The above-ground portion of a plant stand. It may be expressed as percentage of ground cover.


Compounds, such as sugars, starch and other soluble carbohydrates (nonstructural) and cellulose and hemicellulose (structural), that are made of carbon, hydrogen and oxygen, usually in the ratio of 1:2:1 (CH2O).


A carbohydrate formed from glucose that is the major constituent of the plant cell walls.

Carrying Capacity

The maximum total stocking rate that can be achieved over a specified length of time (for example AU/ha for the grazing season). The sum of all grazing days and stocking rates will determine the maximum carrying capacity of the pasture, which maintains a target level of production without affecting the ecosystem.


In grasses, the collar is located on the outside of the leaf, where the blade attaches to the sheath.

Companion Crop

A companion crop is a cover crop (usually a cereal crop) grown with a perennial forage during the establishment year, but may also include annual or short-lived forage species in mixtures. Companion crops are competitive with forage seedlings.

Compound Leaf

A leaf that is divided into two or more parts (leaflets).

Continuous Grazing

A grazing practice where grazing is on one pasture and the livestock have unrestricted access for long grazing periods.

Cool-season Plants

Plant species that grow best in cool temperatures (15 – 25ºC). In photosynthesis, they first produce a 3 carbon acid (3 – phosphoglyceric acid) to make carbohydrates. This C3 photosynthesis occurs at cooler temperatures than C4 photosynthesis, but is less efficient at warmer temperatures. All perennial forages used in Alberta are cool-season species.


Coumarin changes to dicoumarol, an anticoagulant, when the hay from forage species containing coumarin becomes moldy. Anticoagulants prevent blood from clotting. Coumarin was once commonly found in sweet clover, but newer varieties are coumarin-free.

Cover Crop

See Companion crop.

Creeping Root

An underground stem, a rhizome.


Transfer the pollen from the flower of one plant to the flower of another plant of the same species.


The portion of a plant where the stem and the root meet and where tiller buds and rhizomes are first formed. The crown of perennial forages overwinters to produce new tillers and additional rhizomes in the spring.

Crude Fibre

This is the fibrous part of the plant that has very little nutritional value and is not very digestible. Cellulose is an example of the fibre in the plant. The terms acid detergent fiber (ADF) and neutral detergent fiber (NDF) are generally used instead of crude fiber.

Crude Protein

Proteins are made up of amino acids. Protein is determined by measuring the nitrogen in the forages and multiplying by 6.25. Plant proteins are used by the animal to produce animal proteins (e.g. meat and milk).


A population of a plant species that has been bred and selected for specific characteristics such as winter hardiness or disease resistance; in the crop sciences, a cultivar is a cultivated variety (also known as variety).