Soil erosion is cause for many concerns, primarily because of the destruction it can leave in its path, both immediately and over time. Erosion can contribute to crop loss, pollution, soil degradation, and soil infertility. Economic and environmental impacts are felt in the immediate aftermath of storms or other disturbances and in the long-term effects of those alterations.
Soil Erosion Caused by Wind
Wind erosion is most often seen in flat, bare areas where there isn’t enough natural vegetation to hold the soil in place, or if the land has been cultivated. Dry and sandy soils are increasingly susceptible along with other regions where soil may be loose.
Wind erosion can damage the land it travels over, as well as surrounding natural vegetation, by removing soil and depositing it somewhere else. Soil erosion takes vital nutrients with it and weakens vegetation, making it vulnerable to disease. Wind erosion dries out the soil and strips its moisture, making it lighter and more susceptible to movement. As dust and dirt are flung into the air, particles drift and move in various directions and sometimes for great distances.
As sediment moves back toward the ground, it settles on everything in its path. Sediment in the form of dust and dirt blows through house doors and windows, which can trigger allergies and upper respiratory conditions. Drifting sediment builds up and suffocates crops while it covers roads and highways.
Wind erosion also creates changes in the land’s topography as sediment builds up over time and causes changes to the soil formation process. This sediment buildup comes full circle and exacerbates the cycle when the next wind event picks it up and carries it elsewhere.
Wind erosion requires a minimum velocity be achieved in order to move soil or pick it up. The force needed to move soil in a significant trajectory is known as threshold velocity. Once this threshold is reached, and depending on the type of soil or its current moisture content, determinations can be made on which type of erosion the land will experience. Factors like the soil particle size, whether the soil formed into clods, and the wind’s power will all determine how wind erosion shows up.
There are three types of erosion caused by wind: saltation, suspension, and creep. Although soil can be blown away from nearly any height, most wind erosion occurs at less than one meter off the surface.
Saltation erosion is responsible for 50% to 80% of wind erosion. In this type of erosion, wind has reached threshold velocity at approximately 20 kph and travels less than one meter off the ground. Fine particles of dust are put into motion by the wind and start to drift horizontally, prompted by the wind’s path. As these particles are propelled by wind, they increase their speed. This action leads to pronounced erosion by causing one or more erosion types to come together at once.
Because saltation erosion travels four times longer in distance than it does in height, saltation has plenty of time to interact with the soil it’s passing over and through. As these particles strike again, whether with each other or in a rebound fashion, they inevitably disturb more soil. The spinning action of soil and sediment particles, as well as the force at which particulates push forward and downward, make them powerful enough to destroy the stable surface crust of the soil. This opens the way for suspension and surface creep erosion.
When suspension erosion occurs, fine dirt and particles are lifted into the wind. If these particles are light and dry, they might be tossed into the wind, where they churn and spin. Drifting particles collide with others, sometimes sending the particles high enough to create a cloud. These particulates can travel great distances and leave deposits to settle in their wake. Suspension erosion is the most easily recognized and most often associated with wind erosion even though it accounts for a smaller percentage of wind erosion events.
Surface Creep Erosion
Surface creep erosion accounts for approximately 25% of wind erosion. Some soil particles will be too heavy for the wind to lift. In this event, particles are rolled across the surface like tumbleweeds. As they roll, they dislodge soil or encounter other particles in saltation.
Wind erosion can be minimized through various preventative methods. From creating windbreaks to weighing down soil, there are steps to take to minimize the damage from wind erosion.
- Get soil to stick together using an organic matter to moisten the soil, or increase watering to make soils heavier.
- Increase the soil’s roughness to make it less likely to move. Tilling soil increases its chances of forming clods to make it heavier and chunkier and reduce the chances of being carried away by the wind.
- Increase natural vegetation to prevent wind from reaching soil while increasing its ability to stay in place. Vegetation also works to hold seeds and saplings in place, reducing risk to their well-being and growth process.
- Plant shade trees that filter the elements and keep the soil moist, making it harder to move.
- Follow principles of strip planting, terracing, and crop rotation.
- Put geotextiles to use. These natural fabrics, which can be woven or non-woven, are designed to modify the land or anchor soil into place.
As land is cultivated or cleared, the soil is made vulnerable to the environmental effects of wind and rain. Soil erosion by any means can be devastating to the environment, the economy, and human health.
Crops and new plantings are at risk of wind erosion as nutrients are depleted and the soil’s fertility is degraded over time. Pollutants such as fertilizer and pesticides are carried through the air and deposited across several miles.
Preventing wind erosion today is crucial to maintaining active and lively agriculture while preventing infrastructure failure, economic hardship, and risks to human health. Taking action now to minimize the effects of wind erosion can mean the difference between a healthier earth and devastating loss.