Loss of surface soil due to rain falling on soil without vegetational cover:

When rain falls on soil without vegetational cover, it can lead to the loss of surface soil. This is primarily due to the lack of protection provided by vegetation. The following factors contribute to this process:

1. Erosion:
Raindrops falling on bare soil can cause the dislodging of soil particles and create small craters. This process is known as splash erosion. The impact of raindrops can break apart the soil structure, displace the top layer of soil, and expose the underlying layers. This displacement of soil particles by the force of raindrops is the first step in the erosion process.

2. Runoff:
When rain falls on soil without vegetational cover, it often does not infiltrate the soil efficiently. Instead, it runs off the surface, carrying the loose soil particles with it. This runoff is more pronounced on sloping surfaces where the water gains momentum and carries more soil particles downhill. Over time, the continuous runoff of rainwater can result in the formation of gullies, rills, or even large-scale erosion.

3. Lack of root binding:
Vegetation plays a crucial role in soil stability through its root system. The roots of plants penetrate and bind the soil particles together, providing structural integrity to the soil. In the absence of vegetation, the soil is more susceptible to erosion because there are no roots to hold it in place. As a result, the soil is easily carried away by the force of moving water.

4. Reduced water absorption:
Soil without vegetational cover tends to have poor water absorption capacity. The lack of vegetation means there are no roots to create channels for water infiltration or to enhance the soil's ability to hold water. Consequently, much of the rainwater remains on the surface, increasing the likelihood of erosion.

5. Decreased organic matter:
Vegetational cover contributes to the accumulation of organic matter in the soil. When rain falls on soil without vegetational cover, it can wash away the organic matter that would otherwise enrich the soil. Organic matter is essential for soil fertility as it improves soil structure, retains moisture, and provides nutrients for plants.

In conclusion:
When rain falls on soil without vegetational cover, it can lead to the loss of surface soil through erosion, runoff, lack of root binding, reduced water absorption, and decreased organic matter. Therefore, it is crucial to maintain vegetational cover to protect the soil from erosion and ensure its long-term fertility.