Functionalizing earthworms for soil health monitoring by North Central farmers

Commodities

Practices

Soil biology has become a hot topic in recent years with the increased focus on soil health and  regenerative agriculture practices. While many farmers see soil biology as beneficial and seek to increase biological activity in their fields and pastures, many of the tests for measuring soil biology target microfauna: bacteria and fungi. These tests, largely considered soil health tests, can be expensive, difficult to interpret, and farmers cannot easily "ground-truth" the results in
their own fields (e.g., visual observation). In contrast, earthworms have been identified for their beneficial impact on agricultural soils for centuries, as they can readily be observed by farmers in their own fields. Despite this, there is a lack of quantitative evidence to make use of the empirical observations made by farmers on soil health by observing earthworms. The abundance as well as specific types of earthworms are often related to a shift in management practices such as reduced tillage, cover cropping, livestock integration and diversified crop rotations.

This project will provide farmers with an earthworm-based soil health test, calibrated and validated by on-farm assessments of earthworms and soil health indicators (n=432 observations) across a suite of diverse management practices (n=48 cropping systems) across Illinois. Cropping systems vary from conventional corn-soybean rotation with chisel tillage, to varying degrees of ecological intensification and regenerative practices, including cover cropping, diversified crop rotations (e.g., wheat, barley), pastures and livestock integration into row crop fields, and strip
tillage to no-tillage. Earthworm biomass abundance, feeding type (e.g., epigeic, endogeic) and keystone species will be quantified at three timepoints annually over each of three years, to identify both seasonal variation in earthworm dynamics and potential practical trade-offs in the timing of earthworm assessment for soil health monitoring by farmers. Co-measurement of soil health using USDA NRCS recommended indicators (e.g., aggregate stability, respiration) will be used to relate the abundance and type of earthworms to soil health status.

Twice-annual project meetings with collaborator farmers will provide feedback to co- develop earthworm-based assessment of soil health. Annual field days in the south, central and north Illinois regions hosted by collaborator farmers will enable feedback on the earthworm-based soil health tool from additional farmers, crop consultants and conservationists. Ultimately, this work will produce an earthworm soil health test protocol that is DIY for farmers, supported by a North Central US earthworm classification guide and interpretation guidelines made available via
high-quality, in-print booklets and online.

Objective 1: Evaluate earthworm abundance, feeding groups, and keystone species as a function of management practices, individual and stacked, in on-farm assessments across 48 fields and pastures in four regions of IL, at multiple timepoints annually.

Outcome 1: Build scientific basis for a farmer-usable earthworm-based soil health test.

Objective 2: Determine relationships of soil health indicators approved by USDA NRCS with earthworm abundance, feeding group, and keystone species.

Outcome 2: Establish earthworm type-specific soil health interpretations.

Objective 3: Develop and disseminate earthworm-based soil health test and interpretation guide.

Outcome 3: Enable on-farm soil health monitoring by farmers.