Thirty participating small-scale vegetable farmers implement new tarp management plans to reduce their tillage intensity and report greater flexibility in bed management, 40 hours of labor savings, and an increase in net income by $1000 per tarped acre.
Small-scale vegetable farms (<15 acres) commonly depend on intensive, repeated tillage that is detrimental to soils and long-term productivity while continuing to struggle with weeds. For these farms, the consequences of heavy tillage are magnified by land constraints for sufficient cover crop windows and the high material and labor costs associated with organic mulches and amendments. These farmers represent an increasing majority of Northeast vegetable farms but there are few examples of successful reduced tillage (RT) and no-tillage (NT) management with scale-appropriate tools and equipment. These farmers have many concerns with reducing tillage, including weed and plant residue management, low soil temperatures and fertility, and poor crop establishment and/or lower yields. While RT strategies have been demonstrated to improve labor efficiencies and profitability on larger farms, benefits have been slow to accrue for smaller farms.
To advance adoption of RT on these small-scale vegetable farms, we will investigate opaque plastic tarps as a low-cost, labor-saving practice to reduce tillage intensity and add management flexibility. Despite farmer interest in tarping to address weed challenges, there has been little research that explores tarping as an RT strategy under a range of small-scale vegetable production systems. Our approach is designed to use tarps to overcome commonly cited concerns with RT. Our research and extension team, which includes our farmer advisors, will bring together expertise across the Northeast region (NY, ME, MA, PA) to take a whole-systems approach to advancing RT for these producers.
Our integrated research and education effort starts with farmer-centered workshops using Dialogue Education (DE) strategies that facilitate peer-peer learning. Together, farmers will identify opportunities for RT, evaluate tarp rotation strategies to reduce risks of RT, and design individualized on-farm RT transition plans specific to their own goals. Subsequent farmer-led on-farm experimentation will be supported over multiple years through direct consulting, virtual discussion groups, webinars, and field days that help farmers evaluate and share their results, participate in knowledge sharing networks, and learn research findings to foster continued innovation of these RT systems.
Using established permanent bed systems trials (NY, ME) with a history of different soil and crop management regimes, our research will explore how tarping, tillage and additional soil management practices change soil fertility, weed dynamics, and crop performance and the needed labor, equipment and other inputs required to improve success of RT and NT for small-scale vegetables.
1) Tarping will lower weed pressure and labor use and increase available soil nitrogen, crop productivity and profitability across tillage systems (Obj. 1)
2) Tarping benefits will be greatest in no-till relative to conventional and shallow tillage systems (Obj. 1).
3) Tarping impacts on weeds, labor use, and profitability will be greatest within unmulched, bare soil systems (Obj. 2).
4)Tarping benefits will be optimized when combined with additional soil management practices (straw mulch, deep compost amended; Obj. 2).
Objective 1: Evaluating tarping with conventional, shallow, and no-tillage in a permanent bed system
While tarps have shown some potential to improve no-till systems, most farmers are still combining tarps with conventional tillage practices. Our goal is to advance farmer adoption of RT systems by understanding how tarps interact with tillage intensity to affect agronomic and economic performance.
- Treatments: Three different tillage intensities (conventional, shallow and no-till) will be tested with and without tarping over two years. The impact of tillage and tarps will be examined in both a season-long crop (winter squash, Yr 1) and a double crop (lettuce/brassica, Yr 2). We will modify tarping and tillage as appropriate for each crop within the rotation (e.g. variable frequency, timing, duration).
- Methods: Tillage plots consist of three 1.2m beds, 23m long on 1.8m centers (Figure 1). Each tillage main plot is split into three soil management subplots (8m each), detailed in Obj. 2. Conventionally tilled beds will be rototilled to a 20cm depth. Shallow tillage (<10 cm) will be implemented using a power harrow or rototiller adjusted to minimum depth. Hand tools will be used in no-till beds as needed to manage weeds and crop residue. Tarps will be applied for a minimum of 3 weeks following seedbed preparation and removed before planting. Untarped beds will be tilled 1-2 times based on soil conditions and planting date. Fertility management is described in Obj. 2. In-season weed control will be done using a combination of tractor cultivation and hand weeding.
In year 1, tillage and tarps will applied in May and beds planted to winter squash by mid-June (1 row per bed, 0.6m spacing) and harvested by October (Table 3). Then tarped beds will tilled and amended in fall, weather permitting, and tarped overwinter in advance of a spring lettuce crop. In year 2, tillage will be applied to untarped beds, tarps will be removed and beds transplanted to lettuce in mid-May (3 row, 0.38m spacing). Lettuce will be harvested in late June, tillage treatments applied, and tarps laid prior to transplanting a brassica crop in late July (2 row, 0.46m spacing). The brassica crop will be harvested in October.
- Data Collection and Analysis: We will use a comprehensive set of field measurements to evaluate tarp and tillage effects on soils, labor, weeds, and crop yields. Soil temperature will be measured continuously at the soil surface (<2cm, Hobo Pendant) during tarp application and summarized to daily averages. Soil moisture (% soil water content) will be measured (0-20cm) using a portable TDR probe (Spectrum Technologies) before tarp application, at tarp removal, and weekly through the growing season. Soil nitrogen will be assessed at planting (early crop available N) and end-of-season (risk for leaching) by collecting soils (0-20cm) and analyzing for inorganic nitrogen (NO3-N and NH4-N). Prior to crop harvest, we will assess dominant weeds and collect weed counts and total biomass. Total and marketable yield will be measured and culls assessed to isolate any treatment effects on pests or disease. Standard soil tests (0-20cm) at the end of the season will document changes in soil nutrients. All labor hours and equipment operations will be recorded (e.g. tillage, bed preparation, planting, handling tarps, hand weeding) to document total labor and equipment hours and used in crop budgets (Ho unpublished) to calculate net income per crop and over the rotation. We will analyze data for tillage, tarp, and tillage x tarp main effects using R and JMP statistical software.
Objective 2. Integrating tarps, tillage and additional soil management practices to optimize RT systems
Organic mulches (e.g. straw, hay) and soil amendments (e.g. compost) used in combination with RT can provide soil cover and suppress weeds while building organic matter, soil tilth and good moisture retention but there are tradeoffs with these approaches. These practices may affect the functionality of tarps in an RT system. We will examine how tarping can be combined with additional soil management practices to provide benefits and improve RT success.
- Treatments: Within each of the tillage treatments described above we will investigate three contrasting soil management systems (SMS): 1) unmulched, bare soil (low input) 2) annual application of straw mulch (high-residue soil cover) and 3) historic deep compost (highly amended).
- Methods: A moderate compost rate (5-6 T/A) will be applied to all 3 SMS, with supplemental nitrogen added as needed based on crop fertility recommendations (New England Vegetable Guidelines 2018). Straw mulch (SMS 2) will be applied annually (5-6 tons per acre). In year 1, straw mulch will be left in-place overwinter and raked to pathways prior to tillage and tarping in spring. Winter squash will be planted and straw mulch reapplied after first cultivation, 10-14 days post planting. Straw mulch will be left in place until fall tillage and tarping, when straw will be raked to pathways. In year 2, straw will remain in pathways, lettuce grown without mulch, but the brassica amended with straw mulch. Deep compost application in previous years resulted in over-accumulation of soil nutrients; the legacy of this practice will be examined in SMS 3, and contrasted with the low input legacy of SMS 1.
- Data Collection and Analysis: Sampling of soil temperature, soil moisture, and soil nitrogen availability, labor and yield and economic budgets prepared for each subplot as described in Obj 1. We will analyze data for mulch effects and tillage x tarp x mulch interactions.
To begin, we will share our project objectives and desired outcomes with 1,000 vegetable farmers in Maine, New York and other NE states through email and online newsletters. Three hundred will respond to a survey about their current tillage, tarps, compost and soil management and inform Dialogue Education (DE) workshops.
We will then recruit 120 farmers considering or using tarps to participate in DE workshops on “Tarping for small-scale vegetables”. Four full-day workshops will take place (NY and ME, two per state) targeting 30 farmers each (Winter ‘19-’20). Facilitator Stewart, a CCE vegetable production educator, is trained in dialogue-based education practices (Vella 2002; Global Learning Partners 2017). Dialogue Education format helps farmers overcome the hurdle between acquiring new information and changing practice. The strategy generates excitement among participants, supports their ability to integrate others’ experiences, and empowers them to adopt new strategies. Farmers will leave with a field plan to implement RT practices suitable to their farm.
DE Workshops will follow this basic format:
- Understand the perceived needs of participants related to tarping, gauge baseline knowledge of tarping, soil management practices, and RT and group participants by similar needs, scale, etc.
- Using dialogue approach, present new information (research and invited speaker experiences) and strategies, followed by discussion of concerns, additional information from farmers, etc.
- In small groups, farmers work together with facilitators to draft their own management plans.
- Small groups share insights with the larger group, ensuring that knowledge is available to everyone. Remaining questions are addressed by the larger group.
- Small groups reconvene and refine plans based on additional information.
- Whole group discussion on projected economic and soil health benefits that might be realized by the proposed changes, guided by existing research.
In summer 2020, 60 farmers will implement on-farm experiments guided by targeted changes identified in field plans at DE workshops. All participants will join our RT network and receive in-season updates on research trials and share observations through Cornell Small Farm Program social media (Facebook, Twitter, Instagram). We will use email surveys (winter 2020-21) to summarize farmer findings and then host 2-3 webinars to re-engage DE participants (90), share findings among farms, address knowledge gaps and help refine practices for the following year.
In summer 2021, we will work with 50 farmers to implement refined practices. We will host 2 on-station field days in summer 2021, resulting in 100 additional farmers improving their understanding of tarping and RT practices based upon research results. We will engage another 200 farmers in learning through winter meetings with farmer speakers who will describe their on-farm experiences (Winter ‘21-22).
In summer 2022, we will synthesize on-farm trial results from 50 DE farmers. Phone interviews will verify reported changes in practices and select farm stories will be shared widely through conference presentations, websites and popular articles (e.g. Small Farms Quarterly).
1. 300 small-scale vegetable farmers respond to a survey, sharing their current tillage, tarping, and soil management strategies and learning about our research goals (Oct ‘19).
In early October 2019, we developed and distributed an online survey to better understand how farmers across the region were using tarps, any challenges that they have experienced, and emerging questions that could be addressed through our research. The survey was shared through our established extension networks in NY and ME using electronic newsletters and grower lists, including our RT grower contact list in the Cornell Small Farms Program (400+). All registered workshop participants were also encouraged to complete the survey.
We had a total of 185 respondents with 115 (62%) already using tarps on their farm. We asked respondents that were not currently using tarps (70) what reasons prevented them from using tarps. Of these, 33 were considering using them and they were mostly concerned with their costs and/or uncertain about how they could fit in their crop rotation. Those farms using tarps were generally very small, 49% were farming between 1-5 acres and another 39% on less than 1 acre. Almost all (98%) were using organic practices on some part of their farm. About half (49%) had a gross revenue less than $10,000/yr, while others represented a wide range of annual revenue: 20% between $10,000 and $50,000, 16% between $50,000 and $10,0000, and 15% grossed over $100,000. Sixty percent were beginning farmers (41% farming less than 5 years and 19% between 5 and 10 year) and 40% were farming for 10 or more years.
We are currently compiling and summarizing survey results (25 questions asked) and will complete our analysis within the next reporting period – including results on tarping benefits, challenges, logistics, labor needs, tillage practices, weeds, and compost management. The survey captured a range of tarping experience, where 35% just started using tarps, 37% had found a couple uses, and 28% indicated tarps had become a big part of their farm management. When asked where they are applying tarps, they are being used equally over permanent beds and shaped beds/open fields and were twice as likely to be placed over soil that was not cover cropped compared to cover cropped ground. They are commonly applied after harvest, over crop residue, and over sod. The most targeted crop is leafy vegetables (including lettuce, spinach, and mixed greens) followed by root vegetables (including carrots and beets) and vining crops were the least likely to be tarped.
2. 120 farmers participate in Dialogue Education (DE) workshops (60 in both NY and ME, 2 workshops in each state) that foster peer-to-peer learning, support evaluation of current tillage systems, and result in crop and rotation field plans to implement reduced tillage and tarping strategies (Feb ‘20). Participants, farmer advisors and workshop findings help refine research station treatments (NY, ME), which are implemented Spring ‘20.
In late September 2019, we announced our project and four full-day workshops, Tarping for Reduced Tillage in Small-Scale Vegetable Systems, targeting farmers interested in adopting or improving tarping practices on their farm. Workshops were advertised widely, using established extension networks in NY and ME, electronic newsletters and grower lists, social media (Instagram, Facebook), and our RT grower contacts within the Cornell Small Farms Program (400+). Workshop locations and venues were chosen to recruit farmers across the project region and in partnership with cooperative extension and non-profit partners based on location. We offered three of the four advertised workshops: 1) Northport, ME at the MOFGA Farmer to Farmer Pre-Conference on Nov. 2nd (45 participants) 3) Canandaigua, NY at Cornell Cooperative Extension-Ontario County (CNY; 39 participants) and 4) Voorheesville, NY at Cornell Cooperative Extension – Albany County (ENY; 28 participants). We cancelled a planned workshop in Springvale, ME to be held at the University of Maine Cooperative Extension of York County on Nov. 4th, based on low attendance and considering the state-wide appeal of the MOFGA Pre-Conference workshop. We registered a total of 133 participants and 112 attended across the three workshops offered. At registration, we collected information on tarping experience and asked for the most important topics/questions to inform workshop design.
Workshops were designed with two primary goals: 1) learn how we can use tarping to overcome barriers to reducing tillage in vegetables while managing weeds and improving soil health, and 2) identify specific changes we can make to farm management in the next year resulting in reduced tillage, better weed management, and greater profitability. Each workshop agenda followed a similar general format with presentations by a combination of researchers and invited farmer presentations (2 per workshop) followed small group breakouts/activities based on topic (Example Tarping Workshop Agenda). Content was structure into three general topical areas: 1) tarping as a RT and NT management tool 2) Weed management and tarp tactics and 3) Tarps and soil building. Workshops were designed and facilitated using a Dialogue Education (DE) approach (Example Facilitation Plan) to engage farmers in new information/ideas followed by facilitated small group discussion to integrate ideas, share concerns, and identify additional information needed. We began each workshop with an inventory of current tarping practices/goals and prioritizing issues to discuss through the day. The workshop ended with an individual exercise to give farmers the opportunity to outline changes to farm management using tarping (Farmer Field Plan). This template will be used to support farmers in trialing new practices in coming year. Overall, this workshop approach balanced new information with discussion to gives farmer time to think though and talk about new tarping strategies. One farmer shared “This was one of the BEST workshops that I have attended—ever. So much practical information. So many examples! Both farmer AND researcher info. Interactive, so well-organized with so little fluff or distraction. This workshop was exceptionally useful”. Another said “Presenters kept us engaged, informed and enthusiasm made this an interesting and informative workshop!”
Evaluations from workshops gathered feedback on knowledge gained, specific new ideas learned, and tarping ideas for the coming year. A total of 78 evaluations were collected representing 70% of attendees, with a majority (65) representing farmers (Workshop Evaluation). Sixty five percent of responses rated the overall quality of the workshops as “Excellent” and another 30% rated it as “Good”. Evaluations collected metrics on the amount of knowledge gained based on farmer knowledge before the workshop. For example, in ENY, before the workshop 14% had either a moderate amount or a lot of knowledge (4 or 5 rating) on the logistics of tarping and after the workshop this increased to 75%. This dramatic change in knowledge gain was similar with other topics: reduced tillage (from 7% to 64%), weed management (7% to 80%), cover crops (11% to 72%) and crop rotation planning (4% to 62%). We had a similar impact at other workshops. On the topic of reducing tillage, farmer knowledge levels (4 or 5 rating) went from 16% to 83% (WNY) and from 24 to 88% (ME). Attendees shared the most interesting lessons learned and 1 to 2 examples of how they will use the information on their farm in the coming year, including: how they can address tarping logistics (storing, securing, moving tarps), combine tarping with winter hardy cover crops for effective termination, using tarping for perennial weed control, and tarp timing and duration for different crops and in a rotation (New Tarping Ideas and actions).
3. 90 farmers participate in follow-up discussions via webinar and phone to refine RT and tarping field plans designed in DE workshop (Mar ‘20).
4. Of the 120 farmers who participated in DE workshops, 60 test field plans with alternative management of tarping to reduce tillage (Oct ‘20).
5. 50 DE farmers report findings via year-end surveys and phone interviews, highlighting field observations, crop and labor impacts, and knowledge gaps and suggest refinements to improve results (Dec ‘20). General summaries of on-farm and on-station research are shared through local farmer meetings and electronic media.
6. 90 DE farmers are re-engaged via 2-3 webinars to learn results of on-farm experiments, share findings, and refine on tarping and RT practices. Webinar topics address farmer interest and knowledge gaps identified in followup surveys (Feb ‘21).
7. 50 DE farmers (some continuing, others new) implement refined field plans to test tarping and RT practices on farm (Oct ‘21).
8. 100 additional farmers improve their understanding of tarping and reduced tillage management practices based upon research results shared at on-station field days (Aug ‘21). One year of research data will be shared with participants.
9. 100 additional farmers report knowledge gained on reduced tillage and tarping practices through winter conferences (Feb ‘22). Several DE farmers speak at meetings and describe farm management changes based on experience with on-farm trials. Two years of research data will be shared.
10. 40 DE farmers report on changes to their management, labor use and profitability based upon onfarm trial findings via surveys and phone interviews (Nov ‘22).
Milestone Activities and Participation Summary
November 2019. We offered 3 full day workshops that combined researchers and invited farmer presentations followed small group breakouts/activities based on topic. Workshops were designed and facilitated used a Dialogue Education (DE) approach to engage farmers in new information/ideas followed by facilitated small group discussion to integrate ideas, share concerns, and identify additional information needed. We began each workshop with an inventory of current tarping practices/goals and prioritizing issues to discuss through the day and ended with an exercise to outline a farm-specific management change using tarps. In evaluations, all participants were asked to characterize their knowledge before and after the workshop based on five tarping topics: 1) logistics, 2) reducing tillage, 3) weed management, 4) soil building with cover crop, mulch and/or compost and 5) planning for tarps in rotations.