Strip herbicide applications are used to modify the plant composition of grasslands, idle areas, and old fields. As grasslands, idles areas, and old field mature they often become dominated by a few species of grass or forb. Strip spraying kills the dominating vegetation and gives other species a chance to germinate and grow. Strip spraying when done properly will encourage annuals such as ragweed, foxtail, and partridge pea to germinate and grow. It will provide bare ground in areas where thatch is not too thick. The change in vegetation structure will enhance habitat for a variety of wildlife species.
If there is a thick layer of thatch on the ground, burning or strip disking will need to be done in order to break up that thatch layer. If the thatch is not removed no benefit of strip spraying will been seen as the thick thatch will smoother out any plants that might try to germinate and replace those stunted or killed by the herbicide application.
The recommended method of strip spraying that will give the most benefit should result in strips 30 ft to 75 ft wide. For best results a third of the field should be stripped annually similar to strip disking a field. The area between the strips should be 2 times as wide as the sprayed strips, so that by the end of the three year rotation, the whole field has been sprayed. If you are dealing with tall and thick grass, (cool or warm season) you should mow the strips you intend to spray. After the vegetation begins to regrow apply the herbicide to the mowed strip. Mowing will serve 2 purposes reducing plant height for better contact of herbicide to the area and stressing the plants slightly forcing them to use stored nutrients in order to regrow.
If you have a boom sprayer available there is a second option available for the implementation of strip herbicide application. This method requires that every other nozzle is turned off or plugged. This method allows you to cover the entire field, but herbicide is only applied along small strips were the open nozzles are will have herbicide applied. This method results in smaller strips of dead vegetation compared to the 30 to 75 ft wide strips. If you are dealing with tall vegetation this method would require the whole field to be either mowed or burned before spraying in order to get better coverage. This method should only be done every other year or once every 3 years.
Application timing will vary, but generally should occur when the vegetation has approximately 6-10" of new growth and have depleted their root reserves. Typically this occurs in early spring or fall for Cool-season grasses and late spring for Native Warm-season grasses. If the field is a stagnant stand of golden rod or other forbs strip straying should occur later in early spring when the plants are less than 12 inches tall.
If your field is primarily grasses and you wish to protect the forbs use a grass selective herbicide such as clethodim (Select), ,sethoxydim ( Poast), quizalofop (Assure). The easiest and most cost effective chemical to use is glyphosate which is a non-selective herbicide. In very few instances you may have a field dominated by one forb such as golden rod or other rank perennial forb that is limiting grass growth in these cases you can use a broad-leaf weed selective herbicide such as triclopyr (Garlon), aminopyralid (Milestone), metsulfuron methyl (Cimmaron), or a non-selective herbicide such as glysphosate. Consult with your ag supplier for more information and always follow the herbicide registration label regarding proper use, application rates, and timing.
Recommended Herbicides and Rates for Strip Straying
Round-up, generic brands
2 to 4 quarts/acre
grasses and forbs
6 to 16 ounces/acre
12 to 32 ounces/acre
1 to 2.5 pints/acre
sethoxydim (13 %)
2 to 3 pints/acre
5 to 12 ounces/acre
2 to 4 pints/acre
triclopyr (25%) &
2 to 3 pints
4 to 7 ounces
Remeber small rates of herbicide often do as good as higher rates. Strip straying does not have to completly kill all species in order to be effective. Always read and follow the herbicide label.