Introduction:
Soil conservation is the practice of preventing soil erosion and degradation to maintain and improve soil fertility. Hilly areas are particularly prone to soil erosion due to the steep slopes, which can result in the loss of topsoil and nutrients. Therefore, implementing suitable soil conservation methods is crucial in hilly regions to protect the soil and ensure sustainable agriculture.

Explanation:
Among the given options, step farming in hilly areas is the most suitable method of soil conservation. Below are the reasons why this method is effective:

1. Terracing:
Step farming involves creating terraces on the slopes of hills. Terracing is the process of constructing flat or nearly flat areas on the hillside by cutting into the slope and building retaining walls. These terraces act as barriers that prevent soil erosion by reducing the speed of water runoff and holding the soil in place.

2. Preventing Soil Erosion:
The terraces formed in step farming help to slow down the flow of water down the slope. This prevents the rapid erosion of soil and allows water to infiltrate slowly into the soil. As a result, the soil retains more moisture and nutrients, which are essential for plant growth.

3. Conserving Water:
Step farming also helps in conserving water in hilly areas. The terraces act as small reservoirs, holding water and preventing it from flowing downhill. This reduces the loss of water through runoff and allows for better water management in hilly regions.

4. Increased Agricultural Productivity:
By implementing step farming, hilly areas can be transformed into cultivable land. The terraces provide level surfaces for planting crops, allowing farmers to grow a variety of crops in these regions. This improves agricultural productivity and contributes to the overall development of the area.

Conclusion:
In conclusion, step farming is the most suitable method of soil conservation in hilly areas. It helps to prevent soil erosion, conserve water, and increase agricultural productivity. Implementing this method can significantly improve the sustainability and productivity of agriculture in hilly regions.