Vermont cover crop initiative

Final report for ONE16-288C

Project Type: Partnership
Funds awarded in 2016: $11,111.00
Projected End Date: 12/31/2018
Grant Recipient: University of Vermont Extension
Region: Northeast
State: Vermont
Project Leader:
Jeffrey Sanders
University of Vermont Extension
Expand All

Project Information


This SARE grant looked into the efficacy of applying cover crops using an interseeder across different cropping systems in northern Vermont.  The project demonstrated or attempted to demonstrate an Interseeder Technology interseeder and/or a Dawn Biologic Duo-Seeder on vegetable, grain, and dairy (silage) farms. Cover Crops mixes were planted on 7 of the selected farms with wide ranging results. Vegetable farms were found to be challenging to plant cover crops on with the equipment used for this project due to the row spacing differences between the vegetable crops and the equipment. For the 7 farms that cover crops were grown on the results were varied. The best cover crop was from a grain farm field and there was 847 pounds of dry matter yield and 64% of the soil surface was covered. The poorest results were from a silage system field and the results were 152 pounds of dry matter yield and only 17.25% of the soil surface being covered. There are many possible contributing factors which led to these results including the characteristics of a grain corn vs. silage corn and how those characteristics affect shading and water availability to the cover crop. It was also possible that in some cases herbicide interaction with the cover crop impacted establishment. In vegetable crop systems it is likely that any interseeding equipment used to incorporate seed will need to be modified to fit the individual farmers needs. Vegetable farmers will need to plan out how to lay out beds and row spacing considerations to make interseeding tools work for them. UVM Extension held a cover crop series in the late fall of 2016 and 74 people participated including 34 farmers, 16 Extension educators, 7 state and federal employees, and 7 industry personnel.  In 2017 and 2018 project staff assisted in hosting No-Till Symposiums. These meetings were attended by over 380 people interested in no-till and cover crops. UVM Extension hopes to continue this valuable work of building resiliency and sustainability in our cropping systems.

Project Objectives:

Project objectives include:

  1. Evaluate the efficacy of the InterSeederTM to establish cover crops within multiple cropping systems and diverse soil types in commercial settings.
  2. Document constraints and factors contributing to the success of interseeded cover crops on multiple farm business settings.
  3. Expand the awareness and knowledge of successful cover crop applications in northern climates among farmers and service providers in Vermont.

This project will demonstrate cover crop seeding using the InterSeederTM at 9 commercial farm field locations, including 3 vegetable sites, 3 grain sites, and 3 dairy or livestock sites. We will also conduct outreach in the form of on-farm field days during the fall of 2016 and growing season of 2017 at 4 sites, and through the Vermont No-Till and Cover Crop Symposium. 


Cover cropping is a practice that helps increase soil and crop health, build soil organic matter, reduce soil erosion, and improve water quality. Considerable research and farmer outreach has been conducted in Vermont and throughout the Northeast U.S. on the soil health benefits of adding cover crops to both vegetable and field crop production systems.

However, reaping the benefits from cover crops requires that farmers actually take the steps to implement them into their production systems. Therefore, we must address the real and perceived barriers to adoption of cover cropping which include: timing of planting, costs of time and equipment to implement, and the ability to see returns on these investments. To promote wider adoption of cover cropping in Vermont and across the Northeast, our team believes that we must demonstrate that cover crops can be successfully established in our northern climate.

In Vermont and other northern areas, the exceptionally short growing season poses a major challenge to establishing cover crops in many different cropping systems. Currently, most farmers wait to seed cover crops after their cash crops have been harvested. This often occurs when weather and soil conditions are not ideal for crop growth or soil conservation leading to poor or failed stand establishment and exacerbated soil compaction. To address this challenge, researchers, including UVM Extension agronomist Dr. Heather Darby, have been investigating interseeding as a possible means to establish diverse cover crop mixtures into crops in far northern regions. Interseeding into a cash crop in mid- to late- summer allows the cover crop species more time to establish and grow prior to autumn and winter months.

The Penn State Cover Crop Interseeder and Applicator—now called the InterSeederTM —was designed to help establish cover crops into a cash crop stand to address the challenges of cover crop establishment. Providing farmers with information and access to the InterSeederTM may increase the adoption and implementation of cover crops in Vermont.

Therefore, this project will complement ongoing efforts by applying the results from replicated small plot research trials, evaluating dozens of cover crop mixes suitable for interseeding in Vermont, to a number of different commercial farm settings.

We will demonstrate the use of the InterSeederTM on 9 commercial farm businesses with different production systems and soil types (3 vegetable, 3 grain, and 3 dairy or livestock) using cover crop mixes that are best adapted to interseeding in our climate. Our team will also expand our collective education and outreach efforts focused on cover cropping to both farmer and service provider audiences.


Click linked name(s) to expand/collapse or show everyone's info
  • Dr. Heather Darby
  • Rebecca Maden
  • Sandra Primard
  • Jeffrey Sanders
  • Kirsten Workman
  • Sara Ziegler


Materials and methods:

UVM staff evaluated 9 fields for project suitability. During the summer of 2017 cover crops were interseeded onto 7 fields to demonstrate to farmers the viability of integrating cover crops into a variety of cropping systems. These fields included 3 corn silage fields, three grain fields (two corn and one sunflower) and 1 vegetable farm (sweet corn). The species mixtures and seeding rates (in lbs per acre) were as follows

Silage Farm 1: Annual Rye 20 lbs/ac, Radish 1.5 lbs/ac

Silage Farm 2: Annual Rye 20 lbs/ac, Radish 1.5 lbs/ac, Medium Red Clover 5 lbs/ac

Silage Farm 3: Annual Rye 18 lbs/ac, Radish 1.5 lbs/ac, Medium Red Clover 3 lbs/ac

Grain Farm 1: Annual Rye 20 lbs/ac, Radish 3 lbs/ac

Grain Farm 2: Annual Rye 20 lbs/ac, Radish 3 lbs/ac

Grain Farm 3: Annual Rye 20 lbs/ac, Radish 1.5 lbs/ac

Vegetable Farm 1: Radish 3 lbs/ac, Clover 10 lbs/ac, Oats 70 lbs/ac

Vegetable Farm 2:  N/A (cover cropped but no cash crop available to interseed into, so not included in this report)

Vegetable Farm 3: N/A (not feasible due to Interseeder equipment limitations in strawberries; see explanation below)

Seeding dates ranged from July to August.  Seeding dates were variable because of the moisture in the soil and maturity of the cash crop at each site.  For example, to use the interseeder in corn the crop must be between the V4 and V6 stage.  

Data collection for the cover crop trials was done on October 25th. Cover crop biomass was assessed by cutting the biomass within a 0.25m2 area to ground height. The samples were weighed and dried to determine dry matter content and dry matter yield on a per acre basis. Ground cover was assessed by photographing a 0.25m2 area. The photos were then processed using the IMAGING Crops Response Analyzer ( to determine the percent ground cover provided by the cover crop at each site.

Demonstration sites were limited to 7 due to the specificity needed to Interseed cover crops on vegetable farms.

Research results and discussion:

The cover crop trials were established on farms in Franklin, Grand Isle, and Lamoille counties in Vermont.  They were seeded using the Interseeder Technologies InterSeederTM and the DAWNR Biologic DuoSeed Cover Crop Inter-Seeder.  The primary difference between the two units is that the InterSeederTM seeds three strips of cover crops between cash crop rows while the DuoSeed seeds only two strips.  The units use the same amount of seed per acre and use a similar seeding design where seed is deposited into a small trench that is opened in the soil and then closed using a press wheel. 

The results of the trial are summarized in Table 1.

Trial Site Cover Crop Mixture DM yield (lbs-ac) % Ground cover  
Farm 1 Grain Annual Rye Radish 482 45.47  
Farm 2 Grain Annual Rye Radish 845 64.19  
Farm 3 Grain Annual Rye Clover Radish 152 17.25  
Farm 4 Silage Annual Rye Clover Radish 188 14.26  
Farm 5 Silage Annual Rye Radish 465 33.85  
Farm 6 Silage Annual Rye Clover Radish 454 28.93  
Farm 7 Veg. Oats Clover Radish 619 60.08  
Farm 8 Veg. N/A    


Farm 9 Veg.  N/A      


The results indicate that there is a wide degree of variability in outcomes when interseeding cover crops.  This is due to mostly to the cover crops potential to compete for sunlight and moisture through the cash crop canopy during establishment.  On the highest yielding trials, the cover crop was on outside rows and had adequate sunlight which significantly improved stand quality.  On Farm 3, the cover crop was seeded near the time of herbicide application which likely impacted the cover crop's performance.  The farmer thought it had been sprayed only with a glyphosate product but found out later that a residual herbicide was applied.  It is evident that herbicides with lasting residuals impair cover crop establishment.  Farm 1's site was a reduced tillage field that had been in annual broadleaf crop production in the last two years with soybeans and sunflowers in 2016 and 2017 respectively.  The significant weed pressure in the field negatively impacted the growth of the cover crops as they struggled to outcompete the weeds.  Farm 4 had a similar weed pressure problem which likely contributed to its poor cover crop performance.  Farm 2 and Farm 7 both had satisfactory cover crops.  Compared to the other sites, the cover crops at these sites likely performed better due to higher levels of sunlight available through the grain corn and sweet corn crops compared to silage corn crops as both grain and sweet corn are grown at significantly lower plant populations.

For this project it was determined that using a one size fits all machine on vegetable operations is not practical and in some cases not feasible at all.  Because of the unique systems developed by different farmers for different crops it is very difficult to get a 30 inch row spacing machine down between the rows consistently.  For this trial we attempted to interseed covers into a strawberry bed and it became apparent that the interseeder would need significant reconfiguration to meet the requirements of the site.  The beds were not spaced in a way that would allow for the machine to avoid damaging the bed or the plastic mulch that was covering it.  Another challenge associated with this project on vegetable farms concerns the use of hilling and mechanical cultivation to suppress weeds.  These practices lead to very deep trenches (6-9 inches) between the rows and beds.  This makes it very difficult for the interseeder to remain straight while traveling down the rows which increases the risk of damaging the cash crop and planting the cover crop at uneven seeding depths. Another challenge of seeding on vegetable farms is that the high cash value crop on a relatively small number of acres means that any damage by the interseeder could have significant economic damage in a vegetable operation.  It is very important on vegetable farms to have an interseeder that is properly set up for the crop being interseeded.



Research conclusions:

This project sought to investigate the feasibility of integrating the practice of interseeding cover crops into a diversity of cropping systems.  UVM Extension staff interseeded cover crops on 7 fields covering three different cropping systems including corn silage, grain, and vegetable systems.  Through the work of this grant we were able to determine that interseeding is a viable and effective method of cover cropping under certain conditions.  In particular the most effective way to interseed cover crops is to have a clear understanding of the limitations of these cropping systems.  The current cash crop as well as the cropping history of the field can provide useful information about how successful interseeding is likely to be.  For example, high yielding corn silage fields are likely to pose complications in establishing cover crops as well as grain corn fields due to low light infiltration.  Furthermore, fields with high weed pressure or herbicide application histories can present challenges to cover crop establishment and germination.  Farmers planning to cover crop must consider what products have been used on the field and whether or not they may contain residuals that will inhibit cover crop germination.  Finally, for vegetable or other unique and variable cropping systems, the farmer must consider if there are any site specific considerations that would present challenges for cover cropping.  If these considerations are all considered prior to attempting to establish cover crop, the farmer will have a greater chance for success.  

Participation Summary
9 Farmers participating in research

Education & Outreach Activities and Participation Summary

40 Consultations
7 On-farm demonstrations
5 Workshop field days

Participation Summary:

575 Farmers participated
140 Number of agricultural educator or service providers reached through education and outreach activities
Education/outreach description:



Planned and promoted fall cover crop series (August-November 2016).

To get the project started, the team offered "A Fall Look at Cover Crops" field day series in late October 2016 to help increase the interest in cover crops and to recruit farmers to participate in the project.  Four field days were offered: two focused on livestock and silage corn, one on vegetable operations, and one was held on a research farm and focused on field research trials (see flyer at: 2016AFallLookatCoverCropsFieldDaySeriesflyer).  Each field day was offered on host farms for two hours and included presentations by the host farmers as well as Extension educators and other agricultural service providers. Topics addressed ranged from the timing of planting and terminating cover crops, species selection (including mixtures), equipment choices (including interseeders), and soil health impacts. Seventy-four (74) people participated in the field days including 34 farmers, 16 Extension educators, 7 state and federal employees, and 7 industry personnel.

On February 16th, 2017 Project staff assisted in the planning and hosting of the 2017 No-Till Symposium.  This meeting was attended by 180 farmers and other stakeholders from around the northeast.  Details are contained in this flyer NTCC-Brochure_2017.

On July 27, 2017 UVM Extension staff hosted an annual field date at the research facility in Alburg.  The field day was attended by 308 attendees and no-till and cover cropping were discussed in various breakout meetings throughout the day.  Here is the flyer for that field day 2017-Field-Day-Flyer.

On August 17 2017 UVM Extension staff hosted a field day at one of our collaborator's farm.  Their was much discussion surrounding the use of cover cropping and a field walk was done.  It was attended by 60 farmers and other service providers.  Here is the flyer for that field day 2017FNLCFieldDay.

On October 12, 2017 a field day was hosted by one of our collaborators to look at cover cropping on vegetable farms.  It was attended by 13 farmers and service providers.  Here is the flyer for that field day 2017-RiverBerryFarm-101217.



The 2018 No-Till Symposium was held March 1st 2018 and had 172 attendees.  Here is the flyer for this event ntcc-brochure-2018. At this event we held a panel discussion with three farmers about their experiences with cover cropping. We had one farmer unable to attend so a substitution was made at the last minute.  The first farmer was Conner Rowley. He is a dairy farmer just getting into cover cropping on his operation. He was pleased with the interseeder and used it again during the 2018 crop season. The second farmer was Nick Manning. He is a no-till corn and grain farmer who had interseeded about 150 acres in 2017.  He had mixed results but likes the concept of getting the cover crop work done early. In his grain operation there is not enough time post-harvest to get good establishment of cover crops so interseeding is an important option.  The third farmer was Larry Gervais who is also a no-till farmer. He talked about the challenges of getting the cover crops planted post harvest and how they try to drill as many acres as possible of winter rye post-harvest.  All three farmers did a good job at conveying their experiences. 

Learning Outcomes

192 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
Key areas in which farmers reported changes in knowledge, attitude, skills and/or awareness:

Based on results from surveys provided at several events this project supported farms reported changes in their knowledge of equipment associated with cover cropping, soil health, knowledge of no-till systems, and the importance of cover crop diversity.  The farmers who attended these field days report having a better understanding about cover crops and recognize the importance of implementing them in their farming operations.

Project Outcomes

75 Farmers changed or adopted a practice
2 Grants applied for that built upon this project
Project outcomes:


A follow-up evaluation was conducted with participants of the 2016 A Fall Look at Cover Crop field day series. Twenty-four responses were received (32% response rate). All but one respondent (96%) indicated they learned new information at the field day they attended, and 75% said they intend to implement and/or apply something they learned at the field day(s) on their farms or in their work with farmers.

Follow-up evaluations from the 2017 No-Till Symposium, 2017 Annual Field day and the survey conducted at the River Berry Vegetable Farm indicate that all respondents learned more about cover cropping and/or other soil building practices.  Specifically, 10% of the respondents to at the 2017 NTCC symposium stated they planned to try cover cropping in 2017.  22% of the respondents in the Annual Field Day survey stated they planned on increasing their cover crop acreage.  40% of the respondents stated in the Annual Field Day Survey stated the would like to learn more about cover crops and cover crop equipment. 

The survey results from the 2018 No-Till Symposium showed that 56 respondents suggested that they would increase their adoption of cover crops in 2018. Results from the survey also listed the three greatest challenges to adoption as timing, termination, and costs. UVM Extension continues to assist farmers with modifying farm management practices to help better establish cover crops. We are also working to help farmers be better at managing cover crops to increase their profitability. The no-till symposium is a great event  for farmers to come together and network with each other and other service providers to better understand these practices and hone their environmental stewardship skills.

Assessment of Project Approach and Areas of Further Study:

Looking back at this project and how it was implemented there are several important aspects which made it successful and several challenges faced. The most important reason why this project was successful is that it was a collaboration between Extension and the farmers. UVM Extension has build a very strong relationship with farm operators across many different systems and farmers that we work with are very good at helping us implement projects which further our understand of different aspects of farming systems in this case cover cropping. This project was also successful because UVM maintains control over the implementation part of the grant. For purposes of demonstration and research UVM managed the planting of the cover crops which keeps the process moving along well. If this is delegated to the farmer the process slows down and implementation will vary more widely than if one entity oversees the plantings. The major challenge of this project was the wide range of cropping systems that we needed to implement the project on. Vegetable systems are the most challenging because the farmers use such a wide variety of row spacing and the timing of planting  varies widely when compared to conventional row crop systems. Although we could not implement the practice on two of the farms we planned on it was still a very successful project.  

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.