Soil erosion could be prevented by

Step 1: Analyze the question The question asks which method can prevent soil erosion. Soil erosion is the removal of the topsoil by agents such as running water (rainfall, flooding) and wind.

Step 2: Explain the concept Erosion happens most when the soil is loose, bare and unprotected. To prevent it, we need to:

• Protect the soil surface from the direct impact of raindrops.
• Slow down the speed of running water and wind.
• Bind the soil particles together.

Common control methods include cover-cropping, planting of trees (afforestation), contour ploughing, terracing, mulching, strip cropping and building wind breaks.

Step 3: Evaluate each option

• A. Flooding a farmland: Flooding is itself an agent of erosion, because moving water carries soil away. It makes erosion worse, so this is wrong.
• B. Cover-cropping: Plants such as legumes or grasses grown over the soil have leaves that break the force of raindrops and roots that bind the soil particles. They also reduce the speed of runoff. This prevents erosion, so it is correct.
• C. Deforestation: Removing trees exposes the soil and loosens it by removing roots. This increases erosion, so it is wrong.
• D. Leaving the soil bare: Bare soil is directly exposed to rain and wind, so it is the most easily eroded. This is wrong.

Step 4: Answer The correct answer is B. cover-cropping.

Tip: For erosion questions, ask yourself, "Does this option cover and hold the soil?" If it does (cover crops, mulching, terracing, afforestation), it prevents erosion. If it exposes or loosens the soil (deforestation, bare soil, overgrazing, flooding), it causes erosion.