Exam 4: Soil Architecture and Physical Properties

A friable soil is usually more likely to be indurated.

Fungal hyphae have an important influence on soil structure because they ______.

Colloidal properties are exhibited by the ___ fraction of soils.

For which substance would the particle density equal the bulk density?

Fungal hyphae play an important role in stabilizing surface soil aggregates.

When preparing a surface soil seedbed, the soil should generally be in the loosest, least dense soil condition in the row where the seed is placed.

A sticky, putty-like feel indicates a high percentage of which soil separate?

Dull gray colors are characterized by _____.

Soil tilth refers to _____.

Soil consistence changes with changes in soil water content.

Subsoiling is a primitive deep tillage technique that results in extremely high subsoil bulk density.

In many soil profiles, the subsoil is high in clay, but is also quite permeable to percolating water. Why?

Tillage when the soil is too wet is likely to increase the soil bulk density.

Which of the following practices is(are) useful in stabilizing surface soil structure?

The drainage class of a soil (the degree to which the soil becomes water-saturated during the year) can be judged by the presence and location of gley in the soil profile.

Flocculation is the process by which certain chemicals in the soil stabilize large soil aggregates.

Which type of soil structure is typically found in surface soil (A horizons)?

Because of their greater surface area per unit of soil mass, silt loams soils generally have a greater capacity than loamy sand soils to ___.

The percentages of which soil components represent the minimum information necessary in order to determine the textural class of a soil?

Using a textural triangle chart, it can be determined that a soil with 45% sand and 20% clay belongs to the ___textural class.