availability of another nutrient.
a process by which pipes placed near plant roots slowly release only as much water as the plants need.
traditional form of agriculture in which forest is cleared and utilized for 8 yrs and left fallow for 10 yrs, small trees & bushes to grow back
the introduction of pesticides and high-yield grains and better management during the 1960s and 1970s which greatly increased agricultural productivity
a technique of growing plants (without soil) in water containing dissolved nutrients
the use of natural substances rather than chemical fertilizers and pesticides to enrich the soil and grow crops
a cross between two varieties of crops, usually by taking pollen from one variety and using it to pollinate the flowers of a different variety.
Genetically modified crops
crops that have had new traits introduced to their genes from different species.
intensive rotational grazing
when farmers graze their animals on only a portion of their land at a time, allowing grasses to fully grow. A more efficient form of grazing.
the wearing away of surface soil by water and wind
a soil layer that consists primarily of organic matter, which serves as a precursor for soil formation
uppermost, dark-colored layer of soil; zone of leaching in young soil
lighter colored subsoil beneath the A horizon, zone of accumulation in which nutrient minerals that leached out of the topsoil and litter accumulate
horizon made of rock fragments on top of unweatered bedrock
The bedrock, which lies below all of the other layers of soil, is referred to as the R horizon.
Soil's ability to hold nutrients and to supply nutrients to a plant
plowing fields along the curves of a slope to prevent soil loss
growth of crops without plowing the soil to prevent erosion and loss of nutrients
shaping the land to create level shelves of earth to hold water and soil; requires extensive hand labor or expensive machinery, but it enables farmers to farm very steep hillsides
Planting of crops in strips with rows of trees or shrubs on each side.
Rows of trees or tall shrubs which slow down the movement of wind across a field
A chemical intended to kill insects and other organisms that damage crops.
A method of pest control that involves the use of naturally occurring disease organisms, parasites, or predators to control pests
Bacillus thuringiensis "BT"
Bacteria used as an insecticide.
Integrated Pest Management
combination of methods like biological control, chemical pesticides and different methods of planting crops to reduce crop loss to an acceptable level.
a genetically modified crop that has a gene to cause the plant to become sterile after the first year
Destruction of vegetation when too many grazing animals feed too long and exceed the carrying capacity of a rangeland or pasture area.
Degradation of land, especially in semiarid areas, primarily because of human actions like excessive crop planting, animal grazing, and tree cutting.
A process in which mineral salts accumulate in the soil, killing plants; occurs when soils in dry climates are irrigated profusely
matter that was once part of a living organism
the volume of open spaces in rock or soil
the ability of a rock or sediment to let fluids pass through its open spaces, or pores
Relative amounts of sand, silt and clay particles in a sample of soil.
Rich, fertile soil that is made up of about equal parts of clay, sand, and silt.
a value that indicated the acidity or alkalinity of a solution on a scale of 0-14, based on the proportion of H+ ions.
soil with a pH of less than 7.
soil with a pH of greater than 7