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Soil Quality
Soil, air and water, are basic natural resources that provide important
ecosystem services. For example, soil is a carbon and nutrient cycling
site and also helps clean both water and air. Much of our drinking water
in Michigan is filtered through soil as it moves into ground and surface
waters. Poorly managed soils can serve as a pipeline for pollutants, such
as nitrate into groundwater, silt into surface waters and nitrous oxide
into the atmosphere.
| Soil quality is a measure
of a soil's function, specifically, a soil's ability to:
- Accept, hold and release nutrients and other chemical constituents.
- Accept, hold and release water to plants, streams and groundwater.
- Promote and sustain root growth.
- Maintain suitable soil biotic habitat.
- Respond to management.
- Resist degradation.
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While soil cultivation can result in soil degradation, including loss
to erosion and decreased soil organic matter content, a sustainable agriculture,
by definition, does not decrease soil quality. While there is currently
no consensus on which set of measures to include in an assessment of soil
quality, scientists generally agree that measures of both abiotic and
biotic soil components will have to be integrated in a holistic manner
to assess soil quality. Balanced biodiversity is increasingly seen as
an essential component of soil quality.
Soil characteristics important to soil
quality include: |
- Soil organic matter
- Water holding capacity
- Water infiltration rate
- Microbial biomass carbon and nitrogen
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- Structure
- Texture
- Bulk density
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- Electrical conductivity
- Nutrient availability and release
- pH
- Balanced biotic diversity
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Management goals for maintaining or improving soil quality include:
- Using renewable soil components (such as organic matter and nutrients)
no faster than they can be renewed.
- Using nonrenewable soil components (such as soil particles) no faster
than substitute resources can be developed.
- Generating or applying potential pollutants associated with soil management
(such as manure or pesticides) only as fast as the soil system can assimilate
or transform them.
Management options that increase soil quality include crop rotations
and cover crops. These options can increase soil organic matter, organic
nitrogen and protect against soil erosion. Ecological pest management
strategies decrease the need for agricultural pesticides and also reduce
soils' exposure to toxic compounds.
Links
REFERENCES:
Cavigelli, M.A., S.R. Deming, L.K. Probyn and R.R. Harwood (eds.). 1998.
Michigan Field Crop Ecology: Managing biological processes for productivity
and environmental quality. Michigan State University Extension Bulletin
E-2646, 92 pp. Click
here to purchase this MSU Extension Bulletin.
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