NCCC211: Cover crops to improve agricultural sustainability and environmental quality in the upper Midwest
(Multistate Research Coordinating Committee and Information Exchange Group)
NCCC211: Cover crops to improve agricultural sustainability and environmental quality in the upper Midwest
Duration: 10/01/2015 to 09/30/2020
Statement of Issues and Justification
This project will support the development and evaluation of cover cropping systems
that conserve soil, recycle nutrients, and improve soil health. Adding cover crops to
cropping systems of the Midwestern United States will facilitate large-scale
improvements in the ecological and environmental functioning of soils that drain to
the Gulf of Mexico or the Great Lakes. While natural ecosystems and perennial
forage systems typically have some plants growing, covering the soil, and taking up
water and nutrients most of the time that the ground is not frozen, annual cropping
systems, like corn and soybean, only have green coverage of the soil for four to six
months each year. Current tillage practices and harvest of plant biomass for fuel or
feed leave soil exposed during fall, winter, and spring without sufficient residue
cover to protect it. This bare soil surface is susceptible to losses of nitrogen,
phosphorus, and sediment to surface waters through runoff; losses of nitrogen to
groundwater or drainage systems through leaching; and losses of carbon dioxide,
nitrous oxide, and methane to the atmosphere through microbial processes. These
losses negatively impact water quality, soil health, and greenhouse gas emissions on
local, regional, and national levels. Thus, incorporating more "green" plants into the
"brown" months of annual cropping systems will help to protect soil and water
quality, reduce emissions of greenhouse gasses, and maintain natural cycles for
water, carbon, nutrients and soil organisms.
In 2012, the USDA National Agricultural Statistics Service (NASS) census of
agriculture included, for the first time, questions about cover crop use and reported
that over 10 million acres of land were planted to cover crops. This number suggests
two things: (1) cover crops are being used on greater than expected acreage and (2)
there is still not enough use of cover crops in the US. Two recent surveys highlight
both the perceived benefit of cover crops and the barriers to adoption. First, a
survey published from the Conservation Technology Information Center (CTIC) and
the Sustainable Agriculture Research & Education (SARE) program, reported that
winter cereal grains were the most popular cover crop used (72% of respondents),
followed by brassicas, legumes, and other annual grasses (62, 58, and 56%,
respectively). However, while the use of cover crops among those surveyed was high,
there are still challenges that these farmers and crop consultants recognized.
Establishment of the cover crop, the time and labor requirements of planting the
cover crop, and cover crop selection were the three most common challenges
reported (46, 44, and 43% of the respondents, respectively). A second survey funded
by the North Central Soybean Research Program, which focused primarily in the
north central region of the US (IL, IN, IA, KS, MI, MN, MO, ND, NE, OH, SD, and WI)
echoed these findings, with cost of cover crop seed also being a major concern.
These results clearly indicate that more research is needed on the management of
cover crops across all cropping systems of the North Central region. Additionally,
specific research efforts are needed to integrate cover crops into various tillage and
manure application systems, improve success of pre-harvest cover crop seeding
systems, and document the value of cover crops to farmers, the general public, and
Cover crops reduce nitrate leaching by utilizing residual nitrate and storing it in
plant tissues (Meisinger et al., 1991; Staver and Brinsfield, 1998; Kaspar et al.,
2007). In the studies reviewed by Meisinger et al. (1991), cover crops reduced both
the mass of N leached and the nitrate concentration of leachate 20 to 80 percent
compared with a no cover crop control. Kaspar et al. (2007) showed that a winter rye
cover crop planted every year in a corn-soybean rotation in Iowa reduced nitrate
load to tile drainage by 61%. More recent work has shown winter rye and oats
reduced nitrate loss through tile drains by 48 and 26%, respectively (Kaspar et al.,
Cover crops reduce erosion by increasing water infiltration rate by improving soil
structure, providing continuous ground cover to protect the soil against raindrop
impact, and reducing the velocity and carrying capacity of overland flow (Langdale et
al., 1991; Dabney, 1998). Kaspar et al. (2001) showed that a rye winter cover crop
following no-till soybean reduced rill erosion by 90% and interrill erosion by 54%.
Cover crops affect soil quality primarily by increasing inputs of organic matter and
recycling of soil nutrients. Winter cover crops have the potential to increase soil
organic C or to slow its rate of decline in agricultural soils (Karlen and Cambardella,
1996; Reicosky and Forcella, 1998; Jarecki and Lal, 2003). Beale et al. (1955)
reported that SOM was 28% higher after 10 yr of a vetch and rye cover crop with
mulch tillage compared with cover crops and moldboard plow tillage. After 9 years,
Moore et al. (2014) found that a rye cover crop in corn silage-soybean rotation
increased SOM by 15% and potential nitrogen mineralization by 38%. Cover crops
have also been shown to increase soil aggregation, decrease bulk density, and
increase water infiltration (Blanco-Canqui et al., 2012). In addition to improving soil
quality, the use of cover crops can lead to direct economic gains. For example,
legume cover crops have been shown increase the yield of the following crop, reduce
the nitrogen fertilizer needed, and provide high quality forage for grazing in the fall
(Samarappuli et al., 2014; Gentry et al., 2013; Henry et al., 2010).
An increase in the use of cover crops will lead to a reduction in nitrate leaching, a
reduction in soil erosion, and an improvement in soil quality. Without cover crops,
losses of N and P will continue to plague the waters of the US even with improved
fertilizer management. The increased demands placed on our agricultural systems
by demands for both food and fuel will lead to a continued decline in soil
productivity and increased degradation of surface and ground water supplies unless
conservation practices like cover crops are implemented on a wider scale. Although
other conservation practices such as wetlands, buffers, terraces, CRP, and perennial
cropping systems all should play a role in our agricultural landscapes, cover crops
are the only in-field practice that has the potential to improve soil productivity,
protect water quality, and reduce emissions of greenhouse gases without taking land
out of production or reducing the production levels of our current annual cropping
systems. In addition to the continued need of field, edge-of-field, and watershed
level data to quantify the effects of cover crops on crop production and water
quality, regional research is required to assess the effects of cover crops on soil
quality, which will certainly be different across different soil types and environments.
Since one of the issues of cover crop use is species selection, future work will focus
on the success of aerial seeding of cover crop seed into standing corn or soybean
crops and the use of cover crops as a potential animal feed source. Recent
preliminary research on cover crops as forage for grazing indicated that up to 2 Mg
ha-1 of dry matter can be accumulated in only two months of growth. In addition,
forage quality of forage pea and Austrian Winter pea in this trial was exceptional,
with very high crude protein content and high digestibility; forage radish and turnip
also had very high digestibility (Samarappuli et al., 2014).
Previous phases of multi-state efforts in cover crop research (NCCC 211) have
worked closely with the Midwest Cover Crops Council and will continue to do so. Our
previous efforts have led to additional membership in the Midwest Cover Crop
Council, which aided in the development of the Midwest Cover Crop Field Guide and
the selector tool. The next phase of this multi-state effort will further enhance the
data set from which the selector tool is based, expand the selector tool to new
states, refine planting windows for cover crop species, provide growth estimates of
cover crops, and add new cover crop species. Having a multi-state approach
enhances knowledge sharing and opportunities for collaborative research efforts
among scientists in the region. This in-turn leads to greater information exchange
between scientists and extension specialists with county extension, local NRCS and
land conservation districts, crop consultants, and farmers themselves. In addition, it
will lead to collaboration on grants that require multi-state efforts. Controlling
erosion, recycling and sequestering crop nutrients, and enhancing soil health are all
important efforts in modern agriculture and research and outreach to support these
efforts will be enhanced through efforts of this multi-state research coordinating
Assess the impact of cover crops on agronomic production and profitability.
Assess the impact of cover crops on water quality.
Develop recommendations for plantings of cover crops (rates, timing, application method) across production systems and across the North Central region.
Evaluate the benefit of cover crops as a dual-use crop (i.e. potentially harvested)
Work with state and federal agencies, crop consultants, and seed dealers and other agricultural businesses to assist in implementation and demonstration of successful cover crop management practices.
Procedures and Activities
1. Evaluate the effectiveness of cover crops and cover crop management practices in providing environmental benefits in annual cropping systems. Research and modeling studies in many of the North Central states are currently underway to evaluate cover crop species and management systems for their effectiveness in providing ecosystem services such as reducing nitrate leaching and erosion, increasing soil carbon sequestration, reducing greenhouse gas emissions, and improving soil quality. There is a critical need for researchers from the different states to meet regularly and exchange information about management systems, methodology, research results, and observations. Research will be coordinated where possible, so that the appropriate variables are measured to allow comprehensive comparisons across the North Central region.
2. Assess the impact of cover crops on agronomic production. Field research and modeling is being conducted on cover crops to evaluate their impact on various aspects of agronomic production systems and practices including: main crop yields, organics, home-grown nitrogen, reduced purchased inputs, cover crop seed production, risk management, pest control, additional forage or biomass production/double crop, timeliness of operations, and economics. On-farm sites established by members of Midwest Cover Crop Council (MCCC) will be utilized to test management practices needed to incorporate cover crops into production systems on field, farm, and watershed scales, and to provide sites for field days and educational activities. Annual meetings, a website, and an email listserve will facilitate the discussion of cover cropping on different soils, cropping systems, and climates, which are important for understanding and improving management of cover crops in the North Central region. This collaboration and interaction between farmers and other MCCC members with NCCC 211 project members will provide valuable feedback and will identify cover crop management problems that need to be addressed.
3. Develop cover crop guides and other extension materials, and work with state and federal action agencies, to assist in implementation and demonstration of improved management practices for cover crops. The NCCC committee will include extension personnel and an NRCS representative, and will coordinate the development of educational materials for cover crop management in the North Central region, which will include pamphlets, videos, and training modules. The committee will also work with the MCCC to assess needs for educational material, the impact of those materials, and to gather input on cover crop knowledge gaps and management problems from producers, consultants, suppliers, and action agencies. In cooperation with MCCC informational meetings, train-the-trainer professional development workshops, and field days will be developed for producers, consultants, NRCS personnel, and extension personnel in different parts of the region. The NCCC committee and the MCCC will work together on a web-based cover crop selector tool for each of the participating states and work to develop a database of results from cover crop experiments. The two groups will also cooperate on a cover crop database, which will be used to supplement and refine the selector tool. The two entities will collaborate on developing proposals for additional funding across the region. Many of the potential representatives on the proposed NCCC committee are also participating in the meetings of the MCCC, which will facilitate communication and coordination between the groups.
Expected Outcomes and Impacts
- Producers, NRCS personnel, Extension personnel, and consultants will have a better understanding of the potential benefits of cover crops and the management practices needed to implement them in annual grain crop systems.
- Cover crop management practices are developed, such as overseeding before grain crop harvest, which will reduce costs, resolve scheduling conflicts, reduce risks, and improve success of cover crop use in North Central cropping systems.
- Cover crop selector tool and cover crop database will be improved and assist producers in making cover crop management decisions.
- Cover crops adoption will increase in the North Central region, especially in corn-soybean systems.
- Increased cover crop use in the North Central region will provide numerous ecosystems services, improved sustainability, and reduction of purchased inputs.
- Producers and retailers will have better understanding of the short-term and long-term return on investment of cover crops in the North Central Region.
Projected ParticipationView Appendix E: Participation
Extension materials, such as pamphlets, videos, and training modules developed or coordinated by the committee will be available as pdf through extension websites in each state and the MCCC website. These materials can also be distributed by others at winter meetings, at field days, as webinars, or incorporated into training modules for producers, NRCS employees, extension personnel, crop consultants, and watershed groups. MCCC members or member groups will make suggestions for needed education topics, distribute materials, provide feedback on materials, and relate personal experiences on using cover crops that can be incorporated into programs or materials.
The recommended Standard Governance for multistate research activities include the election of a Chair, a Chair-elect, and a Secretary. All officers are to be elected first as secretary and then advance to Chair-elect and Chair over a three-year term to provide continuity. Administrative guidance will be provided by an assigned Administrative Advisor.
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Blanco-Canqui, H., M.M. Claassen, and D.R. Presley. 2012. Summer cover crops fix nitrogen, increase crop yield, and improve soil-crop relationships. Agron. J. 104:137-147.
Dabney, S.M. 1998. Cover crop impacts on watershed hydrology. J. Soil Water Conserv. 53:207-213.
Gentry, L.E., S.S. Snapp, R.F. Price, and L.F. Gentry. 2013. Apparent red clover nitrogen credit to corn: Evaluating cover crop introduction. Agron. J. 105:1658-1664.
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