Chapter 18: Soils

Leaching

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How does soil play a role in the Hydrologic Cycle

-water enters the soil though infiltration from the surface -water exits the soil though ground water recharge, evaporation or utilization -vegetation transpires water, which combines with evaporation to form evapotranspiration

There are ______ nutrients that are critical to plant development

13!!!!

Gleysolic

A CSSC soil order defined on the basis of color and mottling that results from chronic reducing conditions inherent in poorly drained mineral soils under wet conditions. High water table and long periods of water saturation.

Podzolic

A CSSC soil order of the coniferous forests and sometimes Heath; leaching of overlying horizons occur in moist cool to cold climates

Cryosolic

A CSSC soil order that dominates then northern third of Canada with permafrost closer to the surface and composed of mineral and organic soil deposits. Generally found north of the tree line or in fine textured soils in subarctic forest or in some organic soils in boreal forest.

Vertisolic

A CSSC soil order that occurs in heavy textured material that is high in clay content (>60% clay) especially smectite a shrinking and sweeping clay. These soils have little development of horizons and are marked by slickensides and usually occur under the layer of highest mixing.

Solonetzic

A CSSC soil order where solonetz denotes saline or alkaline soils. Well to imperfectly drained mineral soils developed under grasses in semiarid to subhumid climates. Limited areas of central and north central Alberta

Luvisolic

A CSSC soil order with eluviation illuviation processes that produce a light colored Ae horizon and a diagnostic Bt horizon. Soils of mixed deciduous coniferous forests. Major occurrence is the St. Lawrence lowland. Luvisols do not have a Solonetzic B horizon.

Organic

A CSSC soil order with peat bog and much soils, largely composed of organic material. Most water saturated for prolonged periods. Are widespread in association with poorly to very poorly drained depressions although Folisols are found under upland forest environments. Exceed 17% organic carbon and 30% organic matter overall

Brunosolic

A CSSC soil order with sufficiently developed horizons to distinguish it from the Regosolic order. Soils under forest cover with brownish horizons although various colors are possible. Also can be with mixed forest, shrubs and grass.

Regosolic

A CSSC soil order with weakly developed limited soils the result of any number of factors young minerals fresh alluvial deposits material instability mass wasted slopes or dry cold climatic conditions

Chernozemic

A CSSC soil order with well to imperfectly drained soils of the steppe grassland forest transition in southern Alberta; Saskatchewan Manitoba okanagan valley BC and Palouse prairie BC. Accumulation of organic matter in surface horizon.

Podsolization

A pedogenic process in cool moist climates; forms a highly leached soil with strong surface acidity because of humus from acid rich trees.

Laterization

A pedogenic process operating in well-drained soils that occurs in warm and humid regions; typical of oxisols. Plentiful precipitation leaches soluble minerals and soil constituents. Resulting soils usually are reddish or yellowish.

Salinization

A pedogenic process that results from high potential evapotranspiration rates in deserts and semi arid regions. Soil water is drawn to surface horizons and dissolved salts are deposited as the water evaporates

Gleysation

A process of humus and clay accumulation in cold, wet climates with poor drainage.

Canadian system of soil classification (CSSC)

A soil classification system based on observable soil properties actually seen in the field; published in 1987 by the Canadian Soil Survey Committee. Adapted to Canada's environment the CSSC consists of 10 soil orders.

Diagnostic subsurface horizon

A soil horizon that originates below the epipedon at varying depths may be part of the A and B horizons important in soil description as part of the soil taxonomy

Pedon

A soil profile extending from the surface to the lowest extent of plant roots or to the depth where regolith or bedrock is encountered; imagined as a hexagonal column the basic soil sampling unit

Loam

A soil that is a mixture of sand, silt and clay in almost equal proportions with no one texture dominant an ideal agricultural texture.

Pedogenic regimes

A specific soil forming process keyed to a specific climatic regime laterization, calcification, salinization and podsolization among other not the basis for soil classification in the soil taxonomy

Solum

A true soil profile in the pedon ideally a combination of O A E and B horizons

Soil profile

A vertical section of soil extending from the surface to the deepest extent of plant roots or to regolith or bedrock.

Saturation

All of the empty space between soil particles is filled with water- this water will slowly drain into the ground water.

Soils derived from a granite parent will often be rich in ____, since the hydrolysis is a major erosional method for granite.

CLAY since the hydrolysis is a major erosional method for granite.

What is the most important mineral?

CLAY because it holds onto moisture and nutrients BOTH of which are essential for life.

______ & ________ environments tend to have highly acidic soils, while ______ regions tend to have alkaline soils

COLD & HUMID while DRY

Transformation

Changing the physical and chemical structure of the soil components in the soil

Dark soils

Dark soils are organic rich, since most organic matter starts at the surface, top soils tend to be dark

Structure

Defines the way particles are grouped together *see power point*

Humus

Fully decomposed organic matter that helps bind soil particles and allows air and water to flow through the soil. *appears as a darker soil* SOIL FORMATION: Biological Activity A mixture of organic debris in the soil worked by consumers and decomposers in the humification process; characteristically formed from plant and animal litter deposited at the surface.

Green or blueish soils

Green or blueish soils are indicative of very moist or saturated, low oxygen conditions

Bacteria

Helps break down organic matter and contribute to the nitrogen cycle SOIL FORMATION: Biological activity

Decalcification

In moist climates, heavy rains dissolve calcium carbonate in the soul and removes it to the ground water -since calcium is a base (and a plant nutrient), decalcified soils tend to be acidic

Mineral Matter

Inorganic component of soil make up of fine sediment particles (sand/silt/clay)

Soil science

Interdisciplinary science of soils. Pedology concerns the origin classification distribution and description of soil. Edaphology focuses on soil as a medium for sustaining higher plants.

Translocation

Movement of the material up and down through the soil but not lost.

Field capacity

Once the excess soil water is removed and only water that has bonded to soil particles are left- roots can access this water.

Subgroup

One of the five levels of hierarchical generalization of several levels of soil detail and grouping a subdivision of great groups in the CSSC

Great group

One of the five levels of hierarchical generalization of several levels of soil detail and grouping- a subdivision of each of the ten soil orders in the CSSC

Family

One of the five levels of hierarchical generalization of several levels of soil detail and groupings a subdivision of soil subgroup in the CSSC.

Humification

Organic matter breaks down into humus

Soil atmosphere

Oxygen and other gases that occupy the open space between mineral and organic matter

Young soils tend to contain more ________minerals than __________ BUT through time the _________minerals are transformed into _______minerals

PRIMARY than SECONDARY but through time the PRIMARY, SECONDARY

The majority of the soil matric is composed of mineral matter, which originates from the erosion of a ______________.

Parent rock SOIL FORMATION: Parent material

While parent material can lend its colour to the soil, _______processes will change this

Pedogenic

What does precipitation have to do with soil?

Precipitation controls the downward movement of nutrients and provides water to the soil for numerous chemical reactions. -*chemical reactions are slower in colder weather* SOIL FORMATION: climate

Red or Yellow soils

Red or yellow soils are indicative of good drainage and aeration

Removal

Removal of soil material through erosion or leaching

Soils derived from sandstone will often be rich in ______

SAND because sand drains quickly and holds few nutrients

What are the 3 soil texture size categories

Sand Silt Clay

Pedogenic process

Soil forming processes that indicate a gain, loss or transformation of materials within a soil body.

Overland flow can _____

Strip the upper surface of the soil away

TRUE/FALSE: Pedogenic processes doesn't take place in every area and in every soil

TRUE

What does temperature have to do with organic matter?

Temperature controls the rate of decay of organic matter. -warm regions tend to have low organic matter. -cold regions have high organic matter *less biomass over all, because it doesn't decay quickly it piles up* SOIL FORMATION: climate

What can be use to determine the texture of soil?

Texture Triangle

Cation-exchange capacity (CEC)

The ability of soil collides to exchange cations between there surfaces and the soil solution; a measured potential that indicates soil fertility

Soil fertility

The ability of soil to support plant productivity when it contains organic substances and clay minerals that absorb water and certain elemental ions needed by plants through adsorption.

Enrichment

The addition of new mineral or organic matter to the soil -can be delivered to the soil by a flooding river or by overland flow. SOIL FORMATION: Pedogenic process

Epipedon

The diagnostic soil horizon that forms at the surface; not to be confused with the A horizon may include all or part of the illuviated B horizon

Illuviation

The downward movement and deposition of finer particles and minerals from the upper horizon of the soil a depositional process. Deposition usually is in the B horizon, where accumulations of clays, aluminum, carbonates, iron and some humus occur.

Desertification

The expansion of deserts worldwide, related principally to poor agricultural practices (overgrazing and inappropriate agricultural practices) improper soil-moisture management, erosion and salinization, deforestation and the ongoing climatic change an unwanted semipermanent invasion into neighboring biomes

Calcification

The illuviated (deposited) accumulation of calcium carbonate or magnesium carbonate in the B and C soil horizons.

Order

The principal classification of the five levels of hierarchical generalization of several levels of soil detail and grouping- consisting of the ten soil orders in the CSSC

Eluviation

The removal of finer particles and minerals from the upper horizons of soil; an erosion process within a soil body. the downward movement of fine materials in the lower part of the soil

SOIL FORMATION: Time

The soil forming process takes anywhere from decades, centuries and millennia's to form. -There is no fixed timeline - all depends on the interaction between the soil forming processes and the rates of reactions.

Wilting point

The thin film of water that is tightly bonded to particles - plants cannot extract this water.

Soil porosity

The total volume of space within a soil that is filled with air, gases or water (as opposed to soil particles or organic matter

What is soil

The upper layer of the land surface that plants use and depend on for nutrients, water, and physical support.

Soil horizons

The various layers exposed in a pedon. Roughly parallel to the surface and identified as O A E B C and R (bedrock)

What do Earthworms and insects do?

They mix and rework the soil through digestion SOIL FORMATION: Biological activity

What do rabbits, moles and other animals do?

They mix the soil, however they can also cause extensive destruction. SOIL FORMATION: Biological activity

White-ish soils

White-ish soil layers are indicative of salt forming properties (evaporation) *white soil can also indicate leaching*

Primary Minerals

are derived directly from the parent material Examples: a Granite parent will yield feldspar, quartz and mica minerals

Secondary Minerals

are derived from chemical weathering of the primary minerals

colloids

are extremely small mineral and organic components *plant food* -clay based soils are high in colloids and bond well with nutrients which result in high plant nutrients which is good for agriculture

Heavy rainfall can ________

move nutrients down through the soils into the ground water

Organic Mater

soil made of living or dead organisms *very important- it produces nutrient rich mixture of humus*

Soil activity

strongly related to nutrient availability and is therefore critical to plants and agriculture.