AC-Ch. 3 Soil Science

Question 1

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

Answer 1

Actinomycetes

Question 2

(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.

Answer 2

Aggregate

Question 3

Negatively charged ion.

Answer 3

Anion

Question 4

Ability of a soil to maintain its pH.

Answer 4

Buffering capacity

Question 5

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

Answer 5

Bulk density

Question 6

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.

Answer 6

Capillary water

Question 7

Positively charged ion.

Answer 7

Cation

Question 8

What are the most abundant cations in soil?

Answer 8

Calcium. Magnesium. Potassium. Sodium. Aluminum.

Question 9

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.

Answer 9

CEC

Question 10

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

Answer 10

Clay

Question 11

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

Answer 11

Field capacity

Question 12

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.

Answer 12

Food Chain

Question 13

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

Answer 13

Gravitational water

Question 14

Layer of soil within the soil profile.

Answer 14

Horizon

Question 15

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.

Answer 15

Humus

Question 16

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

Answer 16

Hydroxide

Question 17

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

Answer 17

Ion

Question 18

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

Answer 18

Leach (leaching)

Question 19

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

Answer 19

Loam

Question 20

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

Answer 20

Macropore

Question 21

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

Answer 21

Micropore

Question 22

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

Answer 22

Mineralization

Question 23

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

Answer 23

Nematode

Question 24

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

Answer 24

Nutrient cycling

Question 25

Layer of organic at the soil surface.

Answer 25

Organic layer

Question 26

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

Answer 26

Parent material

Question 27

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

Answer 27

Permanent wilting point

Question 28

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

Answer 28

pH

Question 29

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

Answer 29

Rhizosphere

Question 30

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

Answer 30

Root exudates

Question 31

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

Answer 31

Saline soil

Question 32

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

Answer 32

Sand

Question 33

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

Answer 33

Silt

Question 34

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

Answer 34

Sodic soil

Question 35

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

Answer 35

Sodic soil

Question 36

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.

Answer 36

Soil compaction

Question 37

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

Answer 37

Soil food web

Question 38

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

Answer 38

Soil profile

Question 39

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

Answer 39

Soil structure

Question 40

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

Answer 40

Soil texture

Question 41

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.

Answer 41

Structural cells

Question 42

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

Answer 42

Structural soil

Question 43

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

Answer 43

Structural soil

Question 44

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

Answer 44

Suspended sidewalk