Lesson 2.1 Key Terms

Across

6. – The arrangement of primary soil particles into compound particles or aggregates that are separated from adjoining aggregates.
8. – A unit of soil structure such as an aggregate, crumb, prism, block, or granule, formed by natural processes (in contrast with a clod, which is formed artificially by compression of a wet clay soil).
12. – The removal of soluble constituents from soils or other materials by percolating water.
13. – The relative proportion in a soil of the various size groups of individual soil
14. – The artificial application of water to soil for the purpose of increasing plant production.
15. matter – Matter found in or produced by, living animals and plants, which contains carbon, hydrogen, oxygen, and often nitrogen and sulfur.
17. – The horizon of weathered rock or partially weathered soil material from which the soil is formed.
19. – The capacity of soil or rock for transmitting a fluid. The degree of permeability depends upon the size and shape of the pores, the size, and shape of their interconnections, and the extent of the latter.
21. – In soil science, a group of textural classes in which the particles are finer than gravel but coarser than silt, ranging in size from 2.00 to 0.5 millimeters in diameter. It is the textural class of any soil that contains 85 percent or more of sand and not more than 10 percent of clay.
23. – Accumulation of water-worn pebbles larger than two millimeters in diameter.
26. – The mineral and organic surface of the earth capable of supporting upland plants. It has been (and is being) formed by the active factors of climate and biosphere exerting their influence on passive parent material and topography over neutral time.
27. – An organism so small that it cannot be seen clearly without the use of a microscope, a microscopic or submicroscopic organism.

Down

1. – A phylum or division of the animal kingdom; includes insects, spiders, and Crustacea; characterized by a coating which serves as an external skeleton and by legs with distinct movable segments or joints.
2. – A textural class of soils containing 80 percent or more of silt and less than 12 percent clay.
3. – Single-celled microorganisms; some cause human, animal, or plant diseases; others are beneficial.
4. – Any living individual, whether plant or animal.
5. – Microscopic, wormlike, transparent organisms that can attack plant roots or stems to cause stunted or unhealthy growth.
7. – The relative degree of downward movement of water in a soil. Also called permeability.
9. – Refers to the extent of voids or openings in the soil that exist between soil particles and soil peds or clods. These pores hold water and air for absorption by plant roots. About half of soil volume which is in a good physical condition for plant growth is pore space.
10. – Color difference on a mass of moderately poorly drained soil.
11. – A size term denoting particles, regardless of mineral composition, with a diameter less than two microns.
16. – Plantlike organisms that have no chlorophyll; they get their nourishment from living or decaying organic matter.
18. – Mineral matter of variable composition, consolidated or unconsolidated, assembled in masses or considerable quantities in nature.
20. – Unweathered hard rock that lies directly beneath the soil layers or beneath superficial geological deposits, such as glacial drift.
22. – A vertical section of a soil. The section, or face of an exposure made by a cut, may exhibit with depth a succession of separate layers, although these may not be separated by sharp lines of demarcation.
23. – Any vegetation that grows close to the ground, producing protection for the soil.
24. – Soil that consists of less than 52 percent sand, 28 to 50 percent silt, and 7 to 27 percent clay, resulting in a soil texture ideal for gardening.
25. – A layer of soil, approximately parallel to the surface, having distinct characteristics produced by soil-forming processes.