Every year, thousands of acres of native prairie, shrubland, and even forest are sprayed with herbicide to control weeds to benefit livestock production. This practice is expensive and not often profitable when viewed in the light of potential marginal increase in income from livestock production.

Additionally, this practice can have serious impacts on other land uses and landowner objectives such as management of wildlife habitat. Herbicides also kill many plants that are valuable to livestock production since they do not discriminate between desirable and undesirable plants. To make sound land management decisions, landowners need to understand the costs and benefits of spraying weeds.

The term "weed" is commonly used in reference to any undesirable plant or a plant that is out of place.

In native habitats -- prairies, shrublands and forests -- weeds can be introduced plants (i.e. non-native) or native plants, such as eastern redcedar, that have spread into the area because of poor land management.

In fact, a weed can be any kind of plant (a grass, forb, shrub or tree). Examples of introduced, non-native plants that are weeds in native habitats throughout Oklahoma and Kansas are sericea lespedeza, salt cedar, Bermudagrass, Old World bluestems, tall fescue and Johnsongrass.

To determine if native plants that should or should not occur on a specific site, land managers can refer to the USDA Natural Resources Conservation Service ecological site descriptions.

These detailed ecological site descriptions can be found at esis.sc.egov.usda.gov/Welcome/pgESDWelcome.aspx.

The term "weed" is sometimes used to describe a whole group of plants known as forbs. Forbs are any herbaceous plant other than members of the grass, sedge or rush family. Forbs are dicots and usually have broad leaves and brightly colored flowers. Labeling all forbs as weeds is erroneous because most of these plants provide benefit to either livestock or wildlife, and removing these plants from an area can limit production potential.

Examples of some plants commonly considered weeds that provide wildlife benefit and are desirable cattle forage plants include: common yarrow, yellow sweetclover, white clover, lambsquarters, Englemann's daisy, annual sunflower, compass plant, Maximilian sunflower, black medic, pokeweed, elderberry, willow and false indigo.

Some land managers use herbicides to control weeds for aesthetic reasons, believing that the native plant community should look like a lawn or an introduced forage monoculture.

This perception might reflect equating the reduction in weeds to an increase in livestock production. However, the correct question to ask about weed control before any action is taken should be: "Are these plants detrimental to my management goals?"

The answer to this question should be based on objective facts, rather than on cultural attitudes and beliefs.

Abundant populations of some plants, including grasses, forbs and woody plants, can result from changes in weather patterns (such as a wetter than normal autumn) or poor management.

Large amounts of forbs found in one year due to weather are not unusual, and the forbs often decrease in abundance the next year. However, large amounts of forbs that occur following poor grazing management will not be resolved without reducing the stocking rate to match the production potentialof the site.

* Information from Oklahoma Cooperative Extension Service publication NREM-2882.

Stacy Campbell is Ellis County agricultural agent with Kansas State Research and Extension.