Chapter 11-Soil: The Foundation for Land Ecosystems

Rocks break down into smaller and smaller fragments; could be physical or chemical breakdown of rocks

The mineral material of soil that has its origin in the geological history of an area; could be rock or sediment deposited by wind, water, or ice

Fragments of rocks (classified as sand, silt, and clay)

The relative proportions of each type of particle in a given soil (i.e. loam)

A proportion that is commonly found in soil (consists of 40% sand, 40% silt, and 20% clay)

Made up of particles from 2.0 to 0.063 mm in size

Particles that range from 0.063 mm down to 0.004 mm

Anything finer than 0.004 mm

The ease with which a soil can be cultivated; affected by soil texture

The horizontal layers in soil profiles

A vertical slice through the different horizons

Topmost layer that consists of dead organic matter (detritus) deposited by plants (leaves, stems, fruits, and seeds); high in organic content (humus); primary source of energy for the soil community

Topsoil (mixed humus and leached mineral soil); it is a mixture of mineral soil from below and humus from above; usually dark because of humus

The “E” stands for eluviation, which is the process of leaching; zone of leaching (less humus, minerals resistant to leaching)

The dissolving away of many minerals due to the downward movement of water; when nutrients are literally washes from the soil as water moves through it

Subsoil (accumulation of leached minerals like iron and aluminum oxides); characterized by the deposition of minerals that have leached from the A and E horizons; often high in iron, aluminum, calcium, and other minerals; also high in clay and is reddish or yellow in color

Soil order, suborders, groups, subgroups, families, and soil class

The soils ability to support plant growth (farmers use the term tilth of the soil)

Phosphate, potassium, calcium, and other ions

The soil’s capacity to bind and hold nutrient ions until they are absorbed by roots

Material that contains one or more of the necessary nutrients

Includes plant or animal waste or both (i.e. manure and compost)

Chemical formulations of required nutrients, without any organic matter included; more prone of leaching

Water evaporates from stomata (pores) on the underside of the leaves