Managing Smooth Bedstraw (Galium mollugo L.) in Forage Crops

Final Report for ONE04-025

Project Type: Partnership
Funds awarded in 2004: $7,405.00
Projected End Date: 12/31/2005
Matching Non-Federal Funds: $2,772.00
Region: Northeast
State: Maine
Project Leader:
Richard Kersbergen
University of maine Cooperative Extension
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Project Information

Summary:

Many hayfields in Maine that have not been intensively managed or in rotation with row crops have experienced a proliferation of Smooth Bedstraw. Cattle, sheep and horses will not eat Bedstraw, and its spreading nature in hayfields significantly reduces grass and legume yield.

Control of Bedstraw is difficult for many livestock producers. Some herbicide options exist, but have limited effectiveness and have grazing or harvest restrictions associated with their use. Numerous calls come to Extension offices throughout the state when Bedstraw begins to flower and growers visually see how dominant the plant has become in their fields.

Four possible options were investigated and evaluated to control Smooth Bedstraw in established pastures and hayfields. Two herbicide treatments, (Roundup or glyphosate, and Crossbow), a fertility treatment (Nitrogen applications), and a tillage treatment were compared to a control (two mowings per year).

The glyphosate treated plots with the no-till treatment demonstrated the need to control the seed deposition from the previous season before attempting such method for control. The seed deposited on the soil from the 2003 growing season was given ample opportunity to grow and proliferate without competition. For the 2005-6 trial, we will wait to apply the glyphosate treatment until the fall, to allow the new seedlings to grow and then be killed by the systemic herbicide before no-till drilling in early September.

Crossbow (Tryclopyr and 2,4-D) effectively controlled bedstraw, since we applied the treatment in late summer (August) and had kept the bedstraw from setting seed during the current growing season. Other researchers have demonstrated the short (one-year) length of time that bedstraw seed remains viable in or on the soil. Producers who are trying to compete against this weed must use this to their advantage and control bedstraw flowering during the growing season with mowings in late June and again in late July or early August. If not, seed dropped during this period will germinate and grow the following spring and summer, despite herbicide treatment the year prior.

Tillage, cover crops and bare fallow effectively depleted the soil of viable seed in one season and killed the perennial crown of existing bedstraw. Some plants were found in these plots, but very few, and most were quickly shaded out by an aggressively growing new seeded forage crop the following season.

When we harvested forage yields from 28 inch by 20 ft plots and separated forage from bedstraw, we got similar results, with the Crossbow treatment and the tillage treatment having less than 1% bedstraw. The other three treatments had significantly higher percentages at 33.7%, 26% and 28.7% for control, glyphosate/no-till, and nitrogen respectively. The nitrogen plots were not significantly different from control or glyphosate/no-till.

When we compared the yields of the plots, we found that the nitrogen application significantly increased the yield per acre over all other treatments (approx 1863 pounds of dry matter per acre compared to 1215 pounds per acre for the control). The increase in forage yield did favor the production of desirable forage as compared to bedstraw, but the yield of bedstraw was not significantly higher than control, whereas the yield of desirable forage was significantly higher than control.

Outreach efforts have included a fall field day (2004) at the site with three farmers participating (Rain and cold day) and a summer field day (2005) with 17 farmers participating. There have been 48 email requests for information related to the project. I was invited to a pasture workshop in Dresden to discuss the project progress (60 people) and also discussed the project at a forage pesticide recertification meeting at Maine Farm Days in Clinton (85 people). Additional outreach was conducted at the Maine Grass Farmers Network Conference in October (110) farmers and NRCS employees. I have presented on Bedstraw at the New England In-Service training for Agricultural Professionals (Certified Crop Advisors- American Society of Agronomy) in February of 2005. Articles about the project have been published in Country Folks, Maine Farmer, Agriculture Today and several local papers, including an electronic paper http://belfast.villagesoup.com/Community/Story.cfm?StoryID=26135. A summary was published in Country Folks, July 2nd, 2005.

I have had requests from NH, Maine and Vermont for information results from this study. I have also been asked by Steve Taylor (Commissioner of Agriculture, NH), to speak on this topic at the New Hampshire Farm and Forest meetings in February, 2006.

This project will continue so we can collect two years of data and to add additional treatment options. Plans also include publications and presentations with weed science periodicals and a fact sheet for New England distribution.

Introduction:

Smooth Bedstraw has become a problem weed in many forage crops, especially pastures and haycrops. It can significantly reduce yields of forage grasses and legumes. Smooth Bedstraw is a perennial that spreads by seed as well as with underground rhizomes. It has numerous, relatively upright stems and produces white to greenish flowers in June and July. Individual plants can grow 1 to 3 feet tall and spread to 3 feet or more in diameter.

Bedstraw grows throughout the Northeast. The weed is prevalent in infrequently mowed hay fields of low fertility and low pH, and tolerates low soil Nitrogen and low pH better than the desired forage species. Bedstraw also thrives in well-managed fields because of its adaptation to a wide variety of environmental conditions. Smooth Bedstraw prefers moist, cool conditions, but can tolerate drought.

Many hayfields in Maine that have not been intensively managed or in rotation with row crops have experienced a proliferation of Smooth Bedstraw. Cattle, sheep and horses will not eat Bedstraw, and its spreading nature in hayfields significantly reduces grass and legume yield.
Control of Bedstraw is difficult for many livestock producers. Some herbicide options exist, but have limited effectiveness and have grazing or harvest restrictions associated with their use. Numerous calls come to Extension offices throughout the state when Bedstraw begins to flower and growers visually see how dominant the plant has become in their fields.

Four possible options were investigated and evaluated to control Smooth Bedstraw in established pastures and hayfields. Two herbicide treatments, (Roundup or glyphosate, and Crossbow), a fertility treatment (Nitrogen applications), and a tillage treatment were compared to a control (two mowings per year).

Pre-Research Assumptions:
Fertility management is probably the easiest and most likely option for many growers. By fertilizing the existing grasses, it is anticipated that they will out-compete the bedstraw and reduce its vigor. Tillage, cover crop and bare fallow will probably be the most effective in eradicating the weed, but also may have the highest price tag and have minimal use with small and part time farmers who lack the equipment to perform these operations. Many livestock producers are also unwilling to use herbicides, so alternatives must be investigated.

Project Objectives:

The Cooperating farmer, Welles Thurber, owns a hayfield with a remarkably uniform stand of bedstraw. The objective of this study was to find methods of controlling the bedstraw so this field could become a productive field for the variety of agricultural pursuits that Wells would like to pursue.

The project would set up replicated plots that would demonstrate possible alternatives that landowners might use to control this invasive weed.
Field days were held in the fall of 2004 and the summer of 2005 to demonstrate the results of treatments.

Articles have been published in numerous magazines (Country Folks, Ag Today, Maine Farmer) and summary reports have been mailed to Extension educators and NRCS field staff in numerous states in the Northeast.
The research trial will continue for another year, and another replicated plot with an additional treatment has been constructed on the same site.

Presentations have been made to various professional groups (Certified Crop Advisors- American Society of Agronomy), and farmer meetings. Presentations are scheduled for the Northeast Weed science meetings in Jan, 2006 and at the NH Farm and Forest meeting in Manchester, NH.

Cooperators

Click linked name(s) to expand
  • G.P. Wells Thurber

Research

Materials and methods:

Our research design involved a randomized complete block design with four treatments and a control (mowing 2X per year). Each block will be 50X50 feet with the plots being 10X50 within each block. Soil samples were taken to check soil pH (6.0). Treatments were as follows:

1) Control (mowing 2X during the summer to replicate a hayfield or pasture situation)

2) Nitrogen Management (200 lbs. per acre of N applied in a split application with one in spring, and the second after mowing in July). Plots were mowed to prevent seed formation.

3) One mowing with Crossbow herbicide applied in September (traditional broadleaf herbicide recommendation). Plots were mowed during the season to prevent seed formation.

4) Glyphosate herbicide applied just prior to flowering in June. Re-seed using a no-till drill.

5) Repeated tillage beginning in June, with a buckwheat cover crop and a short fallow period. Re-seed in August.

Evaluation of plots were conducted in the spring and summer of 2005. The following measurements were taken:

1) Bedstraw stem counts in .25 meter square subplots (three measurements in each plot).

2) Dry yield of forage and bedstraw in 20 ft by 28 inch subplots.

Research plots were marked and randomized in May. Fertilization of the nitrogen subplots was done immediately, along with soil samples and documentation of existing plant species. The participating farmer suggested an additional treatment (burning) for a possible option in the spring of 2005. The glyphosate treatment was done in June, prior to flowering and the tillage plots with cover crops (buckwheat) was also done in June. Glyphoste treatment provided a good kill of the existing forage and bedstraw population. Three weeks after glyphosate treatment, a no-till drill was used to seed a pasture mix of grasses and legumes (Hobby Horse mix). The tillage treatment received two crops of buckwheat with tillage between both treatments and a final seeding of forage in late August (Hobby Horse Mix). The Crossbow herbicide treatment was also applied to the plots in late August of 2004. In all plots, bedstraw was prevented from flowering and setting seed.

Research results and discussion:

Results and Discussion/Milestones

In the Spring of 2005, stem counts were taken in 3 subplots within each plot.

For control, there were an average of 110 bedstraw stems per .25 meter square, with the nitrogen amended plots averaging 127 and the glyphosate treated/no-till plots averaging 215 stems. The tilled plots averaged 2.5 stems ad the Crossbow treated plots had 0 stems per .25 meter square.

The glyphosate treated plots with the no-till treatment demonstrated the need to control the seed deposition from the previous season before attempting such method for control. The seed deposited on the soil from the 2003 growing season was given ample opportunity to grow and proliferate without competition. For the 2005-6 trial, we will wait to apply the glyphosate treatment until the fall, to allow the new seedlings to grow and then be killed by the systemic herbicide before no-till drilling in early September.

Crossbow (Tryclopyr and 2,4-D) effectively controlled bedstraw, since we applied the treatment in late summer (August) and had kept the bedstraw from setting seed during the current growing season. Other researchers have demonstrated the short (one-year) length of time that bedstraw seed remains viable in or on the soil. Producers who are trying to compete against this weed must use this to their advantage and control bedstraw flowering during the growing season with mowings in late June and again in late July or early August. If not, seed dropped during this period will germinate and grow the following spring and summer, despite herbicide treatment the year prior.

Tillage, cover crops and bare fallow effectively depleted the soil of viable seed in one season and killed the perennial crown of existing bedstraw. Some plants were found in these plots, but very few, and most were quickly shaded out by an aggressively growing new seeded forage crop the following season.

When we harvested forage yields from 28 inch by 20 ft plots and separated forage from bedstraw, we got similar results, with the Crossbow treatment and the tillage treatment having less than 1% bedstraw. The other three treatments had significantly higher percentages at 33.7%, 26% and 28.7% for control, glyphosate/no-till, and nitrogen respectively. The nitrogen plots were not significantly different from control or glyphosate/no-till.

When we compared the yields of the plots, we found that the nitrogen application significantly increased the yield per acre over all other treatments (approx 1863 pounds of dry matter per acre compared to 1215 pounds per acre for the control). The increase in forage yield did favor the production of desirable forage as compared to bedstraw, but the yield of bedstraw was not significantly higher than control, whereas the yield of desirable forage was significantly higher than control (see tables 1 and 2, available from Northeast SARE or by directly contacting the project manager).

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Research conclusions:

Outreach efforts have included a fall field day at the site with three farmers participating (Rain and cold day). There have been 45 email requests for information related to the project. I was invited to a pasture workshop in Dresden to discuss the project progress (60 people) and also discussed the project at a forage pesticide recertification meeting at Maine Farm Days in Clinton (85 people). Additional outreach was conducted at the Maine Grass Farmers Network Conference in October (110) farmers and NRCS employees. I have presented on Bedstraw at the New England In-Service training for Agricultual Professionals (Certified Crop Advisors) in February of 2005. Articles about the project have been published in Country Folks, Maine Farmer, Agriculture Today and several local papers, including an electronic paper http://belfast.villagesoup.com/Community/Story.cfm?StoryID=26135. A summary was published in Country Folks, July 2nd, 2005.

I have had requests from NH, Maine and Vermont for information results from this study. I have also been asked by Steve Taylor (Commissioner of Agriculture, NH), to speak on this topic at the Farm and Forest meetings in February, 2006.

This project will continue so we can collect two years of data and to add additional treatment options. Plans also include publications and presentations with weed science periodicals and a fact sheet for New England distribution.

Participation Summary

Education & Outreach Activities and Participation Summary

Participation Summary

Education/outreach description:

As mentioned in the above summary, outreach has included a fall field day (2004) at the site with three farmers participating (Rain and cold day) and a summer field day (2005) with 17 farmers participating. There have been 48 email requests for information related to the project. I was invited to a pasture workshop in Dresden to discuss the project progress (60 people) and also discussed the project at a forage pesticide recertification meeting at Maine Farm Days in Clinton (85 people). Additional outreach was conducted at the Maine Grass Farmers Network Conference in October (110) farmers and NRCS employees. I have presented on Bedstraw at the New England In-Service training for Agricultural Professionals (Certified Crop Advisors- American Society of Agronomy) in February of 2005. Articles about the project have been published in Country Folks, Maine Farmer, Agriculture Today and several local papers, including an electronic paper http://belfast.villagesoup.com/Community/Story.cfm?StoryID=26135 . A summary was published in Country Folks, July 2nd, 2005.

I have had requests from NH, Maine and Vermont for information results from this study. I have also been asked by Steve Taylor (Commissioner of Agriculture, NH), to speak on this topic at the New Hampshire Farm and Forest meetings in February, 2006.

Future plans also include publications and presentations with weed science periodicals and a fact sheet for New England distribution.

Project Outcomes

Project outcomes:

No economic analysis was one for this project. It should be noted, however, that there are significant costs associated with the “effective” control mechanisms. Crossbow herbicide will cost about $50 per acre for materials alone (at 3 qt per acre rate) and will eliminate all broadleaf plants in the field, including alfalfa and clovers. The glyphosate treatment (about $25 per acre herbicide cost) will require re-seeding, along with the herbicide costs. Tillage will require both time and subsequent loss of production long with machinery and seed costs.

Assessment of Project Approach and Areas of Further Study:

Areas needing additional study

Additional methods for control, especially organic options in pasture settings need to be investigated. For 2006, a burn treatment will be explored, using a commercial blueberry burner to see if the temperatures will be hot enough to kill the perennial crown and destroy any viable seed.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.