Comparing fall- and spring-planted row crop to pasture conversion after multiple years of grazed diverse continuous cover crops

Final report for FNC22-1332

Project Type: Farmer/Rancher
Funds awarded in 2022: $15,000.00
Projected End Date: 01/15/2024
Grant Recipient: Knutson Shorthorns
Region: North Central
State: Minnesota
Project Coordinator:
Zachary Knutson
Knutson Shorthorns
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Project Information

Description of operation:

42 acres of row crop ground being converted to perennial pastures after 3 years of continuous cover crops. Cover crops were grazed by 30 cow/calf pairs and 10 ewe/lamb pairs. In addition to this field, we have ~95 acres of permanent pasture, consisting of 32 acres very long-term established native pasture & waterways, 55 acres converted to pasture in 2021 via oat/pea nurse crop, and 8 acres converted to pasture in 2020 spring-planted with no nurse crop, chemicals or fertilizers. We have been grazing cattle for 10 years, rotationally grazing for 6 of those, and rotating between 3-7 times a week for 3 of those.


Land is continuously becoming scarcer, so many graziers are looking for ways to effectively convert row crop land to perennial pastures.  One approach becoming more popular is using continuous covers followed by establishing perennials. We want to compare fall- and spring-interseeding with a fall-planted nurse crop. The continuous covers combined with ruminants kickstarts the soil biology, the nurse crop suppresses weeds, and the baleage of the nurse crop generates cash flow to offset establishment costs.

We have a field that has been in continuous covers since October 2020. We want to graze diverse summer annuals in Summer 2022, followed by a mix of biennials in Fall 2022. We will add diverse perennials into half the field in the fall, and interseed the same perennials on the other half in Spring 2023. We will compare the nurse crop baleage quantity and quality, and pasture height in Fall 2023 to compare the plantings.

If spring-interseeding is economically comparable to fall, producers could plant the fall cover and postpone the commitment to converting the land until spring when they have more information about the upcoming marketing year. Communities also benefit from new perennial pastures being established through increased availability of local grass-fed proteins.

Project Objectives:
  1. Examine fall- and spring-planted perennial pastures within continuous cover crops on land historically used for row crops
  2. Compare nurse crop yields of fall-planted and spring-interseeded perennial pastures
  3. Evaluate changes in soil test results from subsequent years of continuous cover crops 
  4. Share findings with other graziers through the Land Stewardship Project, social media websites, and via regenerative grazing group discussion


Materials and methods:

An inverted L shaped field with green color on one entire leg and partially into the other, wider, leg to cover approximately half of the field

June 4th, 2022. The Summer Annual mix was planted.  It was an 11-way mix: dwarf BMR sorghum-sudangrass, BMR grazing corn, kale, collards, safflower (baldy), mung beans, sunn hemp, african cabbage, plantain, chicory, and crimson clover. Our goal for blending the dwarf sorghum-sudangrass and grazing corn was to compare their growth performance. Additionally, we wanted regrowth after grazing which we heard wouldn't happen with grazing corn alone. We added several forbs and legumes for diversity in soil health. The plantains and chicory were added for their grazing qualities and also because they tend to come back as perennials long-term. They were also cheaper/easier to plant as part of the custom summer annual mix than trying to buy them individually and blend them into a grass/alfalfa mix in the fall planting.

The fall perennials were a hand-mixture of a grass pasture mix (Meadow fescue, tall fescue, festulolium, bromegrass, perennial ryegrass, orchardgrass, annual orchardgrass), grazing alfalfa, and medium red clover. The grasses were selected for long-term longevity under grazing conditions. 

The fall perennials were mixed with Austrian winter peas for the winter nurse crop. Planting was done on 8/24/22 with 3 inches of rain coming spread out over the 5 days post-planting in a light drizzle. We would have liked to use Icicle winter peas as well, but we were unable to acquire these due to delayed harvest of new seedstock. If the Austrian winter peas don't overwinter, we will plan to inter-seed 4010 forage peas in the spring for additional protein and tonnage in the nurse crop forage. We had planned to use winter triticale with the nurse crop, but volunteer triticale and winter cereal rye was significant over the summer and into the fall planting window. Our agronomist advised against adding additional small grains as they could shade out the perennials we want to establish. If these volunteer plants don't overwinter adequately, we will plan to interseed oats in the spring as the nurse crop.

On May 10, 2022, we seeded oats and peas blended with perennials on the other half of the field. While there was a modest stand of red clover in that field, the Austrian winter peas did not survive the winter. Interestingly, the Austrian winter peas had a modest survival rate on the side with the perennial grasses that were seeded in the fall.

As of November 9, 2022, the perennial grasses are up to 6 inches tall after a nice combination of 3/4" rain and 60 degrees F for the week prior.

The fall-seeded side of the field was cut on May 21st, 2023 and baled as dry hay on May 30, 2023.

We did a 2nd cutting in July 2023 to match the spring side for efficiency of scale and to remove the winter cereal rye before it self-seeded. This wasn't the ideal timing for a 2nd cutting in terms of yield due to the severe drought we experienced from the end of May through July, but it ended up working well because the quality of forage that regrew after the winter cereal rye was removed was significantly better for grazing.

The spring-seeded side of the field was cut on July 2nd and baled/wrapped on July 4th, 2023s baled with an average of 3-4x4 (loose) round bales per acre (approximately 2400lbs/acre). On the same day (July 4th), approximately half of the fall-seeded field was also baled. We intended to cut the entire field due to the winter cereal rye shading the perennials, but we had equipment break down and only half the field was cut. This side yielded 2-4x4 (loose) round bales per acre (approximately 1600lbs/acre).

Research results and discussion:

Improved Landscape Diversity: Number of Species

Prior to our first turn-out (August 2nd, 2022), the number of species that grew to a grazable height was limited, compared to the diversity in our summer annual mix (listed above). The species we were able to identify at a grazable height included: volunteer triticale, winter cereal rye, hairy vetch, sorghum-sudangrass, grazing corn, sunn hemp, collards, medium red clover (was not planted, but has shown up via herd impact and wind spread from neighboring pastures), and kale.

Giant ragweed and hairy vetch regrowth were the highest density plants on the 42-acre field. Due to the high density of ragweed, we decided to brush-hog the field to avoid large stems in next year's nurse crop hay. One observation after mowing was the sorghum-sudan grass grew much more rapidly, and the crimson clover spread significantly. Additional species such as african cabbage, plantain and chicory also became much more populous. The kale regrowth was significantly better than the initial pre-mowing growth.

The second turn-out on the field was on November 10th, 2022. Growth was lackluster due to us transitioning from no drought to a D1 drought during the time between first grazing and second grazing. However, diversity was strong and the plantain and red/crimson clovers were relatively strong growers. The perennial grasses were 2-6" tall as of November 10th, so the ~20 acres with perennials planted will not be grazed a second time with the hopes that it will give us better first-cutting hay yields or earlier grazing opportunities. 

Improved Soil Quality/Health

Results from our first year-over-year soil test: Phosphorous had a strong increase of 46%. Potassium decreased 2.33%, however this was attributed to a different testing method that only tested the bioavailable potassium instead of all potassium present. The median pH change was 0. Organic matter median change was +0.1 percentage point. Calcium increased 19%. Magnesium increased 28.6%. CEC increased 2%. These changes were not evaluated for statistical significance.

The next soil sample test (April 2023) will extend our results to a 2-year-over-year comparison on the above factors and will also provide year-over-year change data on Nitrogen, zinc, sulfur, boron, manganese, and copper.

The April 2023 soil sample test did not indicate any significant differences in soil quality from year 2 to year 3. The field remained deficient in N, P, and K. Our hypothesis is that the lack of nutrients combined with multiple years of drought inhibited plant growth, and therefore the plants were unable to create additional nutrients through cycling and natural processes. It is possible that an improvement in nutrition could be experienced under better growing conditions, but the multi-year cover crop grazing did not cure the deficiencies that were in place when we started, under the drought conditions we experienced.

Improved Forage Yield 

The fall-seeded mix had higher production and lower costs. The spring-seeded side had additional costs in the oats/peas mixture and extra planting pass compared to the fall mix. The fall-seeded side produced 1.25 tons/acre on May 30th, whereas the spring-seeded side didn't produce this yield until July 4th. By July 4th, the fall-seeded side had produced an additional 0.75 tons/acre above the spring-seeded side.

  • Fall side first cutting (May 2023): averaged slightly under 1-5x6 (tight) round bale per acre (approximately 2500lbs/acre).
  • Spring side first cutting (July 2023): averaged 3-4x4 (loose) round bales per acre (approximately 2400lbs/acre).
  • Fall side second cutting (July 2024): averaged 2-4x4 (loose) round bales per acre (approximately 1600lbs/acre).


Participation Summary
2 Farmers participating in research

Educational & Outreach Activities

2 Workshop field days

Participation Summary:

35 Farmers participated
5 Ag professionals participated
Education/outreach description:

We had a field day in July 2022 with the Land Stewardship Project where farmers/ranchers were able to view the summer annuals for grazing and the second-year growth of a different field converted to perennial pastures in a different method. There were 15 farmers/ranchers who attended, along with 2 agricultural professionals.

We had a field day on July 29, 2023 with the Practical Farmers of Iowa. We started the field day by discussing the various approaches we've taken to convert row crops to perennial pasture, then we walked through 3 fields that reflected 4 different approaches to converting the land. We also discussed our rotational grazing practices, forage quality and soil testing data.

We have continued to post about our farm's rotational grazing practice on our facebook page, Knutson Shorthorns, though the pasture walks and field days are more impactful in reaching other farmers about this project.

Learning Outcomes

4 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
Lessons Learned:
  • Hairy vetch overwintered in our southeastern Minnesota farm (zone 4b) over the winter of 2021-2022. Having 15% of the winter mix seemed to be too much because it was very high density in summer 2022 and posed concerns of vetch toxicity. We did not have any issues with the vetch toxicity, but it was dry and we waited for it to die back from maturity. We also moved the cows quickly across the field.
  • Our key takeaway was that grazing cover crops won't cure the soil deficiencies that are present in this field. Our opinion, after conducting this research, is that it's important to remedy nutrient/pH deficiencies initially, and then use the cover crops/grazing to improve the soil thereafter.

Project Outcomes

2 Farmers changed or adopted a practice
1 New working collaboration
Success stories:

There were a few farmers visiting the field day who were making plans to convert poor farmland into perennial pastures. By learning from our experiences of trying multiple methods, they are excited to move forward using the most efficient conversion method that we've found. They were grateful for this project because we were able to save them several years of lackluster production because they won't be repeating the learning-curves we had through grazing cover crops in nutrient-deficient soils.

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.