The 'Dirt' on Dirt

Day to day,  I think it's safe to assume that most of us don't think about the soil beneath our feet, and would be surprised to discover the incredible importance of healthy soil in maintaining a healthy environment. In reality, the abundance and distribution of healthy soil is vital for the health of our agriculture, air and water quality, as well as animal productivity. The health of our soil is at risk though, and it's important to understand how this can impact us all.

There are currently two major worldwide issues surrounding soil quality that require immediate action and attention: accelerated soil loss, and reductions in soil health and quality. We may think in some cases of soil loss as a cause of reductions in soil health.

Natural soil erosion, which is defined as the removal of soil by water or wind, is a natural background erosion in which soil is removed from an area at about the same pace as new soil is being naturally deposited. This process has been happening for hundreds of millions of years naturally via rain and wind.

The issue of accelerated soil erosion however, (where soil is being removed at a faster pace than can be replaced), is a far more recent and urgent problem. As well as being significantly more recent, accelerated soil erosion is ones of today’s most widespread environmental problems and occurs in most areas of the world.

Accelerated soil erosion is an extremely real threat worldwide. Human’s unsustainable cultivation and tillage of the earth’s soil has lead to damage of the upper horizons of soil and the vital nutrients that it holds, making it unsuitable for future generations to grow sufficient crops without artificial fertilizers.

While urbanization, poor land management, deforestation and other human practices are to blame for recent spikes in soil loss, the majority of the 75 billion metric tones of soil being removed every year is caused by unsustainable agricultural practices (Pimentel et al, 1995).This problem is accentuated in many areas like Africa and Asia where developing countries lack access to soil fertilizers and contributes to pollution. Soil runoff also results in polluted waterways and drinking water when disturbed soil is transported across distances.

In addition to the physical removal of soil by (relatively) recent anthropogenic practices, the destruction of soil health by humans is also a pressing concern. Soil health is defined as the “capacity of soil to function as a vital living system... to sustain plant and animal productivity, maintain... air and water quality, and promote plant and animal health.” Human practices like agriculture lead to massive amounts of soil being removed from the earth’s surface. As this upper level of soil holds most of the valuable nutrients necessary for plant growth, removal of it disturbs the health of the area’s remaining soil.

When soil can no longer sustain plant and animal productivity due to reduction of soil health, the land is often abandoned and rendered unusable for plant growth. In this way, issues of soil loss and health closely related. Both of these problems are getting worse and are being accelerated by human incentives to cultivate land for farming and urbanization.