Management and Control of Candian Thistle in Limited Access and Field Locations
Jordan Dawn, a co-operator of Enormous Brontosaurus Organic Farm in Letcher, SD received a 2001 SARE grant to generate a method(s)for controlling Canadian Thistle in specific areas of their vegetable farm. Jordan and his wife Gail, grow a variety of vegetables, melons, medicinal herbs, culinary herbs and flowers on the 180 acre farm. They perform all the planting and harvesting by hand and market their products at a farm market stand in Mitchell. The Enormous Brontosaurus Organic Farm has been USDA-MOSA certified and has been following a sustainable and organic practice since 1990.
Since they are a certified organic farm they are not allowed to use commercial herbicides; so the goal of this project was to find a solution to the problem that is compatible to their farming practices and keep the noxious weed from spreading on their land and any adjacent property. The process began by dividing the area into plots and mowing each plot, they left the thistle about four inches high in each plot so that the results from the experiment could be determined. They created a grid system with various treatments such as tilling, hoeing, burning, applying vinegar, salt, calcium, sulfur and phosphorus.
Each individual plant was counted in each of the sampling areas before and after the treatment was added. All the species data was converted to density based on a unit of one square meter and the averaged with the plot that it was identical too.
The results from this experiment found that there was a reduction of the number of species in each of the plots that were treated. “The greatest reduction (to zero) occurred in subplots treated with salt (NaCl), either alone or in combination with other treatments. The least reduction occurred in subplots with vinegar (7 species remaining), phosphorus (5 species remaining) and calcium with hoeing (5 species remaining). The rest of the treated subplots had two or fewer species remaining,” noted Dawn.
While the outcome of this experiment established some good short term results, they are concerned with the long-term affects that may results from using these techniques. However; the project demonstrated that cultivation as the right times and with the correct tools and can be highly effective. Also keeping the patches mowed to reduce the amount of moisture available to the plant will help diminish the amount of growth and seeds that they produce.