Final report for FW23-425

FW23-425 (project overview)

Project Type: Farmer/Rancher

Funds awarded in 2023: $24,296.00

Projected End Date: 12/31/2025

Grant Recipient: Lazy Acres Farm

Region: Western

State: Oregon

Principal Investigator:

Beth Portesi

Lazy Acres Farm

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Project Information

Summary:

There is an increasing trend of small-scale farmers utilizing season extension methods to prolong their growing season and protect their crops from unpredictable weather patterns, especially with the impacts of climate change. However, farmers and researchers have found that using season extension methods can have negative consequences for soil health. Frequent tillage is a method used in conjunction with crop production in high tunnels and low tunnels. Experts and farmers are calling for further research and sustainable management practices when utilizing season extension methods.

Can using no-till practices in conjunction with season extension methods be an alternative management strategy for small farmers?

We will:

Determine if using no-till practices in high tunnels or low tunnels has a measurable impact on soil health by performing soil tests.
Determine if plastic mulch in conjunction with no-till practices has a measurable impact on soil health.
Compare crop production and correlation of soil health in high tunnels and low tunnels using no-till methods against outdoor control.
Produce an educational video series and host a farm demonstration day to share project findings and facilitate practical knowledge exchange on the outcomes of season extension methods and plastic mulch in conjunction with no-till on soil health.

Project Objectives:

Determine if no-till practices have a measurable impact on soil health in high tunnels or low tunnels by:
1. Measuring diversity and quantity of soil biology using soil tests. Tests will be performed at beginning of the season, middle of the season, and end of the season.
  (Beth Portesi, Casey Ameil)
  (Year 1-1.5)
Determine if plastic mulch has a measurable impact on soil health in high tunnels and low tunnels using no-till practices by:
1. Measuring diversity and quantity of soil biology using soil tests. Tests will be performed at beginning of the season, middle of the season, and end of the season.
  (Beth Portesi, Casey Ameil)
  (Year 1-1.5)
Compare crop production and correlation of soil health in high tunnels and low tunnels using no-till methods against outdoor control by
1. Measuring yield by weight
  (Beth Portesi, Casey Ameil)
  (Year 1-1.5)
Produce an educational video series and host a farm demonstration to share project findings and facilitate practical knowledge exchange on the outcomes of season extension methods and plastic mulch on soil health.
(Beth Portesi, Casey Ameil, Maud Powell)
(Year 1-1.5)

Timeline:

Date	Activities	Team Members
September 2023	Conducted team kick-off call.	Beth Portesi, Casey Ameil, Maud Powell
September 2023	Get baseline soil test. Construct high tunnel and low tunnel.	Casey Ameil
October 2023	Overwintered previous seasons crops as a cover crop.	Casey Ameil
November - January 2024	Monitored cover crop growth.	Casey Ameil
February - March 2024	In the process of cutting cover crop and covering with occultation tarps to decompose. First soil test will be taken this month (March 2024).	Casey Ameil
April 2024	Apply compost and organic fertilizer to beds. Lay down plastic mulch on specific beds.	Casey Ameil
April - October 2025	Transplant, grow and harvest lettuce.	Casey Ameil
Spring 2025	Conduct mid-project soil test	Casey Ameil
October 2025	Conduct end of project soil test	Casey Ameil
End of October 2024	Get final soil test.	Casey Ameil
November -December 2025	Produce educational video content and blog post	Beth Portesi
January 2025	Prepare final report	Beth Portesi

Cooperators

Click linked name(s) to expand/collapse or show everyone's info

Maud Powell - Technical Advisor
Maud.Powell@oregonstate.edu
Associate Professor of Practice, OSU Small Farms
Oregon State University, Southern Oregon Research & Extension Ce (Other college or university)
569 Hanley Road
Central Point, OR 97502

Research

Materials and methods:

Objective 1: Determine if no-till practices have a measurable impact on soil health in high tunnels or low tunnels

Methods Conducted:

We established permanent no-till beds in three treatment areas:

High Tunnel: 30’ x 100’ high tunnel

Low Tunnels: Outdoor beds covered with Agribon AG-19 floating row cover on 1/2” electrical conduit hoops

Outdoor Control: Uncovered outdoor beds

Timeline of Activities:

September 2023: Conducted team kick-off call with Beth Portesi, Casey Ameil, and Maud Powell; collected baseline soil test; began high tunnel construction

October 2023: Overwintered previous season’s crops as cover crop on all beds

November 2023 - January 2024: Monitored cover crop growth through winter

February - March 2024: Terminated cover crop by cutting and covering with occultation tarps for decomposition

April 4, 2024: Collected first soil samples and submitted to Oregon State University Soil Health Laboratory

April 2024: Applied compost and organic 4-4-4 fertilizer uniformly to all beds; laid plastic mulch on designated beds

April - June 2024: Initial transplanting, growing, and harvesting of lettuce

Summer 2024: Completed high tunnel construction (construction required additional time to accommodate a 7% slope in the landscape, necessitating modifications to all ground posts and hoops)

August 2024 - October 2025: Continued lettuce transplanting, growing, and harvesting through full growing season

Late March 2025: Planted beds in high tunnel and outdoor control for primary data collection season

July 16, 2025: Collected mid-season soil samples

October 6, 2025: Collected final soil samples

November 2025 - January 2026: Produced educational video and published blog post

Note on Study Duration: This research represents a single year of growing season data. To fully understand the long-term effects of no-till practices on soil health markers in high tunnel environments, additional years of soil testing would be beneficial. Future retesting would help establish trends and determine whether the observed changes in soil biology (particularly microbial biomass) stabilize, recover, or continue to change over time.

Soil Health Indicators Measured:

All soil tests were performed by the Oregon State University Soil Health Laboratory using the following indicators:

Biological:

Soil microbial biomass (chloroform fumigation method)

Active carbon (potassium permanganate reduction)

Organic matter (calculated from total organic carbon)

CO2 respiration (24-hour and 96-hour incubation)

Potentially mineralizable nitrogen (28-day incubation)

Physical:

Water stable aggregates (Cornell Sprinkle Infiltrometer method)

Texture (hydrometer method)

Moisture content

Chemical:

pH and electrical conductivity

Macronutrients: P, K, Ca, Mg (Mehlich 3 extraction)

Cation exchange capacity (sum of bases estimation)

Objective 2: Determine if plastic mulch has a measurable impact on soil health using no-till practices

Methods Conducted:

Within each treatment area (high tunnel, low tunnel, outdoor control), we established paired beds: one bed with black plastic sheet mulch and one bed without plastic mulch (bare soil with organic matter surface coverage). Both bed types received identical inputs of compost, fertilizer, irrigation, and lettuce transplants throughout the growing season. Soil samples were collected from both mulched and non-mulched beds at each testing interval.

Objective 3: Compare crop production and correlation with soil health

Methods Conducted:

Transplanted Salanova lettuce varieties in multiple successions from April through October

Recorded total harvest weight (in pounds) from each bed by treatment type

Maintained consistent irrigation through drip systems across all treatments

Applied 50% shade cloth during summer months to manage heat stress

Research results and discussion:

Soil Health Results: High Tunnel vs. Outdoor Control (No-Till)

Table 1: Soil Health Indicators Over Time

Indicator	Location	April 2024 (Baseline)	July 2025 (Mid-Season)	October 2025 (Final)	% Change
Organic Matter (%)	High Tunnel	6.52	7.70	10.04	+54.0%
	Outdoor	6.78	7.60	10.46	+54.3%
Active Carbon (ppm)	High Tunnel	693	765	893	+28.9%
	Outdoor	683	834	884	+29.4%
Water Stable Aggregates (%)	High Tunnel	50	56	49	-2.0%
	Outdoor	55	49	35	-36.4%
CO2 Respiration 24hr	High Tunnel	67	39	72	+7.5%
	Outdoor	55	59	55	0%
Microbial Biomass (ug/g)	High Tunnel	4,687	814	1,604	-65.8%
	Outdoor	4,368	803	1,537	-64.8%
PMN (mg N/kg soil/day)	High Tunnel	1.52	0.83	0.93	-38.8%
	Outdoor	1.22	0.73	1.04	-14.8%
pH	High Tunnel	7.21	7.25	7.48	+3.7%
	Outdoor	7.05	7.47	7.21	+2.3%
CEC (meq/100g)	High Tunnel	28	35	39	+39.3%
	Outdoor	28	33	39	+39.3%

Key Findings: No-Till Impact on Soil Health

Positive Outcomes:

Organic Matter Increased Significantly: Both high tunnel (+54.0%) and outdoor (+54.3%) beds showed substantial increases in organic matter over the study period, rising from approximately 6.5% to over 10%. This indicates that no-till practices effectively build soil organic matter regardless of season extension method used.
Active Carbon Improved: Active carbon, an indicator of readily available food for soil microbes, increased by approximately 29% in both treatments. This suggests healthy carbon cycling in no-till systems.
Cation Exchange Capacity Increased: CEC rose by 39% in both treatments, indicating improved nutrient-holding capacity of the soil.
Water Stable Aggregates Protected in High Tunnel: The high tunnel maintained relatively stable aggregate structure (50% to 49%), while outdoor beds experienced a significant decline (55% to 35%). This suggests the high tunnel environment may help protect soil structure from degradation.

Areas of Concern:

Microbial Biomass Declined: Both treatments showed substantial decreases in microbial biomass over the study period (approximately 65% reduction). This may indicate that intensive lettuce production, even with no-till practices, can stress soil microbial communities. The mid-season (July 2025) readings showed the lowest microbial biomass values, with partial recovery by the final sampling.
Potentially Mineralizable Nitrogen Decreased: PMN declined in both treatments, though the outdoor control showed better recovery by the final sampling. This suggests nitrogen cycling may be affected by intensive production.

Crop Production Results: Mulch vs. No Mulch

Table 2: Total Lettuce Harvest by Treatment (lbs)

Treatment	No Mulch	With Mulch	Difference
High Tunnel	36.5	30.4	+6.1 lbs (+20.1%)
Outdoor	36.2	34.3	+1.9 lbs (+5.5%)

Key Findings: Plastic Mulch Impact

No-Mulch Beds Outperformed Mulched Beds: Contrary to common assumptions about plastic mulch benefits, beds without plastic mulch produced higher yields in both environments: high tunnel no-mulch beds produced 20.1% more lettuce than mulched beds, and outdoor no-mulch beds produced 5.5% more lettuce than mulched beds.
High Tunnel Performance: Total yields were comparable between high tunnel (36.5 lbs no-mulch) and outdoor control (36.2 lbs no-mulch), suggesting that for lettuce production, the high tunnel’s primary benefit may be season extension rather than yield increase.
Mulch Effect More Pronounced in High Tunnel: The negative impact of plastic mulch on yield was more significant in the high tunnel environment (-20.1%) compared to outdoor (-5.5%). This may be related to the “desert effect” mentioned in existing literature, where the combination of covered production and plastic mulch creates challenging conditions for soil biology.

Correlation Analysis: Soil Health and Crop Production

The data suggests that beds without plastic mulch, which maintained better soil-surface contact and organic matter interaction, produced higher yields. This aligns with our hypothesis that practices supporting soil biology (no-till, no plastic barrier) correlate with improved crop production.

Participation summary

2 Farmers/Ranchers participating in research

Research outcomes

Recommendations for sustainable agricultural production and future research:

Recommendations for Farmers:

Consider no-till practices as a viable management strategy for high tunnel and low tunnel production
Evaluate the necessity of plastic mulch, particularly in high tunnel environments where it may reduce yields
Incorporate cover cropping and rest periods to support microbial community recovery
Monitor water stable aggregates as an early indicator of soil structure changes
Continue monitoring soil health over multiple seasons to track long-term trends

Study Limitations:

This research represents a single year of growing season data. While the results show promising trends for no-till practices in season extension environments, continued soil testing over multiple years would be necessary to: confirm whether soil health improvements are sustained long-term, determine if microbial biomass recovers or continues to decline under intensive production, and establish whether high tunnel soil markers diverge significantly from outdoor controls over time.

Education and Outreach

2 On-farm demonstrations

1 Published press articles, newsletters

1 Other educational activities: Youtube Video

Participation summary:

8 Farmers/Ranchers

Education and outreach methods and analyses:

Educational Activities Completed

Farm Visits and Demonstrations (Year 1):

Throughout the research period, we hosted visits from three farming couples to tour the greenhouse and discuss the ongoing research. Given that final results were not yet available during these visits, education focused on: the research process and methodology, current status of the trials, no-till bed preparation techniques, season extension infrastructure setup, and soil sampling procedures.

Final Educational Outreach (November 2025 - January 2026):

Upon completion of the research and analysis of results, we conducted the following outreach activities in lieu of the originally planned farm demonstration day:

Blog Post Publication: Published a comprehensive blog post detailing the research methodology, findings, and practical implications for small-scale farmers interested in no-till season extension practices.
Video Production: Produced educational video content for YouTube and social media platforms, presenting the research results in an accessible format for our audience.

Education and outreach results:

1. YouTube Educational Video

Title: No-Till in a High Tunnel: What 2 Years of Soil Tests Revealed

Platform: YouTube

Runtime: Approximately 3 minutes

Link: https://www.youtube.com/watch?v=NrH0PpsUaas

We produced a short-form educational video summarizing our key findings, designed for accessibility and shareability on social media platforms. The video covers:

Project setup and methodology
Key soil health metrics (organic matter, active carbon, water-stable aggregates)
Challenges observed (microbial biomass decline)
Practical recommendations for farmers

Why YouTube? Publishing on YouTube allows us to reach producers and audiences far longer than a single live education day. The video remains permanently accessible, can be shared across social media platforms, embedded in extension websites, and discovered by farmers searching for information on no-till or high tunnel production. This approach multiplies the educational impact of our research beyond what a one-time workshop could achieve.

Target Audience: Small-scale vegetable producers, market gardeners, beginning farmers, and extension educators interested in no-till practices and season extension.

2. Written Blog Post / Research Summary

Link: https://www.lazyacresfarm.org/post/no-till-in-the-high-tunnel-what-our-two-year-soil-health-study-revealed

A detailed blog post was developed explaining our methodology, presenting data tables, and discussing implications for farmers. This resource provides:

Complete soil test data comparisons (baseline vs. final)
Photographic documentation of the growing season
Interpretation of results in plain language
Specific recommendations for implementation

Distribution: Farm website, social media, SARE project reporting system

3. Soil Test Data and Analysis

All soil health data from Oregon State University's Soil Health Laboratory has been compiled and is available for other researchers and producers. Key metrics tracked include:

Organic matter (%)
Active carbon (ppm)
Water-stable aggregates (%)
Microbial biomass (µg/g)
Cation exchange capacity (meq/100g)
Potentially mineralizable nitrogen

Education and Outreach Outcomes

6 Farmers/Ranchers gained knowledge, skills and/or awareness

Recommendations for education and outreach:

Outreach Methods & Effectiveness

Method	Reach	Advantages
YouTube video	Ongoing, searchable, shareable	Extends beyond single event; accessible 24/7; reaches producers who can't attend in-person events
Blog post	Website visitors, social media shares	Provides detailed data for those wanting deeper understanding
Social media (Instagram, Facebook)	Followers + algorithm reach	Reaches younger and beginning farmers; visual format highlights results
SARE reporting system	Researchers, extension, other grantees	Contributes to body of knowledge; discoverable by others doing similar work

Reaching Underserved Communities

The decision to publish educational content on free, publicly accessible platforms (YouTube, social media, open-access blog) was intentional. This approach:

Removes cost barriers to accessing research findings
Reaches producers in rural areas who may not have access to in-person extension events
Allows non-English speakers to use auto-translation features
Provides flexible, self-paced learning for producers with time constraints

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Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S. Government determination or policy.