What is soil health?
Soil health is how well soil does what we want it to do. More specifically, soil health is the capacity of a specific kind of soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation.

What does soil do?
Healthy soil gives us clean air and water, bountiful crops and forests, productive rangeland, diverse wildlife, and beautiful landscapes. Soil does all this by performing five essential functions:

• Regulating water. Soil helps control where rain, snowmelt, and irrigation water goes. Water and dissolved solutes flow over the land or into and through the soil.
• Sustaining plant and animal life. The diversity and productivity of living things depend on soil.
• Filtering potential pollutants. The minerals and microbes in soil are responsible for filtering, buffering, degrading, immobilizing, and detoxifying organic and inorganic materials, including industrial and municipal by-products and atmospheric deposits.
• Cycling nutrients. Carbon, nitrogen, phosphorus, and many other nutrients are stored, transformed, and cycled through soil.
• Supporting structures. Buildings need stable soil for support, and archeological treasures associated with human habitation are protected in soils.

Assessing soil health.
Soil health is an assessment of how well soil performs all of its functions. It cannot be determined by measuring only crop yield, water quality, or any other single outcome. The health of a soil is an assessment of how it performs all of its functions now and how those functions are being preserved for future use.

Soil health cannot be measured directly, so we evaluate indicators. Indicators are measurable properties of soil or plants that provide clues about how well the soil can function. Indicators can be physical, chemical, and biological characteristics. Useful indicators:

• are easy to measure
• measure changes in soil functions
• encompass chemical, biological, and physical properties
• are accessible to many users and applicable to field conditions
• are sensitive to variations in climate and management.

Indicators can be assessed by qualitative or quantitative techniques. After measurements are collected, they can be evaluated by looking for patterns and comparing results to measurements taken at a different time or field. Here are some examples of indicators of soil health:



For more information on soil health, review the following Web pages: http://urbanext.illinois.edu/soil/sq_info/sq_intro.pdf or http://soils.usda.gov/sqi