Minimal research has been conducted on winter terminated cover crop mixtures in the northern regions of New England. Most of the work has been focused in warmer parts of the Northeast, mainly PA and NY (Sarrantonio, 1994; Stivers-Young, 1998). In New York, a study that evaluated several brassica cover crops, including radish, and oats showed that the brassica plantings accumulated more nitrogen than oats (FNE94-66). There are additional publications that provide information on how to grow cover crops, however, the recommendations are broad based and do not focus on specific needs for cooler climates (Clark, 2008; NRCS, 2011). Darby et al. (2014) has conducted expansive work on integrating cereal rye into cooler production regions. However, farmers are increasingly interested in reaping the benefits of multispecies mixes and struggling with how to incorporate these cover crops into their short growing season. A preliminary trial indicated greater percent soil cover from oat, clover, radish mixes planted 4-Sep compared to 16-Sep. For this project, we propose to evaluate a broader range of planting dates to capture optimum cover crop productivity. An ongoing project, funded by the Vermont Specialty Crop Block Grant, titled Maximizing Nitrogen from Cover Crops on Vermont Vegetable Farms (Madden et al., 2016), evaluates soil and biomass nutrients for fall planted oats and vetch and spring planted oats and peas at three planting dates. These are synergistic projects evaluating different cover crops in short growing seasons.
There are also several current SARE-funded outreach efforts related to our topic. The ONE16-284c project encourages peer-to-peer learning on cover crop adoption through discussions and field meetings throughout New Hampshire. This project also proposes a component of peer-to-peer learning by highlighting success stories that will be shared through a written publication. Our project will use a similar technique except be specifically geared towards farmers in northern regions of New England. Our research on planting dates, species selection, nutrient cycling, and soil health influenced by winter terminated cover crops also has the potential to be incorporated in project ENE16-144, which proposes to form a Northeast Cover Crops Council and create a comprehensive cover cropping decision making tool and in doing so, will synthesize data. Darby is a collaborator on this SARE project.
The proposed project will add unique information on winter terminated cover crops grown in cold climates. Planting date, nitrogen cycling, and impacts on soil health have not been documented in this climate or diverse range of soil types. This project has a high likelihood of also providing critical information towards the development of a comprehensive cover cropping decision making tool.
The goal of this project is to increase the acres of effective cover crops on vegetable farms in northern climates to
improve soil health, nutrient cycling, and crop productivity while reducing the chance for nonpoint source nutrient
pollution to the environment.
The question is can winter-terminated cover crops improve soil health, nutrient cycling, and reduce the risk of runoff
as compared to a standard cereal rye cover crop?
We will work towards this goal by developing, evaluating, and verifying the effectiveness of winter terminated
cover cropping strategies that will help maintain and improve soil productivity.
The specific objectives of the project are to:
1) Evaluate the impact of winter terminated cover crops on soil health, nitrogen cycling, and soil cover compared
to a standard winter rye cover crop;
2) To determine optimum planting dates that allow winter terminated cover crops to maximize biomass production
and soil cover; and
3) To develop and distribute cover cropping information that is applicable to vegetable farmers located in northern
regions of New England.
These objectives will be met through on- farm research and delivered to farmers through an extensive outreach
program. The outreach materials will be delivered via guides, web-based resources, and outreach events.
Objective 1: Three on-farm research trials were initiated in August of 2017 to evaluate the impact of winter-terminated cover crops on soil health, nitrogen cycling, and soil cover. The on-farm research sites represented a variety of soil types including loam (Borderview Farm), sandy loam (River Berry Farm) and clay loam (Pomykala Farm). Table 1 shows 18 cover crop treatments that included single species as well as mixes. All of the 18 cover crop treatments were evaluated at the Borderview Farm site where only a subset of these treatments were evaluated at River Berry and Pomykala Farm research sites.
All 18 treatments were planted at Borderview Farm on August 24, in a randomized complete block design with 4 replications, in 5’x20’ plots. At the time of planting, soil samples were taken to measure the baseline soil nitrate-N. Five cores were taken per plot each 10-12” deep. All soil samples collected for this project were dried at approximately 105⁰F and sent to the University of Vermont Agricultural and Environmental Testing Lab for analysis. On October 19, biomass was sampled by clipping the contents in one 0.5m2 quadrat per plot. All biomass samples collected for this project were weighed, dried at approximately 105⁰F, and weighed when dry to calculate yields. All biomass samples will be ground and analyzed for total N concentration using NIR analysis FOSS DS2500. Percent cover was recorded on the same day, by taking photos of one 0.5m2 quadrat per plot. The percent of soil covered will be analyzed using the IMAGING Crop Response Analyzer online program. Lastly, soil samples also were taken day of harvest to measure the end of season soil nitrate-N. Five cores were taken per plot each 10-12” deep.
Treatments 13 (oats, clover, and radish), 15 (cereal rye & vetch), and 18 (control) were planted at River Berry Farm on August 21, in a randomized complete block design with 3 replications, in 10’x300’ strip plots. At the time of planting, soil samples were taken to measure the baseline soil nitrate-N. Eight cores were taken per plot each 10-12” deep. On October 20, biomass was sampled by clipping the contents in three 0.5m2 quadrats per plot. Percent cover was recorded on the same day, by taking photos of two 0.5m2 quadrats per plot. The percent of soil covered will be analyzed using the IMAGING Crop Response Analyzer online program. Lastly, soil samples also were taken day of harvest to measure the end of season soil nitrate-N. Eight cores were taken per plot each 10-12” deep.
Treatments 11 (radish), 13 (oats, clover, and radish), 14 (cereal rye), and 18 (control) were planted at Pomykala farm on August 21, in a randomized complete block design with 3 replications, in 10’x75’ plots. At the time of planting, soil samples were taken to measure the baseline soil nitrate-N. Eight cores were taken per plot each 10-12” deep. On October 20, biomass was sampled by clipping the contents in two 0.5m2 quadrats per plot. Percent cover was recorded on the same day, by taking photos of two 0.5m2 quadrats per plot. The percent of soil covered will be analyzed using the IMAGING Crop Response Analyzer online program. Lastly, soil samples also were taken day of harvest to measure the end of season soil nitrate-N. Eight cores were taken per plot each 10-12” deep.
In April 2018, the living and/or terminated cover crop biomass will be sampled, percent cover photos will be taken, and plots will be sampled for soil nitrate-N concentration, as described above, at the three farms. The soil sampling will continue every two weeks until July, in order to track the concentration of soil nitrate-N over the course of the growing season. Farmers will record crop yield from each of the treatment plots.
In May 2018, the winter rye will be terminated at all farms. The active carbon (reaction with potassium permanganate solution) will be measured to gain an understanding of the organic matter concentration that is readily available to the microbial community. We will also measure wet aggregate stability using the Cornell Sprinkle Infiltrometer, which steadily rains on a sieve containing a known weight of soil aggregates between 0.25-2.0 mm for five minutes. These soil health parameters will be measured by taking a 6” deep x 2” wide soil sample, per plot. These samples will be sent to Cornell Soil Health Testing Laboratory (Geneva, NY) for analysis.
OBJECTIVE 2: In order to meet objective 2, the 18 treatments listed in Table 1 were planted at Borderview Farm on August 24, September 11, September 19, and September 27 in a randomized complete block with split plots and 3 replications. Plot size was 5’x20’. Main plots were planting date and subplots were cover crop treatments.
On October 19 (Riverberry & Pomykala Farms) and October 31 (Borderview Farm), biomass was sampled by clipping the contents in one 0.5m2 quadrat per plot in order to calculate yields. Only the biomass from the August 24 planting date will be analyzed for N concentration, as described above. Percent cover was recorded on the same day, by taking photos of one 0.5m2 quadrat per plot. The percent of soil covered will be analyzed using the IMAGING Crop Response Analyzer online program. In April 2018, biomass and percent cover will be sampled again, as previously described.
All data will be analyzed using mixed model analysis using SAS (SAS Institute, 2008). All treatment factors in this experiment will be considered fixed with the exception of replicates. Mean separation among treatments involving cover crop type and planting date will be obtained using the Least Significant Difference procedure when significant F-tests (P<0.10) are observed.
OBJECTIVE 3: The approach to meeting objective 3 is described under the ‘Outreach and education’ section
Originally we planned to plant 5 winter killed cover crop treatments and winter rye at Borderview Farm; however, because we had available cover crop seed and an interest in continuing treatments used in our preliminary study, referenced below, we planted 16 cover crop treatments, winter rye, and a control for a total of 18 treatments.
For the planting date trial at Borderview, we originally planned to include only three winter terminated cover crop treatments and cereal rye as the control, however, since we had the space we used the same 18 treatments in all four planting dates.
We originally planned for 3 winterkilled cover crops and winter rye at River Berry, however, due to space constraints we reduced to 1 winterkilled cover crop treatment and a winter rye and vetch mix. The farm owner, David Marchant, had been growing the winter rye and vetch mix seed and was especially interested in having it evaluated, which inspired us to include it as a treatment at his farm and Borderview Farm.
For Pomykala Farm we had planned for 1 winterkilled cover crop and winter rye, but had space for two winterkilled cover crop treaments and winter rye. The farm owner, Bob Pomykala, was especially interested in tillage radishes, which inspired us to include it as a treatment at his farm and Borderview Farm.
Preliminary results show that cover crop biomass yields drastically decreased with later planting dates, ranging from 2635 to 288 lbs acre-1 dry matter between the August 24th and September 27th plantings. Treatment 7 of Everleaf oats, Duration clover, and Appin turnip, showed the highest average yield of 2484 lbs acre-1. Differences in percent cover do not appear as extreme between treatments, however, between the August 24th and September 27th planting the range was 82.6-38.2% ground cover.
From the field-based research portion of this project, we sought to evaluate winter terminated cover crops in comparison to winter rye and the impact of planting date on cover crop biomass and cover. Preliminary conclusions are that earlier planting dates yield more biomass and percent cover than later planting dates and there will be variability in yield based on the type of cover crop grown. We will have more detailed results showing comparisons with winter rye, nutrient analysis, statistical evaluation, and impact after the second year of the field-based research and outreach portions of this project are completed.
Education & Outreach Activities and Participation Summary
In order to meet objective 3, There were 4 field days were held to highlight the benefits of cover cropping and strategies to implement cover crops on farms in Vermont.
The Annual Northwest Crops and Soils Field Day was held on July 27th at Borderview Farm in Alburgh, VT. This field day had 302 participants from around the region. The field day highlights many research projects as well as relevant agricultural topics. This year the focus was on soil health and strategies to help farms build resilient soils. The tours included research information on cover crops, species and planting dates relevant to the region, and also information on cover crop planting strategies.
Cover cropping was highlighted at two additional on-farm tours that occurred in August and September in Thetford and Bridport, VT. These events were focused on improving and protecting water quality. Cover crop information was provided to attendees including planting date, species selection, and termination/planting strategies. These field days had a total of 34 attendees.
A field day was held at River Berry Farm on October 12. David Marchant, owner and operator of River Berry Farm, participated in the event. We looked at and discussed cover cropping equipment, looked at and discussed the cover crop stands, discussed cover cropping as a means for overall soil health, discussed saving cover crop seed, and reviewed additional soil health management strategies, as demonstrated through David Marchant’s practices. There were 13 participants total.
Currently interviews have been set up with Bob Pomykala, David Marchant, and two additional farmers, which will contribute to developing ‘Cover Crop Success Stories’. These stories, along with our research results, and existing research on cereal rye as a cover crop will be compiled to create a bulletin titled, “Cover Cropping on Vegetable Farms in Northern New England.”
Two presentations will be given at the Vermont Vegetable and Berry conference and the NOFA-VT conference in the winter of 2018/2019, after the completion of this research trial. Originally we had planned to give these presentations in the winter of 2017/2018, however, we will have full results and more accurate conclusions to share the following year.
At the Northwest Crop and Soil Field Day, 34% of the participants that responded to the post-event survey indicated that they would try cover cropping or implement new cover cropping strategies as a result of what they learned.
One hundred percent of survey respondents from the October 12 workshop responded saying they gained knowledge on cover cropping benefits/uses and 66% responded saying they gained knowledge on required practices, nutrient balancing, and specialized equipment for cover cropping.