Frequently AskedQuestions

Vegetation Management

Why should we spray around our oil & gas facility?

One of the most important reasons for vegetation control in and around oil and gas facilities is to reduce forest and site fire hazards. Vegetation control also ensures compliance with government regulations. Restricted weeds must be eradicated and noxious weeds must be controlled according to the Alberta Weed Control Act. With a vegetation free site, infestation of rodents will be greatly decreased. Lack of vegetation will reduce snow buildup and also ensure visibility and access to installations and equipment. There is also more SRD directives on controlling invasive species in non-farmland areas as well.

How long will we get control in sprayed areas?

Most of our "bare ground" programs industrial sites use products which will give control for up to one season. These herbicides have lower risks than long term sterilant type products, yet still give season long control. When doing "broadleaf" control in grass areas, heavy infestations of certain weeds such as Canada Thistle and Scentless Chamomile may need a 2nd application during the season.

What is "selective" and "non-selective" spraying?

Selective spraying means that only broadleaf weeds are targeted by the herbicide. Grass species are not injured. It does not mean that "spot spraying" is being done. Therefore, Selective spraying is used for the eradication and control of restricted and noxious broadleaf weeds, which in turn encourages the growth of desirable grass species.

Non-selective spraying is a total vegetation kill application. This means that everything that is sprayed with the herbicide is totally eradicated. Non-selective applications are generally used in plant facilities and around other oilfield installations. Selective spraying is used for control of broadleaf weeds only, within desirable grasses.

What is "spot spraying"?

Spot spraying refers to the targeting of individual plants or patches of plants. This type of application is used when there are only certain spots that require herbicide use.

The main advantage of this type of application is that the herbicide use is reduced.

The main disadvantage is that there may be missed weeds, as well as no active herbicides in the soil for the weeds that have not emerged yet. Typically spot spraying is much slower, which can result in higher maintenance costs for the site. In summary, Blanket spraying usually limits site visits to one per season, and is more cost effective then spot spraying.

What does residual mean, and how will it affect my site?

A residual herbicide is one where the chemical stays active over a period of time and controls weeds and other vegetation with that action. A residual herbicide can reduce the number of herbicide applications on a site. Residual times can vary from a few weeks to over five years. Selective and non-selective herbicides may have residual times. It is important to select herbicides that give the proper time frame of control. If residual times exceed the life of a site, then that particular herbicide should not be used. A good residual time on a non-selective herbicide at a well site is probably one season. "Selective" herbicide residual times are not as critical, as reclaimed sites (with newly planted grasses) are generally not affected after one year’s time.

There are a lot of oilfield installations that are in pastures with livestock. Are these chemicals toxic to livestock?

Any time that livestock are grazing on the same land that requires spraying, this is taken into consideration and spraying is not done on that day. If there is a heavy infestation of weeds present, we advise our client of this and the landowner can be notified. Non-toxic herbicides are available and can be applied to grazing areas. Special consideration must be taken for dairy animals and the timeframe between grazing to slaughter with beef cattle.

How toxic are the chemicals (herbicides) being applied?

LD50 is a laboratory measurement of toxicity. The lower the number, the more toxic an herbicide is. It is interesting to note that all of our herbicides have a LD50 of 2000 - 10,000. In comparison "Killex" (a dandelion killer commonly bought in hardware stores) has a LD50 of 300 - 1200. In essence, our selected industrial herbicides are safer than an "over the counter" product which can be bought by any consumer. This being said, we recognize that "length of exposure" is an important issue with any herbicide application. Many of our products are non-toxic to sensitive species such as honey bees and fish.

Are there certain weather conditions that are better for herbicide application than others?

Contact herbicide applications can be affected by rain. Generally with these types of treatments, we use surfactants or herbicides which can be applied within a few hours or in some cases minutes before a rainfall. Conversely, some herbicides are applied to be absorbed by the roots of a plant and rain is needed to move the chemical to the root zone.