Neptune is a gas giant, meaning it doesn't have a solid surface like Earth. Therefore, it doesn't have soil in the traditional sense.

The interior of Neptune is thought to be composed of:

* A rocky core: Similar to Earth's core, but much larger.

* A layer of ice: Made up of water, methane, and ammonia.

* An atmosphere: Mostly hydrogen and helium, with traces of methane and other elements.

The atmospheric pressure and temperatures at Neptune's depths are extreme, so the concept of "soil" doesn't apply.