Building resilience to extreme rainfall events: cover crop-based reduced tillage strategies for diversified organic vegetable farms

Progress report for LNC19-421

Project Type: Research and Education
Funds awarded in 2019: $199,534.00
Projected End Date: 10/31/2022
Grant Recipient: University of Wisconsin-Madison
Region: North Central
State: Wisconsin
Project Coordinator:
Dr. Rue Genger
University of Wisconsin-Madison
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Project Information

Summary:

Extreme weather events are becoming more frequent because of climate change. In the Upper Midwest, climate models predict increased frequency of heavy and prolonged rainfall events. Extreme rainfall erodes soil, interferes with timely fieldwork, and reduces crop yields. Increasing cover crops and reducing tillage are production strategies that keep soil in place, sustain and enhance soil health, and ultimately increase farm resilience. The project “Building resilience to extreme rainfall events: Cover crop-based reduced tillage strategies for diversified organic vegetable farms” will develop a farmer-led learning community focused on reducing tillage, facilitate data collection and sharing among farms that are experimenting with reduced tillage techniques, and will conduct a replicated on-farm trial using living aisles and testing cover crop termination techniques that are appropriate for organic systems and do not rely on tillage.

Conversations with organic vegetable farmers in our region confirm that while they are keenly aware of the damage tillage can do and have a strong interest in improving soil quality and water infiltration rates through reducing tillage, they are at a loss as to how to control weeds, terminate cover crops, and maintain vegetable yields without tillage.  This proposal builds on their long-standing experience with cover crops to develop no-till techniques that can be used in rotation with crops like potatoes and carrots where soil disturbance will likely always be required, at least for harvest.

This project centers farmer expertise and innovation, supporting experimentation and facilitating peer learning through a farmer Community of Practice (CoP) focused on cover crop-based reduced tillage. The online farmer CoP will share strategies, approaches and outcomes of reduced tillage and cover cropping in vegetable production, and a group of farmer cooperators will track and share indicators of system resilience in their on-farm tests of reduced tillage. Through the CoP, we will produce case studies of how innovative vegetable farmers in the Upper Midwest are adapting to climate change and survey vegetable farmer knowledge, implementation and barriers to using reduced tillage strategies. We will partner with farmers to trial promising reduced tillage strategies for production of three different vegetable crops, emphasising cover crop termination techniques that preserve residues as mulch and are suitable for small scale organic farms, and producing regionally-relevant data to inform farmer decisions. Through this project, we will support and multiply the innovative potential of a community with intimate knowledge of the food production systems on which we all rely.

Project Objectives:

Farmer learning outcomes are increased knowledge of cover crop and reduced tillage strategies for small-scale, diversified organic vegetable production, how success of these strategies may be affected by multiple environmental and production factors, and familiarity with the equipment and skills needed to implement these strategies. Action outcomes are: increased farmer interactions through peer learning groups, greater experimentation with cover crop and reduced tillage strategies in vegetable production, and adoption of successful strategies. These outcomes will increase resilience to climate change and extreme weather events, increasing farm profitability, protecting environmental quality and natural resources, and improving farm community quality of life.

Introduction:

The impacts of climate change in the Upper Midwest are clear: climate is more variable and extreme weather events are more frequent. Average temperatures are rising at an accelerating rate, mostly impacting winter temperatures, and total average precipitation has increased. Increases in extreme rainfall events are clearly predicted from climate models for the Midwest, and both prediction and observation show increased frequency of heavy and prolonged rainfall events especially in spring. Obvious impacts on agriculture from increased extreme rainfall events include inundation of fields, soil erosion, and crop loss. Less obvious but significant impacts of extreme rainfall events include costly delays in field operations such as planting, weed management, and harvest, impacting overall labor needs and timing. 

No-till and reduced tillage production methods and increased use of cover crops are recommended responses to limit damage to soil and crops from extreme rainfall. Row crop farmers in the Midwest have been adopting no-tillage systems and increasing cover crop use, with conventional producers relying largely on herbicides for cover crop termination, and organic producers beginning to adopt mechanical termination methods such as roller-crimping. Most studies of cover crop-based reduced tillage systems have focused on corn and other row crops, with few addressing vegetable production in such systems. Similarly, strategies and equipment for cover crop termination have been developed with a focus on row crops.

Our study aims to explore the impacts of reduced tillage on yield, and its benefits for crop resiliency in an understudied system: diversified and direct-marketed organic vegetables in the Upper Midwest. We will also introduce new technologies for small-scale cover crop management, including a roller crimper designed for walk-behind tractors (Kornecki, 2015). This project will establish on-farm trials of cover crop-based reduced tillage strategies for organic vegetables using high residue cover crops and incorporating perennial cover crops as rainfall infiltration strips and sources of organic mulch. Outreach activities will support farmers who are innovating strategies to manage extreme rainfall events. Peer-to-peer learning will encourage farmers to trial and adopt strategies to increase farm resilience. Increased adoption of reduced tillage methods will reduce soil loss from farmland and improve water quality and farmland ecosystem services. Greater resilience to climate change will improve profitability of diversified organic vegetable production and quality of life for organic vegetable farmers and rural communities.

Cooperators

Click linked name(s) to expand
  • Claire Strader (Educator and Researcher)
  • Dylan Bruce (Researcher)
  • Dr. Julie Dawson (Educator and Researcher)

Research

Hypothesis:

Communities of Practice (CoP) are networks of people with mutual activities or interests, characterized by three dimensions – mutual engagement, joint enterprise and shared repertoires – that facilitate knowledge building and learning through shared practice. Studies of farmer networks using a CoP framework suggest that farmers belonging to CoPs who also accessed knowledge from a variety of sources were more empowered to innovate. We hypothesize that a CoP on reduced tillage in vegetable production will catalyze increased innovation by organic vegetable growers seeking to increase resilience to extreme weather. 

 This project will establish on-farm trials of cover crop-based reduced tillage strategies for organic vegetables using high residue cover crops and incorporating perennial cover crops as rainfall infiltration strips. We hypothesize that different termination methods will have differential impacts on vegetable productivity and soil conditions. 

Materials and methods:

Objective 1: Facilitate a farmer-led community of practice focused on resilience to extreme weather events in small scale diversified vegetable production

Building a farmer-led Community of Practice (CoP) focused on resilience to extreme weather events in small-scale diversified vegetable production is the primary project objective. The CoP will initially focus on cover crop use and reduced tillage in small scale diversified vegetable production, but farmer needs and interests centered around climate change, farming system resilience and economic, environmental and social sustainability will drive the topics covered.

The CoP will exist as an on-line and on-the-ground space for farmers to learn directly from their peers by sharing questions, ideas, strategies and skills (objective 1a). We will support a core group of farmers in testing new vegetable production strategies for resilience to extreme rainfall, with a focus on cover crops and reduced tillage (objective 1b). These on-farm tests will not constitute formal research, but will spark innovation in other CoP members, provide information for case studies for wider publication, and provide leads for future on-farm research into resilience to extreme weather in vegetable production. We will survey CoP members and other vegetable farmers for their knowledge, implementation, challenges and desire for information on cover crop-based reduced tillage strategies (objective 1c).

Objective 1a: Facilitate Community of Practice discussions and gatherings.

Farmer meetings and discussions initiated in 2018 brought together a group of organic vegetable farmers concerned about resilience to extreme weather resulting from climate change. This group will form the core of the CoP. The research team initiated discussions with farmers on the FairShare CSA Coalition listserve of over 300 farmers and agricultural professionals, met with approximately 40 farmers at the Organic Vegetable Production Conference in Madison WI, January 2019, and continued planning this proposal in email and phone conversations with farmers (see letters of support). We will build on these conversations through CoP planning meetings at the Organic Vegetable Production Conference and MOSES Organic Farming Conference in Jan and Feb 2020. At these planning meetings we will determine farmer priorities for resilience to extreme weather events, preferred communication modes for CoP, recruit new participants, and plan project field days and activities.

We anticipate that an email listserve or Google Group will be a suitable way for the CoP to communicate online, though other possibilities may emerge from farmer discussion. While the online space can be initially set up and managed by the research team, ideally the space will ultimately be managed by farmer members of the CoP, potentially through the FairShare CSA Coalition. Considerations for the online space will include: member privacy; content availability for searches by non-members; cost (no budget has been requested for this online space); and effects on farmer engagement of push content (eg email lists) versus pull content (eg discussion forums).

CoP discussions will form the basis for articles to be published in grower publications such as the MOSES Organic Broadcaster or Growing for Market magazine. Articles may include case studies of on-farm experiences with cover crop based reduced tillage (whether positive or negative), impacts of extreme rainfall or other extreme weather events on vegetable production, or summarize topics discussed in the CoP.

Field days will be at one of the three farms hosting replicated on-farm reduced tillage trials (see objective 2). Our initial field day will occur in early spring 2020. Since farmer turnout is likely to be lower in spring, we will video record the presentations to post online. At this field day, we will introduce the CoP and online discussion forum, and demonstrate indicators of soil health including: slake test for aggregate stability; water infiltration rate; water runoff and infiltration using an existing rainfall simulator; soil penetration resistance; and bulk density. We will share resources for soil quality evaluation including the USDA Soil Quality Test Kit Guide (https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_050956.pdf). We will discuss plans for replicated on-farm trials (objective 2) and on-farm independent trials (objective 1b). Fall field days in 2020 and 2021 will include progress reports on on-farm reduced tillage trials for both researcher-managed replicated trials and farmer-managed independent trials. The final field day in fall 2022 will be promoted as a capstone event to the project at which we will present on all aspects of the project.

To increase engagement and share knowledge gained through the CoP, we will facilitate farmer-led workshops at the Organic Vegetable Production Conference in Jan 2021 and 2022. We will facilitate farmer roundtables at the MOSES Organic Farming Conference in Feb 2021 and 2022, and will present research and CoP outcomes as a farmer panel workshop or a research poster at MOSES 2022.  

Objective 1b: Support farmer-led experimentation with cover crop-based reduced tillage strategies

Farmers involved in preliminary discussions about this project indicated interest in independent on-farm research, supported remotely by the research team. We will support a core group of six farmers in testing new vegetable production strategies for resilience to extreme rainfall events, with a focus on cover crops and reduced tillage. While these on-farm tests will not constitute formal research, they will build on a deep base of farmer knowledge of their farms and production systems, and are anticipated to provide leads for future on-farm research into resilience to extreme weather in vegetable production. Strategies to be tested will emerge from farmers’ personal research and CoP discussions. Strategies will be workshopped through phone conversations between farmers and researchers each spring, and although farms will run trials independently, we will seek opportunities to compare systems across sites or track system changes over time. Farmers are not expected to compare production systems side by side, but researchers will discuss the possibility to do so when practical.

Farmers will evaluate production strategies at least three times per season, both visually with photographs of production fields, and through qualitative ratings of system attributes. Strategies will be rated as better, worse, or similar to standard production strategies for the following attributes: yield; labor requirement; weed control; pest pressure; disease pressure; soil quality (as judged by farmer); and overall performance. Evaluation forms will include space for farmers to elaborate on system performance. Farmers will track tillage events by frequency and depth rating (deep, shallow, medium). Farmers will test soil aggregate stability with a slake test at the beginning and end of the season. Slake test results can be recorded visually with photographs at the beginning and end of the test. Farmers will also document field conditions through photographs after major rainfall events.

This core group of farmers will share findings from on-farm trials at field days, workshops and through on-line discussion forums. Several of these farmers, and others who will be identified through surveys and farmer networks, will be interviewed to develop case studies of on-farm innovations for climate change resilience. We anticipate that more farmers will participate to share their innovations and strategies for resilience to climate change and extreme rainfall as the learning community develops.

Objective 1c: Survey farmer knowledge, use and attitudes to cover crop-based reduced tillage strategies in vegetable production.

We will use a survey tool to assess knowledge, on-farm implementation, challenges and desire for information on cover crop-based reduced tillage strategies among diversified vegetable growers. We will seek feedback from core CoP members on a survey draft,  revise the survey based on feedback, and begin survey distribution in January 2020 (pending Institutional Review Board approval).

The survey will be distributed to diversified vegetable farmers through email lists, the project website, at field days, conferences and workshops. While the survey will be anonymous, we will include a question to verify whether respondents are members of the CoP and the length of time that they have participated in the CoP. We will distribute the survey in Jan-Feb each year to evaluate changes in knowledge over the period of the project. Our goal will be a minimum of 100 usable responses, which represents a large proportion of the 922 organic vegetable producers in the North Central Region (USDA NASS 2016 Organic Survey figures). We will analyse survey responses by farmer demographics including organic or conventional production, years farming, location, and farm size. Changes in knowledge among CoP members will be evaluated against the background of changes in knowledge among the wider population of diversified vegetable farmers.

Objective 2: conduct collaborative on-farm research into cover crop-based  reduced tillage strategies that integrate perennial and annual cover crops into diversified vegetable systems

Three farms in south central Wisconsin will host replicated trials of cover crop-based reduced tillage for production of cabbage, pepper and winter squash: Parisi Family Farms, Stoughton WI; High Meadow Farm, Johnson Creek WI; and Two Onion Farm, Belmont WI. Farmers and researchers will work together to establish production beds alternating with strips of a perennial grass-legume mix. Perennial strips will be planted in Fall 2019 with a perennial ryegrass-fescue-white clover mix, as this mix is low growing, easy to manage by mowing, and traffic-tolerant. These strips will be refreshed through overseeding if necessary in following seasons. Width of production beds and perennial strips may be slightly different at different farms depending on available equipment and preferred management styles. Production beds will be around 36-40 inches wide, with perennial strip width ranging more widely, from 20-60 inches, depending on farmer mowing equipment and desire to experiment with mulch production from perennial beds. Soil samples will be taken from the research plot area in Fall 2019 for soil texture analysis, routine nutrient analysis (P, K, pH) and organic matter analysis.  

Production beds will be planted with a rye/vetch cover crop each fall and fertility amendments indicated by soil tests will be applied at this time. Four treatments for cover crop termination will be tested using a randomized split block design with three replications: conventional tillage (CT), no-till roller crimper (RC), no-till sickle bar mowing (SM) and no-till occultation with silage plastic (SP). Treatments will be applied at rye anthesis (early May) to maximize termination rates. Established plots will receive the same management treatments every year and vegetable crops will be rotated among beds in the sequence peppers-cabbage-winter squash. A new roller crimper, compatible with walk-behind tractors and designed specifically for cover crop management on small farms by Dr. Ted Kornecki from the USDA Soil Dynamics Lab, will be used for the RC treatment. A 30” wide sickle bar mower, compatible with walk-behind tractors, will be provided by researchers, unless the farmer prefers to use their own sickle bar mower. We will evaluate cover crop termination rates 2 weeks and 4 weeks after treatment.

Vegetable plots will be 25 feet in length with a single row of plants at 18” spacing. Peppers and winter squash will be planted 2 weeks after cover crop termination (mid-late May), and cabbage will be planted in early July. Vegetable cultivars will be chosen in consultation with farmers but a bush-type winter squash such as Honey Bear will be chosen to allow mowing of living aisles. Transplants will be punch planted by hand into all treatments and a pint of compost will be added to the planting hole. Plots will be irrigated with drip line.

Weed pressure will be recorded for each plot as a population count per square foot at ground level. We will record all labor hours for plot management. Soil temperature and moisture will be tracked using existing equipment. Crop petioles will be sampled for nitrate analysis at 3 timepoints through the season to track plant nitrogen nutrition. Petioles for the most recently matured leaf from each plant will be bulked by plot, and will be shipped overnight on ice to the University of Wisconsin Soil and Forage Lab. In October after completion of harvest, we will assess soil aggregate stability (slake test), bulk density, and water infiltration for each plot following methods in the USDA Soil Quality Test Kit Guide (https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_050956.pdf). We will harvest peppers 6 times between August and September and will harvest cabbage and winter squash in October. Harvest data will include marketable and unmarketable weight and count, and causes of unmarketability. We will analyse data from harvests, soil indicators, weed counts, petiole nitrates and labor hours to evaluate costs and benefits of treatments for different vegetable crops.

Participation Summary
9 Farmers participating in research

Project Activities

Objective 1a: Facilitate Community of Practice discussions and gatherings
Objective 1b: Support farmer-led experimentation with cover crop-based reduced tillage strategies
Objective 2: conduct collaborative on-farm research into cover crop-based reduced tillage strategies that integrate perennial and annual cover crops into diversified vegetable systems

Educational & Outreach Activities

1 Curricula, factsheets or educational tools
3 Online trainings
1 Webinars / talks / presentations
1 Workshop field days

Participation Summary

80 Farmers
20 Ag professionals participated
Education/outreach description:

Due to COVID-19 guidelines on travel and gatherings, in-person field days were not possible in 2020. Instead, we held three gatherings using the Zoom platform. On June 16, we held a discussion of reduced tillage farming systems and previous trials and introduced the online forms for use by farmers to record details of their ongoing trials of reduced tillage methods (5 farmers and 2 researchers in attendance). On July 23, Dana Jokela of Sogn Valley Farm led a discussion of reduced tillage trials conducted at his farm, attended by 3 farmers and 3 research/extension personnel. On August 17, Kat Becker of Cattail Organics described reduced tillage practices and plans at her farm, attended by 5 farmers and 4 research/extension personnel. Recordings and notes from these meetings are at sites.google.com/view/climate-resilience-for-organic/events.

We facilitated a farmer-led workshop and roundtable at the Growing Stronger Collaborative Conference  on Organic and Sustainable Farming (Feb 22-27 2021). Workshop panelists were farmer Dana Jokela, Sogn Valley Farm, farmer Ellen Drews, Astarte Farm, and consultant Jan-Hendrik Cropp, under_cover Consultancy. Panelists and over 100 farmers attended the roundtable session to continue discussion of reduced tillage systems for vegetable production.

We staffed a virtual exhibit booth at the online Practical Farmers of Iowa conference, Jan 21-23 2021, allowing us to share project information and resources with attendees. At this booth, we shared a project overview (CROVP overview) and a handout on the roller crimper that will be used in on-farm research (Small scale roller crimper).

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.