Exam 4: Soil Architecture and Physical Properties

Texture describes the ____ of particles in a soil.

Which type of structure is typically found in sodium-rich sub-surface horizons?

Compared to a similar soil under native vegetation,a soil with a long history of conventionally tilled cropping would have less micropore space.

A chroma greater than 4 generally indicates a soil in good tilth.

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

If a dry soil high in certain types of ____ is moistened,it is likely to swell up with enough force to crack pavements and building foundations.

The plasticity index is the difference between the plastic limit and the liquid limit.

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

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.

The plasticity index is used to determine soil texture.

A friable soil is usually more likely to be indurated.

For any soil,the bulk density is always lower than the particle density.

Colloidal properties are exhibited by the ___ fraction of soils.

Soils of good tilth and high productivity are usually characterized by stable aggregation and a high percentage of macropores.

The percent of total pore space in a soil can be calculated if only the particle density and the organic matter content are known.

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

Roots of most plants have difficulty growing through soil if the bulk density is greater than 1.0 Mg/m³.

For most soils,plowing and harrowing every year improves soil tilth in the long run.

Which of the following is not a textural class name?

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