Soil health is an assessment of ability of a soil to meet its range of ecosystem functions as appropriate to its environment.
The term soil health is used to assess the ability of a soil to:
- Sustain plant and animal productivity and diversity;
- Maintain or enhance water and air quality;
- Support human health and habitation
The underlying principle in the use of the term “soil health” is that soil is not just a growing medium, rather it is a living, dynamic and ever-so-subtly changing environment. We can use the human health analogy and categorise a healthy soil as one:
- In a state of composite well-being in terms of biological, chemical and physical properties;
- Not diseased or infirmed (i.e. not degraded, nor degrading), nor causing negative off-site impacts;
- With each of its qualities cooperatively functioning such that the soil reaches its full potential and resists degradation;
- Providing a full range of functions (especially nutrient, carbon and water cycling) and in such a way that it maintains this capacity into the future.
Soil health is the condition of the soil in a defined space and at a defined scale relative to a described benchmark. The definition of soil health may vary between users of the term as alternative users may place differing priorities upon the multiple functions of a soil. Therefore, the term soil health can only be understood within the context of the user of the term, and their aspirations of a soil, as well as by the boundary definition of the soil at issue.
Different soils will have different benchmarks of health depending on the “inherited” qualities, and on the geographic circumstance of the soil. The generic aspects defining a healthy soil can be considered as follows:
- “Productive” options are broad;
- Life diversity is broad;
- Absorbency, storing, recycling and processing is high in relation to limits set by climate;
- Water runoff quality is of high standard;
- Low entropy; and,
- No damage to, or loss of the fundamental components.
This translates to:
- A comprehensive cover of vegetation;
- Carbon levels relatively close to the limits set by soil type and climate;
- Little leakage of nutrients from the ecosystem;
- Biological productivity relatively close to the limits set by the soil environment and climate;
- Only geological rates of erosion;
- No accumulation of contaminants; and,
- The ecosystem does not rely excessively on inputs of fossil energy
An unhealthy soil thus is the simple converse of the above.
On the basis of the above, soil health will be measured in terms of individual ecosystem services provided relative to the benchmark. Specific benchmarks used to evaluate soil health include CO2 release, humus levels, microbial activity, and available calcium.
- Dryland salinity
- Soil biodiversity
- Soil carbon
- Soil policy (Victoria, Australia)
- Soil quality
- Soil resilience
- Soil structure
- Soil water (retention)
|This article does not cite any references or sources. (September 2007)|
- Living Soils (Greenpeace)