Series 24 - Soil Quality VII - Case Studies of Soil Sedimentation

Summary

This video from Cornell University explores different types of erosion—water and wind—and their impact on landscapes, particularly in agricultural and desertification contexts. It emphasizes the role of plant-based strategies to stabilize soil, such as deep-rooted plants, organic amendments, and windbreaks. The speaker also discusses the challenges posed by events like flooding and desert encroachment, and how strategic planting can mitigate these issues by improving soil structure, water retention, and nutrient availability. The goal is to offer practical solutions for restoring and maintaining productive land in the face of environmental degradation.

Takeaways

• 😀 Erosion can take two forms: material being pulled away (erosion) or material being deposited (sediment deposition), both occurring during flooding events.
• 😀 Flooding not only removes soil but can also bury agricultural land with sand, as seen during the flooding caused by Cesana in New York State.
• 😀 When a levee breaks, farmland is not typically destroyed because the soil is removed, but because the rich soil is buried by sand.
• 😀 Effective remediation strategies for land buried in sand include planting deep-rooted, drought-resistant plants to stabilize the soil and access the older, undisturbed soil below.
• 😀 Organic amendments like organic matter can help improve soil water retention and nutrient holding capacity in sand-buried land.
• 😀 Erosion isn't always caused by water—wind erosion, as seen in dry environments like the Texas Panhandle, can also cause significant damage to agricultural land.
• 😀 Desertification, the process by which desert landscapes encroach upon agricultural land, can happen globally, not just in regions like Northern Africa.
• 😀 Wind erosion can create dunes that encroach on agricultural lands, and techniques such as jute webbing with seeds can help stabilize the dunes.
• 😀 In areas prone to wind erosion, planting certain species like cacti in terraced dune formations can both stabilize the land and improve agricultural productivity.
• 😀 Plants can stabilize soil by acting as windbreaks, reduce wind speed, and capture more soil material, all of which help protect against further erosion and desertification.
• 😀 In addition to stabilizing soil and reducing wind, plants add organic matter to the soil, creating a more supportive environment for future vegetation and ecosystem recovery.

Q & A

What are the two main types of erosion discussed in the script?

The two main types of erosion discussed are water erosion and wind erosion. Water erosion involves the removal of soil, while wind erosion can either remove soil or deposit it, particularly in arid environments.

How does wind erosion differ from water erosion in terms of its effects on the landscape?

Wind erosion often results in the deposition of sand and soil, creating dunes, while water erosion typically involves the removal of soil, leading to loss of fertile ground or flooding. Both can significantly impact agricultural land, but they affect different aspects of the landscape.

What are some common consequences of flooding and erosion events on farms, as mentioned in the script?

Flooding and erosion can either wash away or bury farms. In cases of flooding, the soil may be buried under layers of sand or debris, making it temporarily unusable, even though the soil itself is not lost.

What management strategy is suggested for dealing with soil buried by sand due to flooding?

One suggested management strategy is to plant deep-rooted, drought-resistant plants that can stabilize the soil, improve water retention, and potentially reach the fertile soil beneath the sand.

Why is it important to use drought-resistant plants in areas affected by sand burial?

Drought-resistant plants are essential because they can survive in the challenging conditions of buried soil, particularly in areas with low water retention. These plants help to anchor the soil and promote soil recovery.

How does organic matter contribute to soil stabilization and erosion control?

Organic matter enhances water-holding capacity, nutrient retention, and overall soil structure. While it may not directly affect soil infiltration, it helps to retain water and nutrients, making the soil more resilient against erosion.

What is one example of a wind erosion management strategy used in desertification areas, like in the Texas Panhandle?

In desertification-prone areas, one management strategy is to plant vegetation in a way that stabilizes the soil. This could include using jute webbing to support seed growth or planting cactuses to create terraced dunes that reduce wind erosion.

What role do plants play in reducing wind erosion, according to the script?

Plants reduce wind erosion by stabilizing the soil and creating windbreaks. These windbreaks lower wind speed, preventing the entrainment of soil particles and helping to capture additional soil and organic matter.

How does the planting of vegetation impact the environment in the long term, as discussed in the presentation?

Long-term, planted vegetation contributes to soil stabilization, increases organic matter in the soil, and helps create a more hospitable environment for other plants to grow. These effects support sustainable land management and prevent further degradation.

What is the significance of the example from Morocco in the context of wind erosion management?

The example from Morocco illustrates the impact of desertification and the role of plants in stabilizing sand dunes. The approach used in Morocco demonstrates how vegetation can not only halt wind erosion but also improve soil conditions for future agricultural use.