AC-Ch. 3 Soil Science Flashcards Preview

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Flashcards in AC-Ch. 3 Soil Science Deck (44)
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1

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

Actinomycetes

2

Close cluster or mix of small particles of soil and/or organic matter of varying sizes that are bonded together; sand, gravel or small rocks in soil and/or sand, gravel, or small rocks used under paved surfaces

Aggregate

3

Clusters of flowers or fruits that appear as a single unit

Aggregate

4

Individual tree crowns that form a canopy

Aggregate

5

Ion that carries a negative charge

Anion

6

Ability of a soil to maintain its pH

Buffering capacity

7

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

Bulk density

8

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

Capillary water

9

Positively charged ion.

Cation

10

What are the most abundant cations in soil

Calcium. Magnesium. Potassium. Sodium. Aluminum.

11

Ability of a soil to absorb and hold cations. Affected by soil pH. Measures soil fertility, clay composition, and enginnering characteristics.

Cation exchanged capacity CEC

12

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

Clay

13

Substance or solution that oozes out of injured plant cells or is secreted through membrane pores

Exudate

14

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

Field capacity

15

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

Gravitational water

16

Layer of soil within the soil profile

Horizon

17

Dark colored, stable form of organic matter that remains after most of the plant or animal residues have decomposed

Humus

18

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

Ion

19

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

Leach (leaching)

20

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

Loam

21

Relatively large space between soil particles that is usually air filled and allows for water movement and root penetration

Macropore

22

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

Micropore

23

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

Mineralization

24

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

Nematode

25

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

Nutrient cycling

26

Layer of organic at the soil surface

Organic layer

27

Soil bedrock or base material from which a soil profile develops

Parent material

28

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

Permanent wilting point

29

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

pH

30

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

Rhizosphere