Alaska vegetable production using a high residue cover crop system to reduce erosion and decrease weeds

Progress report for FW20-361

Project Type: Farmer/Rancher
Funds awarded in 2020: $12,300.00
Projected End Date: 09/30/2022
Host Institution Award ID: G268-21-W7900
Grant Recipient: Alaska Specialty Crops
Region: Western
State: Alaska
Principal Investigator:
Jeff Smeenk
Alaska Specialty Crops
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Project Information


Wind erosion is a major concern in the loess soils of the southern Matanuska-Susitna region. Likewise, weed control is a major expense in both conventional and organic vegetable production.   We’ve read about transplanting vegetables into roller-crimped cover crop residue and, if this technique could be modified for Alaska conditions, these high-residue systems may have the potential to both decrease erosion and hold back weed pressure.  None of the Ag professionals consulted knew of any commercial operations in Alaska using high-residue systems for vegetable production so we almost have to start from scratch.  Important questions include which cover crop mixes are appropriate and when should they be planted.  Will a roller-crimper be adequate for terminating the cover crop and is the milk stage the optimal time?  To this end we propose planting 5 cover crop mixes at different dates to be roller-crimped prior to snowfall.  Vegetables will be transplanted into the residue in 2021 and marketable yield along with weed control effort will be measured.  Outreach will consist of field days highlighting the 2020 cover crops and 2021 vegetable crops.  The results will be presented at the State’s SARE conference, and the Conservation District’s State-wide meeting.  The findings will also be released as a bulletin and a YouTube video.  If this high-residue strategy is successful (and cost effective) it has the potential of both decreasing soil erosion through soil protection and building soil health by decreasing cultivation.

Project Objectives:
  1. At the end of the first growing season determine which of the 5 cover crop mix/planting date combinations gives the densest ground cover as determined by biomass weight and percent ground cover.


  1. At the end of the second growing season determine if planting directly into the cover crop residue is more effective than planting into a 6” strip where the residue has been removed as determined by measuring marketable yield.


  1. At the end of the second growing season evaluate the effectiveness of high-residue planting by comparing the marketable yields and time spent on weed control from each treatment against the no-residue control plot.


  1. At the end of the second growing season evaluate the interest in the technique by polling the conference attendees and determining the number of views associated with the YouTube video 6 months after being uploaded.

Project Timeline

Obj 1.   

June ‘20               - Establish cover crop plots

Sept. ‘20              - Terminate all cover crops with a roller crimper and  evaluate resulting crop residue

                                                from each treatment

Obj 2.   

June ‘21               - Plant cabbages into residue in each of the various plots

Sept. ‘21              - Harvest and grade the cabbages.  Measure total and marketable yields from each



Obj 3.

June ‘21               - Plant cabbages into residue of each of the various plots

Sept. ‘21              - From each plot compare time spent weeding with marketable yield


Obj 4.

Oct. ’21                 - Develop Powerpoint, technical bulletin and YouTube video

Nov. ‘21               - Survey attendees at Conservation District Conferences

Feb. ’22                                - Survey attendees at SARE Conference

June ’22               - Evaluate comment section of video

Aug. ’22                - Poll NRCS, Extension and Conservation District personnel for client interest in practice


Click linked name(s) to expand/collapse or show everyone's info
  • Michelle Jezeski - Technical Advisor
  • Anne-Corrine Kell - Producer
  • Ben VanderWeele - Producer


Materials and methods:

Research Materials and Methods

To evaluate the optimal cover crop mix - planting date combination (Objective 1) trials will be established on three farms (two conventional farms and a certified organic farm).  As soon as the ground thaws all sites will be tilled and seeded with forage radish to provide an initial ground cover.  In the 1st week of June a mix of warm-season cover crops (Sudex-Cowpea) will be no-till seeded into the terminated radish cover crop.  In the 1st week of July four cool-season cover crop mixes (Oat-Pea, Oat-Pea-Buckwheat, Cereal Rye, and Triticale-Pea) will be planted into terminated forage radish for the early cool-season planting.  In the 1st week of August the four cool-season cover crop mixes will be planted into terminated forage radish for the late cool-season planting.  The cover crops will be terminated with a roller crimper when one of the species reaches the milk stage of seed formation or a week before predicted frost date (Mid-September), whichever comes first.  In the second season the entire site (all 10 plots) will be planted with cabbages.  Within each cover crop plot two rows of cabbage will be hand transplanted.  One row will be planted directly into the residue and the adjacent row will be plated into a 6” strip that has been cleared of residue.  Throughout the growing season the plots will be monitored for weed pressure and the time spent on weed control in each treatment will be recorded.


The evaluation of the 5 cover crop mixes should give an indication of the amount of residue each mix will contribute.  Prior experiences with trying to establish cover crops into tilled plots have become weedy messes and our technical advisor suggests using a no-till planter to plant the cover crop into a stale seedbed so for this project we hope to fabricate a no-till planter small enough to work in a market garden situation.


The early and late planting dates will give an indication of the optimal time to plant the trials.  The warm-season cover crops are not expected to go to seed under Alaska conditions so it is anticipated that Sudex-Cowpea mix won’t need to be terminated until September.  With the cool-season mixes there is the chance that the early planting will go to seed and will need to be terminated mid-summer to avoid seed formation.  The late-planting may actually produce more vegetative biomass since it may not go to seed and need to be terminated until just prior to snow fall.  Transplanting the vegetable directly into the residue versus into a small strip where the residue has been removed (Objective 2) will give an indication of potential nutrient and pest issues associated with transplanting directly into high residue levels. 


The materials that we anticipate using are the cover crop species in the various mixes (Oats, Rye, Triticale, Buckwheat, Austrian Winter Pea, Sudex and Cowpea) along with the forage radish used to establish the initial site and the cabbage transplants used to evaluate the treatments.  On the equipment front a roller-crimper for a two-wheel tractor has being fabricated and funds are requested in this proposal towards a locally fabricated no-till planter for small tractors.  In addition to the farmer’s contribution towards the project an agricultural intern from the Soil and Water Conservation will be contracted to perform plot maintenance and record data under the supervision of the PI.


For the research component of this project we plan on collecting cover crop biomass estimates (grams per sq ft) and percent ground cover (with a beaded string) or depth of crimped residue (in mm) in year one.  In year two the starting amount of residue will be measured, the total cabbage yield and the marketable cabbage yield of each plot will be measured.  The weed pressure will be estimated by monthly weed counts in each plot and the time spent on weed control in each treatment will be recorded to estimate the cost of each treatment.


The overall project will be considered successful if any of the cover crop mixes at its optimal planting date has lower weed control expenses while still producing equivalent marketable yields as the no cover crop (control) plot (Objective 3).  The overall goal of the project is to determine if a system using high residue is more effective than the no-residue strategy we currently use.

Research results and discussion:

2021 Annual Report

In the year of establishment an early and late planting of 10 cover crop mixes were established.  The early planting was terminated before any species produced viable seed using a hand crimping method.  The late season planting was terminated by a killing frost well before any species began flowering.  As of April 2021, all treatments have residue laying on the ground and are covered by 18" of snow.  They await measurement of ground cover (beaded string method) and determination of  overwintering biomass (dry wt/sq ft).

One of our participating farmers was not able to allocate the irrigated space early enough for us to plant the cover crops.      His operation will contribute the transplants for all sites and we will use imported residue to simulate the residue treatment for his 2021 growing season.

The equipment side of the project is completely off schedule and has forced us to change field protocols to keep the biological aspects on schedule.

Roller Crimper:   The fabrication shop in our area has been overwhelmed with work and was not able to complete our roller crimper in time for the project.      As a temporary solution we used a 2' piece of Aluminum 'C-channel' with a set of strings as a make shift crimper.  Several YouTube videos feature cover crop crimping by hand and we essentially followed their examples.  So, rather than crimping all the plots in an hour with a mechanized roller-crimper, it took the district's intern most of a day at each location to crimp the plots.

No-till Planter heads:   I have only found one vender that will sell individual no-till heads and they are not used to shipping to Alaska.  I've tried getting them to air freight the pallet, which surprisingly is the least expensive option, but they are not a Homeland Security Preferred Shipper so that method turned out to be a dead end.  I've also found a trucking company that routinely goes between Montana and Alaska  but the vender's usual trucking company is not set up to drop the pallet off to another shipping company.  The project budget has funds for the purchase of the no-till heads but I'm struggling with how to get them here.      Recently, the local trucking company that used to only go between Montana and Alaska is trying to expand their operations and would be willing to coordinate shipping directly from the Esch facility to Alaska.  The no-till heads won't get here in time for the early cover crop planting so we'll put the treatments using conventional tillage methods.  I'm also leaning on the no-till company to be a bit more responsive and sell me the needed no till heads

2022 Annual Report

In Spring of 2021 there were no treatments that had overwintering residue heavy enough to give any level of weed mulching effect.  This observation was met at both the Sun Circle site and the Rebarchek Incubator Farm site.  The only weed smothering effects were seen associated with the heavy oat planting put in around the plots to serve as a walkway.   The mulching effect of the former walkways was incredible, while all the plots were growing weeds through the residue the former walkways were almost weed free.  A consultation with the WSARE tram allowed us to modify the original proposed treatments to use the heavy reside from the walkways to serve as a weed mulch in the treatment.  The straw residue was removed from 1/3 of the area and dumped on top of the existing residue in another 1/3 of the area giving three rates of oat straw residue: none, 1X and 2X.

Although some level of weed mulching effect was seen in the 1X and 2X treatment areas the grower asked us to terminate the trial mid-season.  She notices a significate increase in slug damage associated with the mulch.  As an organic grower with limited options for slug managaement removing the reside was the best option.

On the Rebarchek Incubator Farm location there was no level of weed suppression associated with the cover crops and not as much oat straw was planted for walk ways so there was no option to use reside to hinder weed growth.  Rather, on this site oats were planted in mid-August and the last week in August at 4 rates to determine if increasing the seeding rate would compensate for later planting times (essentially, can money buy time).  The first two planting dates went fine with the heavy planting rates giving almost a full coverage of all surface area of the plots.  Unfortunately, due to an unanticipated state-wide shortage of oats the September plantings could not be seeded.

The five no-till planter heads located in the Spring of 2020 were finally delivered to Alaska in September of 2021- 16 months after identifying a source in Pennsylvania.  As of May 13th 2022 the heads are still covered with 2' of snow.  I have been working with a local fabricator to re-design the planned no-till planter after he determined that my original design would not work with the planned tractor.  A no-cost extension was applied for to allow the project to fabricate the planter and shoot videos of it putting in various cover crops.

Three powerpoint presentations have been given on the status of Alaska Cover Crop projects and this SARE project has been prominently featured.   In the Winter of 2021 a (Zoom) presentation was made to the Western States Cover Crop Group.  In November 2021 the presentation was given at the Alaska state-wide SARE conference in Anchorage and in February 2022 the presentation was given (via Zoom) as part of the Kenai Peninsula Ag Workshop Series.

Planned activities for the time extension granted to the project include:

1  Fabricationg the no-till planter

2.  Multiple seeding dates using multiple seeding rates to determine if a spring-seeded oats can provide adequate residue for a later summer vegetable crop.

Participation Summary
3 Farmers participating in research

Educational & Outreach Activities

5 Consultations
1 Webinars / talks / presentations
1 Workshop field days

Participation Summary:

20 Farmers
15 Ag professionals participated
Education/outreach description:

Educational Outreach Activities and Materials

To achieve Objective 4 the project and its results will be communicated to growers through presentations at winter conferences, bulletins, a YouTube video and through educating the state’s Agricultural Professional that provide consulting to the growers.  Growers will be invited to attend planned field days that will be held each year but historically, these events have very low producer involvement.  Previous Field Days organized by the conservation district or University Extension have had Agency personnel and master gardeners attend but no commercial growers.  Growers have stated that ‘Alaska summers are too short to attend field days.  That’s what the winter meetings are for.’  With this history in mind we plan on focusing our outreach efforts on preparing a technical bulletin that covers the project and its findings to be distributed by NRCS and Extension personnel.  With more and more people using videos to get their information we’ll also make a video demonstrating the various treatments and the overall outcome of the project.  If history is any indication the most effective form of outreach will be the presentations at various winter meetings that producers attend.  In addition to the Powerpoint presentation the networking between sessions is a great time for producers to ask questions about the topic. 

The project and its results will be communicated to the general public by inviting the Master Gardeners and Garden Club members along with the general public to visit the site on a Field Day (since they’re more likely to attend).  Another way of getting the project out to the general public is to ghost-write an article for our local newspaper. 

Winter 2021 Report:

In Early September one of the sites was featured as part of the Alaska State Fair's Antique Power Clubs Demonstration Weekend.  Over the two day event I gave presentations to about 100 participants with about 20 individuals asking questions detailed enough to give an impression that they were actual growers.

In March  (2021) I was asked to give an update on Cover Cropping in Alaska to the Western Cover Crop Consortium and this SARE Study was one of the projects I talked about.   In additions to the growers on the Zoom Webinar, I estimate there were about 15 Ag professionals attending.

Learning Outcomes

1 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation

Project Outcomes

1 Farmers intend/plan to change their practice(s)
1 Grant received that built upon this project
3 New working collaborations
Project outcomes:

Winter 2021 Report:

Our project has only had the initial conditions set for the 2021 evaluation so the project is not along far enough to cause changes in system sustainability.  That said, the project has provided the motivation and funds to start accumulating the equipment to make the practice of cover cropping more mainstream in Southcentral Alaska.  Currently, there exists a 'chicken-or-egg' dilemma with cover cropping:  No one cover crops because no one has the equipment to facilitate the practice and the equipment isn't available because no one uses cover crops.  This SARE project is providing the motivation to fabricate some of the necessary equipment to give the practice of cover cropping a  fair chance of succeeding.

Success stories:

Winter 2021 Report:

In the year of establishment (2020) the project has not shown adequate results to generate success stories from farmers.  We hope to generate these kinds of results when we conduct the treatment evaluation in the 2021 growing season where we introduce a vegetable crop into the residue.


Winter 2021 Report:

The project is not at that stage yet but we've been taking photographs and video footage for future use.  Alaska growers have a strong history of not attending field days during the 3 month growing season.  Consequently, all Ag Professionals have learned to take a lot of photographs to show growers during the winter meetings.  Likewise, with the incredible growth of educational material available on YouTube, we're now creating video of all our projects.

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.