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Soil Horizons
Enviro. Techniques Test #1 - Part A
| Question | Answer |
|---|---|
| generally defined as the unconsolidated, thin, variable layer mineral and organic material, usually biologically active, that covers most of the Earth’s land surface. | Soil |
| “any solid earth material that can be removed without blasting” | Soil (Engineer definition) |
| the term that refers to the layer of loose material covering the bedrock of the earth. | Regolith |
| represents the three-dimensional section of soil. | Soil pedon |
| What is the minimum size of a pedon? | 1 m² at the surface and 1.5 m deep. |
| Contains all the properties needed in order to classify and study the soil in an area? | Soil pedon |
| Defined by its morphological properties, including the number, kind and arrangement of horizons, color, texture, structure, accumulation of clay, iron oxides, humus, silica and carbonates. | Soil pedon |
| The differentiated layers in a pedon? | Soil Horizons |
| Develop as various processes alter the parent material and create soils that have unique characteristics. | Soil Horizons |
| Such factors as precipitation, temperature, organic material and biological activity are? | The various processes that alter the parent material and create soils. |
| Defined as a layer of soil, approximately parallel to the soil surface, with characteristics produced by soil forming processes. | Soil Horizons |
| Is the upper part of the pedon. It is most influenced by rainfall, roots and microorganisms. | Solum |
| It consists of the A and B horizons, AND it is the weathered components of the pedon. | Solum |
| Determine the nature and composition of soil. | Parent materials |
| Include igneous, metamorphic or sedimentary rock. | Parent materials |
| Climate, biota, topography and time all contribute to the physical and chemical weathering of... | Parent materials |
| Includes the collection of all the generic horizons, which are the natural organic layers on the surface, the solum (A and B horizons), and the parent material beneath the solum. | Soil profile |
| Means “washout”. For example, the leaching of clay, iron and aluminum oxides. | Eluviation |
| Eluviation is a process that occurs in the... | A horizon |
| Means “wash-in.” The process can accumulate leached minerals or clay. | Illuviation |
| Differentiated on the basis of characteristics that reflect the differences in the strengths of the dominant processes or a major contribution of an additional process. | Great groups |
| Differentiated on the basis of the kind and arrangement of horizons that reflect conformity to the central concept of the great group, a gradation towards another soil order, or the presence of a special horizon. | Subgroups |
| A forest soil normally associated with coniferous vegetation on igneous-rock derived parent materials. High acidity in the A horizon results in formation of a bleached Ae horizon and deposition of iron and aluminum in the B horizon. | Podzolic |
| A forest soil found in areas with parent materials derived from sedimentary rocks. Dominant process is eluviation (washout) of clay from the Ae horizon and its deposition in the Bt horizon. | Luvisolic |
| Found throughout Canada wherever temporary or permanent water saturation cause formation of gleyed features in the profile. | Gleysolic |
| Found usually at the surface of the mineral soils. | Organic layers |
| They contain more than 17% organic carbon by weight. | Organic layers |
| Two groups of organic layers are recognized: | O group and the L-F-H group |
| May be present at the surface horizon of mineral soils, or at any depth beneath the surface in buried soils. | Organic horizons |
| Consists of organic litter derived from plants and animals deposited on the surface. | Organic horizons |
| Include L, F, H or Of, Om, Oh horizons. | O Horizon |
| Either water saturated or nearly saturated for much of the year unless artificially drained. | Organic horizons |
| Have developed under imperfectly to well-drained conditions i.e. grassy plains, forests. | L, F, H layers - Folisolic Soils |
| Layers range from least decomposed to most decomposed. | L, F, H (Folisolic Soils) |
| Organic layers that develop primarily from leaves, twigs, woody materials, and with or without a minor components of mosses (litter layer). | L, F, H (Folisolic Soils) |
| Usually not saturated for prolonged periods. | L, F, H layers (Folisolic Soils) |
| Of, Om, Oh are: | O layers |
| Have developed under poorly drained conditions, under conditions of being saturated most of the year; i.e. swamps. | O layers |
| an organic layer developed mainly from mosses, rushes, and woody materials. | O layers |
| Abbreviation for the fibric layer. | Of |
| Abbreviation for the mesic layer. | Om |
| Abbreviation for the humic layer. | Oh |
| The least decomposed of all the organic soil materials. It has large amounts of well-preserved fiber that are readily identifiable as to the botanical origin. | Fibric layer |
| Has 40% or more of rubbed fiber by volume. | Fibric layer |
| The intermediate stage of decomposition with intermediate amounts of fiber, bulk density, and water-holding capacity. The material is partly altered both physically and biochemically. | Mesic layer |
| Layer that fails to meet the requirements of fibric or of humic characteristics. | Mesic layer |
| Is the most highly decomposed of the organic soil materials. It has the least amount of fiber, the highest bulk density, and the lowest saturated water-holding capacity. | Humic layer |
| It is very stable and changes very little physically or chemically with time unless it is drained. | Humic layer |
| Layer has less than 10% rubbed fiber by volume and a pyrophosphate index of three or less. | Humic layer |
| This is an organic layer characterized by an accumulation of organic matter in which the original structures are easily discernible. | L layer |
| This is an organic layer characterized by an accumulation of partly decomposed organic matter. The original structures in part are difficult to recognize. | F layer |
| The layer may be partly comminuted (divided into small parts) by soil fauna, or it may be a partly decomposed mat permeated by fungal hyphae. | F layer |
| This is an organic layer characterized by an accumulation of decomposed organic matter in which the original structures are indiscernible. | H layer |
| Has greater humidification chiefly through the action of organisms. | H layer |
| This layer has a zoogenous _____ form consisting mainly of spherical or cylindrical droppings of microarthropods. | humus (in the H layer) |
| It is frequently intermixed with mineral grains, especially near the junction with a mineral layer. | H layer |
| Defined as the stable, dark-colored organic material that accumulates as a byproduct of decomposition of plant or animal residues added to the soil. | Humus |
| Contains less than 17% organic matter by weight. | The mineral layers |
| Is the zone of removal of materials in solution or suspension, or the zone of maximum accumulation of organic matter or both (organic matter darkens the soil). | A horizon |
| Is the zone of maximum leaching or eluviation of clay, iron and aluminum oxides. | A horizon |
| Slightly coarser in texture having lost some finer materials to the lower horizons. | A horizon |
| It is the surface layer. | A horizon |
| Is characterized by the enrichment of organic matter, leached minerals or clay accumulated by illuviation. | B Horizon |
| May also be characterized by the development of some kind of change in structure, color, or chemical condition, often due to oxidation (iron staining). | B Horizon |
| The layer that determines the classification. | B Horizon |
| It is the subsurface layer. | B Horizon |
| Is relatively un-weathered material from which the soil has developed. | C Horizon |
| Least affected by processes that form the horizons above it as it is further below the surface. | C Horizon |
| In time, upper layers of the C horizon may become part of the solum. | C Horizon |
| It is the parent material. | C Horizon |
| For mineral soils in general, the _____ _____ extends from the mineral surface to either 25 cm below the depths where the parent material begins (C horizon) or to a depth of 2 m, whichever is less. | Control Section |
| T/F: When possible, the soil should be described and classified to a depth of at least 1 m. | True |
| Soil is a product of _________ and ________ _______ acting on rocks, and decomposition acting on _______ and _____ ______over time. | chemical and physical weathering vegetation and animal matter |
| Which parent material can only be weathered primarily through physical weathering, and results in course and sandy soils. Where is it found? | Igneous bed rock, Northern Ontario |
| Due to its mineral composition, it is softer than granite and Weathers easily and to a finer particle size such as silt and clays. | Sedimentary rock, Southern Ontario |
| How many interrelated natural factors are active in soil formation? | Five |
| What are the five natural factors active in soil formation? | Climate. Biota (living matter). Topography Time. Parent Materials |
| Factors include temperature, precipitation and wind. | Climate |
| Affects the rate of chemical and physical weathering, and the biological processes responsible for soil profile development. | Climate |
| Organic matter, profile differentiation, nutrient cycling and structural stability are enhanced by? | Biota (living matter) - activities of soil organisms |
| Gives soil a darker color, greater moisture and cation holding capacity. | Organic matter (produced by biota) |
| Configuration of the soil surface, i.e. slope, elevation and landforms. | Topography |
| Can increase or decrease the work of climate in the formation of soil, i.e. flat land may hold water longer than rolling terrain. | Topography |
| Slope and orientation of the land to the sun influences soil temperature, moisture and thus soil formation. | Topography |
| A factor concerns glaciation which occurred 10,000 to 12,000 years ago in this region. As a result soils are relatively “young” and not as thick as in areas in which glaciation did not occur, for example Kansas. | Time |
| A factor concerns the slow development soil; it may take tens of thousands of years for a highly weathered and develop soil to form. | Time |
| The system has five categorical levels, each one carrying the differentiating criteria of the preceding levels. | Soil Keys |
| Taxa based on soil properties that reflect the nature of the soil environment and major soil forming processes. | Order |
| Has no B horizon. Found throughout Canada wherever pedogenic conditions prevent the formation of B horizons (unstable slopes, sand dunes, floodplains, etc.). | Regosolic |
Created by:
ctherria
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