2. Frozen layers of soil, occurring in arctic or subarctic regions,
which have not thawed for a long time.
5. The quality of the soil that enables water to move downward through
7. The well decomposed, more or less stable part of the organic matter
in mineral soils.
11. The mineral soil particles less than 0.002 millimeter in diameter.
12. The upper part of the soil, which is the most favorable material
for plant growth, ordinarily rich in organic matter.
16. Unconsolidated material, largely undecomposed organic matter, that
has accumulated under excess moisture.
18. The downward entry of water into the immediate surface of soil or
20. Individual rock or mineral fragments from 0.05 millimeter to 2.0
millimeters in diameter.
1. A layer of soil, approximately parallel to the surface, having distinct
characteristics produced by soil-forming processes.
3. Of or pertaining to rivers; produced by river action.
4. Rounded or angular fragments of rock as much as 3 inches (2 millimeters
to 7.6 centimeters) in diameter.
6. The wearing away of the land surface by water, wind, ice, or other
geologic agents and by such processes as gravitational creep.
8. Particles that range in diameter from the upper limit of clay (0.002
millimeter) to the lower limit of very fine sand (0.05 millimeter).
9. A vertical section of soil extending through all its horizons and
into the parent material.
10. Wetness characterized by zero or positive pressure of the soil water.
13. The downward movement of water through the soil.
14. Material, such as sand, silt, or clay, deposited on land by streams.
15. Solid rock that underlies the soil and other unconsolidated material
or that is exposed at the surface.
17. Capable of supporting plants,
19. The direction in which a slope faces
aspect, bedrock, clay, erosion, fluvial, gravel, horizon, humus, infiltration,
peat, percolation, permafrost, permeability, profile, sand, saturation,
silt, soil, topsoil