Unit 3 : Soil Chemistry Flashcards
discipline embracing all chemical and mineralogical compounds and reactions occurring in soils and soil-forming processes.
Soil chemistry
scientific discipline concerned with all aspects of soils, including their physical and chemical properties, the role of organisms in soil production and in relation to soil character, the description and mapping of soil units, and the origin and formation of soils.
Pedology
Mostly organic matter such as decomposing leaves. The O horizon is thin in some soils, thick in others, and not present at all in others.
Humus or organic
Mostly minerals from parent material with organic matter incorporated. A good material for plants and other organisms to live.
Topsoil
Leached of clay, minerals, and organic matter, leaving a concentration of sand and silt particles of quartz or other resistant materials – missing in some soils but often found in older soils and forest soils.
Eluviated
Rich in minerals that leached (moved down) from the A or E horizons and accumulated here.
Subsoil
The deposit at Earth’s surface from which the soil developed.
Parent material
A mass of rock such as granite, basalt, quartzite, limestone or sandstone that forms the parent material for some soils – if the bedrock is close enough to the surface to weather. This is not soil and is located under the C horizon.
Bedrock
describes the breaking down or dissolving of rocks and minerals on the surface of the Earth.
Weathering
light, warm, dry and tend to be acidic and low in nutrients. These soils have quick water drainage and are easy to work with. They are quicker to warm up in spring than clay soils but tend to dry out in summer and suffer from low nutrients that are washed away by rain.
Sandy soil
a heavy soil type that benefits from high nutrients. They remain wet and cold in winter and dry out in summer.
Clay Soil
a light and moisture retentive soil type with a high fertility rating.
Silt Soil
high in organic matter and retains a large amount of moisture. This type of soil is very rarely found in a garden and often imported into a garden to provide an optimum soil base for planting.
Peat Soil
can be either light or heavy but always highly alkaline due to the calcium carbonate or lime within its structure.
Chalk Soil
a mixture of sand, silt and clay that are combined to avoid the negative effects of each type. These soils are fertile, easy to work with and provide good drainage. Depending on their predominant composition they can be either sandy or clay loam.
Loam Soil
