last apes test!
Terms in this set (62)
A severe reduction in the quality of soils. The term includes soil erosion, salinization and soil exhaustion (loss of fertility).
1 inch of top soil requires
200-1000 years to form
The process by which wind, water, ice, or gravity transports soil and sediment from one location to another
caused by the direct force of falling drops of rain on bare soil. Causes splashing in which soil particles are lifted and then dropped into a new position.
Peeling off thin layers of soil from the land surface; accomplished primarily by wind and water
removal of layers of soil, creating channels or ravines too large to be removed by normal tillage operations
why does erosion occur?
removing plants activities such as clear-cutting, and road construction lead to increased erosion
role of plants
roots anchor soil, leaves dissipate the force of falling raindrops so soil is disrupted less
conversion of hillside from forest to grass can double runoff and increase nutrient leaching by many times. Tropical rainforest issue-topsoil is washed away quickly-subsoil is left- nutrient poor
the farming practice that overuses the land by repeatedly growing crops faster than the soil can be regenerated. This practice may lead to desertification
occurs when too many animals graze for too long and exceed the carrying capacity of a rangeland area; reduces grass cover, exposes the soil to erosion by water
more on overgrazing
western rangelands now support 50% of livestock they once did due to overgrazing, reduce biodiversity, invasion of shrubs such as prickly pear cactus
control the number and duration of grazing animals, rotational grazing, riparian protections
the process in which soil particles and decaying organic matter accumulate in layers on the ground or at the bottom of large bodies of water, contributing to the formation of sedimentary rock
taylor grazing act
A United States federal law that regulates grazing on federal public land. The Secretary of the Interior has the authority to handle all of the regulations, and he became responsible for establishing grazing districts. Before these districts are created there must be a hearing held by the state.
The removal of groundwater faster than it can be recharged by precipitation, lowering the water table.
Degradation of land, especially in semiarid areas, primarily because of human actions like excessive crop planting, animal grazing, and tree cutting.
more on desertification
70% of drylands are being eroded, USDA estimates that about 4.6 billion tons of soil are eroded from US croplands and rangelands each year, 1/5 of US cropland is considered vulnerable to soil erosion
Process that occurs when soils in arid areas are brought under cultivation through irrigation. In arid climates, water evaporates quickly off the ground surface, leaving salty residues that render the soil infertile.
water saturation of soil that fills all air spaces and causes plant roots to die from lack of oxygen; a result of overirrigation
a way of turning the earth by plowing, disking, harrowing, & chiseling that aerates the soil & works weeds & old crop residue into the soil to nourish it, but also leaving the surface bar allowing wind & water to erode topsoil
contour strip cropping
farming operations performed on the contour with crops planted in narrow strips, alternating between row crops and close-growing forage crops
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
Rows of large trees or bushes planted between fields to help block the wind and prevent soil erosion.
The practice of rotating use of different fields from crop to crop each year, to avoid exhausting the soil
Growing two or more different crops at the same time on a plot. For example, a carbohydrate-rich grain that depletes soil nitrogen and a protein-rich legume that adds nitrogen to the soil may be intercropped.
planting a plot with several varieties of the same crop
Complex form of intercropping in which a large number of different plants maturing at different times are planted together. See also intercropping. Compare monoculture, polyvarietal cultivation.
concurrent use of forestry and agricultural techniques on the same land area to improve degraded soil and offer economic benefits
Which of the following types of agriculture is most characteristic of developed countries?
Sustainable agriculture is characterized by all of the following except
The term undernutrition refers to people who
eat less than the basic minimum number of daily calories
Since 1950, the majority of the increase in food production is a result of the ____ revolution.
The process least likely to conserve soil nutrients is
Marasmus is a
result of lack of calories and protein..
In tropical and temperate areas, 1 inch of topsoil takes an average of ____ years to form.
Of the following human activities, the one which probably contributes least to soil erosion is
In alley cropping,
crops are planted between hedgerows of trees or shrubs that are used for fruits or fuelwood.
Malnutrition and associated infections could be reduced by
encouraging breast-feeding, teaching women about child care and water sterilization, immunization
In your garden plot on the island of Hawaii, you have carefully planted ten different species, all of which mature at different times. Some take nutrients from the soil. Some return nutrients. Some crops are used for food; others for fuel or medicine. You are practicing ____.
Anemia can be the result of a deficiency in
Most overgrazing is caused by
too many grazing animals for too long a time
Salt buildup may
eventually make the land unproductive.
Which of the following practices leads to desertification?
soil compaction, irrigation, overgrazing, surface mining
Sustainable agriculture is characterized by major use of
Out in your wheat fields in Oklahoma, you decide to plant several different varieties of wheat. A student from Oklahoma State University studying sustainable agriculture observes that you are practicing ____.
The term malnutrition refers to people who
suffer from poor food quality.
Plowing, breaking up, and smoothing soil in fall to plant in the spring is
deficiency can cause goiter, which can lead to deafness.
Sustainable management of rangelands would include
allowing no or limited grazing on riparian areas.
Intercropping involves growing
several different crops on a plot of land.
Planting crops in alternating rows of close-growing plants
is called strip cropping
All of the following are types of interplanting except
Administration of ____ will prevent the majority of blindness in developing countries in the world.
vitamin A capsules
Use of perennial crops would reduce
the amount of water used, the amount of fossil fuel used, soil erosion.
is a result of lack of protein
Overnutrition is characterized by diets
high in meat.
Most soil erosion is caused by
Contour farming involves
plowing at right angles to slopes.
An agricultural style that prevents erosion on steep slopes is
Industrialized agriculture requires large inputs of
pesticides, water, fossil fuels, inorganic fertilizers.