Question

Which of the following is most likely to cause erosion of farmland during a severe drought? A. water runoff B. soil creeping downhill C. wind D. ice

Short answer

C. wind

Step-by-step solution

Understanding Erosion Process

Erosion refers to the process by which soil and rock are removed from the Earth's surface by natural processes. The primary agents of erosion include water, wind, ice, and gravity.

Analyze Severe Drought Conditions

A drought is a prolonged period of abnormally low rainfall, leading to a shortage of water. In a severe drought, water availability is minimal, eliminating water-based erosion such as water runoff (Option A) and reducing ice-related processes (Option D) due to typically warmer conditions.

Consider Soil Movement

Soil creep (Option B) is a slow mass movement of soil particles down a slow slope. While it can contribute to erosion, it is not heavily reliant on environmental conditions like drought and occurs rather slowly.

Assess the Role of Wind

During a drought, the lack of moisture in the soil makes it more susceptible to wind erosion (Option C). Wind can pick up and transport loose, dry soil particles, especially if the vegetation that normally holds the soil in place is weakened by drought.

Conclusion Based on Analysis

Based on the analysis of the effects of a severe drought on erosion processes, wind is the most likely cause of erosion during such conditions, as it can move loose, dry soil particles easily.

Key concepts

Drought Conditions

A drought is a prolonged period without significant rainfall. This means that water, which is normally present to support plant life and keep soil moist, is largely absent.
Without moisture, the soil dries out and becomes more fragile. This fragility can make the soil more vulnerable to other forces of erosion, like wind. During a drought, vegetation is also affected. Plants struggle to survive, and some may die off, further reducing the soil's stability.

• Drought reduces soil moisture
• Weakens plant life, which normally protects soil
• Increases vulnerability to other erosive agents

So in essence, drought conditions set the stage for other natural processes to have a greater impact on erosion.

Wind Erosion

Wind erosion is a process where the wind removes and transports topsoil from one location to another. It tends to occur in dry and open areas where vegetation is scarce.
During a drought, the lack of moisture means soil particles are loose and lightweight, making them easy targets for the wind.

• Occurs in dry, open, and bare soil areas
• Wind lifts loose soil particles easily
• Can lead to the loss of valuable topsoil

Wind erosion can be particularly damaging to farmland, as the fertile topsoil, essential for growing crops, may be blown away, reducing the land's agricultural viability.

Soil Movement

Soil movement refers to the displacement of soil particles from one place to another. It occurs naturally due to various factors, such as gravity, water, wind, or human activities.
During drought conditions, soil creep (a type of soil movement involving the slow sliding of soil downhill) is not significantly affected, as it's more related to gravitational pull than environmental conditions.

• Occurs through forces of gravity, water, wind
• During drought, soil is more vulnerable to wind
• Soil movement can lead to land degradation

Soil movement, when accelerated by drought and wind erosion, can result in a significant impact on land integrity and health.

Natural Processes of Erosion

Erosion is a natural process where soils and rocks are worn away and transported by natural forces like wind, water, ice, and gravity.
Each type of erosion plays a different role in shaping the landscape, but their effects can be intensified by certain conditions. During a drought, water-related erosion processes are reduced due to the lack of rain. However, this offers an advantageous situation for wind erosion to dominate.

• Driven by natural elements: wind, water, ice, gravity
• Varies in intensity based on environmental conditions
• Tends to reshape landscapes over time

Understanding these natural processes helps us appreciate how landscapes evolve and emphasizes the importance of land conservation, especially during severe conditions like droughts.