AC-Ch. 3 Soil Science Flashcards

1
Q

Group of soil bacteria resembling fungi. They play a role in the decomposition of organic matter and the release of mineral elements.

A

Actinomycetes

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2
Q

(1) Close cluster or mix of small particles of soil and/or organic matter of varying sizes that are bonded together. (2) Sand, gravel or small rocks in soil and/or used under paved surfaces. (3) Clusters of flowers or fruits that appear as a single unit. (4) Individual tree crowns that form a canopy.

A

Aggregate

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3
Q

Negatively charged ion.

A

Anion

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4
Q

Ability of a soil to maintain its pH.

A

Buffering capacity

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5
Q

Mass of soil per unit volume. Often used as a measure of compaction.

A

Bulk density

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6
Q

Water held in the capillary pores of the soil much of this water can move in any direction and is readily available to plant roots.

A

Capillary water

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7
Q

Positively charged ion.

A

Cation

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8
Q

What are the most abundant cations in soil?

A

Calcium. Magnesium. Potassium. Sodium. Aluminum.

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9
Q

Cation Exchange Capacity: The ability of a soil to attract, retain, and exchange positively charged cations. Affected by soil pH and particle size. A measure of soil fertility and clay composition.

A

CEC

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10
Q

Soil particles with a typical grain size less than .004 mm.

A

Clay

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11
Q

Maximum soil moisture content following the drainage of water due to the force of gravity.

A

Field capacity

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12
Q

A linear network of links in a food web, often starting with an autotroph, also called a producer, and typically ending at an apex predator, detritivore, or decomposer.

A

Food Chain

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13
Q

Water that drains from the larger soil macropores due to the force of gravity.

A

Gravitational water

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14
Q

Layer of soil within the soil profile.

A

Horizon

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15
Q

Dark colored, stable form of organic matter formed by the decomposition of plant and animal matter, and a rich source of nutrients improving soil health.

A

Humus

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16
Q

Polyatomic anion of hydrogen and oxygen present in alkaline substances that attracts the monoatomic hydrogen cations in acids.

A

Hydroxide

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17
Q

Atom or a group of atoms with a positive or negative charge.

A

Ion

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18
Q

Tendency for elements or compounds to wash down through or into the soil.

A

Leach (leaching)

19
Q

Soil texture classification based on a certain ratio of sand, silt, and clay. Considered ideal for plant growth.

20
Q

Relatively large space between soil particles (mainly betweeen aggregates) that is usually air filled and allows for water movement and root penetration.

21
Q

Space between soil particles that is relatively small and likely to be water filled.

22
Q

Process in which an organic substance is converted to or trapped in inorganic substance.

A

Mineralization

23
Q

Microscopic roundworm. Many are beneficial organisms, but some feed on plant tissues and may cause disease or damage.

24
Q

Movement of mineral elements within an ecosystem as organic matter decomposes, releasing bound nutrients back to plants.

A

Nutrient cycling

25
Q

Layer of organic at the soil surface.

A

Organic layer

26
Q

Soil bedrock or base material from which a soil profile develops.

A

Parent material

27
Q

Point at which a plant cannot pull any more water from the soil and suffers permanent damage.

A

Permanent wilting point

28
Q

Unit of measure that describes the alkalinity or acidity of a solution. Negative log of the hydrogen ion concentration.

29
Q

Soil area immediately adjacent to and affected by plant roots. Typically has a high level of microbial activity.

A

Rhizosphere

30
Q

Sugar and other substances that are released into the soil as the root caps and external layers are sloughed off.

A

Root exudates

31
Q

Soil with a high concentration of soluble salts. Can cause poor plant growth.

A

Saline soil

32
Q

Soil particles with a size between.06 and 2.0 mm in diameter.

33
Q

Soil particles with a grain size between .004 and .062 mm.

34
Q

Soil with relatively low levels of soluble salts and a concentration of sodium high enough to adversely affect soil structure.

A

Sodic soil

35
Q

Symptoms include waterlogging erosion soil surface crusting and poor plant growth.

A

Sodic soil

36
Q

Compression of the soil often as a result of vehicle or heavy equipment traffic that breaks down soil aggregates and reduces soil volume and total pore space especially macropore space.

A

Soil compaction

37
Q

(1) Complex network of interconnected food chains within the soil ecosystem. (2) The diversity of organisms living, moving, and interactng in the soil.

A

Soil food web

38
Q

Vertical section through the soil and all of the soil horizons.

A

Soil profile

39
Q

(1) Arrangement of soil particles into aggregates. (2) The shape, size, strength, and arragement of the aggregates within the soil.

A

Soil structure

40
Q

Relative fineness or coarseness of the inorganic, mineral, soil particles—specifically the relative proportions of sand, silt, and clay.

A

Soil texture

41
Q

Modular system consisting of units of soil and integrated support structures that serves as both a foundation for paved surfaces and a hospitable environment for tree root growth.

A

Structural cells

42
Q

Pavement substrate that can be compacted to meet engineering specifications yet remains penetrable by tree roots in the urban environment.

A

Structural soil

43
Q

Composed of angular crushed stone clay loam and hydrogel mixed in a weight ratio of 100:20:0.03

A

Structural soil

44
Q

Sidewalk that is reinforced and supported with piers or other structures so that it does not rely on compacted subgrade or soil for support.

A

Suspended sidewalk