24 terms

Ag 1

the lesson learned by the schroeder brothers on their iowa farm is that
erosion and soil nutrient losses are reduced with no-till agriculture
the practice of planting large areas with a single type of crop, monoculture
is a development of industrial agriculture
agricultural practices, where the members of a farming family produce only enough food for themselves and do not make use of large-scale irrigation, chemical fertilizer or machinery and technology is called
subsistence agriculture
industrial agriculture
increased the ability to obtain more food from the same area
which of the following particles is smallest
which soil horizon is most depleted through erosion
desertification of soil
can be caused by overgrazing
which of the following practices leads to the greatest amount of soil erosion from one location
clear-cutting trees from hillsides
what occurs when salts build up in the surface of soil
humus is
composed of organic compounds and is necessary for fertile soils and for holding soil moisture
during most of our species 160,000 year existence and until about 10,000 years ago, we depended on
hunting and gathering
factors involved in soil formation are
weathering of parent material, freezing/thawing, growth of tree roots
removes water soluble nutrients from soil
the O horizon is
primarily composed of organic materials
oxidation of minerals, warm and wet conditions, reactions of water with parent material are all components of
chemical weathering of soils
sachiko and her husband, fred, recently bought a farm that had been left idle for over 20 years. to understand the best uses of the land, they should first investigate
the horizons, texture, structure, pH, slope, and prior erosion history
pH influences
plant growth
how does the conservation reserve program try to protect soil for future agriculture
the CRP pays farmers not to grow crops on land that is not very well suited for crop production
weather can dramatically affect a farmers yield. government subsidies to farmers can compensate for this rick but may lead to
environmental sustainability
how has the US government changed its views of wetlands over the past 40 years
historically we have encouraged the draining of wetlands to make room for agriculture. recently we have reversed this policy and are trying to restore wetlands
we lose 5 to 7 million ha of productive cropland per year to
erosion, over-irrigation and other factors
when surface water flows downhill and removes topsoil in uniform layers
sheet erosion
leaching and the rate of movement of water would be greatest in a soil classified as
the consequences of over-fertilization can include
eutrophication in nearby waters