Correct Option: C. Contour plowing Detailed Explanation: Why Contour Plowing is the Correct Answer:

1. Definition of Contour Plowing: Contour plowing is an agricultural practice where plowing and planting are done along the contours of the land, rather than up and down slopes. This method creates furrows that follow the natural shape of the land, which helps to slow down water runoff and reduce soil erosion.
2. Mechanism of Erosion Prevention:
3. Water Runoff Management: By following the contours, the furrows act as barriers that slow down the flow of water. This reduces the speed at which water can carry soil particles away.
4. Soil Retention: The design of contour plowing helps to retain moisture in the soil, which is beneficial for crops and further reduces the likelihood of erosion.
5. Vegetative Barriers: Often, contour plowing is combined with planting cover crops or maintaining vegetation along the contours, which further stabilizes the soil and prevents erosion.
6. Effectiveness: Studies have shown that contour plowing can significantly reduce soil erosion rates compared to conventional plowing methods. It is particularly effective on sloped land where the risk of erosion is higher.

Why the Other Options are Incorrect or Weaker: A. Crop Rotation: - Explanation: Crop rotation involves alternating the types of crops grown in a particular area over time. While this practice can improve soil health and fertility, it does not directly address the mechanics of soil erosion as effectively as contour plowing. - Weakness: Crop rotation can help maintain soil structure and reduce pest and disease cycles, but it does not create physical barriers to water runoff, which is crucial for preventing erosion. B. Use of Chemical Fertilizers: - Explanation: Chemical fertilizers are used to enhance soil fertility and promote plant growth. However, they do not have any direct impact on soil erosion. - Weakness: In fact, excessive use of chemical fertilizers can lead to soil degradation and increased erosion due to the loss of organic matter and soil structure, making this option ineffective for erosion prevention. D. Monoculture Farming: - Explanation: Monoculture farming is the practice of growing a single crop over a wide area for many consecutive years. This can lead to soil depletion and increased vulnerability to pests and diseases. - Weakness: Monoculture can exacerbate soil erosion because it often leads to a lack of ground cover, which is essential for protecting the soil from wind and water erosion. Without diverse root systems, the soil structure can weaken, making it more susceptible to erosion. Summary of Key Points:

• Contour plowing is the most effective practice for preventing soil erosion as it follows the land's natural contours, slowing water runoff and retaining soil.
• Crop rotation improves soil health but does not directly prevent erosion.
• Chemical fertilizers enhance fertility but do not address erosion and can contribute to soil degradation.
• Monoculture farming increases erosion risk due to lack of ground cover and soil structure degradation.

Revision Summary:

• Contour plowing is the best method for preventing soil erosion.
• It slows water runoff and retains soil moisture.
• Crop rotation, chemical fertilizers, and monoculture farming do not effectively prevent erosion.
• Understanding the mechanics of soil erosion is crucial for effective agricultural practices.