Series 23 - Soil Erosion IV - Erosion by Wind

Summary

This video from Cornell University explores the principles of fluid dynamics, comparing water and wind erosion. It emphasizes the similarities between the two, highlighting how wind can pick up and transport particles, much like water. The video also covers strategies to combat wind erosion, such as using wind breaks, increasing surface roughness, and managing moisture. By understanding the dynamics of wind and its effects on soil, farmers can implement effective techniques to protect crops, conserve moisture, and reduce soil erosion.

Takeaways

• 😀 Wind and water both behave similarly in fluid dynamics, with water being denser and carrying more energy.
• 😀 The energy of flowing water is greater in faster-moving streams and steeper slopes, similar to wind energy in various conditions.
• 😀 Wind can erode soil by picking up particles when its force exceeds the resistance of the soil, much like water erosion.
• 😀 Smaller particles like clay and silt are more easily carried by wind than larger particles like sand.
• 😀 The wind erosion index is a model similar to the water erosion index, considering soil erodability, wind velocity, and soil moisture.
• 😀 Windbreaks are essential for reducing wind speed and erosion by creating surface roughness and blocking the wind's path.
• 😀 The effectiveness of windbreaks is based on their height—sheltering distance extends 10-20 times the height of the windbreak.
• 😀 Surface moisture affects wind erosion; wetter soils are less prone to erosion and more likely to hold vegetation in place.
• 😀 Vegetation helps reduce wind speed near the surface, creating a protected area that prevents erosion and dehydration of plants.
• 😀 Cultivation techniques, like creating ridges or hummocks, can increase surface roughness, which also helps reduce wind erosion.
• 😀 Understanding wind patterns and soil conditions (e.g., moisture and texture) is crucial for effective land management and erosion control.

Q & A

How are wind and water similar in terms of fluid dynamics?

Both wind and water are considered fluids and behave similarly in terms of fluid dynamics. While water has more mass and therefore more energy behind its flow, air (wind) behaves as a fluid as well, and the principles of flow and resistance in both cases are comparable.

What factors contribute to the erosive potential of water and wind?

For both water and wind, the erosive potential depends on factors such as the velocity of the flow, the nature of the surface (e.g., soil texture), and the moisture content. In wind erosion, factors like the wind velocity, moisture level in the soil, and the presence of vegetation are crucial.

How does the mass of water impact its energy compared to wind?

Water has more mass than air, which means that for the same flow rate, water carries more energy. This difference is why fast-moving water, such as in a steep slope, has a much higher erosive potential than slow-moving water.

What role does the type of object play in wind erosion?

The resistance of an object to movement in the wind depends on its size and surface area. Smaller particles, like clay and silt, experience less resistance than larger particles like sand, making them more easily moved by wind.

How does the concept of windbreaks help reduce wind erosion?

Windbreaks reduce wind energy and the distance over which the wind can carry soil particles. By creating barriers (e.g., trees or shrubs) that interrupt the wind flow, they reduce soil movement, protect crops, and limit erosion.

What is the rule of thumb for the effectiveness of windbreaks?

A windbreak's effectiveness typically extends 10 to 20 times the height of the barrier. For example, a 10-foot tree can shelter an area 100 to 200 feet downwind.

How does moisture in the soil influence wind erosion?

Moist soil is less prone to wind erosion because the moisture acts like a glue, binding the particles together. The more moisture in the soil, the less likely the wind is to pick up and carry it away.

What effect does vegetation have on wind erosion?

Vegetation helps to stabilize soil by acting as a barrier that reduces wind speed close to the surface. It increases surface roughness, which slows down the wind and reduces its ability to erode soil.

How do cultivation practices impact wind erosion?

Cultivation practices, such as plowing, can increase surface roughness by creating ridges or hummocks. These features act as windbreaks by creating wind shadows, reducing wind speed and soil erosion.

What is the significance of the wind's direction when placing windbreaks?

The direction of the wind is crucial when placing windbreaks. Windbreaks should be positioned against the prevailing wind direction to be most effective. If the wind direction is misjudged, the windbreaks may not significantly reduce wind erosion.