A number of new words and phrases are associated with Holistic Management, particularly with those aspects related to the use of grazing animals in restoring landscapes to health. This glossary defines many of the new terms, along with a few others that involve new ways of looking at the land in order to judge its condition.
Animal-Days per Acre (ADA) or Hectare (ADH). A term used to express simply the volume of forage taken from an area in a specified time. It can relate to one grazing in a paddock or several, in that multiple grazings can be added to give a total ADA or ADH figure. If you’re running a breeding herd, or mixed-species herd, you will need to convert animal numbers to standard animal units (SAU; see the definition below) to better assess the volume of forage required to feed the herd or, following a grazing, the volume of forage taken. The ADA or ADH figure is arrived at by a simple calculation, as follows:
Note: If you’re running a single class of animals, such as summer yearlings, you can forgo the conversion to standard animal units.
Animal Impact. The sum total of the direct physical influences animals have on the land—trampling, digging, dunging, urinating, salivating, rubbing, and so on. Most commonly achieved with herding animals in high concentration. The larger the herd, the greater the effect.
Biodiversity. The diversity of plant and animal species—and their genetic material and the age structure of their populations—within a given community.
Biomass. The mass, or volume, of life—plants, animals, and microorganisms.
Brittleness Scale. All terrestrial environments, regardless of total rainfall, fall somewhere along a continuum from nonbrittle to very brittle. For simplicity, we refer to this continuum as a 10-point scale—1 being nonbrittle and 10 being very brittle. Completely nonbrittle environments are characterized by (1) reliable precipitation, regardless of volume; (2) good distribution of humidity throughout the year as a whole; (3) a high rate of biological decay in dead plant material, which is most rapid close to the soil surface (thus, dead trees rot at their bases and topple over relatively quickly); (4) speedy development of new communities on any bare surface; and (5) the development of complex and stable communities even where they are not physically disturbed for many years. In such environments it is virtually impossible to produce or maintain millions of acres where the ground between plants is bare, other than on croplands that are continually exposed by machinery.
Very brittle environments, on the other hand, are characterized by (1) unreliable precipitation, regardless of volume; (2) poor distribution of humidity through the year as a whole; (3) the chemical (oxidizing) and physical (weathering) breakdown of dead plant material, generally slowly and from the upper parts of plants downward (thus, dead trees remain standing for many years); (4) very slow development of communities from bare soil surfaces unless physically disturbed; and (5) algae and lichen covering soil surfaces for centuries unless adequately disturbed. In such environments it is very easy to produce millions of acres where the ground between plants is bare or algae- or lichen-capped, merely by resting the land excessively, burning it frequently, or overgrazing many grass plants. Such areas tend to maintain biodiversity and stability only when they receive adequate disturbance periodically.
Capping, Immature. Describes a soil surface that has sealed with the last rainfall and on which there is no visible sign yet of successional movement. Capping is initiated by raindrop action on an exposed soil. The energy from the raindrop breaks crumb structure and frees fine soil particles, which, in turn, seal the surface so the soil cannot respire easily. Some people use the term “crusting” instead of “capping”.
Capping, Mature. Describes an exposed soil surface on which succession has proceeded to the level of an algae-, lichen-, or moss-dominated community and has stalled at that level. If not adequately disturbed, such communities can remain in that state for centuries, provided the soil is level enough to inhibit erosion by water.
Cell. See Grazing Cell.
Closed Plan. The grazing plan created for the slow-or nongrowing months of the year, including the time reserve planned for drought. In this plan you ration out the forage over the months ahead to a theoretical end point, which should be a month or more after your most pessimistic estimate of when new growth could occur.
Community Dynamics. The development of communities of living organisms. This process is ongoing due to the constant interplay of species, changing composition, and changing microenvironment. However, the greater the biodiversity within a community, the more complex, and thus the more stable, it tends to be.
Crumb Structure. A soil that has good crumb structure is made up largely of aggregates or crumbs of soil particles held together when wet or dry with glue provided by decomposing organic matter. The space around each crumb provides room for water and air, and that, in turn, promotes plant growth.
Desertification. A process characterized by a loss of biodiversity, plant mass, and soil cover. Symptoms include increased incidence of flood and drought, declining levels of soil organic matter, increased soil surface exposure, and erosion.
Drought (or Time) Reserve. The number of days or months of grazing you plan to reserve in case of drought. This time period would extend from the end of an average nongrowing season to a month or so past the date you expect to receive new growth. Base your estimate on the longest possible weather records available.
Effective Recovery Period. A period in which a severely grazed plant has actually grown new leaves and stems and restored energy reserves in, depending on the species, reestablished roots, stem bases, or crowns. This can occur only under active growing conditions.
Forbs. Tap-rooted herbaceous plants, often referred to as weeds.
Graze- or Trample-to-Recovery Ratio. The number of days animals are on a piece of land, divided into the number of days they will be off it before returning. Generally, the shorter the grazing periods and the longer the recovery periods—the higher the ratio—the better the performance of both land and animals, although there is more to it than that. Bear these general points in mind in deciding: A very high ratio, especially during the growing season, when all recovery time is effective in terms of growth, will tend to result in improved soil condition due to considerably more root growth and organic matter buildup. However, when soils are leached, rainfall is high, or excessive lignin develops in plants, individual livestock performance could drop. This drop is somewhat offset by the very short grazing periods necessary to achieve the high ratio. Generally, a high ratio will allow for a higher stocking rate and, thus, higher financial return per acre or hectare. A doubling of stocking rate generally leads to higher profitability unless individual performance drops 40 percent or more, which normally does not happen.
Grazing Cell. An area of subdivided land that is planned as one unit to regulate the time that plants and soils are exposed and reexposed to grazing and trampling. A cell is always planned on a single Grazing Plan and Control Chart and often, especially in the beginning, includes only one herd. A cell can incorporate any number of subdivisions (paddocks) with varying recovery periods—all of which must be visible on one chart. Several smaller cells can be combined to form one large cell for planning purposes.
Grazing, Frequent. Grazing that takes place with short intervals between the actual grazings on the plant. With most plants, frequent grazing is not harmful as long as the defoliation is light.
Grazing Selections. The number of times you plan to have animals move through a paddock in the nongrowing season (when there is no significant regrowth between grazings).
Grazing, Severe. Grazing that removes a high proportion of the plant’s leaf in either the growing or nongrowing season. In the growing season this causes a temporary setback in the plant’s growth. In the more brittle environments, severe grazing at some time during the year is generally beneficial to most bunched perennial grass plants, and especially those with growth points, or buds, at their bases. Most herding animals—including cattle, sheep, and goats—are severe grazers.
Herd Effect. The impact on soils and vegetation produced by a large herd of animals in high concentration or in an excited state. Herd effect is not to be confused with stock density, as they are different, although often linked. You can have high herd effect with very low stock density (e.g., the bison of old that ran in very large herds at very low stock density, as the whole of North America was the paddock). You can have high stock density with no herd effect, such as when two or three animals are placed in a one-acre paddock. At ultra-high densities, the behavior of livestock will often change adequately to provide herd effect (see Ultra-High-Density Grazing).
Note: Herd effect is the result of a change in animal behavior and usually has to be brought about by some actual management action—using an attractant, or crowding animals to ultra-high density. Herd effect generally provides the (animal) impact needed to break up a capped soil surface; to compact soil enough to get good seed-to-soil contact; and to trample dead plant material to the ground, where it provides soil cover and slows water movement and erosion. Applied too long or too frequently, it tends to pulverize most soils and cause excessive compaction.
Low-Density Grazing. Sometimes referred to as patch or selective grazing, this refers to the grazing of certain areas while others nearby are left ungrazed and on which plants become old, stale, and moribund. Normally, it is caused by stock grazing at too low a density, too small a herd, or a combination of those, with too short a time in a paddock. Once it has started, even by only one grazing, it tends to get progressively worse, as the nutritional contrast between regrowth on grazed areas and old material on ungrazed areas increases with time. The common remedy calls for holding stock longer to force them to graze everything equally (nonselectively), but that is a bad mistake, which results in stock stress and poor performance. Low-density grazing is corrected by increasing density and generally shortening grazing time to avoid stock stress.
Mineral Cycle. The cycle of mineral nutrients from soil to above-ground plants and animals and back to the soil again. A healthy and productive environment will promote the movement of minerals from deep soil layers to above-ground plants with a minimum of mineral loss from soil erosion or mineral leaching.
Open-Ended Plan. The grazing plan created for the growing months of the year. In this plan, you are trying to grow as much forage as possible, and you do not have to plan to a specific date. The plan remains open because you don’t know when growth will end or exactly how much forage will grow before then.
Overgrazing. This occurs when a plant that has been bitten severely in the growing season gets bitten severely again while using energy it has taken from its crown, stem bases, or roots to reestablish leaf. Generally, this results in the eventual death of the plant. In intermediate stages it results in reduced production from the plant. Overgrazing commonly occurs at three different times: when the plant is exposed to the animals for too many days and they are around to regraze it as it tries to regrow; when animals move away but return too soon and graze the plant again while it is still using stored energy to reform leaf; and immediately following dormancy when the plant is growing new leaf from stored energy.
Overrested Plant. A bunched perennial grass plant that has been rested so long that accumulating dead material prevents light from reaching growth points at the plant’s base, hampering new growth and eventually killing the plant. Overrest occurs mainly in brittle environments where, in the absence of large herbivores, most old material breaks down gradually through oxidation and weathering rather than rapidly through biological decay.
Paddock. A division of land within a grazing cell, either fenced off or demarcated for herding. Several or many paddocks together make up a cell, provided they are planned as one unit on a grazing chart. The American term pasture, when used to define an area of land, is synonymous with paddock.
Pasture. A planted grass or other forage crop. (In the United States, pasture can refer to grass on the range, a planted grass sward, or a division of land. To avoid confusion, we use the word paddock to refer to a division of land, pasture to refer to a planted grass sward or forage crop, and rangeland to refer to natural forage.)
Planned Grazing. The planning of livestock grazing that simultaneously covers many variables: animal behavior, breeding, performance, wildlife needs, other land uses, weather, plant growth rates, poisonous plants, dormant periods, droughts, and so on. The purpose of such planning is to use livestock to bring about the future landscape described in a holisticgoal. The phrase is a common abbreviation for Holistic Management grazing planning.
Rest, Partial. This takes place when grazing animals are on the land but without a full complement of pack-hunting predators to maintain bunching-herd behavior most of the time. As a result, animals barely disturb soil surfaces and trample little material onto the ground. Partial rest commonly results in damaged algae or lichen communities but no successional advance to more complex, stable communities.
Rest-Tolerant Grasses. Perennial grasses that are able to thrive under rest in very brittle environments. Commonly, such plants have some growth points, or buds, along their stems well above ground, where unfiltered sunlight can reach them; or they are short in stature or sparse-leafed, enabling unfiltered light to reach their ground-level growth points. In the past, such grasses tended to be found in steep gorges and other sites that large grazing animals did not frequent. Today, however, because overgrazing is believed to be linked to animal numbers and numbers have been reduced, grasses that don’t require grazing to thrive have an advantage. Rest-tolerant grasses can be found all over.
Rest, Total. Prolonged nondisturbance to soils and plant or animal communities. A lack of physical disturbance or fire.
Rotational Grazing. Grazing in which animals are rotated through a series of paddocks, generally on some flexible basis but without any planning that addresses the many variables inherent in the situation.
Standard Animal Unit (SAU). A single class of animal against which you rate all the other classes or species of animals in a herd to better assess the herd’s forage requirements. A mature cow is often used as the standard, equaling 1 animal unit. A cow and her calf would thus be 1.5 units, a bull 2 units; 5 sheep would equal 1 animal unit, and so on: SAU × days = animal-days (the amount of forage the standard animal would eat in a day).
Stock Density. The number of animals run on a subunit (paddock) of land at a given time; this could be from a few minutes to several days. Usually expressed as the number of animals (of any size or age) run on one acre or hectare.
Stocking Rate. The number of animals run on a unit of land, usually expressed in the number of acres or hectares required to run one full-grown animal throughout the year or part thereof.
Strip Grazing. The grazing of animals on narrow strips of land, generally behind a frequently moved electric fence. In some cases, different areas are strip-grazed within a paddock.
Succession. An important aspect of community dynamics, succession describes the stages through which biological communities develop. As simple communities become ever more diverse and complex, succession is said to be advancing. When complex communities are reduced to greater simplicity and less diversity, succession is set back. If the factors that set it back are removed, succession will advance once again.
Transect. A selected piece of land on which data are gathered or photos are taken year after year to monitor any changes arising from management practices.
Ultra-High-Density Grazing. Grazing livestock so that they are at extremely high densities throughout the day. Generally, those densities are achieved by herding the stock, by enclosing them in a small area with movable fencing, or both. The aim is to induce herd effect, and thus high animal impact, over most of the land, one piece at a time.
Water Cycle. The movement of water from the atmosphere to the soil (or the oceans) and eventually back to the atmosphere. An effective water cycle is one in which plants make maximum use of rainfall, little evaporates directly off the soil, and any runoff causes no erosion and remains clear. Also a good air to water balance should exist in the soil, enabling plant roots to absorb water readily. For the water cycle to be effective in brittle environments, the soil must be covered with living plants or litter, as vast amounts of water are lost through the bare, exposed soil between plants.