Occultation Impacts on Soil Health and Plant Termination in Oregon

Commodities

• Agronomic: corn, radish (oilseed, daikon, forage)
• Vegetables: beans

Practices

• Crop Production: no-till
• Education and Training: on-farm/ranch research
• Soil Management: soil analysis

Occultation tarping has the potential to transform Oregon’s small farm management practices in ways that help farmers save money, access in-expensive, easy to implement strategies to terminate cover crops, and manage weeds in the field while protecting soil tilth. We want to study this ‘ground-breaking’ no-till strategy to better understand the impacts on soil health and plant termination. 

Occultation, “weeding with tarps” involves laying down a thick, black plastic /vinyl tarp for 4-8 weeks. Under the tarp, the weed seeds germinate in the moist environment, plants die due to lack of sunlight, and then decompose back into the soil with the help of the active soil food web. Once the tarp is removed, the clean seed bed is planted/seeded and minimal soil disruption occurs.

Our research question is, “What effects does occultation have on plant termination and soil health?” We will contract with OSU Soil Lab to conduct soil tests encouraged by the Soil Health Institute to measure the effect of occultation on soil organic carbon concentration, carbon mineralization potential, and soil aggregate stability. These are all indicators of soil health. 

Verdant Phoenix Farm’s team includes a professional educator / experienced no-till farmer, a retired PhD research advisor, farm assistant, and technical advisor / ag professional from Jackson Soil and Water Conservation District. Our project has significant support because there are a growing number of organic farmers interested in no-till, but they are not sure how to terminate plants and protect soil tilth.

We plan to share our findings through field days, on-farm demonstrations, and through interviews on the popular No-Till Growers podcast (reaching over 15,000 listeners weekly), and has over 275,000 YouTube subscribers, internationally.
Our team will also develop a “Guide for occultation implementation: Occultation Protocol for No-Till Systems in Oregon” to share the practice in Oregon and beyond.

Project Research Objectives: Our project will determine if occultation tarping has a positive impact on:

1. Soil organic carbon concentration, compared to tillage.
2. Soil carbon mineralization potential compared to tillage.
3. Soil aggregate stability compared to tillage.
4. Plant termination by percentage. Qualitatively measure, through observation and photo documentation the percentage of plants terminated using a scale:1 = < 10%, 2= >20%, 3= <50%, 4=> 50%, 5= >90%

Education Objectives:

Objective 1: Develop case study, record observations, photo document, and record impact data on soil health, plant termination, and crop yield over the course of the project.

Objective 2: Establish educational field tours to demonstrate occultation techniques, impacts, and benefits to producers, gardeners, land managers, and ag professionals.

Objective 3: Plan, design, and write a fact sheet and publication to serve as a “Guide for occultation
implementation: Occultation Protocol for No-Till Systems in Oregon”. We will work with the project team, our technical advisor, research advisor, ag professionals from SOU, JSWCD, and OSU Small Farms to collaboratively develop content and publish the Guide for use by other farmers and producers. (Letters of support included) This Guide will be available in print (at least 200) and our team will pursue publishing the fact sheet through OSU Extension.

Objective 4: Present findings through in-field demonstrations and presentations for OSU Small Farms program, OSU Small Farms Conference, Jackson Soil and Water Conservation District (JSWCD) workshops, OSU Land Steward classes, Friends of Family Farmers, and others when requested. At least 100 people will attend. 

Objective 5: Print and distribute fact sheet / "Guide" through ag partners, technical advisor, and other community partners so that over 200 copies are provided to interested producers and ag professionals to increase the impacts of this research and broader adoption of the practices.

Objective 6: Prepare and deliver an online workshop / podcast to disseminate project findings via “No-Till Growers” podcast online. No-Till Growers have an active listening audience of approximately 15,000 weekly podcast listeners and 275,000 YouTube subscribers, internationally.  No-Till Growers have committed to supporting this project (letter included) and their goal is to help promote and share no-till strategies so there is greater adoption of the practice.