AC-Ch. 3 Soil Science Flashcards
Group of soil bacteria resembling fungi. They play a role in the decomposition of organic matter and the release of mineral elements
Actinomycetes
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
Clusters of flowers or fruits that appear as a single unit
Aggregate
Individual tree crowns that form a canopy
Aggregate
Ion that carries a negative charge
Anion
Ability of a soil to maintain its pH
Buffering capacity
Mass of soil per unit volume. Often used as a measure of compaction
Bulk density
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
Positively charged ion.
Cation
What are the most abundant cations in soil
Calcium. Magnesium. Potassium. Sodium. Aluminum.
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
Soil particles with a typical grain size less than .004 mm.
Clay
Substance or solution that oozes out of injured plant cells or is secreted through membrane pores
Exudate
Maximum soil moisture content following the drainage of water due to the force of gravity.
Field capacity
Water that drains from the larger soil macropores due to the force of gravity.
Gravitational water
Layer of soil within the soil profile
Horizon
Dark colored, stable form of organic matter that remains after most of the plant or animal residues have decomposed
Humus
Atom or a group of atoms with a positive or negative charge
Ion
Tendency for elements or compounds to wash down through or into the soil
Leach (leaching)
Soil texture classification based on a certain ratio of sand, silt, and clay. Considered ideal for plant growth.
Loam
Relatively large space between soil particles that is usually air filled and allows for water movement and root penetration
Macropore
Space between soil particles that is relatively small and likely to be water filled
Micropore
Process in which an organic substance is converted to or trapped in inorganic substance
Mineralization
Microscopic roundworm. Many are beneficial organisms, but some feed on plant tissues and may cause disease or damage
Nematode
Movement of mineral elements within an ecosystem as organic matter decomposes, releasing bound nutrients back to plants
Nutrient cycling
Layer of organic at the soil surface
Organic layer
Soil bedrock or base material from which a soil profile develops
Parent material
Point at which a plant cannot pull any more water from the soil and suffers permanent damage.
Permanent wilting point
Unit of measure that describes the alkalinity or acidity of a solution. Negative log of the hydrogen ion concentration.
pH
Soil area immediately adjacent to and affected by plant roots. Typically has a high level of microbial activity
Rhizosphere
Soil with a high concentration of soluble salts. Can cause poor plant growth
Saline soil
Soil particles with a size between.06 and 2.0 mm in diameter
Sand
Soil particles with a grain size between .004 and .062 mm
Silt
Soil with relatively low levels of soluble salts and a concentration of sodium high enough to adversely affect soil structure
Sodic soil
Symptoms include waterlogging erosion soil surface crusting and poor plant growth
Sodic soil
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
Soil compaction
Complex network of interconnected food chains in an ecosystem in this case in the soil.
Soil food web
Vertical section through the soil and all of the soil horizons
Soil profile
Arrangement of soil particles into aggregates
Soil structure
Relative fineness or coarseness of a soil due to particles size
Soil texture
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.
Structural cells
Pavement substrate that can be compacted to meet engineering specifications yet remains penetrable by tree roots in the urban environment.
Structural soil
Composed of angular crushed stone clay loam and hydrogel mixed in a weight ratio of 100:20:0.03
Structural soil
Sidewalk that is reinforced and supported with piers or other structures so that it does not rely on compacted subgrade or soil for support
Suspended sidewalk
