Question

What is soil disturbance?

Answer 1

Soil disturbance can generally occur in different forms:

• Biological disturbance, such as overgrazing, which limits the plants ability to harvest CO2 and sunlight.
• Chemical disturbance, such as over application of nutrient and pesticide, can disrupt the soil food web functions.
• 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:

• water erosion; transporting soil, nutrient, and water to offsite locations, which negatively impacts water quality and quantity.
• wind erosion; transporting soil, and nutrient to offsite locations, which negatively impacts air quality, human health, and animal health.
• ponding water; which stays saturated on the surface for long periods of time, a result of reduced infiltration and increased runoff.
• crusting easily, which restricts plant emergence.
• soil organic matter depletion.