soils questions 3

C. higher soil temperatures on the north slopes

A wildlife biologist in South Africa notes that the soils on south-facing slopes are wetter and deeper than those on north-facing slopes, and therefore support more wildlife. What likely accounts for this difference? A. differences in rainfall from one area to another B. more rapid plant growth on the south slopes C. higher soil temperatures on the north slopes D. more solar radiation on the south slopes E. sandier soils on the north slopes

D. the water table

If you dug a deep hole in your back yard and water started to seep into the hole it would fill the hole up to ________. A. the infiltration rate B. the percolation rate C. field capacity D. the water table E. the liquid limit

A. gravitational

In which of the following "forms" of soil water are pesticides, excess plant nutrients and waste chemicals most apt to move through soils? A. gravitational B. unsaturated C. available D. hygroscopic E. capillary

A. uniformly textured sandy loam profile

In which of the following situations would you expect downward movement of soil water through the profile to be most rapid? A. uniformly textured sandy loam profile B. sandy loam in upper layers with a clay band underneath C. sandy loam in upper layers with a layer of coarse gravel underneath D. clay texture throughout the profile E. silt loam in upper layers underlain by a sandy layer

E. both B and D

Plant roots obtain access to soil water in which of the following ways? A. The roots contract and leave room in the pores for the water to move in. B. Roots extend into moist soil area. C. Water vapor moves from the wet soil areas to the root surfaces. D. Water flows to the roots by capillarity. E. both B and D

C. It has a positive and a negative side.

The following are characteristics of a water molecule. A. The H to O to H angle is approximately 90o C. B. The two H atoms are on diametrically opposite ends of the molecule. C. It has a positive and a negative side. D. It is attracted to surfaces with negative but not positive charges. E. It is held in soils by adhesion but not adsorption.

A. the presence of macropores in the soil

The likelihood of polluting groundwater with pesticides and plant nutrients is enhanced by _____. A. the presence of macropores in the soil B. light tillage of the upper centimeter or so of soil C. the use of tillage to control weeds D. the production of oats rather than wheat E. conventional tillage as a choice compared with conservation tillage

B. not influenced appreciably by the force of gravity

The matric potential of soil water is _____. A. influenced greatly by the content of salts in the soil B. not influenced appreciably by the force of gravity C. is generally higher than that of pure water outside the soil D. is little affected by soil solids E. is lower in a sandy soil with 20 percent soil water than in a clay soil with same percentage of moisture

B. septic tank and drain field

The most common form of on-site waste water treatment for homes not hooked up to sewer lines is the _______. A. active composting method B. septic tank and drain field C. chemical "flush" system D. electrical induction sterilization E. soil enrichment process

D. the high specific heat of the soil

The primary characteristic of subsoils that accounts for the ability of ground circulating heat pumps to moderate temperatures in houses in both summer and winter is _____. A. the high redox potential of the soil B. the high heat of the evapotranspiration C. the ready conduction of heat in the soil D. the high specific heat of the soil E. the low oxygen content of the subsoil

B. the tendency of a substance to accept or donate electrons

The redox potential is a measure of _____. A. molecular oxygen content B. the tendency of a substance to accept or donate electrons C. carbon dioxide content D. the ferric ion content E. the balance between hydrogen and hydroxyl ions in solution.

A. decreases ...... stream bank erosion.

Urban development of land under natural vegetation or agriculture usually greatly _____ soil infiltration capacity and therefore greatly increases _______. A. decreases ...... stream bank erosion. B. increases ...... stream bank erosion. C. decreases ...... groundwater recharge. D. increases .......groundwater recharge.

D. drip or trickle

Where high-value crops or individual ornamental shrubs are to be grown and water is expensive, the most efficient type of irrigation to use would be ______. A. center pivot B. basin flooding C. furrow D. drip or trickle

E. remove excess water

Which of the following actions would best assure good aeration in a soil? A. increase the soil temperature B. add organic residues C. use a plastic mulch D. use cover crops, especially legumes E. remove excess water

A. hydric soils

Which of the following is (are) considered necessary features for an area to be delineated as a wetland? A. hydric soils B. shallow standing water C. aquatic vegetation D. organic soils E. all of the above

C. nitrogen gas

Which of the following is not a major factor in determining the soil aeration status? A. redox potential B. volume of macropores C. nitrogen gas D. carbon dioxide E. oxygen

D. creation of more macropores

Which of the following processes are most apt to encourage good soil aeration? A. root respiration B. organic matter decomposition C. diffusion of oxygen from the soil to the atmosphere D. creation of more macropores E. reaction of oxygen with organic matter

E. none of the above

Which of the following will increase the evaporation (E) from the soil surface? A. adding straw mulch to the soil surface B. the use of no-till culture C. stubble mulch farming D. plastic mulch E. none of the above

A. the expansion of water when it freezes

Alternate freezing and thawing of soils results in the "heaving" of plants and the destruction of shallow building foundations. This effect is due primarily to _____. A. the expansion of water when it freezes B. the wetting and drying of swelling-type clays C. pressure from upward movement of water from lower horizons D. the breaking down of soil aggregates due to freezing and thawing E. the hydration of adsorbed cations on the soil colloids

A. involves both adhesion and cohesion

Capillarity in soils _____. A. involves both adhesion and cohesion B. is enhanced by the symmetrical nature of the water molecule C. is independent of the matric potential in soils D. is not involved in the process of water uptake from soils E. does not account for unsaturated water movement in soils

A. methane

Compared to upland soils, wetland soils would be characterized by an abundance of _____. A. methane B. CO2 C. NO3- D. SO42- E. Fe3+