[The Cooperative Soil Survey] Soils Tutorial: Glossary

Glossary

Definitions from the Soil Science Society of America (SSSA)

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Back slope The steepest inclined surface and principle element of many hillslopes Back slopes in the profile typically range from gently sloping to very steep and linear and descend to a foot slope. They are erosional forms produced mainly by mass wasting and running water.

Base saturation The degree to which material having cation-exchange properties is saturated with exchangeable bases (sum of Ca, Mg, Na, K), expressed as a percentage of the total cation-exchange capacity.

Bedding planes Fine stratifications, less than 5 millimeters thick, in unconsolidated alluvial, eolian, lacustrine, or marine sediments.

Bedrock The solid rock that underlies the soil and other unconsolidated material or that is exposed at the surface.

Bench terrace A raised, level or nearly level strip of earth constructed on or nearly on the contour, supported by a barrier of rocks or similar material, and designed to make the soil suitable for tillage and to prevent accelerated erosion.

Blowout A shallow depression from which all or most of the soil material has been removed by wind A blowout has a flat or irregular floor formed by a resistant layer or by an accumulation of pebbles or cobbles. In some blowouts the water table is exposed.

Bottom land The normal flood plain of a stream, subject to flooding.

Boulders Rock fragments larger than 2 feet (60 centimeters) in diameter.

Broad-base terrace A ridge-type terrace built to control erosion by diverting runoff along the contour at a nonscouring velocity. The terrace is 10 to 20 inches high and 15 to 30 feet wide and has gently sloping sides, a rounded crown, and a dish-shaped channel along the upper side. It may be nearly level or have a grade toward one or both ends.

Back slope	The steepest inclined surface and principle element of many hillslopes Back slopes in the profile typically range from gently sloping to very steep and linear and descend to a foot slope. They are erosional forms produced mainly by mass wasting and running water.
Base saturation	The degree to which material having cation-exchange properties is saturated with exchangeable bases (sum of Ca, Mg, Na, K), expressed as a percentage of the total cation-exchange capacity.
Bedding planes	Fine stratifications, less than 5 millimeters thick, in unconsolidated alluvial, eolian, lacustrine, or marine sediments.
Bedrock	The solid rock that underlies the soil and other unconsolidated material or that is exposed at the surface.
Bench terrace	A raised, level or nearly level strip of earth constructed on or nearly on the contour, supported by a barrier of rocks or similar material, and designed to make the soil suitable for tillage and to prevent accelerated erosion.
Blowout	A shallow depression from which all or most of the soil material has been removed by wind A blowout has a flat or irregular floor formed by a resistant layer or by an accumulation of pebbles or cobbles. In some blowouts the water table is exposed.
Bottom land	The normal flood plain of a stream, subject to flooding.
Boulders	Rock fragments larger than 2 feet (60 centimeters) in diameter.
Broad-base terrace	A ridge-type terrace built to control erosion by diverting runoff along the contour at a nonscouring velocity. The terrace is 10 to 20 inches high and 15 to 30 feet wide and has gently sloping sides, a rounded crown, and a dish-shaped channel along the upper side. It may be nearly level or have a grade toward one or both ends.