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Soil Quality Assessment
Overview
Soil quality is an assessment of how well soil performs all of its functions
now and how those functions are being preserved for future use. It cannot be
determined by measuring only crop yield, water quality, or any other single
outcome.
Soil quality 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 properties, processes, or characteristics of
soils. They can also be morphological or visual features of plants. 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, and
- 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.
Examples of soil quality indicators:
Indicator |
Relationship to Soil Health |
Soil organic matter (SOM) |
Soil fertility, structure, stability, nutrient retention; soil
erosion |
Physical: soil structure, depth of
soil, infiltration and bulk density; water holding capacity
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Retention and transport of water and nutrients; habitat
for microbes; estimate of crop productivity potential; compaction, plow
pan, water movement; porosity; workability |
Chemical:
pH; electrical conductivity; extractable N-P-K |
Biological and chemical activity thresholds; plant and microbial activity
thresholds; plant available nutrients and potential for N and P loss |
Biological: microbial biomass C and N;
potentially mineralizable N; soil respiration.
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Microbial catalytic potential and repository for C and N;
soil productivity and N supplying potential; microbial activity measure
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Soil Quality Indicators: Physical Properties Information Sheets:
The following documents require
Adobe
Acrobat
Aggregate Stability (PDF, 380KB)
Available Water Capacity (PDF, 210KB)
Bulk Density (PDF, 340KB)
Infiltration (PDF, 315KB)
Slaking
(PDF, 500KB)
Soil Crusts (PDF, 250KB)
Soil Structure
and Macropores (PDF,
480KB)
For more information go to:
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