Final report for ONE17-293

Project Type: Partnership
Funds awarded in 2017: $14,996.00
Projected End Date: 12/31/2018
Grant Recipient: University of Vermont
Region: Northeast
State: Vermont
Project Leader:
Dr. Heather Darby
University of Vermont Extension
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Project Information

Summary:

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). Between increasingly erratic weather in the Northeast with more heavy rains and drought, and increased concern about agricultural runoff in waterways, there is a growing need for better soil health and nutrient management. In order to provide helpful cover cropping information specific to the northern region of New England, a research trial was done to evaluate seventeen cover crop treatments at three farm locations (Borderview Farm, Pomykala Farm, River Berry Farm). The cover crop biomass yield and percent cover were recorded at cover crop maturity in fall 2017 and after winter, in spring 2018. Soil NO3 was measured consistently during the 2018 growing season. Subsequent cash crop yields and quality were recorded. An additional study was done to evaluate the effect of planting date on cover crop biomass yield and percent cover (Borderview Farm). Four planting dates (24-Aug, 11-Sep, 19-Sep, 27-Sep 2017) were evaluated over 17 cover crop mixes.

Results from the one-year project indicated that earlier planted cover crops (24-Aug) resulted in the greatest fall biomass yields. The mid-Sep (19-Sep) planting date resulted in the highest spring biomass yields. This indicated that overwintering cover crops performed best when planted by mid-Sep and winter terminated cover crops performed best when planted by 24-Aug.  Interestingly, winterkilled cover crop treatments were competitive with overwintering cover crop treatments for providing spring ground cover. This indicates that winter terminated cover crops can still provide adequate residue to protect the soil from erosion in the spring.

During this short term project, the cover crops appeared to have minimal impact on the soil health indicators, active carbon and aggregate stability. The Grand Isle location did see an increase in aggregate stability when tillage radishes were grown. Longer term research is needed to identify impacts of cover crops on soil health. The research indicated that excess soil NO3 was scavenged by the cover crops in the fall. Hence growing cover crops reduces the risk of N loss through the winter months. The research indicated that the winter terminated cover crops mineralized and released NO3 in the early spring (Apr – May) and over wintered cover crops mineralized in Jun. No significant difference was seen in subsequently grown cash crop yield or quality at any of the locations. Overall the one year research project showed that multi-year data is needed to develop cover crop recommendations and strategies that benefit soil, crop, and farm productivity. 

Outreach was done in the form of three field days that were held in collaboration with River Berry Farm, Foggy Meadows Farm (Benson, VT), and Route 5 Farm (Fairlee, VT). The 3 events highlighted the cover crop research and other cover crop topics, including viewing cover crop stands, cover cropping to build soil health, saving cover crop seed, and equipment. These events attracted 49 attendees. Outreach also consisted of two completed research reports and a cover crop bulletin that was distributed at outreach events and at https://www.uvm.edu/sites/default/files/media/CC_Fact_Sheet_Vegetables_Northern_NE.pdf

Project Objectives:

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.

Introduction:

Refining soil health and nutrient management strategies is crucial for a farm’s success given today’s environmental and political climate. Cover cropping can have a tremendous impact soil, water and environmental quality as a whole (Clark, 2008).

Establishing effective cover crops in northern regions is challenging especially when following a full season crop. We must create a promotional campaign that touts not only the environmental benefits of cover cropping but the economic benefits. Farmers are looking to save money on fuel and fertilizer and are more receptive to new ideas than in the past. We hope to prove that cover crops can do just that!

Farmers are requesting information on how to incorporate new species of cover crops onto their farms. Farmers are interested in learning how to fully maximize the benefit of cover crops into their cropping systems. For example, many farmers want cover crops that can reduce erosion, break up compaction, suppress weeds, and not impede spring fieldwork. To meet these types of demands, new innovative cover cropping strategies must be implemented.

One such strategy is developing mixtures of cover crop species that provide a multitude of ecosystem and farm benefits. This project will determine how combinations of plants—rather than single-species cover crops—influence cover-crop yield, soil quality, nutrient retention, and soil cover.

During a soil health meeting offered by the Northeast Organic Farming Association of Vermont (February 2016), the group of 30 growers agreed that there is a need for nutrient credit information for cover crops. During a session where farmers were trying to calculate nitrogen (N) credits from cover crops there was inadequate information when it came to winter terminated species. The Northeast Cover Crop Handbook has excellent tables for estimating N content from vetch and rye but limited for other species. One farmer commented, “well there has to be something available the next season, there was so much cover crop growth prior to winter”!

If farmers are to fit these cover crops into their valuable field space and busy schedules, it is essential that we have relevant and applied information for their growing climate.

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). Darby et al. (2015) 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 and Grubinger, PIs), 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.

Citations Clark, A. (ed). 2008. Managing Cover Crops Profitably. Sustainable Agriculture Network III Series. Beltsville, MD.

Darby, H., C., Burke, L. Calderwood, H. Harwood, D. Heleba, and J. Sanders. 2015. Under Cover: Integrating Cover Crops into Silage Corn Systems. University of Vermont. verified 12-Apr., 2019. https://www.uvm.edu/sites/default/files/media/UnderCoverGuideAug2015_FINAL.pdf.

Sarrantonio, M. 1994. Northeast Cover Crops Handbook. Soil Health Series. Rodale Institute Printing. Emmaus, PA.

Stivers-Young, L. 1998.  Growth, Nitrogen Accumulation, and Weed Suppression by Fall Cover Crops Following Early Harvest of Vegetables. HortScience.

Cooperators

Click linked name(s) to expand
  • Bob Pomykala (Researcher)
  • Roger Rainville (Researcher)
  • David Marchant (Researcher)

Research

Materials and methods:

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).

At Borderview Farm, 4 winter terminated cover crops, 9 winter terminated mixes, 2 overwintering cover crops, and 2 overwintering cover crop mixes (for a total of 17 cover crop treatments, see Table 1) were planted and control plots were installed on August 24th, 2017. The experimental design was a randomized complete block design with 4 replications. Plot size was 5’x20’.

Table 1. Cover crop treatments.

Mix #

Over winter

Variety

Seeding rate lb ac-1

 

Mix #

 

Over winter

 

Variety

Seeding rate lb ac-1

1

No

Annual ryegrass

16

7

No

Everleaf oats

40

Crimson clover

6

Duration clover

5

Arifi radish

2

Appin turnip

2

   

8

No

Bruiser ryegrass

15.2

2

Yes

Fridge triticale

40

Appin turnip

2.11

Eco-till tillage radish

2

9

No

Fria ryegrass

22

Freedom red clover

5

Eco-till radish

3

Lynx winter pea

20

10

No

Everleaf oats

70

3

Yes

Winter rye

40

11

No

Eco-till radish

8

Dynamite clover

1

12

No

Dixie crimson clover

10

Appin turnip

2

13

No

Everleaf oats

70

4

Yes

Hyoctane triticale

60

Eco-till radish

3

Dynamite clover

3

Crimson clover

10

Appin turnip

2

14

Yes

VNS winter rye

75

5

No

Everleaf oats

60

15

Yes

Rye and Vetch

70

Ground hog radish

3

16

No

Fria annual ryegrass

30

6

Yes

Tricale triticale

60

17

Yes

Hairy vetch

24

Dwarf essex rape

3

18

N/A

Control – No cover crop

At the time of planting soil was sampled for nitrate-N concentration. From each plot, five soil cores were taken at 10-12” depth, using a soil probe, mixed in a bucket, and a cup subsampled and dried at 140⁰F. Soil samples were sent to the University of Vermont Agricultural and Environmental Testing Laboratory for analysis.

The cover crop biomass was harvested before heavy frost on October 19th, 2017, by clipping the plant matter contained in two 0.5 m2 quadrats per plot. The biomass was weighed, dried in a drying room at approximately 140⁰F, and weighed again to calculate dry yields. The biomass was ground and analyzed for total N concentration using NIR analysis FOSS DS2500.

The soil was sampled for soil nitrate-N concentration (as described previously) at the time of biomass sampling. Photos were taken of one 0.5 m2 quadrat per plot and evaluated for percentage of soil covered by cover crop. The IMAGING Crop Response Analyzer online program will be used to analyze the photos.

On May 11th, 2018, cover crop plots had both terminated and/or living biomass sampled as described above. The percentage of soil covered with living and/or dead biomass was captured through photos as previously described. For the triticale and rape, winter rye, and winter rye and vetch treatments, the biomass was ground and analyzed for total N concentration using NIR analysis FOSS DS2500.

Plots were sampled for soil nitrate-N concentrations every two weeks from May 9th – August 28th.

On May 10th, 2018, in the tillage radish, winter rye, winter rye and vetch, hairy vetch, and control plots active carbon (reaction with potassium permanganate solution) was measured to gain an understanding of the organic matter concentration that is readily available to the microbial community. We also measured 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 were measured by taking a 6” deep x 2” wide soil sample, per plot. These samples were sent to Cornell Soil Health Testing Laboratory (Geneva, NY) for analysis. Following soil health samples all plots were incorporated with a disc followed by a spike tooth harrow. The tillage events terminated the over-wintering cover crops and also incorporated dead biomass in the winter-terminated cover crop plots.

Sweet corn was planted on June 7th, 2018. Sweet corn was harvested on August 21st, 2018. Plant population and corn yield were recorded for the middle two rows of each plot. Corn ear length was measured for a subsample of five ears per plot.

At River Berry Farm, the oats, tillage radish, clover mix (mix 13) and winter rye and vetch mix (mix 15) were planted in a replicated strip trial on August 21st, 2017, along with a control (mix 18) treatment for a total of 3 treatments. At Pomykala Farm, the oats, tillage radish, and clover mix (mix 13), tillage radish treatment (mix 11), and winter rye treatment (mix 14) were planted in a replicated strip trial on August 21st, 2017, along with a control treatment (mix 18) for a total of 4 treatments. Each strip planting represented a plot and there were three replications per cover crop. Measurements were identical to those described for Borderview Farm. See below for specific details and for when data was collected:

River Berry Farm- Biomass yields harvested and percent cover measured on October 20th, 2017 and April 24th, 2018. All samples from the fall harvest were analyzed for total N concentration. The winter rye and vetch treatment (mix 15) was selected for total N analysis, from the spring harvest. On May 3rd, 2017 the winter rye and vetch (mix 15) and control treatments (mix 18) were sampled for active carbon and wet aggregate stability analysis. Following the soil health sampling, the treatment plots were tilled with a disc followed by a rototiller. Soil nitrate sampling occurred on August 21st and October 20th 2017, and every two weeks from April 28th till August 3rd, 2018. River Berry Farm had grown strawberries where the cover crop had been, which will not be harvested until 2019.

Pomykala Farm- Biomass yields harvested and percent cover measured on October 20th, 2017 and April 27th, 2018. All samples from the fall harvest were analyzed for total N concentration. The winter rye  (mix 14) and radish treatments (mix 11) were selected for total N analysis, from the spring harvest. On May 10th, 2017 the winter rye (mix 14), tillage radish (mix 11), and control (mix 18) treatments were sampled for active carbon and wet aggregate stability analysis. Following soil health sampling plots were tilled with a moldboard plow followed by a disc operation, and finished with a field cultivator. Soil nitrate sampling occurred on August 21st and October 20th 2017, and every two weeks from April 27th till August 28th, 2018. At Pomykala Farm on August 30th, 2018, sweet corn populations were recorded by counting the number of plants in two 10 foot long sections within each plot. Sweet corn height was recorded by measuring three plants per plot. The sweet corn weight and ear length was recorded by weighing 5 ears per plot.

A cover crop planting date study was conducted at Borderview Farm. The 17 cover crop treatments aforementioned were planted on August 24th, September 11th, September 19th, and September 27th, 2017. The experimental design was a randomized complete block with split plots and four replications. Main plots were the 4 planting dates and the split plot treatments were the cover crop treatments. These plots were sampled for cover crop and percent cover using the methods described above, on October 17th 2017 and May 11th. Sweet corn was planted into the September 11th planting on May 24th and again on June 7th, 2018, due to a planting error. Sweet corn was harvested on August 21st, 2018. Plant population and corn yield were recorded for the middle two rows of each plot. Corn ear length was measured for a subsample of five ears per plot.

Mixed model analysis was calculated using the mixed procedure of SAS (SAS Institute, 2008). All treatment factors in this experiment were considered fixed with the exception of replicates. Mean separation among treatments involving cover crop type and planting date were obtained using the Least Significant Difference procedure when significant F-tests (P<0.10) are observed.

 

OBJECTIVE 2: Cover Crop Planting Date

A cover crop planting date study was conducted at Borderview Farm. The 17 cover crop treatments aforementioned were planted on August 24th, September 11th, September 19th, and September 27th, 2017. The experimental design was a randomized complete block with split plots and four replications. Main plots were the 4 planting dates and the split plot treatments were the cover crop treatments. These plots were sampled for cover crop and percent cover using the methods described above, on October 17th 2017 and May 11th.

All data was 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

Research results and discussion:

Objective 1: On-Farm Cover Crop Variety Trial

Seasonal precipitation and temperature were recorded with a Davis Instrument Vantage Pro2 weather station, equipped with a WeatherLink data logger at Borderview Research Farm in Alburgh, VT (Table 2 and 3).

Table 2. Seasonal weather data collected in Alburgh, VT, 2017.

 

2017

Alburgh, VT

August

September

October

November

December

Average temperature (°F)

67.7

64.4

57.4

35.2

18.5

Departure from normal

-1.07

3.76

9.16

-2.96

-7.41

 

 

 

 

 

 

Precipitation (inches)

5.5

1.8

3.3

2.3

0.8

Departure from normal

1.63

-1.80

-0.31

-0.84

-1.59

 

 

 

 

 

 

Growing Degree Days (base 50°F)

553

447

287

18

1

Departure from normal

-28

129

287

18

1

Based on weather data from a Davis Instruments Vantage Pro2 with WeatherLink data logger. Alburgh precipitation data from August-October was provided by the NOAA data for Highgate, VT. Historical averages are for 30 years of NOAA data (1981-2010) from Burlington, VT.

 Table 3. Seasonal weather data collected in Alburgh, VT, 2017-2018

 

2018

Alburgh, VT

January

February

March

April

May

June

July

August

Average temperature (°F)

17.1

27.3

30.4

39.2

59.5

64.4

74.1

72.8

Departure from normal

-1.73

5.79

-0.66

-5.58

3.10

-1.38

3.51

3.96

 

 

 

 

 

 

 

 

 

Precipitation (inches)

0.8

1.2

1.5

4.4

1.9

3.7

2.4

3.0

Departure from normal

-1.26

-0.60

-0.70

1.61

-1.51

0.05

-1.72

-0.95

 

 

 

 

 

 

 

 

 

Growing Degree Days (base 50°F)

3

6

1

37

352

447

728

696

Departure from normal

3

6

1

37

154

-27

88

115

Based on weather data from a Davis Instruments Vantage Pro2 with WeatherLink data logger. Alburgh precipitation data from August-October was provided by the NOAA data for Highgate, VT. Historical averages are for 30 years of NOAA data (1981-2010) from Burlington, VT.

In 2017, August was cooler and wetter than historical averages while September and October were unseasonably hot and dry. The winter months of November thru January were cold and dry. The early months of 2018 experienced a lot of variation. February was unseasonably warm, March was typical, April was unseasonably cold and wet, and May was warm and dry. The months of July and August were warmer and dryer than historical averages.

 

Results from Fairfax Location

Table 4. Cover crop mix yield and quality, Fairfax, VT, 2017-18.                

Mix

Fall 2017

Spring 2018

Dry matter yield

Percent cover

Nitrogen

C:N

Dry matter yield

Percent cover

Nitrogen

lbs ac-1

%

%

Ratio

lbs ac-1

%

%

13

7380

79.1

3.10

12.7

4.37

15

7268*

72.6*

4.39

8.99

1871

66.8

2.88

Control

0

0.231

5.24

LSD (0.10)

2072

8.27

0.519

3.33

NA

NS

NA

Trial mean

4883

50.7

3.75

10.8

NA

5.48

NA

*Treatments marked with an asterisk did not perform statistically worse than the top performing treatment (p=0.10) shown in bold.

NS – There was no statistical difference between treatments in a particular column (p=0.10).

NA – Statistical analysis was not performed as only one treatment had living biomass to measure in the spring.

 

Both treatments 13 (oats, radish, clover) and 15 (winter rye and vetch) performed comparably in the fall for yield and percent soil cover (Table 4). Treatment 15 had a greater nitrogen concentration, which was to be expected as it contained a legume. In the spring, the cover crop that contained winter rye and vetch provided ample soil cover and biomass.

Table 5. Soil active carbon and wet aggregate stability, Fairfax, VT, 3-May 2018. 

Mix

Active carbon

Wet aggregate stability

mg C kg-1

%

15

578

15.8

Control

634

15.3

LSD (0.10)

25.3

NS

Trial mean

606

15.6

The top performing treatment (p=0.10) shown in bold.

NS – There was no statistical difference between treatments in a particular column (p=0.10).

Surprisingly, the control had a greater amount of active carbon in the soil compared to treatment 15 (winter rye and vetch) (Table 5). Soil active carbon was measured prior to termination of the cover crop. Hence, it is possible that the measurement of active carbon would have been higher had the cover crop been amended into the soil before the samples were taken. Ample dead and decomposing weed biomass were present in the control plots and may have contributed to active carbon.

Table 6. Soil NO3-N within the different cover crop treatments, Fairfax, VT, 2017-18. 

Mix

2017

2018

21-Aug

20-Oct

28-Apr

10-May

23-May

6-Jun

19-Jun

18-Jul

3-Aug

mg kg-1

13

23.5

2.26

2.92

5.37

7.79

27.3

22.7

26.0

12.5

15

19.1

3.27

2.03

7.40

17.4

41.5

26.6

28.4

12.5

Control

29.6

20.8

1.95

5.48

15.6

23.2

28.9

26.6

15.3

LSD (0.10)

NS

2.12

0.745

NS

NS

13.9

NS

NS

NS

Trial mean

24.0

8.76

2.30

6.08

13.6

30.6

26.1

27.0

13.4

The top performing treatment (p=0.10) shown in bold.

NS – There was no statistical difference between treatments in a particular column (p=0.10).

 

Clearly, the cover crops helped to scavenge excess nitrogen in the soil. In the fall of 2017, the control plots had the highest level of soil nitrates compared to those with a cover crop. For all treatments, soil NO3-N peaked between 6-Jun and 19-Jun (Figure 1, Table 6). Interestingly, the rye and vetch treatment peaked the highest for soil NO3-N out of all the treatments. This occurred on the 6-Jun sampling and was significantly higher than the other treatments. This indicates that the N from the rye/vetch cover crop took approximately 40 days to begin mineralizing and releasing NO3-N. The high levels of NO3-N in the control show excess nutrients that would likely be lost into the environment. The value of having a cover crop is to scavenge excess nutrients and keep them from leaving the system through leaching or other pathways.

Results from the Grand Isle Location

Table 7. Cover crop mix yield and quality, Grand Isle, VT, 2017-18.          

Mix

Fall 2017

Spring 2018

Dry matter yield

Percent cover

Nitrogen

C:N

Dry matter yield

Percent cover

Nitrogen

lbs ac-1

%

%

Ratio

lbs ac-1

%

%

11

2048*

85.6

2.72*

13.1

15.1

13

2678

84.4*

2.37*

17.0

3.00

14

1401

71.6

2.82

13.6

2279

35.8

2.03

Control

835

44.9

1.66

12.9

17.8

LSD (0.10)

654

10.7

0.500

2.96

NA

7.04

NA

Trial mean

1741

72.4

2.39

14.2

NA

17.9

NA

*Treatments marked with an asterisk did not perform statistically worse than the top performing treatment (p=0.10) shown in bold.

NA – Statistical analysis was not performed as only one treatment had living biomass to measure in the spring.

 

In the fall, treatments 11 (radish) and 13 (oats, clover, radish) were the best performers for yield and ground cover (Table 7). Treatments 11, 13, and 14 (winter rye) had comparable nitrogen concentrations, which may reflect the strong ability for winter rye to absorb available nitrogen. Biomass in the control plots were weeds but still provided adequate ground cover to protect the soil from erosion. Treatment 14 (winter rye) was the best performer for percent soil cover in the spring, which is not surprising since it overwinters.

Table 8. Soil active carbon and wet aggregate stability, Grand Isle, VT, 10-May 2018. 

Mix

Active carbon

Wet aggregate stability

mg C kg-1

%

11

585

39.7

14

574

29.7

LSD (0.10)

NS

7.31

Trial mean

580.0

34.7

The top performing treatment (p=0.10) shown in bold.

NS – There was no statistical difference between treatments in a particular column (p=0.10).

Treatment 11 (radish) outperformed treatment 14 (winter rye) for wet aggregate stability (Table 8). Soil aggregates are formed when biological activity in the soil causes soil particles and organic matter to become glued together. The more glue the more stable a soil aggregate may become. The stronger the aggregate the more resistant it is to being degraded when disturbed by rain or mechanical action. Higher aggregate stability can improve soil drainage and other biological properties. The radish growing in the fall likely improved biological activity and helped to build soil aggregates. Once the radish died from cold winter temperature, microbial activity to decompose the root may have further enhanced the aggregate stability.

Table 9. Soil NO3-N within the different cover crop treatments, Grand Isle, VT, 2017-18. 

Mix

2017

2018

21-Aug

20-Oct

24-May

8-Jun

20-Jun

3-Jul

19-Jul

1-Aug

16-Aug

28-Aug

mg kg-1

11

7.16

3.61*

3.34

5.47

7.38

14.8

25.5

26.3

41.2

44.1

13

6.60

1.40

4.04

5.23

6.58

15.9

20.6

29.0

56.2

45.3

14

5.78

1.44

2.62

4.37

6.35

16.3

24.9

30.0

55.3

32.4

Control

8.20

5.48

2.16

3.37

5.69

17.3

23.8

35.3

54.0

46.6

LSD (0.10)

NS

2.54

NS

NS

NS

NS

NS

NS

NS

NS

Trial mean

6.94

2.98

3.04

4.61

6.50

16.1

23.7

30.1

51.7

42.1

*Treatments marked with an asterisk did not perform statistically worse than the top performing treatment (p=0.10) shown in bold.

NS – There was no statistical difference between treatments in a particular column (p=0.10).

 

There were low levels of soil nitrate in the fall of 2017. Interestingly, control soil nitrate levels were higher indicating that the cover crops were utilizing excess soil nitrate. Throughout the 2018 season, the differing cover crop treatments performed comparably for soil NO3-N concentrations (Figure 2, Table 9). Given the drought conditions that were observed across the growing season, it is possible that cover crop decomposition was slow due to lack of moisture and above average temperatures.

 

Table 10. Sweet corn yield and quality, Grand Isle, VT, 30-Aug 2018.        

Mix

Corn plant height

Population

Corn ear weight

Corn ear length

cm

plants ac-1

lbs

cm

11

165

29,506

0.620

18.9

13

170

28,264

0.511

17.6

14

166

27,953

0.599

18.7

Control

165

28,574

0.558

18.3

LSD (0.10)

NS

NS

NS

NS

Trial mean

167

28,574

0.572

18.4

 NS – There was no statistical difference between treatments in a particular column (p=0.10).

 The sweet corn grown following the cover crop did not show any significant differences for yield or quality, between cover crop treatments (Table 10).

 Results from Borderview Farm

 Table 11. Cover crop mix yield and quality, Alburgh, VT, 2017-18.       

Mix

Fall 2017

Spring 2018

Dry matter yield

Percent cover

Dry matter yield

Percent cover

lbs ac-1

%

lbs ac-1

%

1

3126

88.9*

490.0

37.0

2

2992

80.7

1075

74.0*

3

3561*

92.3*

720.0

35.0

4

3297

89.9*

768

45.0

5

2808

84.0*

1383

64.0

6

2221

82.9

1378

56.0

7

4388

78.3

1229

43.0

8

3438*

88.5*

805

39.0

9

3165

92.5*

486

34.0

10

2961

80.9

1288

75.0*

11

2890

95.2

323

14.0

12

1590

86.8*

796

84.0*

13

2964

85.0*

1463

78.0*

14

2076

84.3*

2720*

100.0

15

1088

69.9

2862

100.0

16

3122

73.8

1557

96.0*

17

1104

82.5

1714

100.0

Control

668

44.5

1559

100.0

LSD (0.10)

984

12.0

583

28.8

Trial mean

2568

82.7

1252

65.3

*Treatments marked with an asterisk did not perform statistically worse than the top performing treatment (p=0.10) shown in bold.

At Borderview Farm, the best performers for fall yield were treatments 3 (winter rye, clover, turnip), 7 (oats, clover, turnip), and 8 (ryegrass, turnip) (Table 11). All treatments had adequate soil cover and would have been protected from erosion. In the spring, two of the treatments consisting of overwintering varieties, treatments 14 (winter rye) and 15 (winter rye and vetch), had the best yields. These two treatments were among the top performers for spring ground cover. Interestingly, the control and two winterkilled treatments (treatment 10 – oats and 13 – oats, radish, crimson clover) also were top performers for ground cover, which may indicate that the dead plant materials were effective as a spring cover.

Table 12. Soil active carbon and wet aggregate stability, Alburgh, VT, 10-May 2018. 

Mix

Active carbon

Wet aggregate stability

mg C kg-1

%

11

517

47.3

14

544

45.1

15

526

46.5

17

553

46.3

Control

530

53.6

LSD (0.10)

NS

NS

Trial mean

534

47.8

NS – There was no statistical difference between treatments in a particular column (p=0.10).

Among the treatments evaluated for active carbon and aggregate stability, there were no significant differences (Table 12).

Table 13. Soil NO3-N within the different cover crop treatments, Alburgh, VT, 2017-18. 

Mix

2017

2018

18-Oct

9-May

21-May

21-Jun

5-Jul

19-Jul

31-Jul

16-Aug

28-Aug

mg kg-1

1

11.9

9.53*

11.9

25.9

38.9

29.5

22.2

8.46

5.52

2

7.51

4.65

7.34

28.2

29.3

26.6

30.3

10.9

4.56

3

11.5

7.57*

11.5

33.7

35.8

36.4

34.4

9.63

5.34

4

5.51

8.65*

10.1

28.6

27.0

35.4

27.0

8.95

7.11

5

10.3

10.9

13.4*

30.1

27.9

25.0

21.0

6.39

4.98

6

11.2

8.96*

9.93

25.8

29.2

26.8

25.6

10.3

4.67

7

16.9*

10.9

18.5

43.4*

36.8

49.7

29.1

13.0

9.91

8

10.8

8.94*

12.5

34.3

41.3

37.9

30.5

14.5

7.41

9

12.0

7.06*

13.3*

25.5

33.3

33.7

26.0

9.53

5.07

10

10.7

6.44

9.64

21.2

28.3

25.9

22.5

9.39

4.71

11

5.54*

9.35*

13.8*

32.0

27.9

33.9

26.2

14.0

5.57

12

21.5

7.21*

9.44

27.4

27.9

30.1

33.7

15.4

4.71

13

9.46

9.73*

16.5*

38.2

32.6

38.8

23.6

12.6

6.45

14

9.46

6.33

8.16

28.9

32.6

49.3

34.2

15.4

7.29

15

15.4

4.09

5.88

25.7

42.0

36.8

35.9

11.8

8.83

16

16.2

11.1*

10.9

33.1

33.6

32.8

23.0

12.0

7.71

17

8.56

3.44

11.6

51.3

35.1

40.7

29.0

10.9

12.6

Control

26.6

3.31

7.78

25.2

31.5

41.0

31.9

12.1

7.20

LSD (0.10)

10.1

4.50

5.57

11.3

NS

NS

NS

NS

NS

Trial mean

12.3

7.68

11.2

32.8

35.0

28.1

11.4

6.65

31.0

*Treatments marked with an asterisk did not perform statistically worse than the top performing treatment (p=0.10) shown in bold.

NS – There was no statistical difference between treatments in a particular column (p=0.10).

 When most treatments were close to peak soil NO3-N for the season, on 21-Jun, treatments 7 (oats, clover, turnip) and 17 (hairy vetch) were top performers (Figure 3, Table 13). This is not surprising since both of those treatments contained nitrogen fixing varieties.

 Table 14. Sweet corn yield and quality Alburgh, VT, 2018. 

Mix

Population

Yield

Ear length

plants ac-1

lbs ac-1

cm

1

6098

4878

17.7

2

5082

3717

16.4

3

6534

7144

17.5

4

6970

5518

17.0

5

5808

5634

16.7

6

5518

4995

17.2

7

6534

7289

16.9

8

7115

7841

17.8

9

7696

7492

17.2

10

4792

4821

17.2

11

6098

2846

18.7

12

6534

4995

18.4

13

5808

9554

17.6

14

5518

3543

16.7

15

4646

2904

16.8

16

5953

7318

17.6

17

5082

6040

16.5

Control

5518

4182

17.5

LSD (0.10)

NS

NS

NS

Trial mean

5961

5595

17.3

NS – There was no statistical difference between treatments in a particular column (p=0.10).

 No significant differences were seen in the sweet corn grown following the cover crop treatments (Table 14).

DISCUSSION

At both Pomykala Farm and Borderview Farm, there was no measurable impact on the subsequent cash crop that would indicate differences between the cover crop treatments. However, it is interesting to note of when peak soil NO3-N generally was at each farm. For River Berry Farm, peak soil NO3-N was between 6-Jun and 19-Jun, approximately 75 days after the field was prepped and planted with strawberries. This was earlier than the other farms and may be influenced by River Berry’s light soil, which would have warmed faster than the soils at the other two farms. Also, regular irrigation at River Berry Farm likely helped cover crops decompose more quickly. At Pomykala Farm, peak was on 16-Aug, which was approximately 45 days after field prep and planting. This was fairly late in the season and likely influenced by the extremely hot and dry conditions experienced during the growing season. At Borderview Farm, peak was from 21-Jun to 19-Jul, which was 30-60 days after field prep and planting of the sweet corn.  

 

It is important to consider the effect of soil texture and seasonal differences on soil NO3-N availability from cover cropping. Also, using a winterkilled cover crop variety may provide the benefit of not having to manage terminating the crop in the spring, when timing of this may be difficult due to wet, spring conditions. Cover cropping decisions will likely be based on the demands and goals within each operation and field management considerations.

Objective 2: Cover Crop Planting Date Trial

Seasonal precipitation and temperature were recorded with a Davis Instrument Vantage Pro2 weather station, equipped with a WeatherLink data logger at Borderview Research Farm in Alburgh, VT (Table 15).

Table 15. Seasonal weather data collected in Alburgh, VT, 2017-2018.

 

2017

2018

Alburgh, VT

August

September

October

November

December

January

February

March

April

May

Average temperature (°F)

67.7

64.4

57.4

35.2

18.5

17.1

27.3

30.4

39.2

59.5

Departure from normal

-1.07

3.76

9.16

-2.96

-7.41

-1.73

5.79

-0.66

-5.58

3.10

 

 

 

 

 

 

 

 

 

 

 

Precipitation (inches)

5.5

1.8

3.3

2.3

0.8

0.8

1.2

1.5

4.4

1.9

Departure from normal

1.63

-1.80

-0.31

-0.84

-1.59

-1.26

-0.60

-0.70

1.61

-1.51

 

 

 

 

 

 

 

 

 

 

 

Growing Degree Days (base 50°F)

553

447

287

18

1

3

6

1

37

352

Departure from normal

-28

129

287

18

1

3

6

1

37

154

Based on weather data from a Davis Instruments Vantage Pro2 with WeatherLink data logger. Alburgh precipitation data from August-October was provided by the NOAA data for Highgate, VT. Historical averages are for 30 years of NOAA data (1981-2010) from Burlington, VT.

 In 2017, August was cooler and wetter than historical averages while September and October were unseasonably hot and dry. The winter months of November thru January were cold and dry. The early months of 2018 experienced a lot of variation. February was unseasonably warm, March was fairly typical, April was unseasonably cold and wet, and May was warm and dry. Overall, between August and May there were a total of 1705 growing degree days, which is 608 more than historical averages.  

Results by planting date

Table 16. Cover crop yield and coverage for each planting date across all mixtures, Alburgh, VT, 2017-2018.

Planting date

Fall 2017

Spring 2018

Dry matter yield

Percent cover

Dry matter yield

Percent cover

lbs ac-1

%

lbs ac-1

%

24-Aug

2568

82.7

1223

65.3*

11-Sep

2138

87.9

1307

48.4

19-Sep

1240

81.1

1868

69.0

27-Sep

288

38.1

1104

58.0

LSD (0.10)

173

3.33

201

5.94

Trial mean

1558

72.5

1375

60.2

*Treatments marked with an asterisk were not statistically different compared to the top performing treatment (p=0.10) shown in bold.

Unsurprisingly, the 24-Aug planting generated the most biomass in the fall (Table 16). However, the 19-Sep planting generated the most biomass and percent cover in the spring, although the 24-Aug planting provided a comparable amount of cover. These observations are not surprising, as we would expect some species such as annual ryegrass and oats to produce significant quantities of biomass if planted in late summer. The amount of biomass would decline with later planting dates. However, winter grains must be planted a bit later to establish just prior to winter. Planting winter grains to early may result in high quantities of biomass that can smoother the plant crown over the winter.  Other research has shown that planting by late September produces the best yields. This study supports this evidence as highest spring cover crop biomass was obtained from the 19-Sep planting date.

Results by cover crop treatment

Table 17. Cover crop yield and soil coverage for each cover crop treatment, Alburgh, VT, 2017-2018. 

Mix

Fall 2017

Spring 2018

Dry matter yield

Percent cover

Dry matter yield

Percent cover

lbs ac-1

%

lbs ac-1

%

1

1610

80.9

535

44.0

2

1710

76.9

1948

73.3

3

1995*

80.7

1881

56.0

4

1966*

82.2

1752

67.7

5

1814

74.5

779

33.7

6

1507

71.8

2349*

79.0

7

2293

75.6

516

22.3

8

1774

81.4

1062

59.0

9

1828

81.9

1115

58.3

10

1595

73.9

850.0

44.0

11

2004*

90.2

243

16.7

12

1019

59.5

1250

75.0

13

1738

79.6

613

34.3

14

1362

76.2

2586*

91.3*

15

903

60.9

2692

93.7

16

1738

69.7

1724

82.3*

17

729

57.5

1706

92.3*

Control

467

31.2

1157

60.0

LSD (0.10)

367

7.07

427

12.6

Trial mean

1558

72.5

1375

60.2

Treatments marked with an asterisk were not statistically different compared to the top performing treatment (p=0.10) shown in bold.

Across all plantings, the top performer for fall yield was treatment 7 (oats, clover, turnip), while treatment 3 (winter rye, clover, turnip), 4 (triticale, clover, turnip), and 11 (radish) performed comparably (Table 17). Top performers for the spring yield included overwintering varieties that had the advantage of being able to grow again in the spring. For the spring, the top performers were treatments 6 (triticale and rape), 14 (winter rye), and 15 (winter rye and vetch). Out of the 4 top performing treatments for spring percent cover, 3 of them had an overwintering variety in their mix.

Results for each planting date

Table 18. Cover crop yield and coverage for the 24-Aug 2017 planting, Alburgh, VT, 2017-2018. 

Mix

Fall 2017

Spring 2018

Dry matter yield

Percent cover

Dry matter yield

Percent cover

lbs ac-1

%

lbs ac-1

%

1

2909

92.9*

610

38.7

2

2435

87.2*

982

65.3

3

3703*

91.2*

834

40.0

4

3359*

88.7*

553

60.0

5

3003

81.4

1284

76.0*

6

2137

81.0

1554

57.3

7

4260

76.9

1240

25.3

8

3290*

93.5*

697

52.0

9

3159*

92.2*

520

37.3

10

2401

85.8*

1314

70.7*

11

2931

95.4

200

4.00

12

1589

85.1*

802

81.3*

13

3069

84.1*

1407

70.7*

14

1949

84.6*

2777

100.0

15

1092

71.3

2516*

100.0

16

3363*

70.6

1483

96.0*

17

901.4

81.8

1681

100.0

Control

688

44.5

1559

100.0

LSD (0.10)

1150

13.0

720

30.8

Trial mean

2568

82.7

1223

65.3

*Treatments marked with an asterisk were not statistically different compared to the top performing treatment (p=0.10) shown in bold.

From the 24-Aug planting, treatments 3 (winter rye, clover, turnip), 4 (triticale, clover, turnip), 7 (oats, clover, turnip), 8 (ryegrass, turnip), 9 (ryegrass, radish), and 16 (ryegrass) were the top performers for yield in the fall (Table 18). Interestingly, none of the top performers for fall yield were top performers for spring yield. Two out of 6 successful fall yielding treatments included overwintering varieties, however, they also included turnip which would not survive the winter and generate more biomass in the spring.

In the spring, treatments 14 (winter rye) and 15 (rye and vetch) were top performers. This makes sense considering that winter rye and vetch will over winter and continue to grow in the spring. Another interesting result is that in the spring, top performers for percent cover included overwintering treatments, yet also included the control. It is possible that the weed seeds, naturally found in the soil, were able to grow well enough to provide comparable ground cover.

Table 19. Cover crop yield and coverage for the 11-Sep 2017 planting, Alburgh, VT, 2017-2018. 

Mix

Fall 2017

Spring 2018

Dry matter yield

Percent cover

Dry matter yield

Percent cover

lbs ac-1

%

lbs ac-1

%

1

2253

95.5*

176

17.3

2

2729*

93.8*

1764

58.7

3

2258

95.4*

1730

36.0

4

2579*

94.3*

644

33.3

5

2403*

94.4*

476

10.7

6

2341

79.6

2522*

70.7

7

3186

92.6*

203

10.7

8

2321

94.8*

696

26.7

9

2349

94.2*

1136

29.3

10

2477*

91.3*

851

42.7

11

2806*

97.8

89.2

5.33

12

1443

88.1*

1841

77.3*

13

2138

84.1*

208

10.7

14

1659

89.6*

2793

98.7*

15

1327

78.2

2502*

98.7*

16

2242

84.6*

1741

65.3

17

1069

77.3

2175*

100.0

Control

898

56.8

1973*

78.7*

LSD (0.10)

830.0

16.2

924

27.8

Trial mean

2138

87.9

1307

48.4

*Treatments marked with an asterisk were not statistically different compared to the top performing treatment (p=0.10) shown in bold.

The top performers from the 11-Sep planting for fall yield were treatments 2 (triticale, radish, clover), 4 (triticale, clover, turnip), 5 (oats, radish), 7 (oats, clover, turnip), 10 (oats), and 11 (radish) (Table 19). The treatments generally performed well for percent cover in the fall. In the spring, unsurprisingly, overwintering varieties were more successful with generating biomass and top performers included treatments 6 (triticale, rape), 14 (winter rye), 15 (winter rye and vetch), and 17 (hairy vetch). Surprisingly, the control had a comparably high yield for the spring, which was likely due to the weed seed bank coming out of dormancy. 

 Table 20. Cover crop yield and coverage for the 19-Sep 2017 planting, Alburgh, VT, 2017-2018. 

Mix

Fall 2017

Spring 2018

Dry matter yield

Percent cover

Dry matter yield

Percent cover

lbs ac-1

%

lbs ac-1

%

1

915

90.5*

759

52.0

2

1412*

87.4

3192

96.0*

3

1746

91.7*

3301*

86.7*

4

1535*

90.1*

3416*

100.0

5

1539*

87.4

932

29.3

6

1343*

89.6*

3313*

97.3*

7

1286

92.4*

231

10.7

8

1257

94.0*

1816

94.7*

9

1482*

94.3*

1643

86.7*

10

1219

85.1

773

30.7

11

1599*

97.7

246

20.0

12

910.3

47.9

1680

94.7*

13

1334*

93.5*

332

20.0

14

1497*

89.7*

2777

89.3*

15

1041

74.6

4466

98.7*

16

1081

82.5

2217

98.7*

17

846

55.1

2003

100.0

Control

276

16.4

520.0

37.3

LSD (0.10)

449

10.2

1173

16.4

Trial mean

1240

81.1

1868

69.0

*Treatments marked with an asterisk were not statistically different compared to the top performing treatment (p=0.10) shown in bold.

The top performers from the 19-Sep planting for fall yield included treatments 2 (triticale, radish, clover), 3 (winter rye, clover, turnip), 4 (triticale, clover, turnip), 5 (oats, radish), 6 (triticale, rape), 9 (ryegrass, radish), 11 (radish), 13 (oats, radish, clover), and 14 (winter rye) (Table 20). Top performers for the spring yield included overwintering varieties. Specifically, top performers were treatments 3 (winter rye, clover, turnip), 4 (triticale, clover, turnip), 6 (triticale, rape), and 15 (rye and vetch).

 

Table 21. Cover crop yield and coverage for the 27-Sep 2017 planting, Alburgh, VT, 2017-2018. 

Mix

Fall 2017

Spring 2018

Dry matter yield

Percent cover

Dry matter yield

Percent cover

lbs ac-1

%

lbs ac-1

%

1

364

44.9

593

68.0*

2

265

39.4

1854*

73.3*

3

274

44.4

1659

61.3

4

390

56.7*

2393

77.3*

5

312

34.8

422

18.7

6

206

37.2

2008*

90.7

7

440

40.4

388

42.7

8

230

43.1

1040

62.7

9

321

46.9

1159

80.0*

10

282

33.6

461

32.0

11

678

70.1

436

37.3

12

132

16.8

676

46.7

13

409

56.5*

507

36.0

14

344

40.8

1998*

77.3*

15

150

19.3

1284

77.3*

16

268

41.1

1456

69.3*

17

100

15.6

965

69.3*

Control

26.2

6.95

577

24.0

LSD (0.10)

164

14.8

546

26.6

Trial mean

288

38.1

1104

58.0

 *Treatments marked with an asterisk were not statistically different compared to the top performing treatment (p=0.10) shown in bold.

From the 27-Sep planting, the highest fall yielding performer was treatment 11 (radish) (Table 21). The top performers for spring yield including overwintering varieties, representing treatments 2 (triticale, radish, clover, pea), 4 (triticale, clover, turnip), 6 (triticale, rape), and 14 (winter rye).

Results from the planting date by variety interaction

The interaction of planting date and variety were significant for fall yield (p=0.0007), fall percent cover (p=0.0019), spring yield (p<0.0001), and spring percent cover (p<0.0001), meaning that cover crop mixture performance differed by planting date. (Figure 4, 5, 6, 7). It was expected that winter terminated cover crops such as oats, annual ryegrass, and tillage radish would produce more biomass and soil coverage if planted in late summer compared to fall. Cover crop mixtures with winter terminated and surviving species tended to experience less variability in cover and yield across planting dates.

The trend within each planting date was that the top performers for yield in the spring included an overwintering variety, which is unsurprising since these varieties will be able to grow more biomass in the spring after winter dormancy. However, it is interesting to note that in the 24-Aug, 19-Sep, and 27-Sep plantings top performers for spring percent cover included treatments that did not overwinter. This indicates that these mixes were still able to provide the benefit of ground coverage, consisting of dead plant materials from the fall. Using a winterkilled cover crop variety may also provide the benefit of not having to manage terminating the crop in the spring, when timing of this may be difficult due to wet, spring conditions. Also, it was clear that planting earlier in the fall would result in great fall biomass yields. Cover cropping decisions will have to be made based off of the demands within each operation and field management considerations.

 

Research conclusions:

Results from the one-year project indicated that earlier planted cover crops (24-Aug) resulted in the greatest fall biomass yields. The mid-Sep (19-Sep) planting date resulted in the highest spring biomass yields. This indicated that overwintering cover crops performed best when planted by mid-Sep and winter terminated cover crops performed best when planted by 24-Aug.  Interestingly, winterkilled cover crop treatments were competitive with overwintering cover crop treatments for providing spring ground cover. This indicates that winter terminated cover crops can still provide adequate residue to protect the soil from erosion in the spring.

During this short term project, the cover crops appeared to have minimal impact on the soil health indicators, active carbon and aggregate stability. The Grand Isle location did see an increase in aggregate stability when tillage radishes were grown. Longer term research is needed to identify impacts of cover crops on soil health. The research indicated that excess soil NO3 was scavenged by the cover crops in the fall. Hence growing cover crops reduces the risk of N loss through the winter months. The research indicated that the winter terminated cover crops mineralized and released NO3 in the early spring (Apr – May) and over wintered cover crops mineralized in Jun. No significant difference was seen in subsequently grown cash crop yield or quality at any of the locations. Overall the one year research project showed that multi-year data is needed to develop cover crop recommendations and strategies that benefit soil, crop, and farm productivity. 

It would be important for work to continue in this area. Clearly a longer-term study is needed to see soil health and crop benefits from cover cropping. This short term study did observe soil health benefits on one farm. This farm immediately started to shift cover crop species. 

 

Participation Summary
3 Farmers participating in research

Education & Outreach Activities and Participation Summary

25 Consultations
2 On-farm demonstrations
2 Published press articles, newsletters
2 Webinars / talks / presentations
3 Workshop field days

Participation Summary

459 Farmers
176 Number of agricultural educator or service providers reached through education and outreach activities
Education/outreach description:

In order to meet Objective 3, four 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, 2017 & July 26, 2018 at Borderview Farm in Alburgh, VT. This field day had a total of 526 participants from around the region. The field day highlights many research projects as well as relevant agricultural topics. In both years there was a strong focus 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. Farmers will able to tour the cover crop plots and subsequent planted sweet corn. Resource material on cover cropping was made available to farmers.

Cover cropping was highlighted at three additional on-farm tours that occurred in August and September in Middlebury, 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 59 attendees.

A soil fertility/health program was hosted for vegetable growers in collaboration with other colleagues at UVM. These programs were held at 4 locations throughout the state in the winter of 2018 (Rutland, Burlington, Middlebury, and Brattleboro) and 62 attendees. Each session was a day long event focused on understanding soil health, soil fertility, and strategies to achieve farm goals as they relate to crop, soil, and regulations. Cover cropping was covered with the audience and topics such as species selection, planting date, termination methods, and fertility/soil health benefits were covered. Resource materials on cover cropping was distributed to the audience.

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, the cover crop stands, cover cropping as a means for overall soil health, saving cover crop seed, and reviewed additional soil health management strategies, as demonstrated through David Marchant’s practices. There were 13 participants total.

Interviews were set up with Bob Pomykala, David Marchant, and two additional farmers in December 2017, to contribute to developing ‘Cover Crop Success Stories’. Several of these stories, along with our research results, and existing research on cereal rye as a cover crop, were compiled to create a bulletin titled, “Cover Cropping on Vegetable Farms in Northern New England.”

The bulletin “Cover Cropping on Vegetable Farms in Northern New England” used existing research that has been focused on developing strategies for integrating cereal rye into cropping systems. This includes information on seeding options, planting dates, seeding rates, termination strategies. Benefits of cover crops (nutrient cycling, soil building) and challenges were covered. Current information on cover crop mixtures was included. Lastly, farmer cover crop success stories were included in the bulletin. The guide will be peer-reviewed by farmer collaborators. The guide will be posted online at www.uvm.edu/extension/cropsoil.

Cover-Cropping-on-Vegetable-Farms-in-Northern-New-England-SARE

 

Learning Outcomes

47 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
Key changes:
  • 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.

Project Outcomes

1 Farmers changed or adopted a practice
2 Grants applied for that built upon this project
4 New working collaborations
Project outcomes:

The collaborating farm has adopted growing tillage radishes as a cover crop for the last two seasons. This farm was introduced to tillage radishes through this project and provided a research site allowing the farm to see the benefits of this cover crop. The farm is characterized by heavy clay soil that is difficult to manage and often becomes compacted. The farm had been interested in potentially using tillage radish to break-up compacted layers. The first year of the research experiment the collaborating farm saw immediate benefits on soil structure and found the clay field with tillage radishes much easier to work. The results also indicated improvements in soil aggregate stability. This type of improvement was exciting to the farmer as this may indicate the soil may drain better and ultimately provide for higher yielding crops.

Assessment of Project Approach and Areas of Further Study:

It would be important for work to continue in this area. Clearly a longer-term study is needed to see soil health and maybe even crop benefits. This short term study did see some soil health benefits on one farm. The soil health improved in physical structure as measured by increasing aggregate stability. This farm immediately started to shift cover crop species towards the tillage radish to help further improve the physical properties of the soils. Future studies should again include tracking soil NO3 over time. Soil NO3 availability will vary seasonally, depending on weather conditions. Also, it would be beneficial to perform this study again at a research farm, where additional soil amendments/fertilizers can be controlled. That said, it is possible that fertilizers applied at the participating farms influenced the soil NO3. 

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.