Soil disturbance can generally occur in different forms:
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Biological Disturbance, such as overgrazing, which limits the plants ability to harvest CO2 and sunlight.
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Chemical Disturbance, such as over-application of nutrient and pesticide, can disrupt the soil food web functions.
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Physical Disturbance, such as tillage, which we will focus on in this article.
A typical soil is approximately 45% mineral (sand, silt, and clay), 5% soil organic matter, 25% water, and 25% air. The water and air portions exist in the pore spaces between the soil aggregates. Over time, tillage implements reduce and remove the pore spaces from our soils; restricting infiltration and destroying the biological glues which hold our soils together.
Ultimately tillage results in one or more of the following:
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Water Erosion - transporting soil, nutrient, and water to offsite locations, which negatively impacts water quality and quantity.
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Wind Erosion - transporting soil, and nutrient to offsite locations, which negatively impacts air quality, human health, and animal health.
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Ponding Water - which stays saturated on the surface for long periods of time, a result of reduced infiltration and increased runoff.
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Crusting Easily - which restricts plant emergence.
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Soil Organic Matter Depletion
The impacts from tillage can be reversed by minimizing soil disturbance to rebuild soil aggregates, pore spaces, soil glue, and soil organic matter.
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Tools
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USDA-NRCS Tillage Energy Estimator – provides an idea of the magnitude of diesel fuel savings under different levels of tillage
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USDA-NRCS – Examples of residue cover under different tillage systems.