Soil Degradation and Erosion

Defined as the “loss of land's physical, chemical, biological, and ecological qualities due to either natural or human-caused disturbances,” soil degradation is one of the largest and most dangerous environmental threats to humanity. Soil degradation can take many forms, some of which include soil erosion, compaction, salinization, desertification, and pollution. Such problems can affect agricultural productivity and, by extension, food security across the globe.

Soil Erosion

Soil erosion is the most frequent cause of soil degradation and is often caused by weathering. It leads to an average loss of 75 billion tons of soil a year, which amounts to around 400 billion US dollars annually. Topsoil, the surface layer of soil, is often the most nutritious and valuable part of the soil. Unfortunately, this is also the layer that is easily removed by winds or water runoff during heavy rainfall.

In arid and semi-arid regions, heavy winds can lead to erosion and desertification, damaging topsoils and affecting local crop harvests. Climate change is also largely responsible for the increasing frequency of soil erosion. The abnormal rainfall and extreme climate conditions caused by climate change often further increase the weathering and physical threats that the field surface must resist.

Monocropping, a farming technique where only one crop species is repeatedly planted over multiple strips of land, can lead to nutrient depletion. This results in land degradation and soil erosion. Additionally, conventional tillage of soil, using manual tilling or moldboard plowing, can lead to loose soils, resulting in a loss of topsoil to winds and weathering.

Overgrazing, a phenomenon known as The Tragedy of the Commons, is another example of poor pasture management. It destroys grass and, subsequently, topsoil cover, which is often associated with long-term depletion of topsoil nutrients. A severe case of soil erosion and land degradation may take decades to recover, even with intervention.

Soil Salinization

Soil salinization is another example of soil degradation. As suggested by its name, soil salinization refers to an excessive accumulation of salts in the soil. This phenomenon occurs due to inadequate watering, high evaporation rates, or poor drainage.

There are proton pumps that line the cellular membrane of plant roots. These proton pumps actively transport salts and ions into the plant roots through the apoplast or symplast route, allowing the roots to passively absorb water as a result of osmosis. Soil salinization can increase the salt concentration in plant roots, creating an osmotic gradient between the roots and the soil. This can cause shriveling in plant cells, known as plasmolysis.

Soil salinization is often harder to mitigate or prevent compared to soil erosion since salt content is not visible to the eye unless practical damage has already been done to plants. Unfortunately, by that time, the salinization may have already slowed crop growth and rendered the soil unsuitable for further cultivation.

How to Fix Soil Degradation

Although soil degradation may take a long time to fully remedy, there are fortunately many preventive measures that can be taken to ensure your soil remains in good condition. Practicing no-till or reduced tillage techniques can lower the soil’s vulnerability to erosion and weathering by allowing the soil to naturally rest.

Another method is to practice crop rotation by alternating the crop types grown in your soil by season. Such techniques can help ensure that there isn’t a singular nutrient being depleted, while also providing a range of different nutrients from the plants to the soil. Happy farming!

Works Cited

https://eos.com/blog/soil-degradation/

https://eos.com/blog/soil-erosion/