Final Report for ONC15-001
Project Information
MSU Extension Presque Isle County, in partnership with three Michigan Conservation Districts, the Natural Resource Conservation Service (NRCS) and local field crop producers received $29,810 in grant funds from the NC-SARE Partnership Grant Program for the ‘Northeast Michigan Aerial Cover Crop Seeding Demonstrations’ project. This project investigated and demonstrated cooperative aerial seeding as a method of timely cover crop establishment on Northeast MI corn and soybean acres. Cereal rye (CR), an oat-oilseed radish blend (O-OR) and winter wheat (WW) were aerially overseeded into 17 fields (662 total acres) of corn and soybean prior to harvest in 2015. 400 acres were managed as research and demonstration sites highlighted by a comprehensive outreach campaign and series of four extension events designed to educate producers on the potential benefits and challenges of aerial cover crop overseeding.
Data was collected on cover crop establishment, biomass yield and tissue nitrogen. Establishment was compromised by variable soil moisture conditions and competition with standing corn in some fields, as well as apparent herbicide carryover in one instance (averaging 33.65% overall). Recorded biomass yields were modest (averaging 396 lbs DM/a for O-OR and 904 lbs DM/a for CR), but this measure was partially confounded by combine clipping of cover crops at soybean harvest. Estimated plant available nitrogen (PAN) from cover crops was average for non-legume species (3-14 lbs/a in 2016). 83% (n=18) of project participants reported increased knowledge of cover crops and aerial seeding technology. 46% (n=13) reported increasing their use of cover crops by an average of 108 acres per grower in 2015, and 50% of growers (n=8) expressed interest in continuing cooperative aerial cover crop seeding in the future. However, this was not pursued in 2016 due to the relatively high cost of this practice over other establishment methods. This project was followed-up in 2016 with a study investigating early season interseeding of cover crops in corn using high clearance ground equipment.
SARE Aerial Seeding Final Report Figures
Introduction:
Cereal rye (CR) is the most popular winter cover crop in northern climates due to its ability to germinate under relatively cool temperatures and produce abundant biomass (1, 2). Enhanced nutrient use efficiency (3, 4), water holding capacity (5) and yield stability (6, 2) associated with CR cover crop use are of interest to producers in Northeast Michigan, who commonly farm coarse textured, low OM soils. Winterkilled cover crops, such as oats and oilseed radish (O-OR), are also of interest due to the reduced risk of spring planting interference they offer. The potential for increased profitability on the farm, as well as external benefits to the larger community in the form of enhanced water quality and improved economic stability, have stimulated grower interest in cover crops. However, adoption of winter cover crops remains low in Northeast MI because timely establishment on local corn and soybean acres using traditional seeding equipment is frequently precluded by harvest operations that carry-on into November and poor late-season field conditions (7, 2).
Alternative seeding technologies (aerial and high clearance ground equipment) are available to address this barrier by overseeding a cover crop prior to fall harvest of corn or soybeans (8). Yet, the significant financial and logistical investments required to drop seed from an airplane or access high clearance seeding equipment often outweigh somewhat less tangible improvements in long-term soil health.
Yet, a 2012 survey conducted by North Central SARE found that under drought conditions corn and soybeans planted after cover crops yielded 10.6% more, on average, than fields without covers. Cover crops can certainly pay off, but what can be done to enhance the viability of aerial seeding? Cover crop innovators in other states such as Iowa and Indiana have tackled this problem by developing cooperative aerial seeding programs coordinated by local agriculture professionals (9). These programs aggregate acres to be seeded across a few counties, thereby reducing producers’ individual costs for seed and aerial application. Following this example, the Northeast Michigan Aerial Cover Crop Seeding Demonstrations project was designed to investigate and demonstrate cooperative aerial seeding as a method of timely cover crop establishment on Northeast MI corn and soybean acres.
- Establish four 100 acre aerial seeding demonstration sites in 2015 featuring corn and soybeans overseeded with cereal rye or an oat-oilseed radish blend
- Recruit additional producers and aggregate acres to be seeded through the Northeast Michigan Aerial Cover Crop Seeding Program
- Deliver four outreach events to 1) educate producers on cover crop benefits/challenges and the opportunity of cooperative aerial overseeding, 2) demonstrate aerial overseeding in the field, 3) allow growers to assess results of aerial cover crop seeding and 4) share information on various methods of cover crop termination
- Encourage participation in NRCS conservation programs (EQIP and CSP) that provide financial incentives for cover crop use
Cooperators
Research
- Establish four 100 acre aerial seeding demonstration sites in 2015 featuring corn and soybeans overseeded with cereal rye or an oat-oilseed radish blend
Between late March and late June 2015, the project partners held three planning meetings to identify a seed supplier and aerial seeding service provider, address seeding logistics and plan our outreach events. Collaborating growers selected fields for the project, made the decision to trial a winterkilled oat-radish blend and winter wheat as alternatives to cereal rye, selected seeding rates and determined what data would be collected. On August 27, 2015 Al’s Aerial Spraying of Ovid, MI flew from three local airports to seed 295 acres of cereal rye at 112 lbs/a, 300 acres of oat-radish blend at 40 lbs/a and 67 acres of winter wheat at 3 bu/a in corn and soybean fields in Presque Isle, Alpena and Otsego Counties (Figure 1). 400 of the cereal acres were established through the grant as research and demonstration sites with more extensive monitoring and data collection than the remaining paid acres. Cover crop stand counts, fall biomass and tissue nitrogen data was collected in fall 2015. Spring biomass and tissue nitrogen data was collected from cereal rye fields in spring 2016.
- Recruit additional producers and aggregate acres to be seeded through the Northeast Michigan Aerial Cover Crop Seeding Program
The opportunity to participate in aerial cover crop seeding was promoted among local corn and soybean producers through our Aerial Seeding Workshop in July, mailing of a promotional flier, a press release to local media and personal contacts by the project partners. Four growers signed-up to participate in addition to the four original grower collaborators (total of eight), seeding an additional 144 acres of oat-radish blend at $32/ac (seed and plane), 30 acres of cereal rye at $33.50/ac (seed and plane), and 67 acres of wheat at $30/ac (plane only).
- Deliver four outreach events to 1) educate producers on cover crop benefits/challenges and the opportunity of cooperative aerial overseeding, 2) demonstrate aerial overseeding in the field, 3) allow growers to assess results of aerial cover crop seeding and 4) share information on various methods of cover crop termination
Aerial Seeding Workshop
On July 14th, 2015 the project partners offered a Cooperative Aerial Cover Crop Seeding Workshop in Hillman, MI. 21 producers and 11 agency partners attended this event to hear presentations on Cover Crops 101 (James DeDecker), Cooperative Aerial Seeding (Kay Holubik and Blaine Baker, Lenawee Conservation District), Cost Share Opportunities through NRCS (Perry Smeltzer, NRCS) and the Dover Oat-Radish Blend available to our growers through LaCrosse Seed (Jay Hallenbeck, LaCrosse Seed). Lunch was served at the event, sponsored by Monsanto.
Field Demonstration
On August 27th, 2015 22 producers and agency partners came out to participate in aerial seeding operations in Presque Isle, Montmorency and Otsego Counties. Growers delivered seed to three local airports, assisted with ground crew activities where needed, and observed seeding operations from the field with their friends and neighbors.
Aerial Seeding Field Tour
On October 16th, 2015 the project partners offered an Aerial Seeding Field Tour. Thirteen participants joined the tour to view the results of aerial cover crop interseeding operations conducted in late August and learned about using cover crops to enhance their production systems. The event began with a rainfall simulator demonstration to communicate the effect of cover crops and other management practices on soil erosion, water infiltration and environmental quality. Participants were then bussed to aerial seeding field sites, receiving free SARE cover crop resources and a boxed lunch along the way.
Cover Crop Termination Webinar
On March 28th, 2015 the project partners offered a Cover Crop Termination Strategies webinar as part of the annual MSU Extension Field Crops Webinar Series. 51 participants joined the webinar to hear a presentation by Mike Plumer, Conservation Ag Consultant, sharing recommended best practices for terminating various cover crop species and also contingency planning for unexpected circumstances related to weather, herbicide failures, etc. The webinar was recorded, and is available here.
- Encourage participation in NRCS conservation programs (EQIP and CSP) that provide financial incentives for cover crop use
NRCS cost share opportunities for cover crops available through the EQIP and CSP programs were presented by District Conservationist Perry Smeltzer at our Aerial Seeding Workshop in July and Field Tour in October. 83% (n=18) of respondents to our 2015 evaluation survey indicated that participation in our project increased their knowledge of NRCS cost share opportunities for cover crops. 23% (n=13) reported increasing their use of NRCS cost share opportunities as a result of our project.
Cover Crop Establishment
Cover crop establishment was highly variable across our field sites. Percent establishment averaged 30.5% for CR and 36.8% for O-OR, resulting in average stands of 614,205 plants/acre CR and 290,622 plants/acre O-OR (Figures 2 & 3). Although percent establishment was slightly greater in O-OR, the higher seeding rates used for CR resulted in better stands of CR than O-OR. Establishment was compromised in some cases by low soil moisture/excessive surface drainage, surface erosion, competition with standing crops, and possibly herbicide carryover in one instance. Establishment was better on fine textured, high organic matter and well-structured soils with moderate amounts of residue cover. One drawback of cooperative aerial seeding relying on a long distance service provider is the need to select one common date for seeding across many different cropping systems. It appeared that ideal seeding dates would have been somewhat different in corn vs. soybean, according to the cover crop species selected and relative maturity of the standing cash crop.
Biomass Yield and Nitrogen Cycling
Fall biomass yields averaged 646 lbs DM/a for CR and 396 lbs DM/a for O-OR on November 15, 2015 (Figure 4). Our measure of fall biomass was confounded in fields where cover crops grew tall and were clipped by a combine at cash crop harvest, prior to biomass sampling. This clipping was most pronounced in soybeans, removed some amount of cover crop biomass from our sample, and likely also affected cover crop architecture and total biomass yields. Cutting green cover crop biomass at harvest was also a practical concern for producers. In some cases, growers had prepared for this challenge by replacing knives on their cutter bar and adjusting combine settings. In other cases, green biomass intermixed with soybeans obviously increased harvest losses. Fall biomass was also measured at an adjacent field site where CR was drilled following soybean harvest (“Brandt post”) to compare to our overseeded CR. This site yielded only 63 lbs DM/a, or 10% of the overseeded CR.
CR spring biomass production was less than expected, averaging 297 lbs DM/a on May 15, 2016 (Figure 5). A warm and dry spring allowed growers to terminate CR in a timely manner. This was important to those who intended to follow CR with corn, in order to avoid nitrogen immobilization and excessive soil drying. However, early termination also limited CR spring biomass yields and possibly contributions to weed control, etc. in subsequent crops. Various combinations of herbicide (mostly glyphosate) and/or tillage were used to terminate cover crop growth in the spring. In two fields, cover crops to be terminated included OR that had volunteered from seed produced in fall of 2015. In one field, spring termination of volunteer OR was not successful, compromising the growth and harvest of second year soybeans (Figure 6)
The nitrogen concentration of cover crop biomass was measured in fall (CR and O-OR) and spring (CR) to estimate plant available nitrogen (PAN) for subsequent crops. While we did not expect the non-legume covers selected to supply nitrogen, growers had interest in their ability to capture and recycle nitrogen. Estimated PAN ranged from 3 to 20 lbs/a, varying according to dry biomass yields and the nitrogen concentration of cover crop biomass, which was not consistently higher in one cover species over the other, but perhaps driven by soil N status (Figure 5). This suggests that CR and O-OR can both be used to capture residual soil N following a cash crop, although CR may be better equipped to deliver N to a subsequent crop by overwintering, unless allowed to mature and increase in C:N ratio which could contribute to N immobilization.
Educational & Outreach Activities
Participation Summary:
See description of outreach events above.
No independent publications were created under this project. However, SARE’s Managing Cover Crops Profitably and the Purdue Midwest Cover Crops Field Guide were distributed to all project partners and participants at outreach events
Project Outcomes
13 producers, 5 public agency staff, and 1 agribusiness professional responded to our 2015 evaluation survey. The respondents reported managing or directly impacting 14,030 tillable acres in Northern Michigan. Of the 19 respondents 58% participated in our Aerial Seeding Workshop, 39% participated in our Aerial Seeding Field Tour and 37% participated in cooperative aerial seeding activities.
- Prior to initiation of our project in 2015, respondents reported planting an average of 86 acres to cover crops (1,375 acres total). In 2015, the average cover crop acreage per respondent increased to 108 acres (1,726 acres total).
- Respondents rated the performance of each cover crop-cash crop combination we trialed
- Cereal rye into corn
- Poor = 25%
- Fair = 50%
- Good = 25%
- Excellent = 0%
- Cereal rye/wheat into soybean
- Poor = 0%
- Fair = 13%
- Good = 62%
- Excellent = 25%
- Oat-radish into corn
- Poor = 11%
- Fair = 56%
- Good = 22%
- Excellent = 11%
- Oat-radish into soybean
- Poor = 0%
- Fair = 50%
- Good = 50%
- Excellent = 0%
- 83% (n=18) of respondents reported that participation in our project increased their knowledge of cover crops
- 46% (n=13) of respondents reported that they increased their use of cover crops as a result of our project
- 83% (n=18) of respondents reported that participation in our project increased their knowledge of aerial seeding technology
- 44% (n=18) of respondents rated aerial seeding as a favorable method of cover crop establishment for Northeast Michigan
- Cereal rye into corn
Participant comments:
- Aerial seeding is the only way for us to get cover crops in after soybeans. Already participating in NRCS programs for cover crops. Timing of seeding is a big factor. Having a solid plan for the next year after a fall cover crop is important to make the investment worthwhile.
- Timing of aerial seeding could be adjusted.
- Overall, a very useful program with lots of opportunity for the producers of NE Michigan.
- Distribution of the oat-radish was somewhat uneven/light at the wooded field edges. This program gave us an opportunity to use a technology that we were interested in, but could not previously justify given our small acreage.
- Aerial seeding was cost prohibitive.
- Aerial seeding was done too early. Hard to fit cover crops in on clay ground that needs to be fall tilled for moisture management.
- Tried cover crops, but does not fit current rotation and tillage practices.
- Cereal rye after silage harvest has been more successful than the aerial seeding. Flying rye into/after silage might be successful.
- Oat-radish stand was very uneven. Perhaps overlap areas did better. Plane was enjoyable to watch and the neighbors enjoyed it.
- Harvest was difficult with rye in soybeans. Already enrolled in NRCS programs requiring 100ac in cover. Aerial seeding is cost prohibitive in our region.
- Timing of rain after seeding is critical. Seeding rate too low for oat-radish. Is aerial seeding cost effective? Operation is too small to get NRCS points for cost share programs.
- Timing is crucial for interseeding.
63% (n=46) of respondents participating in our Cover Crop Termination Strategies webinar indicated that they plan to utilize, expand or improve their use of recommended cover crop management practices across 4,500 acres of field crops, generating approximately $7.30/ac of savings or added revenue, or $32,850 total.
The eight growers participating in aerial seeding responded to an informal follow-up survey in fall of 2016 to gauge their experience and determine how use of this technology may have affected other aspects of their cropping systems.
- For the most part, growers maintained their traditional crop rotation, soil fertility, tillage and pest management practices, simply inserting the overseeded winter cover crops into their rotation.
- One grower eliminated tillage on a field where the cover crop prevented fall tillage and the soil did not dry enough for spring tillage. Another grower increased tillage intensity to terminate CR before potatoes in 2016.
- One grower reduced fertilizer N inputs by 10 lbs/a in 2016 oats based on their estimated PAN credit from the previous cover crop
- None of the growers experienced new or unusual pest problems that they would contribute to the cover crop
- Two growers faced the challenge of volunteer OR in 2016. An application of 2-4D successfully controlled volunteer OR in oats. An application of glyphosate did not provide adequate control of volunteer OR in soybean, and the cover crop complicated harvest.
- Two growers reported that 2016 cash crops planted after CR tolerated drought conditions better than crops elsewhere, and estimated that cover cropped fields out-yielded other fields by an average of 12.5%.
- Five of eight growers expressed interest in future cooperative aerial cover crop seeding opportunities
Economic Analysis
Our service provider charged $20 per acre for aerial seeding. This cost was slightly higher than the $15-19 average cost of drilling or broadcasting and incorporating a cover crop in Michigan according to the 2015 MSU Custom Machine and Work Rate Estimates publication based on statewide survey results (Stein, 2016). Most of the participating growers viewed aerial seeding as relatively expensive and risky compared to establishing a cover crop with traditional ground equipment, noting these as significant barriers to adoption. In some cases, growers may fail to account for family labor, seed on-hand and/or other costs when planting cover crops by traditional means, making custom aerial seeding appear even more expensive. The cost of aerial seeding must also be balanced against the advantage of timely establishment. Aggregating at least 1,000 plus acres for cooperative aerial seeding would allow the group to negotiate a lower per acre price. Enrolling a larger number of acres may be possible when farms are relatively profitable. However, the recent decline in commodity prices and farm profitability has made investments in cover crops less attractive for local growers. Experimenting with high clearance ground equipment in 2016, we have been able to reduce seeding costs to $8-9 per acre, which may be more feasible.
Farmer Adoption
See above
Areas needing additional study
Farmers would benefit from additional research on several aspects of aerial cover crop seeding:
- Optimizing timing of aerial overseeding for particular cover-cash crop combinations
- Optimizing seeding rates for aerial over seeding according to species, seeding date, soil types, etc.
- Seed treatments for improving, speeding or delaying germination of interseeded cover crops
- Facilitating cooperative or other means of low cost access to high clearance ground seeding equipment