Fashioning Amendments and Seeding Techniques to Rebuild Essential Genera of Endophytes and other soil Nutrient mobilizers (FAST REGEN)

View the project report

Commodities

• Agronomic: corn, peas (field, cowpeas), wheat
• Additional Plants: Camelina

Practices

• Crop Production: cover crops, seed saving
• Soil Management: soil microbiology, soil quality/health
• Sustainable Communities: local and regional food systems

Geopolitical conflict, supply chain problems, high fuel and fertilizer prices, or legislative reactions to climate concerns could cause Western farmers to suddenly need to work without synthetic fertilizers and herbicides. Farmers could respond to this existential risk with a regenerative agriculture approach, planting dense, diverse cover crops to suppress weeds and rebuild soil microbial activity and soil organic matter (SOM). However, rapid transitions are challenging and socially dangerous, as recent Sri Lankan experience demonstrates.

Residual herbicides and a dearth of appropriate symbiotic microbes may impair cover crops. Adding compost to improve microbial activity and SOM is expensive and logistically difficult at scale. Farmers consequently transition infrequently and gradually from conventional to regenerative soil management.

A robust microbial community can “learn” from repeated exposures to efficiently metabolize herbicides. Emerging cover crop roots should carry and nourish a symbiotic microbial community throughout the topsoil. Theoretically then, planting diverse cover crops with supportive microbes might clear herbicide residues, smother weeds, add SOM, and create a microbial community that can support a subsequent cash crop. An ideal combination would allow farmers to make a fast regenerative agriculture transition, over a single winter.

This 2-year, 2-farm research project will use a mix of three cover crops – winter wheat, Austrian peas, and winter camelina – and three supporting concepts to replace herbicide and chemical fertilizer in commercial field corn production.

Concept 1: Anti-herbicide compost

To remove herbicide residues that might impede cover crops, in year 1 we will cultivate microbial metabolizers of atrazine, 2,4-D, and glyphosate in compost. We will mix deciduous leaves and spent coffee grounds in a 21 cubic foot ComposTumbler®, inoculated with herbicide treated soil and standard compost. Herbicide exposure will begin at 6.25% of standard application rates for 10 cubic feet of 6-inch-deep topsoil after 1 week of composting, and double each week for 6 weeks, reaching 200% at the beginning of week 7.

Concept 2: Epigenetic adaptation

We planted commercially purchased winter wheat, Austrian pea, and winter camelina seeds in monocultures on regeneratively managed, herbicide-free plots in the fall of 2022 for both seeds and bacterial inoculants. These locally harvested seeds should have locally relevant genetic traits and epigenetic adaptations (GNE19-028).

Concept 3: Symbiotic composts

We will collect plant tissues (e.g., panicles, chaff, non-viable seeds, root samples) and soil from the monocultures to obtain crop-specific endophytic bacteria and other beneficial microbes. We will inoculate leaf-and-coffee compost in crop-specific 18 cubic foot Rubbermaid® compost bins.  

Biochar

We produce biochar from brush piles using Ring-of-Fire flame-capped kilns, and sift it through hardware cloth and wire mesh to obtain different grades, including dust-like ultrafine and coarse (¼ to ¾ inch) grades.

Seed balls

In the fall of year 1 we will manufacture separate seed balls for each cover crop. We will collect seeds from monocultures to use as nuclei of seed balls. We will tumble seeds in a mortar mixer with powdered clay, water, compost tea, and biochar in various combinations. Some seed balls will have an outer anti-herbicidal layer.

FAST REGEN

A block randomized experiment on 0.2 acre of a 2-acre field will compare 6 treatments’ effects on soil chemistry, herbicide residues, and microbial activity; cover crop mass; and field corn yield and elemental composition in year 2. We will plant two additional blocks to evaluate the individual concepts at smaller scale. Blocks will be 20-foot squares (400 sf each), in triplicate for each treatment (6*3+2 =20 blocks total). All blocks receive conventional herbicides and fertilizers in the spring of year 1. We will attempt to treat all blocks within 1 week of soybean harvest in year 1. The remainder of the 2-acre field will be divided into two control areas treated with herbicides and either conventional fertilizer or composted pig manure.

Treatments

AHBC=Anti-Herbicide BioChar: SCT=Symbiotic Compost Tea.

We will terminate cover crops with a small crimper roller shortly prior to corn planting in year 2. Field corn planting and harvest will then proceed as usual.

FAST REGEN diagram 2022.12.01

Objectives

1. Confirm that exposing compost to herbicides accelerates its herbicide decomposition capacity before and after application to soil.
2. Compare growth rates of cover crops with and without endophyte enrichment, anti-herbicidal treatments, and local genetic and epigenetic adaptation
3. Describe trade-offs in complexity and expense versus effectiveness of the 6 treatments for improving field corn yields and soil health measures, and compare with conventional management.
4. Share findings through field days, video and print publications, and local conferences.