Exam 7: Soil Aeration and Temperature

Some 40 to 50% of the solar radiation in humid regions is used to heat the soil.

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

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 _____.

Which of the following processes are most apt to encourage good soil aeration?

The heat of vaporization of water is 540 cal/g.A soil containing 30 kg water per 100 kg soil solids lost one sixth of that water by evaporation.If one tenth of the energy needed to evaporate the water came from the soil solids how much would the temperature of those solids be lowered?

The redox potential of a soil is -250 mV.Which of the following forms of the pertinent elements would you expect to find in the soil?

Anaerobic conditions commonly prevail in liberally watered flower pots with mineral soil as the growing medium even though the containers have holes for drainage in the bottom of the pot.

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

If the CO₂ content of soil air is 3.5%,it is 100 times higher than that of the atmosphere.

Reduced forms of iron and manganese along with soil organic matter largely control the color of well-drained soils.

The following is the reduced form of the essential element depicted

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.

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.

In acid soils you would be concerned if the redox potential was low since it could mean a deficiency of some plant nutrients such as iron and manganese.

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 _____.

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

If you owned a dairy farm with poorly drained clay soils in a humid temperate region which of the following would be most satisfactory from the standpoint of soil aeration and temperature?

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.

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.

Wildfires in forested areas result in the formation of organic compounds that enhance the percolation of water through the soil.