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2.3 Biological Characteristics
Discussion – Impacts of Soil Organic Matter on Soils
Let’s tie together and review some of the physical, chemical, and biological soil concepts covered so
far.
The amount of organic matter in a soil is often less than 5%, but soil organic matter has a great effect
on soil physical structure, chemistry, and biology. In the list below, please indicate which physical
characteristics increase and which decrease as organic matter increases.
Physical
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Chemical
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Contains and stores nutrients especially nitrogen, phosphorus,
and sulfur in a slow release state
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Stabilizes macronutrients and micronutrients
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Buffers pH changes
Biological
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Provides food for soil organisms large and small
Aggregation
Pore space
Water infiltration
Moisture retention
Aeration
Erodibility