Aggregate: A cluster of soil particles held together in a single group such as a clod or crumb. The more stable and round in appearance, the more desirable the aggregate structure.
Biomass: The amount of living material.
Browse: The leaves and small, soft twigs consumed by some animals.
Bulk density: The mass per unit of volume (e.g. lbs/cubic foot) of undisturbed soil including air space. Within a particular soil type, lower bulk density will allow more rapid moisture infiltration and movement through the profile.
Carnivore: An animal that eats other animals.
Climax: A plant community, formerly considered to be that which natural processes tended to support in a stable state in the absence of disturbance or stress. Stress or disturbance as a result of excessive levels of grazing or other factors would cause the community to revert to a lower successional level. With removal of the stressor, the community would then progress through the same stages back to the stable climax community. This view of successional processes, however, has been unsuccessful in explaining plant community changes in some environments, particularly those where “naturalized” alien species have become an important part of the plant community, on areas where extreme degradation of the soil has occurred, or where other environmental influences like pollution or species extinction have changed the productive potential of the site.
Defoliation: The act of removing foliage from a plant.
Dormancy: The period when the plant is no longer growing, usually after frost, but may also be due to drought.
Ecological site: One to several soil series potentially capable of producing the same amount, kind, proportion, and abundance of late successional plant species.
Ecological threshold: A threshold of soil or other degradation that, once crossed, changes the potential plant community for a site irreversibly on management level time scales without high levels of management input or extended periods of time.
Ecosystem: The plants, animals, soils, climate and other living and non-living things that affect each other through a series of chemical and physical feedbacks.
Forb: A herbaceous plant with net-veined leaves, often referred to as a weed.
Gross income: The total amount of money received associated with a business.
Herbaceous plant: Plants that are not woody.
Herbage allowance: The amount of forage on offer compared to the amount that the animals can consume.
Herbivore: An animal that eats only plant material in the diet.
Herbivory: The process by which animals consume plants. This includes both wild and domestic, higher animals as well as insects and microbes.
Omnivore: An animal that eats both plants and animals.
Organism: Any living thing.
Overgrazing: Levels of defoliation on an individual plant that, as a result of poor timing, excessively close defoliation, and/or inadequate opportunity for regrowth that weaken, and if continued can kill, that plant. Overgrazing can occur even with low stocking rates.
Overhead cost: Those costs, usually associated with land, facilities, or labor, that do not increase directly with the number of animals.
Overstocking: Forage demand in excess of sustainable carrying capacity for an area. Overstocking will always cause one or more of the following: 1) overgrazing; 2) increased variable costs; 3) decreased animal performance; 4) lower profitability.
Paddock: A subdivision of a grazing unit. Also termed a pasture in the United States. However, paddock is used in this case because it is most often used in reference to controlled grazing management, whereas pasture is a term more commonly used in areas where season long or year- long grazing is most common.
Perennial: A plant that regrows each year from existing crowns, stems, or roots.
Photosynthesis: The chemical reaction carried on by green plants in which they change carbon dioxide from the air and water absorbed from its roots to form simple compounds used for energy using the light from the sun.
Plant community: A collection of plant species growing in the same area or ecological site.
Rhizome: A modified stem below the soil surface that is responsible for reproduction in some plants like Johnson grass and Tobosa.
Ruminant: A herbivore with four stomach compartments and a dental pad in the upper jaw instead of incisor teeth such as a cow, sheep, goat, deer, but not a horse.
Seral: Term used to refer to the successional level of a community growing on an ecological site. A high seral community would have a high proportion of species that are long-lived, use resources efficiently (e.g. conserve them with little waste), and are adapted to lower levels of disturbance. Low or mid seral communities would have a higher proportion of plants that were shorter-lived, more opportunistic and possible less efficient in their resource use. High mid, and low seral may also refer to plants characteristic of these respective communities.
Stock density: A measure of animals per unit area at a given point in time. It is measured in units of animals/area or area/animal, with no measure of time.
Stocking Intensity: Total forage demand per unit area in a paddock for a grazing period
Stocking rate: Forage demand per unit of time usually measured in units based on some standard animal unit per area per unit time such as acres/cow/year, animal unit months/acre, animal unit days/acre, etc.
Stolon: A horizontal, above ground stem that is capable of reproduction. These are the “runners’ commonly seem in species like Buffalograss, Curly mesquite, and Bermuda grass.
Structure: The characteristic size and shape of the soil aggregates.
Succession: Progressive changes over time in the species composition of a plant community where certain species replace others as a result of changing environmental conditions.
Successional level: A measurement of the proportions of plant species in a community compared to some potential. Generally, in more advanced successional stages, or high seral communities, species are usually longer-lived, reproduce less often, and are generally better adapted to conditions where competition is high for limited resources and the plants are generally assumed to be better adapted to moister conditions and are more productive, though there is often much of the energy lost to respiration, such that net productivity approaches respiration.
Transpiration: The loss of moisture through the leaves of plants.
Variable costs: Those costs that increase with each additional unit of production. IN Livestock production, usually associated with feed, veterinary costs, shearing, interest and depreciation on the livestock, etc
Vegetative: denotes the above-ground parts of a plant that are not directly associated with seed production. These may include leaves, stems, stolons, rhizomes, etc. Also may be used for classes of plants that are not woody – that is, not shrubs or trees.
Vegetative Reproduction: Recruitment of new plants from stems stolons or rhizomes.