Viability of integrating field peas into organic cereal grain rotations in Maine

Final Report for FNE15-826

Project Type: Farmer
Funds awarded in 2015: $11,365.00
Projected End Date: 12/31/2015
Region: Northeast
State: Maine
Project Leader:
Jake Dyer
Benedicta Grain Co.
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Project Information


As a rotation with organic grains, dry field peas have the potential to provide many of the same benefits that clover offers and generate revenue by producing an organic protein feed for livestock.  We looked at whether field peas could be grown successfully in Maine.  In 2015 4 varieties of yellow field peas (AC Agassiz, Jetset, SW Midas, and Nette 2010) were trialed over 20 acres in Benedicta, Maine. It was found that all varieties performed well with yields ranging from 3000 to 4100 pounds per acre. Disease and weed pressure were of concern going into this project, but were not major challenges. All varieties lodged just prior to harvest but were still able to be directly combined without swathing. Results from both this project and variety trials in 2014 show that field peas can be successfully grown in Maine.


In order for Maine growers to successfully supply the demand for organic grains, they will need to investigate rotation strategies that utilize alternative crops that are able to generate revenue, minimize production and capital equipment costs, break weed and disease cycles, and limit soil erosion.  Demand for local and organically produced cereal grains has been very strong for the past few years. Common crop rotations used in organic grain systems rely on legume cover crops such as clover to provide fertility, break pest cycles, and reduce soil erosion. Clover has many benefits, but it also requires a full growing season to capitalize on them. Dry field peas have the potential to provide many of the same benefits that clover offers and generate revenue. Are field peas able to be grown successfully in the Northeast? There is limited information available to growers to answer this question. Research efforts by the University of Maine have shown yield potential in small plot trials, but have also raised concerns over disease, weed pressure, and difficulty in harvesting. Growers need field scale evidence to determine if field peas could be a good fit on their farms and if peas can perform well across a variety of soil types and conditions. They also need access to this information and an opportunity to hear and see it firsthand. 

The introduction of a pulse crop such as field peas would provide similar ecological benefits as clover to the cropping system as well as the ability to generate revenue and use current cereal grain equipment. Field peas are a cash crop with a potentially diverse marketing portfolio. Peas are a legume and require significantly less nitrogen fertility than a cereal, and would be effective in breaking some cereal disease cycles. If the stand can be developed quickly and early, the dense canopy field peas produce could compete very well with weeds. Peas harvested in mid-late August or early September would allow the planting of a winter cash or cover crop. The decomposition of pea biomass would also provide nitrogen fertility to the subsequent cash or cover crop.

Growing organic field peas as a monocrop on a large scale in Maine’s humid and often wet climate poses many potential risks. Field peas are primarily produced in the more arid regions of the Unites States and Canada such as Washington, Idaho, Montana, North and South Dakota, Saskatchewan, and Alberta. However, results from a 2014 field pea variety trial at the University of Maine’s Rogers Farm suggested that field peas can be grown in Maine with attractive yields of up to 4500 pounds per acre. This variety trial also highlighted that disease and crop lodging could be significant risks.

Markets for field peas exist in Maine. If it can be determined that field peas are a viable option in organic cereal rotations, it will be beneficial to both organic grain and livestock producers. Field peas are an excellent source of minimally process protein for livestock. Field peas contain approximately 21-25 percent protein and 5 to 20 percent less trypsin inhibitors than soybean allowing them to be directly fed to livestock (Schatz, B. and G. Edres. 2009. Field Pea Production. North Dakota State Extension Service bulletin A-1166.)

Project Objectives:

The objective of this project is two-fold:

1.) Determine if field peas can be successfully grown in organic cereal grain rotations in Maine.
2.) Use trial results such as yield, disease incidence, weed pressure, and standability to determine if certain varieties of yellow field peas perform better in Maine’s climate.


Click linked name(s) to expand/collapse or show everyone's info
  • Dr. Jay Hao
  • Andrew Plant


Materials and methods:

This trial was conducted in Benedicta, ME in 2015 to assess the yield, disease incidence, weed pressure, and standability of four yellow cotyledon, determinate, semi-leafless field pea varieties (Table 1). The experimental design was a randomized complete block with three replications. The field was planted in North to South orientation.

AC Agassiz, Jetset, SW Midas, and Nette 2010 pea seed was sourced from 2 North Dakota based companies, Pulse USA, Inc. and Meridian Seeds, LLC. Seed of all varieties was certified through the South Dakota Crop Improvement Association and was of certified class. Information taken from company sale sheets indicated that all four varieties were similar in resistance to lodging, resistance to powdery mildew, moderate susceptibility to fusarium wilt, and susceptibility to mycospherella. Varieties differed slightly in maturity.

The host field was 20 acres in size. Soil was Thorndike shaly loam with a pH of 6.2. The previous crop was spring barley with a winter killed tillage radish cover crop. The seed bed was prepared using a disk harrow and seed bed conditioner. Peas were planted on May 15 and 16 with a Great Plains 1500 grain drill in 6 inch rows. Each plot was 60’ wide by 1293’ long. The target population was 392,040 plants per acre (9 plants per square foot). The population was adjusted to 348,480 plants per acre (8 plants per square foot) to avoid running out of seed (See Table 2 and Field Map for trial management details). The formula used to calculate the seeding rate was:

Target Population / (1-% loss)
Seeds/# (Germination %)

Peas were inoculated using the OMRI approved, peat based N-Dure from Verdesian Life Sciences, U.S., LLC. The active bacterium, Rhizobium leguminosarum biovar viceae, is specific to peas, lentils, and vetch. Seed was inoculated at a rate of 5.36 ounces per 50 pounds of seed.

The fungus white mold (Sclerotinia sclerotiorum) was a major disease concern. In an attempt to quantify the presence of the disease in the field, soil samples were taken from each block plus a composite sample was taken and sent to Dr. Jay Hao at the plant pathology laboratory at the University of Maine for analysis. The samples were processed and no sclerotia (overwintering structures of the fungus) were found. It was decided that no control measures for white mold were necessary.

Peas were cultivated at spike stage with a rotary hoe approximately 9-10 days after planting (DAP). Pea vines were measured on June 30 and again on July 25. Disease incidence and weed pressure were also noted and visually ranked at these times (Table 3). Wind and rain caused all varieties to lodge on August 27. By the August 30 harvest date, vines were brittle and pods had begun to open. To avoid excess crop loss due to shattering, direct cutting was deemed the best method for harvesting. Ground speed during harvest was reduced to approximately 1.5 miles per hour so that the peas could be fed onto the header platform and not pushed over. Peas were harvested on August 30 (106-107 DAP) using a John Deere 9500 combine with 920F flex header. Seed yields were measured using Massload™ portable weighpads and seed moisture was measured using a Dickey-john M3G™ moisture meter.

Samples of all pea varieties were taken and sent to Dairy One Forage Testing Laboratory in Ithaca, New York for wet chemistry analysis.

Table 1: Field Pea Variety characteristics Table 1: Field Pea Variety characteristics

Table 2.  Field Management Information

Table 2. Field Management Information

Research results and discussion:

Results and Discussion

The growing season of 2015 was favorable for dry pea production in Maine. Weather conditions in May were relatively warm and dry and were conducive to early planting, rapid emergence, and timely weed cultivation. June was cool and damp and provided nearly ideal conditions for vegetative growth. By June 30, heights ranged from 17 inches to 22 inches (Table 3). Flowering of all varieties began around July 8 and ended on July 18. By July 25, heights ranged from 31 inches to 42 inches and all pods were bulking seed. Peas began to yellow and die back beginning on August 9. By August 19, seed moisture was approximately 16%-18% and all varieties were brown and close to ripe. A rain and wind event on August 27 caused a major portion (75-85%) of the field to lodge. Lodging severity was similar across all varieties and up until this storm, all varieties were upright.

Disease incidence was low overall and did not have any noticeable negative impact on any of the varieties (Table 3). Crop emergence was uniform in all varieties and seedling mortality due to disease was not observed. No disease symptoms were noted when the field was scouted in June or July. As peas began to dry down, it was difficult to discern whether they were slightly diseased or merely senescing naturally. Powdery mildew (Erysiphe pisi) was noticed on the occasional plant on August 20 and was not variety specific.


The primary weeds present were mayweed chamomile (Anthemis cotula L.) and wild radish (Raphanus raphanistrum L.). Mayweed chamomile was noted at low concentrations throughout the field. Wild radish was most prolific in the Southerly end of the field where poor weed control in a 2010 soybean crop allowed heavy weed seed rain. Although it was not measured, it is likely that the pea yields were higher in the areas with fewer weeds. Overall, the use of the stale seedbed technique combined with favorable planting and emergence conditions and post crop emergence weed control appeared to give the peas an advantage over the weeds, with no differences among varieties (Table 3).

Nette 2010 and Jetset varieties were visual standouts throughout the trial. Although the field observations in Table 3, do not support this statement, there was a noticeable visual difference in color and plant vigor compared to the other varieties throughout the entire growing season.
Even with lodging, yields were higher than expected with all varieties surpassing 3000 pounds per acre (Table 4). Yields were measured by harvesting 2, 20 foot wide by 1293 foot long swaths from each treatment. Total harvested area per treatment was 1.187 acres. Peas from each treatment were transferred into a truck and weighed on portable scales. Moisture content of each variety was measured and yields were corrected to 14% moisture.


While the study was designed to measure statistical differences between varieties, significant difference in yields between varieties was not able to be determined due to the fact that harvest strips could only be taken from blocks B and C. Operator error due to unfamiliarity with the GPS unit caused the initial planter pass in block A to veer off course resulting in non-uniform block dimensions.

Wet chemistry analysis of all varieties show peas to be a quality livestock feed with relatively high protein, high carbohydrates and total digestible nutrients, and low fiber levels. Results from all varieties were similar. Quality measures averaged across varieties are shown in Table 5.


Field peas were grown successfully in 2015 in Maine using organic production practices. The yields measured in this field-scale trial ranged from 3100 to 4000 pounds per acre and were similar to yields measured in small plot research trials from Maine in 2013 and 2014 and exceeded expectations.  Nette 2010 and Jetset were the highest yielding varieties although a statistical analysis was not performed to determine if they were significantly different to the yields of SW Midas and AC Agassiz.

Weather throughout the 2015 growing season was excellent for dry pea production and was a major factor in the overall success of this project. Early season disease concerns were reduced by relatively warm and dry soil conditions in May which allowed for timely planting, rapid crop emergence, and pre and post emergence weed control. Rapid vegetative growth and canopy formation during June resulted in increased weed suppression due to crop competition. Rainfall throughout July and August was sufficient to maintain high yield potential yet not excessive as to favor disease and weed pressure. Dry conditions during late August were favorable for harvesting the peas in a timely manner and allowed for the planting of a fall rye crop.


The addition of field peas to a cereal grain rotation is beneficial from an economic perspective. Field peas are relatively inexpensive to grow and require few crop inputs. Depending on soil test results, little, if any fertilizer will be required and if pH is in the 6 to 7 range, no lime will be necessary. Equipment and storage requirements are identical for both crops. When substituted for clover, field peas increase production acreage and allow capital expenses such as field equipment and storage structures to be spread over a larger land base therefore decreasing cost per acre. Nitrogen released from breakdown of pea residue should be available to a subsequent winter cereal or cover crop.

Management practices of field peas and spring cereal grains are similar. Timing of field preparation, planting, cultivating, harvesting, and drying and storing are virtually the same for both crops. This can be challenging if weather conditions are not cooperative.

Research conclusions:

I consider this project a success. If the weather conditions are favorable, field peas fit into organic cereal grain rotations very well. 2014 and 2015 were good growing seasons overall with fairly dry conditions late in the summer. Disease and lodging are still a concern especially in the case of a wet growing season. The results of this project are optimistic and field peas are in the crop plan for the 2016 season at the Benedicta Grain Company.

Participation Summary

Education & Outreach Activities and Participation Summary

Participation Summary:

Education/outreach description:

A presentation was given on March 23, 2016 at the Maine Grain Conference at Northern Maine Community College in Presque Isle, Maine.  The powerpoint presentation from the conference is included at the link below.  Total attendance was approximately 80 with 60-65 of the attendees being crop growers. 


Results from this project are available by contacting the author at [email protected] and from the SARE program.


Viability of Integrating Field Peas into Organic Cereal-MGC

Project Outcomes

Assessment of Project Approach and Areas of Further Study:

Potential Contributions

The results of this project show that field peas can be grown successfully as a monocrop in Maine using organic production practices. Existing grain equipment and infrastructure is sufficient for production. Timely pea harvest should leave ample time for planting of winter cover crop.

Market development is under way. As peas are not commonly grown in the New England region, many local livestock producers are not familiar with them as a feed. Analysis results from Dairy One show that peas are indeed a quality livestock feed and hopefully their popularity will catch on if producers are willing to try them. Food markets are also being researched.

Future Recommendations

This project was a great learning experience. The following suggestions/recommendations may be useful to those considering growing field peas in the future.

1. Use clean, disease free seed with high germination.
2. Use 2 – 3 times the recommended rate of inoculant.
3. Calibrate the planter based on population. Imperative to know seeds per pound, germination, and use liberal value for stand loss.
4. Plant into warm moist soil to encourage rapid germination and emergence.
5. Avoid poorly drained fields.
6. Select fields with low weed pressure and use stale seedbed for pre-plant weed control.
7. Take representative soil samples to scout for presence of white mold sclerotia.
8. Harvest as early as possible to avoid lodging and excessive shatter.
9. Pick the rocks!

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.