Exam 7: Soil Aeration and Temperature

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?

The following is the reduced form of the essential element depicted

22 Respiration by plant and animal cells along with photosynthesis releases oxygen and consumes carbon dioxide.

The great bulk of gaseous interchange between the soil pores and the atmosphere occurs by mass flow of the concerned gases.

The specific heat of soil solids is significantly higher than that of water.

The redox potential is a measure of _____.

An abundance of macropores in soils helps assure an abundance of oxygen in the soil.

Forest fires result in sufficiently high soil temperatures to cause the vaporization and movement of certain organic compounds in soils. The main effect of these compounds is to _____.

In natural wetlands one would expect the redox potential to be high because of the low oxygen content.

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 _____.

Which of the following actions would best assure good aeration in a soil?

You would expect the installation of an effective tile drainage system in a naturally poorly drained soil in Iowa to increase soil temperatures in the spring of the year.

Soil temperatures under an organic mulch will likely be lower than that of bare soils in the summer but higher than that of bare soils in the winter.

The redox potential is a measure of the tendency of a substance to accept or donate electrons.

The most important management factors influencing soil aeration in well-drained soils are those that determine the volume of the soil's macropores.

An increase of 5 ^oC in soil temperature is likely to increase shoot growth on most plants much more than a similar increase in the air temperature.

The partial pressure of CO₂ in the soil pores is higher than the partial pressure of this gas in the atmosphere.

A mineral soil has a water content of 25 kg water per 100 kg dry soil. What is the approximate specific heat of this soil, expressed in calories per kilogram?

Three rows of tomatoes were given different mulching treatments. Which of the following would result in the hottest soil in summer?

Heat pumps can take advantage of the fact that subsoils are generally warmer in the winter and cooler in the summer than the atmospheric air.