Soil Health

Soil health, as defined by the United States Department of Agriculture, Natural Resources Conservation Service (nrcs.usda.gov/conservation-basics/natural-resource-concerns/soil/soil-health), is, “the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans.” More specifically, healthy soil provides five essential functions:

1. Regulates water.
2. Sustains plant and animal life.
3. Filters potential pollutants.
4. Cycles nutrients.
5. Provides physical stability and support.

Given the importance of soil as a natural resource, conserving and protecting soil (i.e., improving soil health when needed) is critical for not only food security but also water quality, air quality, and ecosystem services.

Soil Health Composition

Soil health is a comprehensive concept composed of physical, chemical, and biological properties working in combination to support vital ecosystem functions. While carbon content and microbial activity are important, soil health is actually dependent on three properties:

1. Physical properties such as soil aggregation and porosity influence water infiltration and root growth (ohioline.osu.edu/factsheet/anr-0203).
2. Chemical properties such as pH and nutrient availability regulate ion exchange and plant nutrition (ohioline.osu.edu/factsheet/anr-0204).
3. Biological properties such as microbial diversity and enzymatic activity drive nutrient cycling and organic matter transformation (ohioline.osu.edu/factsheet/anr-0205).

These three properties are deeply interconnected, and key functions like plant productivity, water regulation, and nutrient cycling depend on the collective function of all three properties of soil health.

Major Soil Health Principles

1. Minimize disturbance. Reduce physical, chemical, and biological disruptions to soil.
2. Maximize presence of living roots. Feed microbial communities year-round and improve soil structure along with nutrient cycling.
3. Maximize soil cover. Protect soil surface from erosion, rainfall impact intensity, and temperature fluctuations.
4. Maximize biodiversity. Support a wider range of soil organisms and ecological functions.

On-Farm Implementation of Soil Health

The implementation of soil health practices, such as no-till, strip-till, cover crops, and reduced fallow periods, are becoming more prevalent. In Ohio, where corn and soybeans dominate the agronomic landscape, targeted soil health practices that are more relevant for Ohio soils can be implemented. Given the climatic and soil conditions present in the state, common issues of concern include drainage problems, nutrient runoff, nutrient leaching, soil erosion, and soil carbon loss. Targeted soil health practices that address these issues without compromising economic feasibility are becoming better outlined. Programs such as the Environmental Quality Incentives Program (EQIP) (nrcs.usda.gov/programs-initiatives/environmental-quality-incentives-program), the Conservation Stewardship Program (CSP) (nrcs.usda.gov/programs-initiatives/conservation-stewardship-program), and H2Ohio (h2.ohio.gov) help to lessen the financial burden on producers for adopting soil health practices.

Soil Health Principles to Practices

Monitoring Soil Health

On-farm soil health can be monitored over time using high-level scientific testing methods available at the Soil, Water, and Environmental Laboratory (swel.osu.edu/testing) within the School of Environment and Natural Resources at The Ohio State University. Another more cost-effective, yet less informative method of testing soil health, is the in-field assessment designed and outlined by the USDA-NRCS (nrcs.usda.gov/sites/default/files/202210/Cropland_InField_Soil_Health_Assessment_Guide.pdf). Soil health testing is needed less frequently (every three to five years) compared to soil fertility testing (every one to three years) because on-farm soil health changes slowly. It is recommended that initial soil samples be taken from a few representative areas of a farm and then analyzed for a baseline soil health evaluation (ohioline.osu.edu/factsheet/anr-0206). It is also recommended to collect one composite sample from a long-term (20 or more years) undisturbed area near the field (native soil, USDA Conservation Reserve Program, or fencerow) to serve as a potential benchmark or point of reference. This benchmark provides a comparative reference for understanding the soil health gap (benchmark soil health minus on-farm soil health). Marking the sampling locations in a smartphone app is also recommended. Then, over time, as agronomic management changes are implemented, soil samples can be collected at or near the previously marked locations, analyzed, and then referenced to the baseline and benchmark to track soil health and soil health gap changes over time.

Relative background soil health data can also be obtained through the USDA, NRCS Web Soil Survey (websoilsurvey.nrcs.usda.gov/app/) or the SoilWeb mobile app (casoilresource.lawr.ucdavis.edu/soilweb-apps) developed by University of California, Davis. After navigating to the Web Soil Survey, zoom in to or expand an area in the United States by using the “+” or “-” magnifying glass icons available at the top-left corner above the map. Once zoomed in to a particular area, click one of the icons labeled “AOI” that are located at the top-left corner above the map and then outline a field using either the rectangular or polygon AOI button. After the area of interest has been outlined, click the “Soil Data Explorer” tab at the top. A list of soil property and quality ratings will appear on the left side of the screen. This list provides background information on soil within the area of interest, including the soil’s physical, chemical, and general health properties. Each subcategory provides descriptions of the soil factors of interest.

Conclusions

Healthy soil is the foundation of productive and resilient farming systems. By implementing targeted soil health practices, producers in Ohio may improve not only yields but also water quality, ecosystem services, and carbon storage. Long-term monitoring through soil health testing, especially with frameworks like the Cornell Soil Health Laboratory Comprehensive Assessment of Soil Health (soilhealthlab.cals.cornell.edu/testing-services/), enables land managers to make informed decisions and track progress toward more resilient and productive agricultural systems.

Additional Resources

• Baseline Assessment of Soil Health in Ohio
  (soilhealth.osu.edu/sites/soilhealth/files/imce/WhitePapers/Baseline%20Ohio%20Soil%20Health.pdf)
• Biological Soil Health
  (ohioline.osu.edu/factsheet/anr-0205)
• Chemical Soil Health
  (ohioline.osu.edu/factsheet/anr-0204)

• Environmental Quality Incentives Program (EQIP)
  (nrcs.usda.gov/programs-initiatives/environmental-quality-incentives-program)
• H2Ohio
  (h2.ohio.gov)
• USDA, NRCS In-field Assessment Guide
  (nrcs.usda.gov/sites/default/files/202210/Cropland_InField_Soil_Health_Assessment_Guide.pdf)

• Physical Soil Health
  (ohioline.osu.edu/factsheet/anr-0203)
• Soils and Soil Health
  (ohioline.osu.edu/factsheet/anr-0136)
• Soil Health Testing
  (ohioline.osu.edu/factsheet/anr-0206)