Environmental Sustainability in Practice

Soil Loss

Soil is undoubtedly a key resource in agriculture – it holds the nutrients, water and other beneficial organisms agricultural crops need to grow and thrive. It anchors the roots of the plants and it provides a mechanism to move water from the surface to subsurface, which can protect from flooding and offers an additional source of water to crops.

The loss of the most productive and nutrient-rich top layer of soil under dry or extreme rain events (via runoff) can be acute, as it was in the 1930’s, and can also manifest as a longer-term, slower process. Several agricultural practices can contribute to soil loss, including:
  • Cultivation of fields through tillage. Tillage breaks up the top layer of soil to reduce compaction and encourage plant growth, and is also used as a weed control method. This practice has the side effect of drying out the soil and creating better conditions for soil to blow away in the wind or wash away during a heavy rainfall. Done in the fall, such a phenomenon can be exemplified. Tillage also has a significant impact on fungi, especially mycorrhizal fungi, in the soil by destroying them. 
  • Leaving a field fallow. This practice is used together with cultivation to reduce weed populations, reduce the potential for certain crop diseases and build up nutrient stores in the soil. Leaving a field bare over a growing season together with several rounds of cultivation again creates ideal conditions for soil to move.
  • Removing plant materials (‘stubble’) from the field in the fall, or removing/failing to plant trees. Stubble and trees act as wind breaks and can both reduce soil loss and capture soil moving in the wind. Stubble has the additional benefit of capturing snow over the winter to improve soil moisture conditions for the crop in the following spring.

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