Increasing adoption of reduced tillage strategies on organic vegetable farms in the maritime

Final report for SW14-013

SW14-013 (project overview)
Project Type: Research and Education
Funds awarded in 2014: $249,949.00
Projected End Date: 02/28/2018
Grant Recipient: Center for Sust. Ag. Nat Res
Region: Western
State: Washington
Principal Investigator:
Doug Collins
Email
WSU
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Project Information

Summary:

Grower interest in reduced tillage techniques stems from concern over soil quality and energy use. Tillage decimates large-bodied soil organisms, reduces soil carbon storage and weakens the stability of aggregates. Yet, organic vegetable growers in the Pacific Northwest currently pass over their fields 10 to 20 times annually to incorporate cover crops and amendments, prepare the soil for planting, and manage weeds. In response to the interest in tillage reduction, our syndicate of growers, researchers, and Extension educators has worked collaboratively to develop and test reduced tillage strategies for organic vegetable production in the Pacific Northwest since 2009. Incorporating reduced tillage into organic vegetable cropping systems requires careful integration of cover crops with equipment. Cover crops for reduced tillage systems must be winter hardy, produce sufficient biomass to smother weeds, mature early, and preferably add nitrogen to the system. Tools must effectively kill the cover crop without tillage and also prepare the soil to receive a transplant or seed. 

Our goal is to increase organic farmer economic and environmental sustainability through soil conservation and reduced tillage. Through a previous SARE Project (SW11-072) we carried out four on-farm experiments, cover crop variety trials, and initiated a long-term systems experiment. This current project (SW14-013) continues our systems-based work to develop and implement reduced tillage strategies for organic vegetable cropping in the maritime Northwest and other northern climates. Our future focus is to reduce risk for early adopters of reduced tillage by sharing successes and failures. We will also encourage more wide-spread adoption of reduced tillage by building on our previous experience to address specific obstacles and remaining questions, including:

  • Which implements and strategies are most effective to manage residue in zone-tilled ground? (Objective 1)
  • How does reduced tillage affect nutrient cycling and fertility management? (Objective 2)
  • Which cover crops, mixes, and termination strategies perform best? (Objective 3)
  • What specific challenges and opportunities do continuous reduced-tillage present? (Objective 4)

We will address these questions and extend our outreach (Objective 5) by:

  1. Facilitating research with seven commercial organic vegetable producers. We will improve residue management and compare cover crop termination strategies through on-farm trials and demonstrations. (Objectives 1, 3, and 5)
  2. Continuing an on-station long-term reduced tillage cropping systems experiment with three cash crops in rotation and adaptive management to include new cover crops and equipment improvements. Specifically, we will implement more aggressive zone tillage. (Objectives 1, 2, and 4)
  3. Executing 6 cover crop variety trials at two different research stations. (Objective 3)
  4. Reaching out to producers through field days, farm walks, articles, a video, and presentations to state-wide, regional, and national audiences. (Objective 5)
Project Objectives:
  • Develop and analyze best strategies for cover crop residue management in zone tilled organic agriculture systems: Zone tillage has thus far provided the most interest among cooperating growers. Our current zone till treatment will be modified to provide more aggressive in-row tillage and a second zone tiller will extend our ability to reach more farms. We will measure the success of zone tillage by comparing soil temperature and crop yield in zone-tilled and full-tilled treatments in on-farm trials and in our long-term reduced tillage systems trial. We will also measure zone tillage success by comparing the density of volunteer cover crops and weed management in the inter-row for the two cover crop termination methods.
  • Evaluate nitrogen cycling dynamics in reduced tillage organic systems:  Through our previous cover crop trials we have been able to identify a successful legume cover crop (Purple Bounty vetch) for inclusion in our long-term reduced tillage trial. We will focus our evaluation of nutrient cycling dynamics in tilled and reduced tillage treatments following vetch by measuring cover crop N at termination, cover crop decomposition rate dynamics, soil nitrate and plant uptake by broccoli through the season each year.
  • Select cover crops and termination strategies for reduced tillage organic agriculture: Successful cover cropping is essential to reducing risk in adopting reduced tillage organic vegetable production. The cover crop must produce enough biomass to effectively suppress weeds and also reach a late developmental stage to mechanically terminate while accommodating a relatively short growing season. One of the largest barriers to successful organic reduced tillage is termination of the cover crop. We will perform cover crop trials at two research stations (WSU Puyallup and WSU Mount Vernon) during each year of the grant. We will measure above-ground biomass and carbon to nitrogen ratios of different varieties and mixtures, and will also consider timing for termination and compare termination methods (roller/crimper vs. flail mower) for grain cover crops.
  • Develop and analyze strategies for long-term continuous reduced tillage in organic agriculture: To date we have not experimented with continuous reduced tillage methods in northwest Washington. We implement annual fall tillage to prepare the ground for winter cover crop seeding. However, we see the ability to eliminate fall tillage as an important next step to soil quality improvement which has been shown to occur over the long-term. We will measure soil quality indices (e.g. penetrometer, bulk density, chemical properties, and soil fauna) and weed populations in this treatment and the other 5 treatments in the long-term reduced tillage experiment.
  • Provide essential support to 15 western Washington organic producers implementing reduced tillage techniques on their farms. Our surveys show 25-30% of respondents have tried some form of reduced tillage, but only 2 or 3 farmers in our stakeholder base have adopted the techniques we have studied. We will increase the number of commercial farms adopting these techniques through farmer recruitment at our events, and allowing farmers the use of our equipment.

Cooperators

Click linked name(s) to expand/collapse or show everyone's info
  • Colin Barricklow
  • Andy Bary
  • Christopher Benedict
  • Craig Cogger
  • Andrew Corbin
  • Skuter Fontaine
  • Erick Haakenson
  • Steve Hallstrom
  • Jonathan Nichols
  • Tom Thornton
  • Aaron Varadi

Research

Hypothesis:

Soil health concerns in conventional tillage systems have increased interest in reduced tillage practices to enhance soil. Traditional organic production relies on soil disturbance through field cultivation to manage weeds. High residue mulch created by terminating cover crops in spring can minimize disturbance and suppress annual weeds. Large amounts of cover crop residue can, however, reduce soil temperature and interfere with planting and weeding. Strip tilling is a form of reduced tillage that prepares a planting strip similar to full width tillage and thus has promise for adoption. Three new reduced tillage tools and techniques were trialed in western Washington to increase adoption : 1) powered strip tillage, 2) continuous minimum tillage, and 3) strip-planting cover crops. We hypothesized that:

  1. Powered strip tillage would increase soil temperature and vegetable yield relative to no till
  2. Continuous reduced tillage would produce similar cover crop and cash crop yields relative to rotational reduced tillage and full till
  3. Flail mowing can provide a broad window for cover crop termination and strip-tilled vegetables
  4. Strip planted cover crops would decrease in-row biomass and  improve strip tiller operation
Materials and methods:

Long-term Reduced Tillage Organic Agriculture Systems Trial

Through a previous SARE project (SW11-072) we initiated a long-term reduced tillage organic agriculture systems trial at WSU-Puyallup in fall 2011.  The experiment was a randomized complete block design with 4 blocks and 6 cropping systems (full plots).  The location of the 4 blocks was optimized after mapping soil organic matter (OM) and weed seed bank density across the 1.7A field.  Each (30’X50’) full plot was split into three (10’X50’) subplots with one of three cash crops planted to each subplot each year.  Cash crops and winter cover crops (grain or vetch) were rotated as follows:  grain – green beans – vetch – broccoli – grain – squash. The 6 cropping systems in the trial varied in cover crop termination and ground preparation method.  Treatments included: 1. flailing+no-till; 2. flailing+zone till; 3. flailing+complete till; 4. roll/crimp+zone till; 5. roll/crimp+ no-till; 6. continuous reduced-till+flailing+ zone-till  (Figure 1).

Figure 1. One of four replicates (top) and rotation scheme (bottom) in the WSU Puyallup Long-term Organic Reduced Tillage Systems Experiment. Sq=squash; Br= broccoli; Bn = beans.
Figure 1. One of four replicates (top) and rotation scheme (bottom) in the WSU Puyallup Long-term Organic Reduced Tillage Systems Experiment. Sq=squash; Br= broccoli; Bn = beans.

Treatments 1–5 were rotational reduced tillage treatments; tillage was used in the fall to prepare a seed bed for establishing cover crops.  In the spring, cover crops were terminated then ground was prepared for transplanting or seeding with no-till, zone till, or full till.  

 

In 2012 – 2013, zone tilled plots were prepared with a ground-driven Yetter Strip Builder.  Research cooperators have indicated that zone tillage is an area they are most interested in, but have observed that the Yetter does not prepare a cleanly tilled strip.  Also, our on-farm trials in heavier-textured soils with the ground-driven strip tiller demonstrated the necessity for more aggressive zone tillage.  We transitioned this treatment in 2015 to include a second pass with a PTO-driven strip tiller. 

 

The powered strip tiller (Figure 2a-b) combined a coulter and row cleaner (Dawn 1572-RH, Sycamore, IL) in line with a shank and powered multivator (Maschio Model K, Campodarsego, Italy).  In 2012-2015 the no-till was implemented with a custom made tractor-drawn no-till planting aid consisting of a coulter and shank in-line. In 2016 and 2017, the no-till treatment was implemented with a transplanter with no-till attachment (Mech. Transplanter Model 5000WD, Holland, MI) (Figure 3). Full tillage was implemented with a rotary spader throughout the experiment (Full Till; not pictured)

Custom-built powered strip tiller side view.
Figure 2a. Custom-built powered strip tiller side view.
Figure 2b. Custom-built powered strip tiller working in heavy flail-mowed rye residue.
Figure 2b. Custom-built powered strip tiller working in heavy flail-mowed rye residue.
 
Transplanter with no-till attachment.
Figure 3. Transplanter with no-till attachment.

Treatment 6 was a continuous no-till treatment from 2015-2017.  These plots were managed similarly to treatment 3 (full-till) in 2012 – 2013.  In 2014 they were transitioned to a continuous no-till treatment:  plots were tilled in spring 2014 briefly fallowed, seeded to a SorghumXSudangrass summer cover crop, mowed, and seeded with a no-till drill to the winter cover crop.  In spring 2015, cover crops were flailed, then soil prepared with strip tiller.  Following production of the cash crop, residues were mowed, disturbed with an undercutter to reduce weed pressure (Figure 4a), and then cover crop seeded with a minimum-till drill (Landpride 3P500, Salina KS; Figure 4b.)

Undercutting before seeding fall cover crops in continuous reduced tillage treatment.
Figure 4a. Undercutting before seeding fall cover crops in continuous reduced tillage treatment.
Planting cover crops with minimum till drill in continuous reduced tillage treatment.
Figure 4b. Planting cover crops with minimum till drill in continuous reduced tillage treatment.

 

Cover crop maturation, biomass, and weed density were measured from sub plots in the spring.  Light penetration at the soil surface and temperature and moisture were monitored at 10cm depth.  Soil compaction, bulk density and infiltration rate were analyzed once each summer. Changes to the soil food web were analyzed by evaluating the soil nematode community, microbial biomass, and earthworm abundance once per year. Soil were sampled each fall at 0-30 cm for complete nutrient analysis (OM, Bray-1 P, ammonium- and nitrate-N, exchangeable K, Mg, and Ca, pH, and cation exchange capacity). 

 

In all treatments, weeds were cultivated and hand weeded in the intra-row region. Inter-row weeds were cultivated in the full-till plots with a basket weeder or sweeps.  In the no-till and strip-till treatments a Henke Buffalo high residue cultivator (6600 Cultivator, Norfolk, NE) was used to cultivate the inter-row area. Time spent weeding was recorded for each plot.  In-season weed pressure was assessed in the sub-plots (in & between-row) planted to squash by taking species-specific density counts before weeding. Market crops were harvested and evaluated for yield and marketability.

 

Plant-available nitrogen contribution from legume cover crops in tilled and no tilled production systems was measured through six sequential soil nitrate samples, calculation of vetch decomposition rate constants, and analysis of nitrogen uptake by broccoli. 

 

Cover crop variety trials

Strip-tilling rye at different stages for kale production

We performed replicated cover crop trials at the Puyallup research stations to evaluate rye, vetch, and a mixture for use in reduced tillage cropping systems.  Three termination times were evaluated using a flail mower as the termination method.  We evaluated cover crops for above-ground biomass, weed density, nitrogen content, and termination effectiveness (i.e. regrowth). Unfortunately, the vetch cover crop did not do well in winter preceding the 2016 and 2017 summers, so most analysis focused on the rye cover crop with 3 termination timings. Kale was transplanted into flail mowed and strip-tilled rye at three different times:  Early, April 15th, rye boots swollen; Mid, May 7th, rye early pollination; Late, May 21st, rye late pollination.

Cover crop strip planting

Cover crop strip planting, where different cover crops can be planted in the in-row and between row regions, is a promising technique to pair with strip tilling (Figure 8). Rye may be desirable between rows for weed suppression, but the high residue is challenging for strip tillage and may lower soil temperatures. Strip tillage proceeds more easily with lower biomass cover crops. Vetch, clover, and radish produce lower biomass than rye and, in the case of legumes, can contribute additional N. We evaluated crimson clover, common vetch, hairy vetch, and ‘Daikon’ radish with and without precision-planted ‘Aroostook’ rye.

 

We are building on this research in an ongoing trial. We are currently evaluating strip tilled sweet corn planted to 4 different cover crop combinations: common vetch strip planted with ‘Aroostook’ rye, common vetch and ‘Aroostook’ in a traditional mix, common vetch alone, and ‘Aroostook’ alone.

 

On-farm trials

During the summer growing seasons, we performed both replicated on-farm research trials and on-farm demonstrations as follows: 2015, one replicated trial and one demonstration; 2016, one replicated trial and one demonstration, and 2017, one replicated trial. In fall 2017, a cover crop trial was planted at 6 on-farm sites. For the trials and demonstrations, farmers were supplied with seed and paid a stipend for plot maintenance (planting, irrigation, weeding, etc.).  The research team transported specialized equipment to the farms and collected data.  Cover crop biomass and nitrogen content were measured at each farm.  Data collection for the 2017 cover crop trial is continuing through 2018.

Adoption assistance

We encourage adoption of reduced tillage organic techniques by describing clearly the risks associated with reducing tillage and how these risks can be mitigated through best management practices.  Farmer cooperators continue to be instrumental in this strategy because they are best suited to help design and trial new practices that are likely to work in their operations.  These early adopters serve as our stakeholder advisors and are active participants in our outreach efforts. 

 

Research results and discussion:

Long-term Reduced Tillage Organic Agriculture Systems Trial

Tillage effects on soil temperature

In 2016, Strip Till resulted in warmer soil temperatures than No Till in mid-June, three weeks after transplant. In 2017, Strip Till did not increase soil temperature relative to No Till. Following transplant, Full Till tended to have higher soil temperatures than the reduced till treatments in 2016 and 2017 (Figure 5).  

Soil temperature at 10cm in Full Till, No Till, and Strip Till in 2016 and 2017 in squash. Statistical significance was evaluated each day for the mean daily temperature with contrasts between reduced till treatments and full till (top line) and between Strip Till and No Till (bottom line). * indicates p
Figure 5. Soil temperature at 10cm in Full Till, No Till, and Strip Till in 2016 and 2017 in squash. Statistical significance was evaluated each day for the mean daily temperature with contrasts between reduced till treatments and full till (top line) and between Strip Till and No Till (bottom line). * indicates p<0.05, + indicates p<0.1. There was no significant difference between Strip Till and No Till in 2017. Squash was transplanted 25 May in 2016 and 2017.

Continuous reduced tillage cover crop biomass

Removing fall tillage yielded equal or greater rye cover crop biomass compared to Full Till. Vetch biomass was larger in Full Till and rotational reduced till in 2015 compared to the continuous reduced till. (Figure 6a-b).

Aroostook rye cover crop biomass with continuous reduced tillage, rotational reduced tillage, and full tillage. Rotational reduced tillage treatments are tilled in the fall prior to cover crop planting
Figure 6a. Aroostook rye cover crop biomass with continuous reduced tillage, rotational reduced tillage, and full tillage. Rotational reduced tillage treatments are tilled in the fall prior to cover crop planting (Figure 1.)
Common vetch cover crop biomass with continuous reduced tillage, rotational reduced tillage, and full tillage. Rotational reduced tillage treatments are tilled in the fall prior to cover crop planting (Figure 1.)
Figure 6b. Common vetch cover crop biomass with continuous reduced tillage, rotational reduced tillage, and full tillage. Rotational reduced tillage treatments are tilled in the fall prior to cover crop planting (Figure 1.)

 

 

Vegetable crop yield

Squash yield was significantly reduced by the no-till treatment compared to strip tillage (Figure 7). Reduced tillage treatments where flail mowing was used to terminate cover crop also yielded greater squash than treatments where cover crop was terminated with a roller crimper. Continuous reduced tillage, with strip tilling preceding the cash crop, was equal to rotational reduced tillage with strip tillage and full tillage. There was a significant year by treatment effect for broccoli.  In 2016, continuous reduced tillage yielded significantly more broccoli than all other treatments (Figure 7). In 2017, the No Till treatment yielded less broccoli.

Figure 7. Squash and broccoli yield in the WSU Puyallup Long-term Organic Reduced Tillage Systems Experiment. Squash was preceded by Aroostook rye that was terminated with either a roller crimper or flail mower. Broccoli was preceded by common vetch and terminated with a flail mower in all treatments.
Figure 7. Squash and broccoli yield in the WSU Puyallup Long-term Organic Reduced Tillage Systems Experiment. Squash was preceded by Aroostook rye that was terminated with either a roller crimper or flail mower. Broccoli was preceded by common vetch and terminated with a flail mower in all treatments.

Cover crop variety trials

Strip-tilling rye at different stages for kale production

Rye biomass ranged between 2.5 Mg ha-1 to 11 Mg ha-1 and was influenced by termination time; later termination timing produced the highest values (Figure 8). Rye C:N increased with increasing termination date (Figure 9). Only one year of vetch alone and rye/vetch mix data were available due to poor vetch stands. During 2015, the N content of vetch was similar for all three termination dates though the N content in the rye/vetch mix decreased slightly from ‘early’ to ‘late’ (Figure 10). When terminated at mid and late anthesis, rye regrowth was greatly minimized (Figure 11). Between row weed counts were reduced with later termination of the rye cover crop (Figures 11-12). The results of this study indicate that termination timing is an important factor influencing rye biomass production as well as rye regrowth and may contribute to between row weed suppression in organic strip tillage systems.Figure 8. Dry rye biomass post hoc comparisons of cover crop termination treatments, 2015-2017. Letter groupings indicate significantly different means within each year at P

Figure 8. Dry rye biomass post hoc comparisons of cover crop termination treatments, 2015-2017. Letter groupings indicate significantly different means within each year at P<0.05 Tukey’s method.

Figure 9. Rye biomass carbon to nitrogen ratio at time of termination. Post hoc comparisons are of cover crop termination treatments, 2015-2017. Letter groupings indicate significantly different means within each year at P
Figure 9. Rye biomass carbon to nitrogen ratio at time of termination. Post hoc comparisons are of cover crop termination treatments, 2015-2017. Letter groupings indicate significantly different means within each year at P<0.05 Tukey’s method.
Percent N for rye/vetch mix and vetch alone at three different termination times in 2015.
Figure 10. Percent N for rye/vetch mix and vetch alone at three different termination times in 2015.
Figure 11. Broadleaf weed counts at two weeks post termination. Post hoc comparisons are of cover crop termination within each year and tillage treatment, 2015-2017. Letter groupings indicate significantly different means within each year at P
Figure 11. Broadleaf weed counts at two weeks post termination. Post hoc comparisons are of cover crop termination within each year and tillage treatment, 2015-2017. Letter groupings indicate significantly different means within each year at P<0.05 Tukey’s method.
Grass weed counts at two weeks post termination. Post hoc comparisons are of cover crop termination within each year and tillage treatment, 2015-2017. Letter groupings indicate significantly different means within each year at P
Figure 12. Grass weed counts at two weeks post termination. Post hoc comparisons are of cover crop termination within each year and tillage treatment, 2015-2017. Letter groupings indicate significantly different means within each year at P<0.05 Tukey’s method.

 

Kale yield was not significantly different for tillage in any year and ranged from 6.1 Mg/ha-1 to 15.1 Mg/ha-1 for Full Till and 5.6 Mg/ha-1 to 14.6 Mg/ha-1 in Strip Till treatments. There was no statistical difference between termination timing within either tillage treatment for 2015 or 2017, but a similar divergence occurred between ‘middle’ and other terminations in 2016 for both tillage treatments (Figure 13), which most likely resulted from increased precipitation in 2016 during ‘middle’ (Figure 13). These findings suggest that with mid-season high residue weed cultivation, earlier rye cover crop termination may result in adequate yield for both full till and strip till systems. Future investigation with supplemental irrigation to compare rye cover crop terminations would reduce the confounding effects of soil moisture variability between treatments on crop yield. Alternatively, soil moisture sensors could be included in a non-irrigated study to assess treatment effects on soil moisture and yield.

Total kale yield. Post hoc comparisons are of cover crop termination within each year and tillage treatment, 2015-2017. Letter groupings indicate significantly different means within each year at P
Figure 13. Total kale yield. Post hoc comparisons are of cover crop termination within each year and tillage treatment, 2015-2017. Letter groupings indicate significantly different means within each year at P<0.05 Tukey’s method.

Strip Planted Cover Crops

Cover crops strip-planted with ‘Aroostook’ rye had less biomass than cover crops planted alone (p<0.047), likely due to shading or other competition from the rye. When it was planted in-row, ‘Aroostook’ had 2 to 3 times the biomass of other cover crops.

Strip planting lower biomass cover crops, coupled with powered strip tillage, may increase soil temperature and favor warm-season crops such as squash and corn.

Hairy vetch, daikon radish, and crimson clover planted alone or in strips with Aroostook rye.
Figure 14. Hairy vetch, daikon radish, and crimson clover planted alone or in strips with Aroostook rye.
Effect of strip-planting with rye on in-row cover crop biomass at WSU Puyallup Research and Extension Center, 2016.
Figure 15. Effect of strip-planting with rye on in-row cover crop biomass at WSU Puyallup Research and Extension Center, 2016.

On-farm trials

We conducted one on-farm research trial and one on-farm demonstration in summer 2015. The research trial at Kirsop Farm showed an increase in broccoli growth with strip tillage compared to rototilling (P value = 0.1; Figure 16).

Figure 16. Broccoli yield at Kirsop Farm in 2015. P value =0.1.
Figure 16. Broccoli yield at Kirsop Farm in 2015. P value =0.1.

 

One on-farm research trial and two on-farm demonstrations were supported in 2016.  In the on-farm trial at Oxbow Farm strip tillage resulted in significantly less yield of summer squash than full tillage. Results were similar with winter squash at the Organic Farm School in 2017; Full Till had greater yield than Strip Till across 3 squash varieties (Figure 17. p < 0.02).

Yield of three different winter squash varieties at the Organic Farm School, Whidbey Island, WA, 2017.
Figure 17. Yield of three different winter squash varieties at the Organic Farm School, Whidbey Island, WA, 2017.
Research conclusions:
  1. With reduced tillage earthworm populations increase, soil CO2 emissions decrease, annual weeds are suppressed, soil temperature decreases, soil moisture increases, and bulk density and compaction increase.
  2. Rye cover crops can be effectively terminated at early pollination with a flail mower for earlier plantings of cool season vegetables. Even termination at boot did not reduce yield in kale compared to full till, though in-row weeding was done with a high-residue cultivator.
  3. Some equipment is highly specialized and models designed for conventional reduced tillage may require modification for high-residue organic.
  4. Adoption of RT organic agriculture will likely depend on efficient weed control. Manage for the transition to reduce initial weed pressure.
  5. There are two possible paths to successful weed control: 1) Heavy residue to suppress weeds; 2) Cultivation within the no-till area with a high-residue cultivator.
  6. Strip planting lower biomass cover crops, coupled with powered strip tillage, may increase soil temperature and favor warm-season crops.
  7. A possible 3-season approach to adopting reduced-tillage vegetable production for cool-season or warm-season cash crops is to: Year 1, Begin with a season of weed suppression activity such as summer cultivation or summer cover cropping. For a cool-season, heavy nitrogen feeding crop consider a fall-planted vetch crop; Year 2, no-till transplant directly into the terminated cover crop. Keep weeds under control during the cropping season and utilize an undercutter or powered harrow to reduce any persistent weeds; no-till a cover crop into the residue; Year 3, Strip-till for a warm season crop such as corn or squash. Control weeds and monitor for perennial weed pressure (Figure 18a). Poor spring cover crop stands or perennial weed pressure might necessitate tillage (Figure 18b).
Figure 18a. A possible 3 year rotation to reduce tillage in organic vegetable production for cool-season and warm-season crops
Figure 18a. A possible 3 year rotation to reduce tillage in organic vegetable production for cool-season and warm-season crops
Trigger points that might necessitate tillage.
Figure 18b. Trigger points that might necessitate tillage.
Participation Summary
6 Producers participating in research

Research Outcomes

1 Grant received that built upon this project
6 New working collaborations

Education and Outreach

50 Consultations
2 Curricula, factsheets or educational tools
12 On-farm demonstrations
3 Online trainings
1 Published press articles, newsletters
3 Tours
16 Webinars / talks / presentations
2 Workshop field days

Participation Summary:

400 Farmers participated
299 Ag professionals participated
Education and outreach methods and analyses:

Consultations

I have consulted one-on-one with growers and agricultural professionals in Washington, Oregon, Idaho, Alaska, and other states across the country about our research.  Consultations occur via phone or email and often in-person following an educational event. 

Curricula, Fact Sheets, Educational Tools

2 Field day booklets (see resources)

On Farm Demonstrations

Kirsop Farm (3), Oxbow Farm (3), Organic Farm School (2), FinnRiver Farm/Organic Seed Alliance (1), Cloudview Eco Farm (1), Cloud Mountain Farm (2)

Online Trainings

A 7.5 min. video and 2 webinars

Sullivan D. and D.P. Collins. 2018. Reduced tillage in organic vegetable production. WSU Extension Video. [Online]. https://eorganic.info/node/8245

Collins, D.P. 2015. Tillage reduction and cover cropping for enhanced soil quality and weed management in western Washington organic vegetable farms. Organicology Conference, Portland, OR. Invited Speaker. Also broadcast as an eOrganic Webinar.

Collins, D.P. 2015. Tillage reduction and cover cropping for enhanced soil quality and weed management in western Washington organic vegetable farms. USDA NRCS Science and Technology Understanding Organic Agriculture webinar series. Invited Speaker. [online] http://www.conservationwebinars.net/webinars/reduced-tillage-in-organic-specialty-crop-systems

Published press articles, newsletters

SARE Graduate Student Grant Program newsletter 

Tours

Students from Purdue University, WSU President Kirk Schultz and WA congressional staff, SARE staff

Webinars, Talks and Presentations

D.P. Collins, C. Benedict, D. Sullivan, A. Bary, L. Myhre. 2017. New tools and techniques for high residue organic vegetable strip tillage in the Maritime Pacific Northwest. Soil Science Society of America. Poster Presentation. 

D.P. Collins, C. Benedict, A. Bary, C.G. Cogger, Sandra Wayman, A. Corbin. 2016. Selecting management practices and cover crops for reducing tillage, enhancing soil quality, and managing weeds in western WA organic vegetable farms. American Society for Horticultural Sciences. Poster Presentation. 

  1. Sullivan, D.P. Collins, A.I. Bary, C. Benedict. 2016. Strip tillage and cover cropping effects on field water use efficiency. Proceedings of the Soil Science Society of America, Phoenix, AZ. Poster Presentation. 

Collins, D.P. 2015. Tillage reduction and cover cropping for enhanced soil quality and weed management in western Washington organic vegetable farms. Organicology Conference, Portland, OR. Invited Speaker. Also broadcast as an eOrganic Webinar.

Collins, D.P. 2015. Tillage reduction and cover cropping for enhanced soil quality and weed management in western Washington organic vegetable farms. USDA NRCS Science and Technology Understanding Organic Agriculture webinar series. Invited Speaker. [online] http://www.conservationwebinars.net/webinars/reduced-tillage-in-organic-specialty-crop-systems

Collins, D.P. 2017. Ecological soil management; New directions for cover crop management in reduced tillage organic agriculture; Optimizing nitrogen management on organic and biologically-intensive farms. [3 presentations]. Southeast Alaska Farmers Summit, Haines, AK. Invited Speaker.

Collins, D.P. 2017. New tools and techniques for high residue organic vegetable strip tillage in the Maritime Pacific Northwest; Optimizing nitrogen management on organic and biologically-intensive farms [2 presentations].  OSU Farm Fair, Hermiston, OR. Invited Speaker.

Collins, D.P. 2017. New tools and techniques for high residue organic vegetable strip tillage in the Maritime Pacific Northwest. Tilth Alliance Annual Meeting. Vancouver, WA. Invited Speaker.

Collins, D.P. 2017. New directions for reduced tillage organic agriculture. NRCS Conference: Unlock the Secrets to Soil Health, Aurora, OR. Invited Speaker.

Collins, D.P. 2016. New directions for cover crop management in reduced tillage organic agriculture. Tilth Producers of Washington Annual Conference. Wenatchee, WA. Invited Speaker.

Collins, D.P. 2016. Tillage reduction and cover cropping for enhanced soil quality and weed management in western Washington organic vegetable farms. National Coalition for Alternatives to Pesticides Organic Farming Conference, Caldwell, ID. Invited Speaker.

Collins, D.P. 2016. Beyond the soil food web: Managing soil for diverse biological functions. National Coalition for Alternatives to Pesticides Organic Farming Conference, Caldwell, ID. Invited Speaker.

Collins, D.P. 2016. Precision cover cropping for organic strip tillage. National Coalition for Alternatives to Pesticides Organic Farming Conference, Caldwell, ID. Invited Speaker.

Collins, D.P. 2017. Soil quality and organic cropping systems research. American Farmlands Trust, Seattle, WA. Invited Speaker.

Collins, D.P.  2016. Reduced tillage organic agriculture in the Maritime Pacific Northwest: potential for adoption and effect on carbon dioxide emissions. San Juan Islands Agricultural Summit, Friday Harbor, WA.  Invited Speaker.

Collins, D.P.  2016. Organic reduced tillage update: Precision cover cropping, continuous reduced tillage, early cover crop termination and aggressive strip tillage. San Juan Islands Agricultural Summit, Friday Harbor, WA.  Invited Speaker.

Workshops/Field Days

2 field days at the Puyallup Research and Extension Center

 

Number of Farmers and Ag Professionals

Sign-in sheets were available for Puyallup Field Days in 2016. There were 52 unique farmers at these events and 33 unique ag professionals.  About 75% of the people that attended the second field day were unique visitors.

For the other educational events, farmer and ag professional attendance was estimated. For events in Washington, it was assumed that 75% of the attendees were new.  For events in Oregon, Idaho, and Alaska, 100% of attendees were considered new (unique).

Event Unique Farmers Unique Ag Professionals
SSSA 2017 0 25
Hort Sci 2017 0 25
SSSA 2016 0 25
Organicology 2015 56 18
NRCS 2015 37 37
SE Alaska Farmers Summit 40 40
OSU Farm Fair 30 10
Tilth 2017 45 15
NRCS 2016 12 6
Tilth 2016 45 15
Idaho 2016 60 20
AFT 2017 0 22
San Juan Ag summit 22 7
     
Spring field day 2016 38 22
Summer field day 2016 15 12
     
Total 400 299

 

 

37 Farmers intend/plan to change their practice(s)

Education and Outreach Outcomes

Recommendations for education and outreach:

Our current focus is on multi-year weed control strategies and specifically how reducing tillage fits into these strategies. If reduced tillage is to be adopted, the practice needs to decrease weed pressure. In theory, reducing the number of weed species that are brought to the surface should reduce weed pressure. This has been our observation, but some weeds will escape and methods for controlling those weeds need to be available. Perennial weeds are particularly pernicious and a plan for reducing their populations before rotation to reduced tillage is a necessity.

57 Producers reported gaining knowledge, attitude, skills and/or awareness as a result of the project
Key areas taught:
  • Reduced tillage equipment
  • Cover crop and nitrogen management
  • Soil Moisture Monitoring
  • Long term weed management
  • Transition to reduced till
Key changes:

  • Reduced tillage equipment

  • Cover crop and nitrogen management

  • Soil Moisture Monitoring

  • Long term weed management

  • Transition to reduced till

Information Products

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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.