Environmental Science - Chapter 11 Test 2
A loam soil is a mixture of
40 percent sand, 40 percent silt, and 20 percent clay
Most plants grow best when the pH value of the soil is at or near
6.0
Topsoil, the layer of soil composed of mineral soil particles mixed with humus, is found in the
A horizon
In a temperate deciduous forest, which soil horizon contains the leaf litter, twigs, seeds, and humus of the forest surface
O horizon
Humus us (or refers to)
a residue of organic matter that remains after most of the rotting and decomposition has occurred
Of the following choices, the smallest-sized soil particles are
clay
The nutrients supporting the lush growth in tropical rainforests are provided by
decaying biomass on the forest floor
Sheet erosion occurs as a result of
decreased infiltration and increased runoff
The process of soil being washed or blown away is called
erosion
Which of the following soil conservation methods would reduce losses due to wind erosion
establishment of shelterbelts
Which of the following would produce the least amount of sediments that could enter bodies of water
forested areas
Which of the following is a characteristic of sandy soils
good drainage but poor water retention
As far as agricultural applications are concerned, the main distinction between topsoil and the underlying subsoil is that topsoil
has a higher humus content
Deforestation is more damaging to tropical soils than temperate zones soils because
high rainfall, uniform warm temperatures and rates decomposition cause rapid loss of humus
Nutrient-holding capacity of the soil is a measure of
how readily nutrients may be leached from the soil
The spongy, dark brown or black material that remains from rotting dead log is called
humus
The process of water soaking into soil is known as
infiltration
The aspect of a soil which determines its fertility is
ion exchange capacity
Some forest plants can obtain nutrients from a symbiotic association with:
mycorrhizal fungi
A method of agriculture that reduces soil disturbance from cultivation is
no-till planting
A soil that allows very little leaching has good
nutrient-holding capacity
Leaching is a term that refers to
nutrients or other chemicals being removed from the soil by water percolating through the soil
Soil texture is a measurement of the
proportion of sand, silt, and clay-sized particles
Which of the following would result from soil compaction
reduced infiltration of water
Which of the following is an effect of plant cover
reduction in wind and water erosion
Which of the following is a symbiotic relationship found in soils
roots of certain plants and fungi
When soils that lack adequate subsurface drainage are heavily irrigated that
salinity increases
leaf litter on a forest floor helps protect underlying soils from
splash erosion
The best agricultural soils in the world are
temperate grassland soils (mollisols)
Mineralization of a type of soil refers to
the loss of its humus content through oxidation
Most land plants require substantial quantities of water to replace water lost through
transpiration
The major source of minerals that cause soil salinization is
use of irrigation water containing dissolved salts
The gradual breakdown of rock into soil particles by physical and chemical processes is called
weathering
