Impact of weeds
Description of a Weed
There are numerous definitions of a weed, including:
- A plant out of place and not intentionally sown
- A plant growing where it is not wanted
- A plant whose virtues have not yet been discovered. (R.W.Emerson)
- plants that are competitive, persistent, pernicious, and interfere negatively with human activity..etc
No matter what definition is used, weeds are plants whose undesirable qualities outweigh their good points, according to man. Our human activities create weed problems since no plant is a “weed” in nature. Though we may try to manipulate nature for our own good, nature is persistent. Through the manipulation process, certain weeds are controlled, while, other more serious weeds may thrive because favorable growing conditions for them also have been meet. Weeds are naturally strong competitors and those weeds that can best compete always tend to dominate. Both humans and nature are involved in plant breeding programs.
Weeds reduce farm and forest productivity, they invade crops, smother pastures and in some cases can harm livestock. They aggressively compete for water, nutrients and sunlight, resulting in reduced crop yield and poor crop quality. For example, prickle bushes such as Gorse, Blackberries, Prickly Acacia, Parkinsonia and Mesquite can invade vast areas of grazing land preventing productive use of that land.
Weeds contaminate produce, for example:
- Burrs in wool contaminate fleeces
- Grain milled with Saffron Thistle or Amsinckia results in discoloured flour
- Animals that eat specific weeds, such as wild garlic, produce tainted milk and meat
- Spines on fruit of Caltrop and Spiny Emex can damage the feet of stock animals
- Paterson’s Curse irritates the udders of dairy cows and can kill horses
- Hemlock can be lethal to both stock and people.
Weeds can also affect the operation of farm machinery.
Farmers spend a large amount of time and money managing weeds. Despite control efforts, a recent survey of issues facing the agriculture industry found that weeds were the most commonly reported natural resource management issue affecting landowners.