Strip-Till Corn in Established Rotational Organic Alfalfa

Final report for FNC21-1270

Project Type: Farmer/Rancher
Funds awarded in 2021: $8,051.00
Projected End Date: 12/31/2023
Grant Recipient: Enger Farms
Region: North Central
State: North Dakota
Project Coordinator:
Steve Enger
Enger Farms
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Project Information

Description of operation:

This farm is operated by myself and my wife for 43 years. My current farming operation consists of 520 acres of which 65 acres are currently certified organic with an additional 100 acres transitioning to organic. The certified and transitioning organic acres are currently in alfalfa production and full season cover crops. Crops grown on the conventional acres include spring wheat, sunflowers , corn, soybeans and edible beans. Cover crops are grown as it fits into our rotation. I have been using no-till farming practices since 2008, and would like to do no-till organic farming.


Adequate nutrient supply, erosion and weed control are challenges in an organic system. This project over two years will investigate the establishment of wide-row strip-till corn in a living cover crop of established alfalfa and mulching of corn rows with a mower/mulcher to address these challenges.  Alfalfa is a common rotational crop in an organic system that is typically terminated by full width inverted tillage. According to North Dakota State University Extension fertility recommendations alfalfa terminated by tillage will supply adequate nitrogen to a subsequent corn crop without further additions in a conventional cropping system. Tillage however, leaves the soil susceptible to erosion and in-season tillage will be needed for weed control in an organic system. Previous and current studies utilize perennial clover or annual cover crops seeded at or near the same planting date as corn for erosion and weed control.  This system, which was proved feasible in crop year 2020, maintains adequate soil cover for erosion control and weed control. The system needs further investigation of soil health effect, moisture availability, adequate nitrogen and overall crop and economic performance. Additionally, a prototype mower-mulcher implement will need to be developed to mow alfalfa and mulch 44-inch corn rows. 

Project Objectives:
  1. Evaluate performance of wide-row strip-till crop production in perennial alfalfa over two growing seasons
  2. Assess impacts on physical health/qualities of soil 
  3. Monitor soil nitrogen mineralization over two growing seasons
  4. Assess soil biological composition effect of compost
  5. Develop and test prototype mower/mulcher
  6. Conduct a field day and present findings in a pdf format for technology transfer and present information at workshops when requested


Materials and methods:

The plot will be located in the N1/2NW1/4-16-148N-R54W on an area of Gardena loam soils, 0-2% slope. Four year old established alfalfa will be terminated in strips 14-18 inches wide with a paratill implement modified for 44-inch corn row spacing.  Three six-row plots 560 feet long will be established to match planter implement size. The 44-inch rows will allow room for mulcher/mower equipment to pass between rows and side discharge alfalfa mulch into corn rows. Mulching will occur on two or three occasions providing as much low C:N ratio mulch for corn row placement before corn reaches a plant height that limits equipment passage. Compost mulch will be applied at a single and double rate. Corn seeding population will be approximately 32,000 seeds/acre. In-row corn population of the 44-inch rows will be double that of what would be in a 22-inch row to maintain corn population.

On-site soil heath monitoring will be completed at the beginning and the end of the project including infiltration, Visual Evaluation of Soil Structure and aggregate stability. Soil sampling for biological soil health assessment will be completed by compost treatments at the beginning and end of the project. Nitrogen mineralization will be tracked by sampling 0-24 inches of soil and testing for nitrate-nitrogen on a 3-week interval during the growing season on replicated treatment plots the same or similar to the design used in the 2020 year feasibility of concept study.

Small plot area for N mineralization study in 2020 feasibility of concept study with farm composting operation in background.

A field plot tour will be conducted in the summer of 2021 unless drought impacts continue into growing season and delay until 2022. Final results will be summarized at the completion of the last cropping year, distributed and presented as a pdf or PowerPoint.


Research results and discussion:

The paratill was modified for use for strip tilling in year 1. Field strips were established for year one.  

I was not satisfied the way the paratill worked. It left the ground uneven and I had to go too deep. It was not a good practice for no-till farming. I will modify my strip-till implement to cut a 12 inch pass over the row just below the crown of the alfalfa. Under cutting should do a good job of killing the alfalfa. I will only be going about 2-3 inches deep.

No results in 2021. The crop dried up. Should have data from the 2022 crop.

On May 14, 2022, I had a farm accident and was  not able to do our project for 2022. Field strips were not established in year 2. I would like to have an eleven-month extension to December 31, 2023.

To continue the project, I will make the strips for year 3. I will not be using the 14–18-inch-wide Para till implement because it goes deep into the soils and too much moisture would be lost.  Instead, I will use a strip-till implement with a 12-inch straight blade.  Research has indicated shallow knifing just under the crown is a way to terminate alfalfa.  I will set up the strip till implement in strips 12 inches wide to undercut just below the crown.

I did develop a blade for my strip-till implement.  It did not work as planned because it did not go into the ground and if it did, it plugged.  The spring planting was late and I didn't have time to make any changes.  The summer was dry so the corn would not have grown.  What was to be completed for the SARE grant was not done.  

The ground got so dry from six years of alfalfa growth that inter-seeding corn into alfalfa was not possible. The alfalfa  grew because the root system had gone down into the ground five feet.  I knew the alfalfa root depth because we had dug a soil pit in the field.  Rain had been in short supply for two years.  

My field trial was in 2020, year three for alfalfa.  Conditions were good for year three of alfalfa.  My plan was to terminate the alfalfa in no-till organic farming.  I don't believe this is a good practice for our northern part of the country.  The ground is too cold to get the rapid growth we need to shade the ground.  It would be better to try this in year two or three of the alfalfa growing as the ground would not be so dry.  If adequate rain, results would be better.

I came up with a new plan to terminate the alfalfa in 2023.  I cut the first cutting of alfalfa's 2023 crop and baled it.  I let the second cutting grow to early bloom and shredded it for a green manure crop.  This ground had not been worked in over fifteen years.  I was able to chisel plow the alfalfa ground with sixteen inch sweeps.  The field was worked multiple times to get the roots broken up.  I then planted a cover crop in early August.  This cover crop was planted with the intent that it would winter kill and leave residue on the surface. 

The cover crop was a forty-five pound mix of Sorghum Sudan, Oats, Barley, Nitro Radish, Black Oil Sunflower, Clemson Spineless 80 Okra, Brown Flax, and Baldy Safflower. From the 5,400 lbs. of dry matter/acre, the nutrient value of the cover crop residue was 135 lbs. of N, 16 lbs. of P, 184 lbs. of K, 8 lbs. of S.   The carbon to nitrogen ratio on the cover crop was 15.9. Planting these seeds in such dry conditions and then watching them grow and develop was exciting.  Even the clay hill tops were green and lush. 

Working up the alfalfa field was concerning to me.  How much was the soil biology being disturbed? Tillage was completed as quickly as possible so live roots could get growing again.  I thought seeding a multi species cover-crop would heal the soil disturbance.  I thought a biological test should be done to indicate soil health.

Because I had used the Haney Soil Health Analysis before, I had a guideline to follow to indicate good biological activity in the soil.  I knew the soil numbers between 100 and 200 were desirable. Previous respiration tests showed that in 2019 the reading was 52.2.  2020 was 119.  2022 was 139.4,  2023 was 146.8.  These numbers tell us how much the soil can breathe when there is a higher microbial biomass. 

Next, I looked at the soil health score which is the summary of the soil respiration, water extractable organic carbon, and water extractable organic nitrogen.  Score ranges on this are from 0 to 50 with the higher the number, the better it is.  2019 was 7.96, 2020 was 14.34, 2022 was 15.43, 2023 was 18.70.

Then I checked the soil's organic matter.  2019 was 3.5, 2020 was 3.6, 2022 was 3.6, 2023 was 3.8. 

From looking at these three indicators, the soil health in this field was making progress.  Soil respiration, soil health score, and organic matter had all improved, which is a benefit.  

The Haney Soil Health analysis was done in October of 2023.  The results show sufficient nutrients in the soil and in the cover-crop.  There is no need to add more nutrients to the soil to produce a 150 bu. corn crop.

Progress is being made in the chemical, physical, and biological improvements in the soil.  I question if I have enough residue on the surface to suppress weeds this coming growing season.  Our soil moisture has improved.  This will be the first year to grow an organic row crop other than alfalfa.  I will be researching how to control weeds in organic corn this winter. 

Participation Summary
1 Farmers participating in research

Educational & Outreach Activities

50 Consultations
10 On-farm demonstrations
5 Tours
1 Webinars / talks / presentations

Participation Summary:

50 Farmers participated
10 Ag professionals participated
Education/outreach description:

The main event to tell people about the project will be our field day in late summer of 2022. I will use press releases, fliers and social media to communicate information to the public.

Here is a link to the flyer that we used for the field day in 2022.   Field Day July 27th 2022, FNC21-1270

We had about 50 people from 3 states in attendance.  Much discussion was concerning soil infiltration and soil health. We also had a soil pit that showed the roots of the alfalfa in the field.  They went down nearly 5 feet. 

On January 26 and 27, 2024, I will be speaking in Aberdeen, SD, at the Northern Plains Sustainable Agriculture Conference.  My presentation will inter-seeding corn and taking out a field of alfalfa.  

Learning Outcomes

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

When you don't get any rain it is difficult to grow a crop.  It is important to concentrate with no-till farming and look at ways to improve your infiltration rate.  My moisture levels  going into the spring of 2022 is much better than 2021. I'm optimistic  I can grow a good test plot so I can tell others about my project.

Project Outcomes

1 Farmers changed or adopted a practice
Success stories:

None to report

Information Products

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.