Adapting Cover Crops to Northern Climate Conventional Cropping Systems

Adapting Cover Crops to Northern Climate Conventional Cropping Systems

Summary

Grant Activities

The design of this project was that Northeast Minnesota farmers, Troy Salzer, Abe Mach, and Scott Peterson, would grow a small grain crop and then no-till plant a fall cover crop after the small grain in order to increase forage production and evaluate soil health differences. 

A timeline of all crop management is displayed in Table 1 of the figures attachment.

Grant activities began in May 2014. Soil testing was conducted at each of the sites in order to create a “before” picture of soil nutrient availability. The results were used by the farmer to fertilize appropriately for the small grain crop. Grant funds provided a $300 fertilizer stipend for each of the farmers. No additional fertilizer was applied between harvest of the small grain and planting of the cover crop. 

All three of the farmers harvested the small grain crop between August 4, 2014 and August 12, 2014. At two of the sites the small grain was harvested as baleage. At one of the sites the small grain was grazed. Cover crops were planted at each of the sites between August 11, 2014 and August 23, 2014.  Grant funds were used to pay for cover crop seed. Shortly after planting, Abe Mach’s site, which had good highway visibility, was marked with a highway sign identifying it as an NCR-SARE cover crop research plot. Literature handouts about soil health and this specific Farmer/Rancher Grant Project were placed in a clear box fixed to the sign for the public to take. Grant funds were used for the highway sign.

The bulk of the data collection took place 11/10/14 through 11/15/2014. During this period soil samples were collected at all of the sites from the cover crop plots as well as adjacent control plots. Soil samples were submitted to Agvise laboratories where soil nutrients were analyzed as well as CO2 (soil biology). Also at that time, forage samples were collected from the cover crop. Forage samples were collected by scissor clipping five to six, 1 square foot plots at each of the sites. The samples were then dried to calculate dry matter yields (tons DM/acre). The dried samples were then sent into Agvise laboratories for forage quality analyses. Grant funds were used for all soil and forage analyses.

Grant funds were additionally used for paper plates, cups, and napkins for Scott Peterson’s field day, which took place October 15, 2014 (see Outreach section).

Results

It was observed in this year of the project that planting a fall cover crop after small grain in NE Minnesota can produce an economically viable forage crop. However, no soil health conclusions could yet be made.

Small grain yield data is shown in Table 2 of the figures attachment. Yields ranged from 1.18 to ~2.32 tons DM/acre between the sites. Though this data does not directly help evaluate our main objectives, it provides context to which the cover crops were utilized. In NE Minnesota where the growing season is relatively short, cover crops have shown to be more practical after small grains than corn, as it allows more time for the cover crop to establish. 

In order to evaluate the ability of fall cover crops to increase forage production, forage yield determinations and feed analyses were conducted. Cover crop yields were recorded in tons DM/acre. The yields are listed in Figure 1 of the figures attachment. Please note that Abe Mach has two sites shown in the figure. One, entitled “Mach’s,” and one entitled “Mach’s Irrigated.” “Mach’s” was his official SARE site where small grain was planted followed by turnips, peas, and winter rye. “Mach’s Irrigated,” was a garden site of comparable soil fertility where he planted a similar cover crop mix at the same time as his SARE site. The main difference between the sites was that “Mach’s Irrigated,” was irrigated at the time of seedling establishment. The result was that “Mach’s Irrigated” produced 3.8 ton DM/acre more than Mach’s non-irrigated SARE site. Though irrigated forage is virtually nonexistent in NE Minnesota, one more practical lesson that can be learned is that enhanced moisture retention through increased organic matter can be very helpful for cover crop yields, particularly on coarse textured soils, which is what Abe Mach’s ground consists of. 

The yields on both Abe Mach’s SARE cover crop, and Troy Salzer’s site were 1.19 and 1.14 ton DM/acre respectively. These are not tremendous yields for NE MN, however the high relative feed values (RFV) and crude protein (CP) levels add a great deal of validity to the cover crops for forage utility. Figure 2 displays the cover crop feed value analyses.

Considering the yield and feed value potential of fall cover crops, the important question that needs to be answered is, “Is planting a fall cover crop after small grains an economical way to increase forage production in NE Minnesota?” At Troy Salzer’s site a yield of 1.14 tons was produced with a CP level of 21.8 and an RFV of 296. The average value of standing forage of this quality is $120- $150/ton of dry matter. This equates to a gross revenue $136.80 to $171.00 per acre at Troy’s farm. Considering the only costs to put the cover crop in were the seed ($31.40/acre) and planting (~$12/acre), this nets a return of $94.40 to $127.60 per acre. This does not include the value of next spring’s winter rye regrowth, which is anticipated. This cost analysis indicates that planting a fall cover crop after small grain is a cost effective way to increase forage production in Northeast Minnesota.

Alternatively, when the same analysis is applied to the other producers’ cover crops, a different result is experienced. For example, Abe Mach’s cover crop analysis showed an RFV of 123 and a CP of 16.1. The estimated value of this standing forage is approximately $80/ton DM. Abe produced 1.19 tons resulting in a gross value of $95.20/ton DM. Subtracting the $43.40 in costs of seed and planting nets a return of approximately $51.80/acre. Again, an additional benefit of the cover crop is expected in next spring’s regrowth of winter rye. 

Thirdly, an analysis of Scott Peterson’s cover crop shows a net loss. The value of Scott’s cover crop plot, given its lower quality, is approximately $55/ton DM standing. His yield of 0.30 ton DM/acre grosses $16.50/acre. After the cost of seed and seeding, this equates to a net loss of $26.90. At this time we do not have a clear understanding of why Scott’s cover crop did not establish well. One possibility is that because the wheat was planted relatively late many of the seeds did not germinate after planting. Once the wheat was harvested and the soil slightly disturbed with seeding the cover crop, those seeds may have germinated at that time, out competing the cover crop and reducing the forage quality. Turnips were well established in only about 15% of the field. Those areas where the turnips did establish saw 31% higher crude protein and 185% higher Relative Feed Value than natural regenerated areas where turnips did not establish. Samples collected from the turnip areas still did not show tremendous dry matter yield as turnips have very high concentrations of water.

The next question we need to address is, “Do cover crops planted after small grains in Northeast Minnesota improve soil health?” This question is much more difficult to assess. Part of the difficulty is that one year is not sufficient time to see cumulative soil health response from cover crops.  The other difficulty was simply that our soil nutrient and CO2 analyses were quite convoluted. The soil test results for each of the sites are shown in figures three, four, and five. At this time we are not able to draw any conclusions. However, improved sampling strategies will be implemented next year with the use of a GPS to mark and revisit the same sample points for all of the sites through the course of the growing season. This should help alleviate natural within field variability of soil parameters.

Future Work Plan

In 2015 the same ground will be used for the study as was used in 2014. It is expected that the winter rye from 2014’s cover crop will be harvested or terminated by approximately 6/1/2015. Yield will be calculated in cases where it is harvested. Soil testing will occur in May in order to track soil nutrients and guide any needed fertilizer application. Small grain will be planted approximately early June followed by an early August harvest. The same cover crop mix of winter rye, turnips, and peas will then be no-till planted. Fall data collection will mimic 2014’s fall data collection, with the exception of a refined process for soil sampling by using a GPS unit. 

Outreach

On August 11 the Project Director, Troy Salzer, and Project Assistant, Caleb Anderson, gave a presentation to the Carlton County SWCD Board of Supervisors about the use of cover crops in NE Minnesota as well as research that the Carlton County Extension is involved with pertaining to cover crops. Information from this project was shared. Twelve individuals participated.

On August 21^st, a field day was held at Abe Mach’s site to showcase the project.  Approximately 60 people attended. Abe along with Extension Educator, Troy Salzer, spoke about the project. Additionally, the Carlton County NRCS District Conservationist, Will Bomier, spoke some about soil health. Mr. Bomier, demonstrated use of a digital penetrometer to measure soil compaction. Field day participants completed a survey about their knowledge and interest in cover crops, as well as what they learned from this Farmer/Rancher Grant project.  The results of the survey are attached. Also, handouts pertaining to soil health were made available to all participants. The handouts are attached as well. 

On October 1, Carlton County Extension published an article about the project in its newsletter, which was distributed to approximately 2,400 homes in NE Minnesota.

On October 15, a field day was held at Scott Peterson’s site to showcase his project plot. Thirty-two people participated. A poster board was displayed for participants showing photos from Troy Salzer’s and Abe Mach’s project sites, as well as a timeline of some of the grant/cropping events.  Both Scott and Troy shared information about the project for the participants. Participants completed the same survey that was utilized at Abe Mach’s field day. The results are attached. 

In 2015, Carlton County Extension will continue to publish articles about the project in its quarterly newsletter. A new article is currently slated for the 1/1/2015 newsletter.  On February 3^rd, Troy and Abe will attend the Northeast Forage and Grassland Council Winter Meeting, which averages 100 participants, where they will give a presentation on the project. A poster board will also be displayed for people to look at.

The summer and fall of 2015 will include two more field days where the public will have an opportunity to visit the sites.

• Figures
• Photos
• Handout 1
• Handout 2
• Survey Results 2
• Survey Results 1

Objectives/Performance Targets

Accomplishments/Milestones

Impacts and Contributions/Outcomes

Collaborators: