SOIL TYPES AND SOIL CONCERNS

SOIL TAXONOMY The formation of residual soil is a complex

interaction of the CLORPT factors.

These in turn lead to the formation of a variety of soils, distinctly different in physical and chemical characteristics.

This great variety of soils has led to a complex classification system, called soil taxonomy.

This system classifies soil based on physical characteristics:

Colour Texture Degree of nutrients depletion Climatic conditions Organic matter content Soil chemistry, etc.

AN ALTERNATE CLASSIFICATION SYSTEM An earlier model used for classification had

only 4 categories of soil: Pedalfer Pedocal Tundra soils Laterite soils

This system is based on climate, the predominant soil-forming factor

TUNDRA SOILS

Forms in an Arctic environment where precipitation is minimal and average annual temperature are low.

The dominated weathering is achieved by physical means as precipitation is limited

These soils are generally very thin and rocky. Organic matter is minimal.

PEDOCAL SOILS This type of soil contains an accumulation of

calcium carbonate (CaCO3). These soils are found where temperatures

are relatively high and rainfall is low, e.g. arid environments. This tends to prevent leaching of the minerals

Vegetation is predominantly grass or brush

The calcium carbonate build up in the soil gives it a light colour in the B-horizon

Organic nutrients can accumulate , but the lack of water limits plant productivity.

Soils are generally thin.

PEDALFER SOILS Are soils that have iron

oxides, clays or both accumulated in the B-horizon.

These soils are commonly found in temperate, humid environments beneath forest vegetation

Precipitation is more frequent in these areas.

Chemical weathering leads to thicker soils, up to several meters.

Leaching occurs in both the A- and B-horizons which removes calcium carbonates , meaning that the soil is rich in aluminum, iron and some silicon.

The soil is rich in clays and is a reddish colour.

The A-horizon tends to be humus-rich from the forest litter.

LATERITE SOILS These soils develop in

tropical environments such as rainforest.

The annual precipitation and temperatures are extremely high.

Intense leaching which leads to the soil having a very red colour

Microorganisms decompose the vegetation quickly, along with the high level of leaching leads to this being an infertile soil.

RELATIONSHIP BETWEEN CLIMATIC CONDITIONS AND SOIL TYPES

Tundra Pedalfer

Pedocal

Laterite

SOIL CONCERNS Currently soil resources are being taxed to

the extent that more soil is being eroded into the oceans than nature can replenish.

Soils has become subjected to soil depletion The loss of soil from erosion

and soil degradation The loss of fertility, soil pollution

SOIL LOST TO THE OCEANS ANNUALLY1. Cause is poor

agricultural practices.

2. Deforestation, logging, mining and poor farming practices.

3. 4. 5. is caused by desertification, a result of over grazing by animals

SOIL DEPLETION Typically this results from the loss of

vegetative cover. Once the plant roots are removed the soil

becomes vulnerable to the elements.

Soil Orders of Canada

SOIL LANDSCAPE ILLUSTRATIONS

The following is a link which show photos of the different soils found in Canada

http://sis2.agr.gc.ca/cansis/images/intro.html