Soil health refers to the ability of a specific soil to perform multiple functions, including nutrient cycling, sustaining plant and animal growth, maintaining diversity, regulating water dynamics, moderating climate and a whole slew of other attributes we expect of soils. An assessment needs to approach the biological, chemical and physical properties of the soil and how they interact. It's been difficult to create a one-size fits all evaluation process of assessment. Sometimes it might be just as easy to smell it or look at how plants are growing in it to give it a rating, but these measures can be very subjective across noses and viewpoints. The USDA's Natural Resource Conservation Service has developed a field methodology that attempts to standardize some of the physical and biological parameters. The in-field assessment comes in both a short and long form. Check them out – Cropland In-Field Soil Health Assessment Guide:
Short version
https://directives.sc.egov.usda.gov/OpenNonWebContent.aspx?content=44419.wba
Long version
