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21 Cards in this Set
- Front
- Back
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swidden agriculture
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slash and burn
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soil degradation
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negative changes in soil due to
Deforestation Overgrazing Overcultivation |
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detritivore
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energy flows through these organisms, they feed on detritus-dead or decaying matter; Detritivores quickly break down organic matter and recycle nutrients back to the soil; Detritus nibbled by countless bacteria, fungi, protists
These in turn help feed the larger detritivores - insects, pill bugs, earthworms, millipedes. They are important because they: Break up detritus into smaller particles for bacteria and fungi to decompose Constantly aerate the soil as they tunnel through it |
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humus
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leftover small organic particles that make up the O horizon
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soil structure
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the physical characteristics of the soil (ex. particle size, pore spaces, how the grains clump together etc.)
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soil horizons
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a specific layer in the soil which differs from the layers above it and below it
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soil profile
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all the layers visible when you take a section through the soil (the sequence of layers)
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O horizon
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humus
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A horizon
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topsoil, still contains some humus
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top soil
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A horizon; important protective layer of all soil-Soil loses most of its organic content and nutrients when humus is removed and underlying soil can no longer hold water; acts like a sponge and holds water long enough for plants to be hydrated
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E horizon
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below the A horizon, zone of leaching
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B horizon
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subsoil; either red or yellow due to oxides of minerals in the ground like iron or aluminum
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subsoil
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B horizon; either red or yellow due to oxides of minerals in the ground like iron or aluminum
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C horizon
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Basic mineral soil, no organic matter
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parent material
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c horizon; starting point in the formation of new soil
Forms by: Volcanic deposition Glacial deposition Natural weathering of bedrock |
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no-till farming
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relies on special plowing disks - one set opens the soil, seed is dropped in, last set zips the soil back up
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desertification
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healthy soils are turned into sterile soils, with no organic content, no soil structure
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salinization
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Increase in soil salinity, caused by irrigated agriculture;When fresh water evaporates, leaves minute amount of salt behind
Salt gradually builds up in irrigated fields, eventually can no longer grow crops |
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Dust Bowl
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Higher grain prices during World War I convinced farmers that wheat was more lucrative than cattle
Plowed up healthy rangeland to plant wheat Just in time for a prolonged drought |
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windbreaks
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we planted trees to act as windbreaks to erosion of the topsoil
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contour plowing
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helped hold remaining topsoil in place
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