Weed Control

PROJECT BACKGROUND
Triple 7 Ranch is a 25,000 acre native grassland ranch. It is located on the prairie thirty miles southwest of Rapid City, South Dakota between the badlands and Black hills. 2,000 head of bison coexist peacefully with a large variety of wildlife.

PROJECT DESCRIPTION AND RESULTS
This report is a 2001 project spraying Russian thistle with molasses to see if we could get control of the weeds. We tried two methods: spraying with movement of animals to the area to create heavy animal impact and spraying without animal impact.

The buffalo when moved to the areas sprayed with the molasses grazed the plants heavily. To the point where there was some bare dirt. There was significant return growth of the plants as the season went on.

The areas that were sprayed only seemed to have only slightly less production later in the year compared to when the plants were not sprayed.

We have not sprayed molasses on the plants since the late summer of 2001. We have continued to mow one small area while the other four areas have been left alone.

The mowed area has decreased to 1/3 of the original size. The areas left alone have also decreased similarly, but we have seen brushy plants move into these areas where we have not mowed. Our hope is the brushy plants will continue to compete and drive out the thistle. Right now it is building into a desirable habitat area.

We intended to continue to mow the one area and monitor the others to see if the thistle continues to decline and eventually die out or if it will maintain a certain level within the brush. We may also use molasses again on a couple of the areas to see what it does.

In summary, the cost is way to high for the short term results. We only treated about 5 acres total. These areas were all in riparian areas so it was important to us not to use herbicides. If we continue to get brush growth and continue to decrease the thistle it may be worth it to us in the long run. One old site that is about 7 years old has had the brush move in and has reduced the thistle area to 20% of the original area even where there is not brush.

Another factor is drought the last few years. We will continue to monitor this site in the future to see how thing go.

OUTREACH
Feature articles in agricultural and non-agricultural publications such as newspapers, range and extension newsletters, magazines, videos, television, field days, demonstrations, workshops in cooperation with Custer County Conservation District, County Extension and/or South Dakota State University.