I live on less than an acre of land out in the middle of nowhere, with no descendants. Can I deed my land to Fish and Game?

Yes, but they might sell it for they money instead of using it for conservation.  They only way they would want to use it ix if it borders land they already maintain.

You can leave your land to whomever you want.

You should contact them to see if they want it.  If it's isolated they may not want it.

Are you trying to ask if you can leave your land to the government when you die?    Yes, you can put anything you want in your will.

That being said, you cannot force anyone to accept the inheritance.   They are free to decline or turn around and sell your land to someone else.

I don't see why not. Call & ask them if they want it.

You need to contact them in advance. There may be some benefits to you regarding this.