printer version (loads faster)


Glossary of terms for managing wholes

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

Savory Center - The Allan Savory Center for Holistic Management.

SCS - U.S. Soil Conservation Service.

selective grazing - low-density grazing

semi-brittle - In the mid-range between continually moist brittle environments and seasonally dry nonbrittle landscapes. Typically semi-brittle areas are grasslands or tundra. Brittleness diagram.

Related terms: brittleness, brittleness-productivity scale

Related pages: "Brittleness"

Thomas J. Elpel
patchy overgrazing & overresting
Set stocking often results in a mosaic of overgrazed and overrested plants. Livestock ignore stale growth while grazing resprouting plants again and again.

set stocking - Letting animals continuously graze an area for long periods, with no rest periods for plants to recover. The typical result is a mosaic of overgrazed and overrested plants.

Related terms: managed grazing

severe grazing - Grazing that removes a high proportion of the plant's leaves. During the growing season this causes a temporary setback in the plant's growth. In brittle environments, periodic severe grazing usually benefits grasses by removing growth that would otherwise accumulate and shade the growth points at their bases.

Related terms: rest, overrest

Related pages: "Grazing and overgrazing"

sheet erosion - Erosion caused by water running across bare soil.

Related terms: pedestal erosion, litter dam

sigmoid curve

sigmoid curve - An S-shaped curve plotting rate of increase or decrease over time. Rate of change increases over time, then levels off and decreases. This is typical of many self-regulating phenomena in nature. The standard "bell curve" (normal curve) is made of two sigmoid curves back-to-back. Compare exponential curve.

soil crust - (Also capping.) A hard crust that forms on exposed soil in brittle and semi-brittle environments. It starts when rain pounds bare soil, destroying its crumb structure. The soil then hardens as it dries out. Soil crusts cause water to run off soil rather than soaking in, exclude air, and prevent seeds from germinating successfully.

Physical soil crust (immature capping) has nothing growing on it. Biological soil crust (mature capping) has algae, lichen, or moss growing on it; succession has stalled and cannot advance to grassland or forest.

Related terms: physical soil crust, biological soil crust, rest, capping

Related pages: "Soil crust basics", "Environmental restoration", "Desertification"

solar capture - The amount of sunlight energy captured by plants and turned into food that fuels the ecosystem processes. Solar capture can be increased by

Related terms: biological productivity, solar energy

solar dollars - Money generated from human creativity and labor when combined with constant sources of energy such as geothermal heat, wind, tides, falling water, and most importantly the sun. Such energy as a source of wealth is noncyclical (we can't keep reusing the same sunbeams), but is apparently inexhaustible until our sun dies. Wealth derived from this source tends not to damage our life support system or endanger humanity as far as we know.

This is the only form of wealth that can actually feed people. However, it requires the conversion of solar energy through plants that depend on water and biologically active soils, which are natural resources that can be exhausted if used consumptively rather than sustainably. See mineral dollars, paper dollars.

Not until there is an annual net improvement of biodiversity on a whole property (the whole under management) should income from training, hunting, hiking or the like be considered to be solar dollars. While biodiversity is being lost they remain paper dollars. (Indeed they are not to be spat on, but they should not distract us from an unsustainable situation.) If we wish to maintain clarity in this, they could perhaps be defined as 'paper dollars generated as a by-product of solar harvesting'.

-- Chris Henggeler

solar energy - Energy from the sun. Plants combine solar energy with hydrogen from water and carbon from the air to form starches and sugars (for energy storage) as well as cellulose and lignin (the structural components of wood and straw). This plant matter feeds animal life, directly and indirectly, and builds soil organic matter. Even the energy in fossil fuels came originally from the sun, for they formed from vast deposits of plant matter. Coal is essentially frozen sunlight.

The sun also provides the energy that powers winds and weather, evaporates water from oceans and lakes, and carries rain across Earth's surface. The energy of falling water thus comes from the sun.

Related terms: energy flow

Related pages: "Energy flow"

stock day - Animal day.

Jim Howell
dense cattle herd
Stock density is 450 head/acre (180/ha), but stocking rate is much less since they get moved 5 times per day.

stock density - Number of animals run on a given paddock at a particular period of time. This could be from a few minutes to several days (or months, under conventional management). Usually expressed as the number of animals (of any size or age) run on one acre or hectare. Compare stocking rate.

Related terms: animal impact, herd effect

stocking rate - The number of animals run on a unit of land. Usually expressed as the number of acres or hectares required to run one full-grown animal throughout the year or part of a year.

Stocking rate is not stock density. A herd of a million wildebeest has high stock density (they group closely together for protection from predators), but the stocking rate is much lower, since they move continually and graze vast areas.

strip grazing - The grazing of animals in narrow strips of land generally behind a frequently moved electric fence. In some cases, different areas are strip-grazed within a paddock. Combined with a large herd and very frequent moves, strip grazing can produce herd effect over virtually all the soil surface.

Related pages: slide of strip grazing

succession - The process by which life colonizes an area, for instance by turning the bare rock of a volcano or landslide into a jungle or forest. As complexity increases, we say succession is advancing; as it decreases, we say succession declines. An important part of community dynamics.

Related terms: succession level

Related pages: "Community dynamics"

succession level - How far succession has progressed. At low succession levels, biodiversity is low, with many individuals of just a few species. Populations tend to fluctuate widely, and pest outbreaks are often common. At high succession levels, biodiversity is high, with many species present. Populations are fairly stable, and biological productivity tends to be high and stable.

Related terms: community dynamics

Related pages: "Community dynamics"

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

Suggestions for terms or definitions? Email us (opens web form).

Updated 1 November 2005