Soil is the foundation of every terrestrial (land) ecosystem. Soil supports life, provides materials for your food and clothes, purifies water and provides air for you to breathe (because plants grow in the soil). It does so many other things.
If we had no soil, there would be no life. Check out this video for a quick explanation.
Next, we need to conserve our soil, and this video gives a brief explanation about why this is important.
Clay has a great answer! Something I’ll add is that the soil itself is a living system, full of micro-organisms and insects that are crucial to the ecosystem, breaking down dead plant and animal material into food for the next generation of plants and animals. All hail the decomposers of our world!